From 3fff4c42bd0a89869a0eb1e7874cc06ffa4aa0f5 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 22 Sep 2009 16:18:09 +0200 Subject: printk: Remove ratelimit.h from kernel.h Decouple kernel.h from ratelimit.h: the global declaration of printk's ratelimit_state is not needed, and it leads to messy circular dependencies due to ratelimit.h's (new) adding of a spinlock_types.h include. Cc: Peter Zijlstra Cc: Andrew Morton Cc: Linus Torvalds Cc: David S. Miller LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/printk.c | 1 + kernel/sysctl.c | 3 +++ 2 files changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/printk.c b/kernel/printk.c index 602033acd6c7..b997c893cdcf 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -33,6 +33,7 @@ #include #include #include +#include #include diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 1a631ba684a4..6c37048b9db9 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include #include @@ -155,6 +156,8 @@ extern int no_unaligned_warning; extern int unaligned_dump_stack; #endif +extern struct ratelimit_state printk_ratelimit_state; + #ifdef CONFIG_RT_MUTEXES extern int max_lock_depth; #endif -- cgit v1.2.3 From 737f453fd115ea0c9642ed6b30e37e296a4e3ed7 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sat, 1 Aug 2009 03:42:44 +0200 Subject: tracing/filters: Cleanup useless headers Cleanup remaining headers inclusion that were only useful when the filter framework and its tracing related filesystem user interface weren't yet separated. v2: Keep module.h, needed for EXPORT_SYMBOL_GPL Signed-off-by: Frederic Weisbecker Cc: Tom Zanussi Cc: Steven Rostedt Cc: Li Zefan --- kernel/trace/trace_events_filter.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 23245785927f..189663d82aa7 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -18,8 +18,6 @@ * Copyright (C) 2009 Tom Zanussi */ -#include -#include #include #include #include -- cgit v1.2.3 From f3f3f0092477d0165f3f1bf0fd518550b2abd097 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 24 Sep 2009 15:27:41 +0200 Subject: tracing/event: Cleanup the useless dentry variable Cleanup the useless dentry variable while creating a kernel event set of files. trace_create_file() warns if it fails to create the file anyway, and we don't store the dentry anywhere. v2: Fix a small conflict in kernel/trace/trace_events.c Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Cc: Li Zefan --- kernel/trace/trace_events.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 56c260b83a9c..8c91b7c8f047 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -898,9 +898,9 @@ event_subsystem_dir(const char *name, struct dentry *d_events) "'%s/filter' entry\n", name); } - entry = trace_create_file("enable", 0644, system->entry, - (void *)system->name, - &ftrace_system_enable_fops); + trace_create_file("enable", 0644, system->entry, + (void *)system->name, + &ftrace_system_enable_fops); return system->entry; } @@ -912,7 +912,6 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events, const struct file_operations *filter, const struct file_operations *format) { - struct dentry *entry; int ret; /* @@ -930,12 +929,12 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events, } if (call->regfunc) - entry = trace_create_file("enable", 0644, call->dir, call, - enable); + trace_create_file("enable", 0644, call->dir, call, + enable); if (call->id && call->profile_enable) - entry = trace_create_file("id", 0444, call->dir, call, - id); + trace_create_file("id", 0444, call->dir, call, + id); if (call->define_fields) { ret = call->define_fields(call); @@ -944,16 +943,16 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events, " events/%s\n", call->name); return ret; } - entry = trace_create_file("filter", 0644, call->dir, call, - filter); + trace_create_file("filter", 0644, call->dir, call, + filter); } /* A trace may not want to export its format */ if (!call->show_format) return 0; - entry = trace_create_file("format", 0444, call->dir, call, - format); + trace_create_file("format", 0444, call->dir, call, + format); return 0; } -- cgit v1.2.3 From 1889d20922d14a97b2099fa4d47587217c0ba48b Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 24 Sep 2009 21:10:44 +0200 Subject: tracing/filters: Provide basic regex support This patch provides basic support for regular expressions in filters. It supports the following types of regexp: - *match_beginning - *match_middle* - match_end* - !don't match Example: cd /debug/tracing/events/bkl/lock_kernel echo 'file == "*reiserfs*"' > filter echo 1 > enable gedit-4941 [000] 457.735437: lock_kernel: depth: 0, fs/reiserfs/namei.c:334 reiserfs_lookup() sync_supers-227 [001] 461.379985: lock_kernel: depth: 0, fs/reiserfs/super.c:69 reiserfs_sync_fs() sync_supers-227 [000] 461.383096: lock_kernel: depth: 0, fs/reiserfs/journal.c:1069 flush_commit_list() reiserfs/1-1369 [001] 461.479885: lock_kernel: depth: 0, fs/reiserfs/journal.c:3509 flush_async_commits() Every string is now handled as a regexp in the filter framework, which helps to factorize the code for handling both simple strings and regexp comparisons. (The regexp parsing code has been wildly cherry picked from ftrace.c written by Steve.) v2: Simplify the whole and drop the filter_regex file Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Cc: Tom Zanussi Cc: Li Zefan --- kernel/trace/trace.h | 27 ++++--- kernel/trace/trace_events_filter.c | 155 +++++++++++++++++++++++++++++++++---- 2 files changed, 157 insertions(+), 25 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 86bcff94791a..8d0db6018fe4 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -702,20 +702,29 @@ struct event_subsystem { }; struct filter_pred; +struct regex; typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event, int val1, int val2); +typedef int (*regex_match_func)(char *str, struct regex *r, int len); + +struct regex { + char pattern[MAX_FILTER_STR_VAL]; + int len; + int field_len; + regex_match_func match; +}; + struct filter_pred { - filter_pred_fn_t fn; - u64 val; - char str_val[MAX_FILTER_STR_VAL]; - int str_len; - char *field_name; - int offset; - int not; - int op; - int pop_n; + filter_pred_fn_t fn; + u64 val; + struct regex regex; + char *field_name; + int offset; + int not; + int op; + int pop_n; }; extern void print_event_filter(struct ftrace_event_call *call, diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 189663d82aa7..d3c94c139567 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -195,9 +195,9 @@ static int filter_pred_string(struct filter_pred *pred, void *event, char *addr = (char *)(event + pred->offset); int cmp, match; - cmp = strncmp(addr, pred->str_val, pred->str_len); + cmp = pred->regex.match(addr, &pred->regex, pred->regex.field_len); - match = (!cmp) ^ pred->not; + match = cmp ^ pred->not; return match; } @@ -209,9 +209,9 @@ static int filter_pred_pchar(struct filter_pred *pred, void *event, char **addr = (char **)(event + pred->offset); int cmp, match; - cmp = strncmp(*addr, pred->str_val, pred->str_len); + cmp = pred->regex.match(*addr, &pred->regex, pred->regex.field_len); - match = (!cmp) ^ pred->not; + match = cmp ^ pred->not; return match; } @@ -235,9 +235,9 @@ static int filter_pred_strloc(struct filter_pred *pred, void *event, char *addr = (char *)(event + str_loc); int cmp, match; - cmp = strncmp(addr, pred->str_val, str_len); + cmp = pred->regex.match(addr, &pred->regex, str_len); - match = (!cmp) ^ pred->not; + match = cmp ^ pred->not; return match; } @@ -248,6 +248,126 @@ static int filter_pred_none(struct filter_pred *pred, void *event, return 0; } +/* Basic regex callbacks */ +static int regex_match_full(char *str, struct regex *r, int len) +{ + if (strncmp(str, r->pattern, len) == 0) + return 1; + return 0; +} + +static int regex_match_front(char *str, struct regex *r, int len) +{ + if (strncmp(str, r->pattern, len) == 0) + return 1; + return 0; +} + +static int regex_match_middle(char *str, struct regex *r, int len) +{ + if (strstr(str, r->pattern)) + return 1; + return 0; +} + +static int regex_match_end(char *str, struct regex *r, int len) +{ + char *ptr = strstr(str, r->pattern); + + if (ptr && (ptr[r->len] == 0)) + return 1; + return 0; +} + +enum regex_type { + MATCH_FULL, + MATCH_FRONT_ONLY, + MATCH_MIDDLE_ONLY, + MATCH_END_ONLY, +}; + +/* + * Pass in a buffer containing a regex and this function will + * set search to point to the search part of the buffer and + * return the type of search it is (see enum above). + * This does modify buff. + * + * Returns enum type. + * search returns the pointer to use for comparison. + * not returns 1 if buff started with a '!' + * 0 otherwise. + */ +static enum regex_type +filter_parse_regex(char *buff, int len, char **search, int *not) +{ + int type = MATCH_FULL; + int i; + + if (buff[0] == '!') { + *not = 1; + buff++; + len--; + } else + *not = 0; + + *search = buff; + + for (i = 0; i < len; i++) { + if (buff[i] == '*') { + if (!i) { + *search = buff + 1; + type = MATCH_END_ONLY; + } else { + if (type == MATCH_END_ONLY) + type = MATCH_MIDDLE_ONLY; + else + type = MATCH_FRONT_ONLY; + buff[i] = 0; + break; + } + } + } + + return type; +} + +static int filter_build_regex(struct filter_pred *pred) +{ + struct regex *r = &pred->regex; + char *search, *dup; + enum regex_type type; + int not; + + type = filter_parse_regex(r->pattern, r->len, &search, ¬); + dup = kstrdup(search, GFP_KERNEL); + if (!dup) + return -ENOMEM; + + strcpy(r->pattern, dup); + kfree(dup); + + r->len = strlen(r->pattern); + + switch (type) { + case MATCH_FULL: + r->match = regex_match_full; + break; + case MATCH_FRONT_ONLY: + r->match = regex_match_front; + break; + case MATCH_MIDDLE_ONLY: + r->match = regex_match_middle; + break; + case MATCH_END_ONLY: + r->match = regex_match_end; + break; + } + + pred->not ^= not; + + return 0; +} + /* return 1 if event matches, 0 otherwise (discard) */ int filter_match_preds(struct ftrace_event_call *call, void *rec) { @@ -394,7 +514,7 @@ static void filter_clear_pred(struct filter_pred *pred) { kfree(pred->field_name); pred->field_name = NULL; - pred->str_len = 0; + pred->regex.len = 0; } static int filter_set_pred(struct filter_pred *dest, @@ -658,21 +778,24 @@ static int filter_add_pred(struct filter_parse_state *ps, } if (is_string_field(field)) { - pred->str_len = field->size; + ret = filter_build_regex(pred); + if (ret) + return ret; - if (field->filter_type == FILTER_STATIC_STRING) + if (field->filter_type == FILTER_STATIC_STRING) { fn = filter_pred_string; - else if (field->filter_type == FILTER_DYN_STRING) - fn = filter_pred_strloc; + pred->regex.field_len = field->size; + } else if (field->filter_type == FILTER_DYN_STRING) + fn = filter_pred_strloc; else { fn = filter_pred_pchar; - pred->str_len = strlen(pred->str_val); + pred->regex.field_len = strlen(pred->regex.pattern); } } else { if (field->is_signed) - ret = strict_strtoll(pred->str_val, 0, &val); + ret = strict_strtoll(pred->regex.pattern, 0, &val); else - ret = strict_strtoull(pred->str_val, 0, &val); + ret = strict_strtoull(pred->regex.pattern, 0, &val); if (ret) { parse_error(ps, FILT_ERR_ILLEGAL_INTVAL, 0); return -EINVAL; @@ -1042,8 +1165,8 @@ static struct filter_pred *create_pred(int op, char *operand1, char *operand2) return NULL; } - strcpy(pred->str_val, operand2); - pred->str_len = strlen(operand2); + strcpy(pred->regex.pattern, operand2); + pred->regex.len = strlen(pred->regex.pattern); pred->op = op; -- cgit v1.2.3 From 3f6fe06dbf67b46d36fedec502300e04dffeb67a Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 24 Sep 2009 21:31:51 +0200 Subject: tracing/filters: Unify the regex parsing helpers The filter code has stolen the regex parsing function from ftrace to get the regex support. We have duplicated this code, so factorize it in the filter area and make it generally available, as the filter code is the most suited to host this feature. Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Cc: Tom Zanussi Cc: Li Zefan --- kernel/trace/ftrace.c | 64 +++----------------------------------- kernel/trace/trace.h | 9 ++++++ kernel/trace/trace_events_filter.c | 20 ++++++------ 3 files changed, 23 insertions(+), 70 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index cc615f84751b..ddf23a225b52 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1655,60 +1655,6 @@ ftrace_regex_lseek(struct file *file, loff_t offset, int origin) return ret; } -enum { - MATCH_FULL, - MATCH_FRONT_ONLY, - MATCH_MIDDLE_ONLY, - MATCH_END_ONLY, -}; - -/* - * (static function - no need for kernel doc) - * - * Pass in a buffer containing a glob and this function will - * set search to point to the search part of the buffer and - * return the type of search it is (see enum above). - * This does modify buff. - * - * Returns enum type. - * search returns the pointer to use for comparison. - * not returns 1 if buff started with a '!' - * 0 otherwise. - */ -static int -ftrace_setup_glob(char *buff, int len, char **search, int *not) -{ - int type = MATCH_FULL; - int i; - - if (buff[0] == '!') { - *not = 1; - buff++; - len--; - } else - *not = 0; - - *search = buff; - - for (i = 0; i < len; i++) { - if (buff[i] == '*') { - if (!i) { - *search = buff + 1; - type = MATCH_END_ONLY; - } else { - if (type == MATCH_END_ONLY) - type = MATCH_MIDDLE_ONLY; - else - type = MATCH_FRONT_ONLY; - buff[i] = 0; - break; - } - } - } - - return type; -} - static int ftrace_match(char *str, char *regex, int len, int type) { int matched = 0; @@ -1757,7 +1703,7 @@ static void ftrace_match_records(char *buff, int len, int enable) int not; flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE; - type = ftrace_setup_glob(buff, len, &search, ¬); + type = filter_parse_regex(buff, len, &search, ¬); search_len = strlen(search); @@ -1825,7 +1771,7 @@ static void ftrace_match_module_records(char *buff, char *mod, int enable) } if (strlen(buff)) { - type = ftrace_setup_glob(buff, strlen(buff), &search, ¬); + type = filter_parse_regex(buff, strlen(buff), &search, ¬); search_len = strlen(search); } @@ -1990,7 +1936,7 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, int count = 0; char *search; - type = ftrace_setup_glob(glob, strlen(glob), &search, ¬); + type = filter_parse_regex(glob, strlen(glob), &search, ¬); len = strlen(search); /* we do not support '!' for function probes */ @@ -2067,7 +2013,7 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, else if (glob) { int not; - type = ftrace_setup_glob(glob, strlen(glob), &search, ¬); + type = filter_parse_regex(glob, strlen(glob), &search, ¬); len = strlen(search); /* we do not support '!' for function probes */ @@ -2520,7 +2466,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer) return -ENODEV; /* decode regex */ - type = ftrace_setup_glob(buffer, strlen(buffer), &search, ¬); + type = filter_parse_regex(buffer, strlen(buffer), &search, ¬); if (not) return -EINVAL; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 8d0db6018fe4..db6b83edd49b 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -709,6 +709,13 @@ typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event, typedef int (*regex_match_func)(char *str, struct regex *r, int len); +enum regex_type { + MATCH_FULL, + MATCH_FRONT_ONLY, + MATCH_MIDDLE_ONLY, + MATCH_END_ONLY, +}; + struct regex { char pattern[MAX_FILTER_STR_VAL]; int len; @@ -727,6 +734,8 @@ struct filter_pred { int pop_n; }; +extern enum regex_type +filter_parse_regex(char *buff, int len, char **search, int *not); extern void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s); extern int apply_event_filter(struct ftrace_event_call *call, diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index d3c94c139567..8c194de675b0 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -279,15 +279,14 @@ static int regex_match_end(char *str, struct regex *r, int len) return 0; } -enum regex_type { - MATCH_FULL, - MATCH_FRONT_ONLY, - MATCH_MIDDLE_ONLY, - MATCH_END_ONLY, -}; - -/* - * Pass in a buffer containing a regex and this function will +/** + * filter_parse_regex - parse a basic regex + * @buff: the raw regex + * @len: length of the regex + * @search: will point to the beginning of the string to compare + * @not: tell whether the match will have to be inverted + * + * This passes in a buffer containing a regex and this function will * set search to point to the search part of the buffer and * return the type of search it is (see enum above). * This does modify buff. @@ -297,8 +296,7 @@ enum regex_type { * not returns 1 if buff started with a '!' * 0 otherwise. */ -static enum regex_type -filter_parse_regex(char *buff, int len, char **search, int *not) +enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not) { int type = MATCH_FULL; int i; -- cgit v1.2.3 From 369bc18f9a6c4e2686204c1d7476ab684a720968 Mon Sep 17 00:00:00 2001 From: Stefan Assmann Date: Mon, 12 Oct 2009 22:17:21 +0200 Subject: ftrace: add kernel command line graph function filtering Add a command line parameter to allow limiting the function graphs that are traced on boot up from the given top-level callers , when ftrace=function_graph is specified. This patch adds the following command line option: ftrace_graph_filter=function-list Where function-list is a comma separated list of functions to filter. [fweisbec@gmail.com: picked the documentation changes from the v2 patch] Signed-off-by: Stefan Assmann Acked-by: Steven Rostedt LKML-Reference: <4AD2DEB9.2@redhat.com> Signed-off-by: Frederic Weisbecker --- Documentation/kernel-parameters.txt | 7 +++++++ kernel/trace/ftrace.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+) (limited to 'kernel') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 6fa7292947e5..1dc4b9cc20e5 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -778,6 +778,13 @@ and is between 256 and 4096 characters. It is defined in the file by the set_ftrace_notrace file in the debugfs tracing directory. + ftrace_graph_filter=[function-list] + [FTRACE] Limit the top level callers functions traced + by the function graph tracer at boot up. + function-list is a comma separated list of functions + that can be changed at run time by the + set_graph_function file in the debugfs tracing directory. + gamecon.map[2|3]= [HW,JOY] Multisystem joystick and NES/SNES/PSX pad support via parallel port (up to 5 devices per port) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 9a72853a8f0a..91283d40821e 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -78,6 +78,10 @@ ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub; ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub; +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +static int ftrace_set_func(unsigned long *array, int *idx, char *buffer); +#endif + static void ftrace_list_func(unsigned long ip, unsigned long parent_ip) { struct ftrace_ops *op = ftrace_list; @@ -2248,6 +2252,7 @@ void ftrace_set_notrace(unsigned char *buf, int len, int reset) #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata; static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata; +static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; static int __init set_ftrace_notrace(char *str) { @@ -2263,6 +2268,31 @@ static int __init set_ftrace_filter(char *str) } __setup("ftrace_filter=", set_ftrace_filter); +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +static int __init set_graph_function(char *str) +{ + strncpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); + return 1; +} +__setup("ftrace_graph_filter=", set_graph_function); + +static void __init set_ftrace_early_graph(char *buf) +{ + int ret; + char *func; + + while (buf) { + func = strsep(&buf, ","); + /* we allow only one expression at a time */ + ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count, + func); + if (ret) + printk(KERN_DEBUG "ftrace: function %s not " + "traceable\n", func); + } +} +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + static void __init set_ftrace_early_filter(char *buf, int enable) { char *func; @@ -2279,6 +2309,10 @@ static void __init set_ftrace_early_filters(void) set_ftrace_early_filter(ftrace_filter_buf, 1); if (ftrace_notrace_buf[0]) set_ftrace_early_filter(ftrace_notrace_buf, 0); +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + if (ftrace_graph_buf[0]) + set_ftrace_early_graph(ftrace_graph_buf); +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ } static int -- cgit v1.2.3 From aef6f81b55f462082699c06e8e67e6eb5630ed45 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 12 Oct 2009 22:23:24 +0200 Subject: tracing: Rename set_ftrace to set_bootup_ftrace Do this rename because set_ftrace is too much generic and not enough self-explainable as a name. Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Cc: Li Zefan --- kernel/trace/trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 45068269ebb1..866daf8497f1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -129,7 +129,7 @@ static int tracing_set_tracer(const char *buf); static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata; static char *default_bootup_tracer; -static int __init set_ftrace(char *str) +static int __init set_bootup_ftrace(char *str) { strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE); default_bootup_tracer = bootup_tracer_buf; @@ -137,7 +137,7 @@ static int __init set_ftrace(char *str) ring_buffer_expanded = 1; return 1; } -__setup("ftrace=", set_ftrace); +__setup("ftrace=", set_bootup_ftrace); static int __init set_ftrace_dump_on_oops(char *str) { -- cgit v1.2.3 From bf7c5b43a12614847b83f507fb169ad30640e406 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 12 Oct 2009 22:31:32 +0200 Subject: tracing: Remove unused ftrace_trace_addr helper Remove the ftrace_trace_addr() function as only its off-case is implemented and there are no users of it currently. But we keep ftrace_graph_addr() off-case, in case someone come to use the function graph tracer to profit from top-level callers filtering. Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Cc: Li Zefan --- kernel/trace/trace.h | 4 ---- 1 file changed, 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 365fb19d9e11..f22a7ac32380 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -483,10 +483,6 @@ static inline int ftrace_graph_addr(unsigned long addr) return 0; } #else -static inline int ftrace_trace_addr(unsigned long addr) -{ - return 1; -} static inline int ftrace_graph_addr(unsigned long addr) { return 1; -- cgit v1.2.3 From 825332e4ff1373c55d931b49408df7ec2298f71e Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Wed, 14 Oct 2009 08:17:36 +1100 Subject: capabilities: simplify bound checks for copy_from_user() The capabilities syscall has a copy_from_user() call where gcc currently cannot prove to itself that the copy is always within bounds. This patch adds a very explicity bound check to prove to gcc that this copy_from_user cannot overflow its destination buffer. Signed-off-by: Arjan van de Ven Acked-by: James Morris Signed-off-by: Andrew Morton Signed-off-by: James Morris --- kernel/capability.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/capability.c b/kernel/capability.c index 4e17041963f5..c2316d3fa094 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -238,7 +238,7 @@ SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr) SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data) { struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S]; - unsigned i, tocopy; + unsigned i, tocopy, copybytes; kernel_cap_t inheritable, permitted, effective; struct cred *new; int ret; @@ -255,8 +255,11 @@ SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data) if (pid != 0 && pid != task_pid_vnr(current)) return -EPERM; - if (copy_from_user(&kdata, data, - tocopy * sizeof(struct __user_cap_data_struct))) + copybytes = tocopy * sizeof(struct __user_cap_data_struct); + if (copybytes > sizeof(kdata)) + return -EFAULT; + + if (copy_from_user(&kdata, data, copybytes)) return -EFAULT; for (i = 0; i < tocopy; i++) { -- cgit v1.2.3 From 756d17ee7ee4fbc8238bdf97100af63e6ac441ef Mon Sep 17 00:00:00 2001 From: "jolsa@redhat.com" Date: Tue, 13 Oct 2009 16:33:52 -0400 Subject: tracing: Support multiple pids in set_pid_ftrace file Adding the possibility to set more than 1 pid in the set_pid_ftrace file, thus allowing to trace more than 1 independent processes. Usage: sh-4.0# echo 284 > ./set_ftrace_pid sh-4.0# cat ./set_ftrace_pid 284 sh-4.0# echo 1 >> ./set_ftrace_pid sh-4.0# echo 0 >> ./set_ftrace_pid sh-4.0# cat ./set_ftrace_pid swapper tasks 1 284 sh-4.0# echo 4 > ./set_ftrace_pid sh-4.0# cat ./set_ftrace_pid 4 sh-4.0# echo > ./set_ftrace_pid sh-4.0# cat ./set_ftrace_pid no pid sh-4.0# Signed-off-by: Jiri Olsa Cc: Frederic Weisbecker LKML-Reference: <20091013203425.565454612@goodmis.org> Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 234 +++++++++++++++++++++++++++++++++++--------------- kernel/trace/trace.h | 4 +- 2 files changed, 167 insertions(+), 71 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 45c965919cff..0c799d1af702 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -60,6 +60,13 @@ static int last_ftrace_enabled; /* Quick disabling of function tracer. */ int function_trace_stop; +/* List for set_ftrace_pid's pids. */ +LIST_HEAD(ftrace_pids); +struct ftrace_pid { + struct list_head list; + struct pid *pid; +}; + /* * ftrace_disabled is set when an anomaly is discovered. * ftrace_disabled is much stronger than ftrace_enabled. @@ -159,7 +166,7 @@ static int __register_ftrace_function(struct ftrace_ops *ops) else func = ftrace_list_func; - if (ftrace_pid_trace) { + if (!list_empty(&ftrace_pids)) { set_ftrace_pid_function(func); func = ftrace_pid_func; } @@ -207,7 +214,7 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops) if (ftrace_list->next == &ftrace_list_end) { ftrace_func_t func = ftrace_list->func; - if (ftrace_pid_trace) { + if (!list_empty(&ftrace_pids)) { set_ftrace_pid_function(func); func = ftrace_pid_func; } @@ -235,7 +242,7 @@ static void ftrace_update_pid_func(void) func = __ftrace_trace_function; #endif - if (ftrace_pid_trace) { + if (!list_empty(&ftrace_pids)) { set_ftrace_pid_function(func); func = ftrace_pid_func; } else { @@ -825,8 +832,6 @@ static __init void ftrace_profile_debugfs(struct dentry *d_tracer) } #endif /* CONFIG_FUNCTION_PROFILER */ -/* set when tracing only a pid */ -struct pid *ftrace_pid_trace; static struct pid * const ftrace_swapper_pid = &init_struct_pid; #ifdef CONFIG_DYNAMIC_FTRACE @@ -2758,23 +2763,6 @@ static inline void ftrace_startup_enable(int command) { } # define ftrace_shutdown_sysctl() do { } while (0) #endif /* CONFIG_DYNAMIC_FTRACE */ -static ssize_t -ftrace_pid_read(struct file *file, char __user *ubuf, - size_t cnt, loff_t *ppos) -{ - char buf[64]; - int r; - - if (ftrace_pid_trace == ftrace_swapper_pid) - r = sprintf(buf, "swapper tasks\n"); - else if (ftrace_pid_trace) - r = sprintf(buf, "%u\n", pid_vnr(ftrace_pid_trace)); - else - r = sprintf(buf, "no pid\n"); - - return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); -} - static void clear_ftrace_swapper(void) { struct task_struct *p; @@ -2825,14 +2813,12 @@ static void set_ftrace_pid(struct pid *pid) rcu_read_unlock(); } -static void clear_ftrace_pid_task(struct pid **pid) +static void clear_ftrace_pid_task(struct pid *pid) { - if (*pid == ftrace_swapper_pid) + if (pid == ftrace_swapper_pid) clear_ftrace_swapper(); else - clear_ftrace_pid(*pid); - - *pid = NULL; + clear_ftrace_pid(pid); } static void set_ftrace_pid_task(struct pid *pid) @@ -2843,11 +2829,140 @@ static void set_ftrace_pid_task(struct pid *pid) set_ftrace_pid(pid); } +static int ftrace_pid_add(int p) +{ + struct pid *pid; + struct ftrace_pid *fpid; + int ret = -EINVAL; + + mutex_lock(&ftrace_lock); + + if (!p) + pid = ftrace_swapper_pid; + else + pid = find_get_pid(p); + + if (!pid) + goto out; + + ret = 0; + + list_for_each_entry(fpid, &ftrace_pids, list) + if (fpid->pid == pid) + goto out_put; + + ret = -ENOMEM; + + fpid = kmalloc(sizeof(*fpid), GFP_KERNEL); + if (!fpid) + goto out_put; + + list_add(&fpid->list, &ftrace_pids); + fpid->pid = pid; + + set_ftrace_pid_task(pid); + + ftrace_update_pid_func(); + ftrace_startup_enable(0); + + mutex_unlock(&ftrace_lock); + return 0; + +out_put: + if (pid != ftrace_swapper_pid) + put_pid(pid); + +out: + mutex_unlock(&ftrace_lock); + return ret; +} + +static void ftrace_pid_reset(void) +{ + struct ftrace_pid *fpid, *safe; + + mutex_lock(&ftrace_lock); + list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) { + struct pid *pid = fpid->pid; + + clear_ftrace_pid_task(pid); + + list_del(&fpid->list); + kfree(fpid); + } + + ftrace_update_pid_func(); + ftrace_startup_enable(0); + + mutex_unlock(&ftrace_lock); +} + +static void *fpid_start(struct seq_file *m, loff_t *pos) +{ + mutex_lock(&ftrace_lock); + + if (list_empty(&ftrace_pids) && (!*pos)) + return (void *) 1; + + return seq_list_start(&ftrace_pids, *pos); +} + +static void *fpid_next(struct seq_file *m, void *v, loff_t *pos) +{ + if (v == (void *)1) + return NULL; + + return seq_list_next(v, &ftrace_pids, pos); +} + +static void fpid_stop(struct seq_file *m, void *p) +{ + mutex_unlock(&ftrace_lock); +} + +static int fpid_show(struct seq_file *m, void *v) +{ + const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list); + + if (v == (void *)1) { + seq_printf(m, "no pid\n"); + return 0; + } + + if (fpid->pid == ftrace_swapper_pid) + seq_printf(m, "swapper tasks\n"); + else + seq_printf(m, "%u\n", pid_vnr(fpid->pid)); + + return 0; +} + +static const struct seq_operations ftrace_pid_sops = { + .start = fpid_start, + .next = fpid_next, + .stop = fpid_stop, + .show = fpid_show, +}; + +static int +ftrace_pid_open(struct inode *inode, struct file *file) +{ + int ret = 0; + + if ((file->f_mode & FMODE_WRITE) && + (file->f_flags & O_TRUNC)) + ftrace_pid_reset(); + + if (file->f_mode & FMODE_READ) + ret = seq_open(file, &ftrace_pid_sops); + + return ret; +} + static ssize_t ftrace_pid_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { - struct pid *pid; char buf[64]; long val; int ret; @@ -2860,57 +2975,38 @@ ftrace_pid_write(struct file *filp, const char __user *ubuf, buf[cnt] = 0; + /* + * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid" + * to clean the filter quietly. + */ + strstrip(buf); + if (strlen(buf) == 0) + return 1; + ret = strict_strtol(buf, 10, &val); if (ret < 0) return ret; - mutex_lock(&ftrace_lock); - if (val < 0) { - /* disable pid tracing */ - if (!ftrace_pid_trace) - goto out; - - clear_ftrace_pid_task(&ftrace_pid_trace); - - } else { - /* swapper task is special */ - if (!val) { - pid = ftrace_swapper_pid; - if (pid == ftrace_pid_trace) - goto out; - } else { - pid = find_get_pid(val); - - if (pid == ftrace_pid_trace) { - put_pid(pid); - goto out; - } - } - - if (ftrace_pid_trace) - clear_ftrace_pid_task(&ftrace_pid_trace); - - if (!pid) - goto out; - - ftrace_pid_trace = pid; - - set_ftrace_pid_task(ftrace_pid_trace); - } + ret = ftrace_pid_add(val); - /* update the function call */ - ftrace_update_pid_func(); - ftrace_startup_enable(0); + return ret ? ret : cnt; +} - out: - mutex_unlock(&ftrace_lock); +static int +ftrace_pid_release(struct inode *inode, struct file *file) +{ + if (file->f_mode & FMODE_READ) + seq_release(inode, file); - return cnt; + return 0; } static const struct file_operations ftrace_pid_fops = { - .read = ftrace_pid_read, - .write = ftrace_pid_write, + .open = ftrace_pid_open, + .write = ftrace_pid_write, + .read = seq_read, + .llseek = seq_lseek, + .release = ftrace_pid_release, }; static __init int ftrace_init_debugfs(void) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index f22a7ac32380..acef8b4636f0 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -496,12 +496,12 @@ print_graph_function(struct trace_iterator *iter) } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ -extern struct pid *ftrace_pid_trace; +extern struct list_head ftrace_pids; #ifdef CONFIG_FUNCTION_TRACER static inline int ftrace_trace_task(struct task_struct *task) { - if (!ftrace_pid_trace) + if (list_empty(&ftrace_pids)) return 1; return test_tsk_trace_trace(task); -- cgit v1.2.3 From 5cb084bb1f3fd4dcdaf7e4cf564994346ec8f783 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Tue, 13 Oct 2009 16:33:53 -0400 Subject: tracing: Enable records during the module load I was debuging some module using "function" and "function_graph" tracers and noticed, that if you load module after you enabled tracing, the module's hooks will convert only to NOP instructions. The attached patch enables modules' hooks if there's function trace allready on, thus allowing to trace module functions. Signed-off-by: Jiri Olsa Cc: Frederic Weisbecker Signed-off-by: Steven Rostedt LKML-Reference: <20091013203425.896285120@goodmis.org> Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 38 ++++++++++++++++++++++++++++++-------- 1 file changed, 30 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 0c799d1af702..aaea9cda8781 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1270,12 +1270,34 @@ static int ftrace_update_code(struct module *mod) ftrace_new_addrs = p->newlist; p->flags = 0L; - /* convert record (i.e, patch mcount-call with NOP) */ - if (ftrace_code_disable(mod, p)) { - p->flags |= FTRACE_FL_CONVERTED; - ftrace_update_cnt++; - } else + /* + * Do the initial record convertion from mcount jump + * to the NOP instructions. + */ + if (!ftrace_code_disable(mod, p)) { ftrace_free_rec(p); + continue; + } + + p->flags |= FTRACE_FL_CONVERTED; + ftrace_update_cnt++; + + /* + * If the tracing is enabled, go ahead and enable the record. + * + * The reason not to enable the record immediatelly is the + * inherent check of ftrace_make_nop/ftrace_make_call for + * correct previous instructions. Making first the NOP + * conversion puts the module to the correct state, thus + * passing the ftrace_make_call check. + */ + if (ftrace_start_up) { + int failed = __ftrace_replace_code(p, 1); + if (failed) { + ftrace_bug(failed, p->ip); + ftrace_free_rec(p); + } + } } stop = ftrace_now(raw_smp_processor_id()); @@ -2609,7 +2631,7 @@ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer) return 0; } -static int ftrace_convert_nops(struct module *mod, +static int ftrace_process_locs(struct module *mod, unsigned long *start, unsigned long *end) { @@ -2669,7 +2691,7 @@ static void ftrace_init_module(struct module *mod, { if (ftrace_disabled || start == end) return; - ftrace_convert_nops(mod, start, end); + ftrace_process_locs(mod, start, end); } static int ftrace_module_notify(struct notifier_block *self, @@ -2730,7 +2752,7 @@ void __init ftrace_init(void) last_ftrace_enabled = ftrace_enabled = 1; - ret = ftrace_convert_nops(NULL, + ret = ftrace_process_locs(NULL, __start_mcount_loc, __stop_mcount_loc); -- cgit v1.2.3 From c44fc770845163f8d9e573f37f92a7b7a7ade14e Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sat, 19 Sep 2009 06:50:42 +0200 Subject: tracing: Move syscalls metadata handling from arch to core Most of the syscalls metadata processing is done from arch. But these operations are mostly generic accross archs. Especially now that we have a common variable name that expresses the number of syscalls supported by an arch: NR_syscalls, the only remaining bits that need to reside in arch is the syscall nr to addr translation. v2: Compare syscalls symbols only after the "sys" prefix so that we avoid spurious mismatches with archs that have syscalls wrappers, in which case syscalls symbols have "SyS" prefixed aliases. (Reported by: Heiko Carstens) Signed-off-by: Frederic Weisbecker Acked-by: Heiko Carstens Cc: Ingo Molnar Cc: Steven Rostedt Cc: Li Zefan Cc: Masami Hiramatsu Cc: Jason Baron Cc: Lai Jiangshan Cc: Martin Schwidefsky Cc: Paul Mundt --- arch/s390/kernel/ftrace.c | 67 +-------------------------------- arch/x86/kernel/ftrace.c | 76 +------------------------------------- include/trace/syscall.h | 2 +- kernel/trace/trace_syscalls.c | 86 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 91 insertions(+), 140 deletions(-) (limited to 'kernel') diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 57bdcb1e3cdf..7c5752c3423d 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -206,73 +206,10 @@ out: #ifdef CONFIG_FTRACE_SYSCALLS -extern unsigned long __start_syscalls_metadata[]; -extern unsigned long __stop_syscalls_metadata[]; extern unsigned int sys_call_table[]; -static struct syscall_metadata **syscalls_metadata; - -struct syscall_metadata *syscall_nr_to_meta(int nr) -{ - if (!syscalls_metadata || nr >= NR_syscalls || nr < 0) - return NULL; - - return syscalls_metadata[nr]; -} - -int syscall_name_to_nr(char *name) -{ - int i; - - if (!syscalls_metadata) - return -1; - for (i = 0; i < NR_syscalls; i++) - if (syscalls_metadata[i]) - if (!strcmp(syscalls_metadata[i]->name, name)) - return i; - return -1; -} - -void set_syscall_enter_id(int num, int id) -{ - syscalls_metadata[num]->enter_id = id; -} - -void set_syscall_exit_id(int num, int id) +unsigned long __init arch_syscall_addr(int nr) { - syscalls_metadata[num]->exit_id = id; -} - -static struct syscall_metadata *find_syscall_meta(unsigned long syscall) -{ - struct syscall_metadata *start; - struct syscall_metadata *stop; - char str[KSYM_SYMBOL_LEN]; - - start = (struct syscall_metadata *)__start_syscalls_metadata; - stop = (struct syscall_metadata *)__stop_syscalls_metadata; - kallsyms_lookup(syscall, NULL, NULL, NULL, str); - - for ( ; start < stop; start++) { - if (start->name && !strcmp(start->name + 3, str + 3)) - return start; - } - return NULL; -} - -static int __init arch_init_ftrace_syscalls(void) -{ - struct syscall_metadata *meta; - int i; - syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) * NR_syscalls, - GFP_KERNEL); - if (!syscalls_metadata) - return -ENOMEM; - for (i = 0; i < NR_syscalls; i++) { - meta = find_syscall_meta((unsigned long)sys_call_table[i]); - syscalls_metadata[i] = meta; - } - return 0; + return (unsigned long)sys_call_table[nr]; } -arch_initcall(arch_init_ftrace_syscalls); #endif diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 25e6f5fc4b1e..5a1b9758fd62 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -470,82 +470,10 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, #ifdef CONFIG_FTRACE_SYSCALLS -extern unsigned long __start_syscalls_metadata[]; -extern unsigned long __stop_syscalls_metadata[]; extern unsigned long *sys_call_table; -static struct syscall_metadata **syscalls_metadata; - -static struct syscall_metadata *find_syscall_meta(unsigned long *syscall) -{ - struct syscall_metadata *start; - struct syscall_metadata *stop; - char str[KSYM_SYMBOL_LEN]; - - - start = (struct syscall_metadata *)__start_syscalls_metadata; - stop = (struct syscall_metadata *)__stop_syscalls_metadata; - kallsyms_lookup((unsigned long) syscall, NULL, NULL, NULL, str); - - for ( ; start < stop; start++) { - if (start->name && !strcmp(start->name, str)) - return start; - } - return NULL; -} - -struct syscall_metadata *syscall_nr_to_meta(int nr) -{ - if (!syscalls_metadata || nr >= NR_syscalls || nr < 0) - return NULL; - - return syscalls_metadata[nr]; -} - -int syscall_name_to_nr(char *name) -{ - int i; - - if (!syscalls_metadata) - return -1; - - for (i = 0; i < NR_syscalls; i++) { - if (syscalls_metadata[i]) { - if (!strcmp(syscalls_metadata[i]->name, name)) - return i; - } - } - return -1; -} - -void set_syscall_enter_id(int num, int id) -{ - syscalls_metadata[num]->enter_id = id; -} - -void set_syscall_exit_id(int num, int id) +unsigned long __init arch_syscall_addr(int nr) { - syscalls_metadata[num]->exit_id = id; -} - -static int __init arch_init_ftrace_syscalls(void) -{ - int i; - struct syscall_metadata *meta; - unsigned long **psys_syscall_table = &sys_call_table; - - syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) * - NR_syscalls, GFP_KERNEL); - if (!syscalls_metadata) { - WARN_ON(1); - return -ENOMEM; - } - - for (i = 0; i < NR_syscalls; i++) { - meta = find_syscall_meta(psys_syscall_table[i]); - syscalls_metadata[i] = meta; - } - return 0; + return (unsigned long)(&sys_call_table)[nr]; } -arch_initcall(arch_init_ftrace_syscalls); #endif diff --git a/include/trace/syscall.h b/include/trace/syscall.h index 5dc283ba5ae0..e972f0a40f8d 100644 --- a/include/trace/syscall.h +++ b/include/trace/syscall.h @@ -33,7 +33,7 @@ struct syscall_metadata { }; #ifdef CONFIG_FTRACE_SYSCALLS -extern struct syscall_metadata *syscall_nr_to_meta(int nr); +extern unsigned long arch_syscall_addr(int nr); extern int syscall_name_to_nr(char *name); void set_syscall_enter_id(int num, int id); void set_syscall_exit_id(int num, int id); diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 9fbce6c9d2e1..8bda4bff2286 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -14,6 +14,69 @@ static int sys_refcount_exit; static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls); static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls); +extern unsigned long __start_syscalls_metadata[]; +extern unsigned long __stop_syscalls_metadata[]; + +static struct syscall_metadata **syscalls_metadata; + +static struct syscall_metadata *find_syscall_meta(unsigned long syscall) +{ + struct syscall_metadata *start; + struct syscall_metadata *stop; + char str[KSYM_SYMBOL_LEN]; + + + start = (struct syscall_metadata *)__start_syscalls_metadata; + stop = (struct syscall_metadata *)__stop_syscalls_metadata; + kallsyms_lookup(syscall, NULL, NULL, NULL, str); + + for ( ; start < stop; start++) { + /* + * Only compare after the "sys" prefix. Archs that use + * syscall wrappers may have syscalls symbols aliases prefixed + * with "SyS" instead of "sys", leading to an unwanted + * mismatch. + */ + if (start->name && !strcmp(start->name + 3, str + 3)) + return start; + } + return NULL; +} + +static struct syscall_metadata *syscall_nr_to_meta(int nr) +{ + if (!syscalls_metadata || nr >= NR_syscalls || nr < 0) + return NULL; + + return syscalls_metadata[nr]; +} + +int syscall_name_to_nr(char *name) +{ + int i; + + if (!syscalls_metadata) + return -1; + + for (i = 0; i < NR_syscalls; i++) { + if (syscalls_metadata[i]) { + if (!strcmp(syscalls_metadata[i]->name, name)) + return i; + } + } + return -1; +} + +void set_syscall_enter_id(int num, int id) +{ + syscalls_metadata[num]->enter_id = id; +} + +void set_syscall_exit_id(int num, int id) +{ + syscalls_metadata[num]->exit_id = id; +} + enum print_line_t print_syscall_enter(struct trace_iterator *iter, int flags) { @@ -375,6 +438,29 @@ struct trace_event event_syscall_exit = { .trace = print_syscall_exit, }; +int __init init_ftrace_syscalls(void) +{ + struct syscall_metadata *meta; + unsigned long addr; + int i; + + syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) * + NR_syscalls, GFP_KERNEL); + if (!syscalls_metadata) { + WARN_ON(1); + return -ENOMEM; + } + + for (i = 0; i < NR_syscalls; i++) { + addr = arch_syscall_addr(i); + meta = find_syscall_meta(addr); + syscalls_metadata[i] = meta; + } + + return 0; +} +core_initcall(init_ftrace_syscalls); + #ifdef CONFIG_EVENT_PROFILE static DECLARE_BITMAP(enabled_prof_enter_syscalls, NR_syscalls); -- cgit v1.2.3 From 06f43d66ec36388056f5c697bf1e67c0e0a1645c Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 14 Oct 2009 20:43:39 +0200 Subject: ftrace: Copy ftrace_graph_filter boot param using strlcpy We are using strncpy in the wrong way to copy the ftrace_graph_filter boot param because we pass the buffer size instead of the max string size it can contain (buffer size - 1). The end result might not be NULL terminated as we are abusing the max string size. Lets use strlcpy() instead. Reported-by: Li Zefan Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt --- kernel/trace/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index aaea9cda8781..b10c0d90a6ff 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2293,7 +2293,7 @@ __setup("ftrace_filter=", set_ftrace_filter); #ifdef CONFIG_FUNCTION_GRAPH_TRACER static int __init set_graph_function(char *str) { - strncpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); + strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_graph_filter=", set_graph_function); -- cgit v1.2.3 From 1beee96bae0daf7f491356777c3080cc436950f5 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 14 Oct 2009 20:50:32 +0200 Subject: ftrace: Rename set_bootup_ftrace into set_cmdline_ftrace set_cmdline_ftrace is a better match against what does this function: apply a tracer name from the kernel command line. Reported-by: Steven Rostedt Signed-off-by: Frederic Weisbecker Cc: Li Zefan --- kernel/trace/trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4311ec3062f0..026e715a0c7a 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -129,7 +129,7 @@ static int tracing_set_tracer(const char *buf); static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata; static char *default_bootup_tracer; -static int __init set_bootup_ftrace(char *str) +static int __init set_cmdline_ftrace(char *str) { strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE); default_bootup_tracer = bootup_tracer_buf; @@ -137,7 +137,7 @@ static int __init set_bootup_ftrace(char *str) ring_buffer_expanded = 1; return 1; } -__setup("ftrace=", set_bootup_ftrace); +__setup("ftrace=", set_cmdline_ftrace); static int __init set_ftrace_dump_on_oops(char *str) { -- cgit v1.2.3 From 3397e040dfacbb303498ced1baa96be983dcea06 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 14 Oct 2009 16:36:38 -0700 Subject: rcu: Add rnp->blocked_tasks to tracing Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com Cc: npiggin@suse.de Cc: jens.axboe@oracle.com Cc: Josh Triplett LKML-Reference: <20091014233638.GE6763@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar kernel/rcutree_trace.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- kernel/rcutree_trace.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index 4b31c779e62e..1984cdc51e9a 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -155,12 +155,14 @@ static const struct file_operations rcudata_csv_fops = { static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) { + long gpnum; int level = 0; struct rcu_node *rnp; + gpnum = rsp->gpnum; seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x " "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld\n", - rsp->completed, rsp->gpnum, rsp->signaled, + rsp->completed, gpnum, rsp->signaled, (long)(rsp->jiffies_force_qs - jiffies), (int)(jiffies & 0xffff), rsp->n_force_qs, rsp->n_force_qs_ngp, @@ -171,8 +173,10 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) seq_puts(m, "\n"); level = rnp->level; } - seq_printf(m, "%lx/%lx %d:%d ^%d ", + seq_printf(m, "%lx/%lx %c>%c %d:%d ^%d ", rnp->qsmask, rnp->qsmaskinit, + "T."[list_empty(&rnp->blocked_tasks[gpnum & 1])], + "T."[list_empty(&rnp->blocked_tasks[!(gpnum & 1)])], rnp->grplo, rnp->grphi, rnp->grpnum); } seq_puts(m, "\n"); -- cgit v1.2.3 From 72f279b256d520e321a850880d094bc0bcbf45d6 Mon Sep 17 00:00:00 2001 From: Sheng Yang Date: Thu, 22 Oct 2009 19:19:34 +0800 Subject: generic-ipi: Fix misleading smp_call_function*() description After commit:8969a5ede0f9e17da4b943712429aef2c9bcd82b "generic-ipi: remove kmalloc()", wait = 0 can be guaranteed. Signed-off-by: Sheng Yang Cc: Peter Zijlstra Cc: Jens Axboe Cc: Nick Piggin LKML-Reference: <1256210374-25354-1-git-send-email-sheng@linux.intel.com> Signed-off-by: Ingo Molnar --- kernel/smp.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/smp.c b/kernel/smp.c index c9d1c7835c2f..8bd618f0364d 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -265,9 +265,7 @@ static DEFINE_PER_CPU(struct call_single_data, csd_data); * @info: An arbitrary pointer to pass to the function. * @wait: If true, wait until function has completed on other CPUs. * - * Returns 0 on success, else a negative status code. Note that @wait - * will be implicitly turned on in case of allocation failures, since - * we fall back to on-stack allocation. + * Returns 0 on success, else a negative status code. */ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, int wait) @@ -355,9 +353,7 @@ void __smp_call_function_single(int cpu, struct call_single_data *data, * @wait: If true, wait (atomically) until function has completed * on other CPUs. * - * If @wait is true, then returns once @func has returned. Note that @wait - * will be implicitly turned on in case of allocation failures, since - * we fall back to on-stack allocation. + * If @wait is true, then returns once @func has returned. * * You must not call this function with disabled interrupts or from a * hardware interrupt handler or from a bottom half handler. Preemption @@ -443,8 +439,7 @@ EXPORT_SYMBOL(smp_call_function_many); * Returns 0. * * If @wait is true, then returns once @func has returned; otherwise - * it returns just before the target cpu calls @func. In case of allocation - * failure, @wait will be implicitly turned on. + * it returns just before the target cpu calls @func. * * You must not call this function with disabled interrupts or from a * hardware interrupt handler or from a bottom half handler. -- cgit v1.2.3 From 5c828713358cb9df8aa174371edcbbb62203a490 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Fri, 23 Oct 2009 14:58:11 +0200 Subject: ratelimit: Make suppressed output messages more useful Today I got: [39648.224782] Registered led device: iwl-phy0::TX [40676.545099] __ratelimit: 246 callbacks suppressed [40676.545103] abcdef[23675]: segfault at 0 ... as you can see the ratelimit message contains a function prefix. Since this is always __ratelimit, this wont help much. This patch changes __ratelimit and printk_ratelimit to print the function name that calls ratelimit. This will pinpoint the responsible function, as long as not several different places call ratelimit with the same ratelimit state at the same time. In that case we catch only one random function that calls ratelimit after the wait period. Signed-off-by: Christian Borntraeger Cc: Dave Young Cc: Linus Torvalds CC: Andrew Morton LKML-Reference: <200910231458.11832.borntraeger@de.ibm.com> Signed-off-by: Ingo Molnar --- include/linux/kernel.h | 3 ++- include/linux/ratelimit.h | 3 ++- kernel/printk.c | 6 +++--- lib/ratelimit.c | 6 +++--- 4 files changed, 10 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3305f33201be..21d0d822c716 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -240,7 +240,8 @@ asmlinkage int vprintk(const char *fmt, va_list args) asmlinkage int printk(const char * fmt, ...) __attribute__ ((format (printf, 1, 2))) __cold; -extern int printk_ratelimit(void); +extern int __printk_ratelimit(const char *func); +#define printk_ratelimit() __printk_ratelimit(__func__) extern bool printk_timed_ratelimit(unsigned long *caller_jiffies, unsigned int interval_msec); diff --git a/include/linux/ratelimit.h b/include/linux/ratelimit.h index 187bc16c1f15..668cf1bef030 100644 --- a/include/linux/ratelimit.h +++ b/include/linux/ratelimit.h @@ -25,6 +25,7 @@ struct ratelimit_state { .burst = burst_init, \ } -extern int __ratelimit(struct ratelimit_state *rs); +extern int ___ratelimit(struct ratelimit_state *rs, const char *func); +#define __ratelimit(state) ___ratelimit(state, __func__) #endif /* _LINUX_RATELIMIT_H */ diff --git a/kernel/printk.c b/kernel/printk.c index b997c893cdcf..8283dbe15af4 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -1364,11 +1364,11 @@ late_initcall(disable_boot_consoles); */ DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); -int printk_ratelimit(void) +int __printk_ratelimit(const char *func) { - return __ratelimit(&printk_ratelimit_state); + return ___ratelimit(&printk_ratelimit_state, func); } -EXPORT_SYMBOL(printk_ratelimit); +EXPORT_SYMBOL(__printk_ratelimit); /** * printk_timed_ratelimit - caller-controlled printk ratelimiting diff --git a/lib/ratelimit.c b/lib/ratelimit.c index 5551731ae1d4..09f5ce1810dc 100644 --- a/lib/ratelimit.c +++ b/lib/ratelimit.c @@ -20,7 +20,7 @@ * This enforces a rate limit: not more than @rs->ratelimit_burst callbacks * in every @rs->ratelimit_jiffies */ -int __ratelimit(struct ratelimit_state *rs) +int ___ratelimit(struct ratelimit_state *rs, const char *func) { unsigned long flags; int ret; @@ -43,7 +43,7 @@ int __ratelimit(struct ratelimit_state *rs) if (time_is_before_jiffies(rs->begin + rs->interval)) { if (rs->missed) printk(KERN_WARNING "%s: %d callbacks suppressed\n", - __func__, rs->missed); + func, rs->missed); rs->begin = 0; rs->printed = 0; rs->missed = 0; @@ -59,4 +59,4 @@ int __ratelimit(struct ratelimit_state *rs) return ret; } -EXPORT_SYMBOL(__ratelimit); +EXPORT_SYMBOL(___ratelimit); -- cgit v1.2.3 From 9b1d82fa1611706fa7ee1505f290160a18caf95d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 25 Oct 2009 19:03:50 -0700 Subject: rcu: "Tiny RCU", The Bloatwatch Edition This patch is a version of RCU designed for !SMP provided for a small-footprint RCU implementation. In particular, the implementation of synchronize_rcu() is extremely lightweight and high performance. It passes rcutorture testing in each of the four relevant configurations (combinations of NO_HZ and PREEMPT) on x86. This saves about 1K bytes compared to old Classic RCU (which is no longer in mainline), and more than three kilobytes compared to Hierarchical RCU (updated to 2.6.30): CONFIG_TREE_RCU: text data bss dec filename 183 4 0 187 kernel/rcupdate.o 2783 520 36 3339 kernel/rcutree.o 3526 Total (vs 4565 for v7) CONFIG_TREE_PREEMPT_RCU: text data bss dec filename 263 4 0 267 kernel/rcupdate.o 4594 776 52 5422 kernel/rcutree.o 5689 Total (6155 for v7) CONFIG_TINY_RCU: text data bss dec filename 96 4 0 100 kernel/rcupdate.o 734 24 0 758 kernel/rcutiny.o 858 Total (vs 848 for v7) The above is for x86. Your mileage may vary on other platforms. Further compression is possible, but is being procrastinated. Changes from v7 (http://lkml.org/lkml/2009/10/9/388) o Apply Lai Jiangshan's review comments (aside from might_sleep() in synchronize_sched(), which is covered by SMP builds). o Fix up expedited primitives. Changes from v6 (http://lkml.org/lkml/2009/9/23/293). o Forward ported to put it into the 2.6.33 stream. o Added lockdep support. o Make lightweight rcu_barrier. Changes from v5 (http://lkml.org/lkml/2009/6/23/12). o Ported to latest pre-2.6.32 merge window kernel. - Renamed rcu_qsctr_inc() to rcu_sched_qs(). - Renamed rcu_bh_qsctr_inc() to rcu_bh_qs(). - Provided trivial rcu_cpu_notify(). - Provided trivial exit_rcu(). - Provided trivial rcu_needs_cpu(). - Fixed up the rcu_*_enter/exit() functions in linux/hardirq.h. o Removed the dependence on EMBEDDED, with a view to making TINY_RCU default for !SMP at some time in the future. o Added (trivial) support for expedited grace periods. Changes from v4 (http://lkml.org/lkml/2009/5/2/91) include: o Squeeze the size down a bit further by removing the ->completed field from struct rcu_ctrlblk. o This permits synchronize_rcu() to become the empty function. Previous concerns about rcutorture were unfounded, as rcutorture correctly handles a constant value from rcu_batches_completed() and rcu_batches_completed_bh(). Changes from v3 (http://lkml.org/lkml/2009/3/29/221) include: o Changed rcu_batches_completed(), rcu_batches_completed_bh() rcu_enter_nohz(), rcu_exit_nohz(), rcu_nmi_enter(), and rcu_nmi_exit(), to be static inlines, as suggested by David Howells. Doing this saves about 100 bytes from rcutiny.o. (The numbers between v3 and this v4 of the patch are not directly comparable, since they are against different versions of Linux.) Changes from v2 (http://lkml.org/lkml/2009/2/3/333) include: o Fix whitespace issues. o Change short-circuit "||" operator to instead be "+" in order to fix performance bug noted by "kraai" on LWN. (http://lwn.net/Articles/324348/) Changes from v1 (http://lkml.org/lkml/2009/1/13/440) include: o This version depends on EMBEDDED as well as !SMP, as suggested by Ingo. o Updated rcu_needs_cpu() to unconditionally return zero, permitting the CPU to enter dynticks-idle mode at any time. This works because callbacks can be invoked upon entry to dynticks-idle mode. o Paul is now OK with this being included, based on a poll at the Kernel Miniconf at linux.conf.au, where about ten people said that they cared about saving 900 bytes on single-CPU systems. o Applies to both mainline and tip/core/rcu. Signed-off-by: Paul E. McKenney Acked-by: David Howells Acked-by: Josh Triplett Reviewed-by: Lai Jiangshan Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: avi@redhat.com Cc: mtosatti@redhat.com LKML-Reference: <12565226351355-git-send-email-> Signed-off-by: Ingo Molnar --- include/linux/hardirq.h | 24 ++++ include/linux/rcupdate.h | 6 + include/linux/rcutiny.h | 97 ++++++++++++++++ init/Kconfig | 9 ++ kernel/Makefile | 1 + kernel/rcupdate.c | 4 + kernel/rcutiny.c | 294 +++++++++++++++++++++++++++++++++++++++++++++++ 7 files changed, 435 insertions(+) create mode 100644 include/linux/rcutiny.h create mode 100644 kernel/rcutiny.c (limited to 'kernel') diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 6d527ee82b2b..d5b387669dab 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -139,10 +139,34 @@ static inline void account_system_vtime(struct task_struct *tsk) #endif #if defined(CONFIG_NO_HZ) +#if defined(CONFIG_TINY_RCU) +extern void rcu_enter_nohz(void); +extern void rcu_exit_nohz(void); + +static inline void rcu_irq_enter(void) +{ + rcu_exit_nohz(); +} + +static inline void rcu_irq_exit(void) +{ + rcu_enter_nohz(); +} + +static inline void rcu_nmi_enter(void) +{ +} + +static inline void rcu_nmi_exit(void) +{ +} + +#else extern void rcu_irq_enter(void); extern void rcu_irq_exit(void); extern void rcu_nmi_enter(void); extern void rcu_nmi_exit(void); +#endif #else # define rcu_irq_enter() do { } while (0) # define rcu_irq_exit() do { } while (0) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 3ebd0b7bcb08..6dd71fa48429 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -68,11 +68,17 @@ extern int sched_expedited_torture_stats(char *page); /* Internal to kernel */ extern void rcu_init(void); extern void rcu_scheduler_starting(void); +#ifndef CONFIG_TINY_RCU extern int rcu_needs_cpu(int cpu); +#else +static inline int rcu_needs_cpu(int cpu) { return 0; } +#endif extern int rcu_scheduler_active; #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU) #include +#elif CONFIG_TINY_RCU +#include #else #error "Unknown RCU implementation specified to kernel configuration" #endif diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h new file mode 100644 index 000000000000..891073c264dc --- /dev/null +++ b/include/linux/rcutiny.h @@ -0,0 +1,97 @@ +/* + * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright IBM Corporation, 2008 + * + * Author: Paul E. McKenney + * + * For detailed explanation of Read-Copy Update mechanism see - + * Documentation/RCU + */ + +#ifndef __LINUX_TINY_H +#define __LINUX_TINY_H + +#include + +void rcu_sched_qs(int cpu); +void rcu_bh_qs(int cpu); + +#define __rcu_read_lock() preempt_disable() +#define __rcu_read_unlock() preempt_enable() +#define __rcu_read_lock_bh() local_bh_disable() +#define __rcu_read_unlock_bh() local_bh_enable() +#define call_rcu_sched call_rcu + +#define rcu_init_sched() do { } while (0) +extern void rcu_check_callbacks(int cpu, int user); +extern void __rcu_init(void); + +/* + * Return the number of grace periods. + */ +static inline long rcu_batches_completed(void) +{ + return 0; +} + +/* + * Return the number of bottom-half grace periods. + */ +static inline long rcu_batches_completed_bh(void) +{ + return 0; +} + +extern int rcu_expedited_torture_stats(char *page); + +static inline void synchronize_rcu_expedited(void) +{ + synchronize_sched(); +} + +static inline void synchronize_rcu_bh_expedited(void) +{ + synchronize_sched(); +} + +struct notifier_block; +extern int rcu_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu); + +#ifdef CONFIG_NO_HZ + +extern void rcu_enter_nohz(void); +extern void rcu_exit_nohz(void); + +#else /* #ifdef CONFIG_NO_HZ */ + +static inline void rcu_enter_nohz(void) +{ +} + +static inline void rcu_exit_nohz(void) +{ +} + +#endif /* #else #ifdef CONFIG_NO_HZ */ + +static inline void exit_rcu(void) +{ +} + +#endif /* __LINUX_RCUTINY_H */ diff --git a/init/Kconfig b/init/Kconfig index 09c5c6431f42..d367bf6bcc34 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -334,6 +334,15 @@ config TREE_PREEMPT_RCU is also required. It also scales down nicely to smaller systems. +config TINY_RCU + bool "UP-only small-memory-footprint RCU" + depends on !SMP + help + This option selects the RCU implementation that is + designed for UP systems from which real-time response + is not required. This option greatly reduces the + memory footprint of RCU. + endchoice config RCU_TRACE diff --git a/kernel/Makefile b/kernel/Makefile index b8d4cd8ac0b9..e9a0e6ed25cc 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -82,6 +82,7 @@ obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o obj-$(CONFIG_TREE_RCU) += rcutree.o obj-$(CONFIG_TREE_PREEMPT_RCU) += rcutree.o obj-$(CONFIG_TREE_RCU_TRACE) += rcutree_trace.o +obj-$(CONFIG_TINY_RCU) += rcutiny.o obj-$(CONFIG_RELAY) += relay.o obj-$(CONFIG_SYSCTL) += utsname_sysctl.o obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 400183346ad2..7625f207f65e 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -67,6 +67,8 @@ void wakeme_after_rcu(struct rcu_head *head) complete(&rcu->completion); } +#ifndef CONFIG_TINY_RCU + #ifdef CONFIG_TREE_PREEMPT_RCU /** @@ -157,6 +159,8 @@ void synchronize_rcu_bh(void) } EXPORT_SYMBOL_GPL(synchronize_rcu_bh); +#endif /* #ifndef CONFIG_TINY_RCU */ + static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self, unsigned long action, void *hcpu) { diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c new file mode 100644 index 000000000000..0b54efde66ac --- /dev/null +++ b/kernel/rcutiny.c @@ -0,0 +1,294 @@ +/* + * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright IBM Corporation, 2008 + * + * Author: Paul E. McKenney + * + * For detailed explanation of Read-Copy Update mechanism see - + * Documentation/RCU + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* Global control variables for rcupdate callback mechanism. */ +struct rcu_ctrlblk { + struct rcu_head *rcucblist; /* List of pending callbacks (CBs). */ + struct rcu_head **donetail; /* ->next pointer of last "done" CB. */ + struct rcu_head **curtail; /* ->next pointer of last CB. */ +}; + +/* Definition for rcupdate control block. */ +static struct rcu_ctrlblk rcu_ctrlblk = { + .rcucblist = NULL, + .donetail = &rcu_ctrlblk.rcucblist, + .curtail = &rcu_ctrlblk.rcucblist, +}; +static struct rcu_ctrlblk rcu_bh_ctrlblk = { + .rcucblist = NULL, + .donetail = &rcu_bh_ctrlblk.rcucblist, + .curtail = &rcu_bh_ctrlblk.rcucblist, +}; + +#ifdef CONFIG_NO_HZ + +static long rcu_dynticks_nesting = 1; + +/* + * Enter dynticks-idle mode, which is an extended quiescent state + * if we have fully entered that mode (i.e., if the new value of + * dynticks_nesting is zero). + */ +void rcu_enter_nohz(void) +{ + if (--rcu_dynticks_nesting == 0) + rcu_sched_qs(0); /* implies rcu_bh_qsctr_inc(0) */ +} + +/* + * Exit dynticks-idle mode, so that we are no longer in an extended + * quiescent state. + */ +void rcu_exit_nohz(void) +{ + rcu_dynticks_nesting++; +} + +#endif /* #ifdef CONFIG_NO_HZ */ + +/* + * Helper function for rcu_qsctr_inc() and rcu_bh_qsctr_inc(). + * Also disable irqs to avoid confusion due to interrupt handlers invoking + * call_rcu(). + */ +static int rcu_qsctr_help(struct rcu_ctrlblk *rcp) +{ + unsigned long flags; + + local_irq_save(flags); + if (rcp->rcucblist != NULL && + rcp->donetail != rcp->curtail) { + rcp->donetail = rcp->curtail; + local_irq_restore(flags); + return 1; + } + local_irq_restore(flags); + return 0; +} + +/* + * Record an rcu quiescent state. And an rcu_bh quiescent state while we + * are at it, given that any rcu quiescent state is also an rcu_bh + * quiescent state. Use "+" instead of "||" to defeat short circuiting. + */ +void rcu_sched_qs(int cpu) +{ + if (rcu_qsctr_help(&rcu_ctrlblk) + rcu_qsctr_help(&rcu_bh_ctrlblk)) + raise_softirq(RCU_SOFTIRQ); +} + +/* + * Record an rcu_bh quiescent state. + */ +void rcu_bh_qs(int cpu) +{ + if (rcu_qsctr_help(&rcu_bh_ctrlblk)) + raise_softirq(RCU_SOFTIRQ); +} + +/* + * Check to see if the scheduling-clock interrupt came from an extended + * quiescent state, and, if so, tell RCU about it. + */ +void rcu_check_callbacks(int cpu, int user) +{ + if (user || + (idle_cpu(cpu) && + !in_softirq() && + hardirq_count() <= (1 << HARDIRQ_SHIFT))) + rcu_sched_qs(cpu); + else if (!in_softirq()) + rcu_bh_qs(cpu); +} + +/* + * Helper function for rcu_process_callbacks() that operates on the + * specified rcu_ctrlkblk structure. + */ +static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp) +{ + unsigned long flags; + struct rcu_head *next, *list; + + /* If no RCU callbacks ready to invoke, just return. */ + if (&rcp->rcucblist == rcp->donetail) + return; + + /* Move the ready-to-invoke callbacks to a local list. */ + local_irq_save(flags); + list = rcp->rcucblist; + rcp->rcucblist = *rcp->donetail; + *rcp->donetail = NULL; + if (rcp->curtail == rcp->donetail) + rcp->curtail = &rcp->rcucblist; + rcp->donetail = &rcp->rcucblist; + local_irq_restore(flags); + + /* Invoke the callbacks on the local list. */ + while (list) { + next = list->next; + prefetch(next); + list->func(list); + list = next; + } +} + +/* + * Invoke any callbacks whose grace period has completed. + */ +static void rcu_process_callbacks(struct softirq_action *unused) +{ + __rcu_process_callbacks(&rcu_ctrlblk); + __rcu_process_callbacks(&rcu_bh_ctrlblk); +} + +/* + * Null function to handle CPU being onlined. Longer term, we want to + * make TINY_RCU avoid using rcupdate.c, but later... + */ +int rcu_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + return NOTIFY_OK; +} + +/* + * Wait for a grace period to elapse. But it is illegal to invoke + * synchronize_sched() from within an RCU read-side critical section. + * Therefore, any legal call to synchronize_sched() is a quiescent + * state, and so on a UP system, synchronize_sched() need do nothing. + * Ditto for synchronize_rcu_bh(). (But Lai Jiangshan points out the + * benefits of doing might_sleep() to reduce latency.) + * + * Cool, huh? (Due to Josh Triplett.) + * + * But we want to make this a static inline later. + */ +void synchronize_sched(void) +{ + cond_resched(); +} +EXPORT_SYMBOL_GPL(synchronize_sched); + +void synchronize_rcu_bh(void) +{ + synchronize_sched(); +} +EXPORT_SYMBOL_GPL(synchronize_rcu_bh); + +/* + * Helper function for call_rcu() and call_rcu_bh(). + */ +static void __call_rcu(struct rcu_head *head, + void (*func)(struct rcu_head *rcu), + struct rcu_ctrlblk *rcp) +{ + unsigned long flags; + + head->func = func; + head->next = NULL; + local_irq_save(flags); + *rcp->curtail = head; + rcp->curtail = &head->next; + local_irq_restore(flags); +} + +/* + * Post an RCU callback to be invoked after the end of an RCU grace + * period. But since we have but one CPU, that would be after any + * quiescent state. + */ +void call_rcu(struct rcu_head *head, + void (*func)(struct rcu_head *rcu)) +{ + __call_rcu(head, func, &rcu_ctrlblk); +} +EXPORT_SYMBOL_GPL(call_rcu); + +/* + * Post an RCU bottom-half callback to be invoked after any subsequent + * quiescent state. + */ +void call_rcu_bh(struct rcu_head *head, + void (*func)(struct rcu_head *rcu)) +{ + __call_rcu(head, func, &rcu_bh_ctrlblk); +} +EXPORT_SYMBOL_GPL(call_rcu_bh); + +void rcu_barrier(void) +{ + struct rcu_synchronize rcu; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(rcu_barrier); + +void rcu_barrier_bh(void) +{ + struct rcu_synchronize rcu; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu_bh(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(rcu_barrier_bh); + +void rcu_barrier_sched(void) +{ + struct rcu_synchronize rcu; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu_sched(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(rcu_barrier_sched); + +void __rcu_init(void) +{ + open_softirq(RCU_SOFTIRQ, rcu_process_callbacks); +} -- cgit v1.2.3 From 0cd397d33608ae6c97d2ee6c8c43462b419b7e26 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 25 Oct 2009 19:03:51 -0700 Subject: rcu: Add synchronize_srcu_expedited() This patch creates a synchronize_srcu_expedited() that uses synchronize_sched_expedited() where synchronize_srcu() uses synchronize_sched(). The synchronize_srcu() and synchronize_srcu_expedited() functions become one-liners that pass synchronize_sched() or synchronize_sched_expedited(), repectively, to a new __synchronize_srcu() function. While in the file, move the EXPORT_SYMBOL_GPL()s to immediately follow the corresponding functions. Requested-by: Avi Kivity Tested-by: Marcelo Tosatti Signed-off-by: Paul E. McKenney Acked-by: Josh Triplett Reviewed-by: Lai Jiangshan Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com Cc: avi@redhat.com LKML-Reference: <12565226354038-git-send-email-> Signed-off-by: Ingo Molnar --- include/linux/srcu.h | 1 + kernel/srcu.c | 74 ++++++++++++++++++++++++++++++++++++---------------- 2 files changed, 52 insertions(+), 23 deletions(-) (limited to 'kernel') diff --git a/include/linux/srcu.h b/include/linux/srcu.h index aca0eee53930..4765d97dcafb 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -48,6 +48,7 @@ void cleanup_srcu_struct(struct srcu_struct *sp); int srcu_read_lock(struct srcu_struct *sp) __acquires(sp); void srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp); void synchronize_srcu(struct srcu_struct *sp); +void synchronize_srcu_expedited(struct srcu_struct *sp); long srcu_batches_completed(struct srcu_struct *sp); #endif diff --git a/kernel/srcu.c b/kernel/srcu.c index b0aeeaf22ce4..818d7d9aa03c 100644 --- a/kernel/srcu.c +++ b/kernel/srcu.c @@ -49,6 +49,7 @@ int init_srcu_struct(struct srcu_struct *sp) sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array); return (sp->per_cpu_ref ? 0 : -ENOMEM); } +EXPORT_SYMBOL_GPL(init_srcu_struct); /* * srcu_readers_active_idx -- returns approximate number of readers @@ -97,6 +98,7 @@ void cleanup_srcu_struct(struct srcu_struct *sp) free_percpu(sp->per_cpu_ref); sp->per_cpu_ref = NULL; } +EXPORT_SYMBOL_GPL(cleanup_srcu_struct); /** * srcu_read_lock - register a new reader for an SRCU-protected structure. @@ -118,6 +120,7 @@ int srcu_read_lock(struct srcu_struct *sp) preempt_enable(); return idx; } +EXPORT_SYMBOL_GPL(srcu_read_lock); /** * srcu_read_unlock - unregister a old reader from an SRCU-protected structure. @@ -136,22 +139,12 @@ void srcu_read_unlock(struct srcu_struct *sp, int idx) per_cpu_ptr(sp->per_cpu_ref, smp_processor_id())->c[idx]--; preempt_enable(); } +EXPORT_SYMBOL_GPL(srcu_read_unlock); -/** - * synchronize_srcu - wait for prior SRCU read-side critical-section completion - * @sp: srcu_struct with which to synchronize. - * - * Flip the completed counter, and wait for the old count to drain to zero. - * As with classic RCU, the updater must use some separate means of - * synchronizing concurrent updates. Can block; must be called from - * process context. - * - * Note that it is illegal to call synchornize_srcu() from the corresponding - * SRCU read-side critical section; doing so will result in deadlock. - * However, it is perfectly legal to call synchronize_srcu() on one - * srcu_struct from some other srcu_struct's read-side critical section. +/* + * Helper function for synchronize_srcu() and synchronize_srcu_expedited(). */ -void synchronize_srcu(struct srcu_struct *sp) +void __synchronize_srcu(struct srcu_struct *sp, void (*sync_func)(void)) { int idx; @@ -173,7 +166,7 @@ void synchronize_srcu(struct srcu_struct *sp) return; } - synchronize_sched(); /* Force memory barrier on all CPUs. */ + sync_func(); /* Force memory barrier on all CPUs. */ /* * The preceding synchronize_sched() ensures that any CPU that @@ -190,7 +183,7 @@ void synchronize_srcu(struct srcu_struct *sp) idx = sp->completed & 0x1; sp->completed++; - synchronize_sched(); /* Force memory barrier on all CPUs. */ + sync_func(); /* Force memory barrier on all CPUs. */ /* * At this point, because of the preceding synchronize_sched(), @@ -203,7 +196,7 @@ void synchronize_srcu(struct srcu_struct *sp) while (srcu_readers_active_idx(sp, idx)) schedule_timeout_interruptible(1); - synchronize_sched(); /* Force memory barrier on all CPUs. */ + sync_func(); /* Force memory barrier on all CPUs. */ /* * The preceding synchronize_sched() forces all srcu_read_unlock() @@ -236,6 +229,47 @@ void synchronize_srcu(struct srcu_struct *sp) mutex_unlock(&sp->mutex); } +/** + * synchronize_srcu - wait for prior SRCU read-side critical-section completion + * @sp: srcu_struct with which to synchronize. + * + * Flip the completed counter, and wait for the old count to drain to zero. + * As with classic RCU, the updater must use some separate means of + * synchronizing concurrent updates. Can block; must be called from + * process context. + * + * Note that it is illegal to call synchronize_srcu() from the corresponding + * SRCU read-side critical section; doing so will result in deadlock. + * However, it is perfectly legal to call synchronize_srcu() on one + * srcu_struct from some other srcu_struct's read-side critical section. + */ +void synchronize_srcu(struct srcu_struct *sp) +{ + __synchronize_srcu(sp, synchronize_sched); +} +EXPORT_SYMBOL_GPL(synchronize_srcu); + +/** + * synchronize_srcu_expedited - like synchronize_srcu, but less patient + * @sp: srcu_struct with which to synchronize. + * + * Flip the completed counter, and wait for the old count to drain to zero. + * As with classic RCU, the updater must use some separate means of + * synchronizing concurrent updates. Can block; must be called from + * process context. + * + * Note that it is illegal to call synchronize_srcu_expedited() + * from the corresponding SRCU read-side critical section; doing so + * will result in deadlock. However, it is perfectly legal to call + * synchronize_srcu_expedited() on one srcu_struct from some other + * srcu_struct's read-side critical section. + */ +void synchronize_srcu_expedited(struct srcu_struct *sp) +{ + __synchronize_srcu(sp, synchronize_sched_expedited); +} +EXPORT_SYMBOL_GPL(synchronize_srcu_expedited); + /** * srcu_batches_completed - return batches completed. * @sp: srcu_struct on which to report batch completion. @@ -248,10 +282,4 @@ long srcu_batches_completed(struct srcu_struct *sp) { return sp->completed; } - -EXPORT_SYMBOL_GPL(init_srcu_struct); -EXPORT_SYMBOL_GPL(cleanup_srcu_struct); -EXPORT_SYMBOL_GPL(srcu_read_lock); -EXPORT_SYMBOL_GPL(srcu_read_unlock); -EXPORT_SYMBOL_GPL(synchronize_srcu); EXPORT_SYMBOL_GPL(srcu_batches_completed); -- cgit v1.2.3 From 804bb8370522a569bd3a732b9de5fbd55e26f155 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 25 Oct 2009 19:03:52 -0700 Subject: rcu: Add synchronize_srcu_expedited() to the rcutorture test suite Adds the "srcu_expedited" torture type, and also renames sched_ops_sync to sched_sync_ops for consistency while we are in this file. Signed-off-by: Paul E. McKenney Acked-by: Josh Triplett Reviewed-by: Lai Jiangshan Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com Cc: avi@redhat.com Cc: mtosatti@redhat.com LKML-Reference: <12565226353636-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutorture.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 697c0a0229d4..14480e8b2a24 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -547,6 +547,25 @@ static struct rcu_torture_ops srcu_ops = { .name = "srcu" }; +static void srcu_torture_synchronize_expedited(void) +{ + synchronize_srcu_expedited(&srcu_ctl); +} + +static struct rcu_torture_ops srcu_expedited_ops = { + .init = srcu_torture_init, + .cleanup = srcu_torture_cleanup, + .readlock = srcu_torture_read_lock, + .read_delay = srcu_read_delay, + .readunlock = srcu_torture_read_unlock, + .completed = srcu_torture_completed, + .deferred_free = rcu_sync_torture_deferred_free, + .sync = srcu_torture_synchronize_expedited, + .cb_barrier = NULL, + .stats = srcu_torture_stats, + .name = "srcu_expedited" +}; + /* * Definitions for sched torture testing. */ @@ -592,7 +611,7 @@ static struct rcu_torture_ops sched_ops = { .name = "sched" }; -static struct rcu_torture_ops sched_ops_sync = { +static struct rcu_torture_ops sched_sync_ops = { .init = rcu_sync_torture_init, .cleanup = NULL, .readlock = sched_torture_read_lock, @@ -1098,8 +1117,8 @@ rcu_torture_init(void) int firsterr = 0; static struct rcu_torture_ops *torture_ops[] = { &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops, - &sched_expedited_ops, - &srcu_ops, &sched_ops, &sched_ops_sync, }; + &srcu_ops, &srcu_expedited_ops, + &sched_ops, &sched_sync_ops, &sched_expedited_ops, }; mutex_lock(&fullstop_mutex); -- cgit v1.2.3 From cf886c44ec418a01b2c52493465accb81acbf930 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 25 Oct 2009 19:03:54 -0700 Subject: rcu: Improve rcutorture diagnostics when bad torture_type specified Make rcutorture list the available torture_type values when it doesn't like the one specified. Signed-off-by: Paul E. McKenney Acked-by: Josh Triplett Reviewed-by: Lai Jiangshan Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com Cc: avi@redhat.com Cc: mtosatti@redhat.com LKML-Reference: <12565226351868-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutorture.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 14480e8b2a24..3dd0ca23e191 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -1129,8 +1129,12 @@ rcu_torture_init(void) break; } if (i == ARRAY_SIZE(torture_ops)) { - printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n", + printk(KERN_ALERT "rcu-torture: invalid torture type: \"%s\"\n", torture_type); + printk(KERN_ALERT "rcu-torture types:"); + for (i = 0; i < ARRAY_SIZE(torture_ops); i++) + printk(KERN_ALERT " %s", torture_ops[i]->name); + printk(KERN_ALERT "\n"); mutex_unlock(&fullstop_mutex); return -EINVAL; } -- cgit v1.2.3 From 4ce5b90340879ce93d169b7b523c2cbbe7c45843 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 26 Oct 2009 07:55:55 +0100 Subject: rcu: Do tiny cleanups in rcutiny No change in functionality - just straighten out a few small stylistic details. Cc: Paul E. McKenney Cc: David Howells Cc: Josh Triplett Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: avi@redhat.com Cc: mtosatti@redhat.com LKML-Reference: <12565226351355-git-send-email-> Signed-off-by: Ingo Molnar --- include/linux/rcutiny.h | 6 ++---- kernel/rcutiny.c | 49 +++++++++++++++++++++++-------------------------- 2 files changed, 25 insertions(+), 30 deletions(-) (limited to 'kernel') diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 891073c264dc..2c1fe8373e71 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -20,9 +20,8 @@ * Author: Paul E. McKenney * * For detailed explanation of Read-Copy Update mechanism see - - * Documentation/RCU + * Documentation/RCU */ - #ifndef __LINUX_TINY_H #define __LINUX_TINY_H @@ -70,8 +69,7 @@ static inline void synchronize_rcu_bh_expedited(void) } struct notifier_block; -extern int rcu_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu); +extern int rcu_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu); #ifdef CONFIG_NO_HZ diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c index 0b54efde66ac..b33ec3aa377a 100644 --- a/kernel/rcutiny.c +++ b/kernel/rcutiny.c @@ -20,22 +20,21 @@ * Author: Paul E. McKenney * * For detailed explanation of Read-Copy Update mechanism see - - * Documentation/RCU + * Documentation/RCU */ - -#include -#include -#include -#include -#include -#include -#include -#include #include +#include +#include #include -#include +#include +#include +#include #include +#include +#include +#include #include +#include /* Global control variables for rcupdate callback mechanism. */ struct rcu_ctrlblk { @@ -46,14 +45,13 @@ struct rcu_ctrlblk { /* Definition for rcupdate control block. */ static struct rcu_ctrlblk rcu_ctrlblk = { - .rcucblist = NULL, - .donetail = &rcu_ctrlblk.rcucblist, - .curtail = &rcu_ctrlblk.rcucblist, + .donetail = &rcu_ctrlblk.rcucblist, + .curtail = &rcu_ctrlblk.rcucblist, }; + static struct rcu_ctrlblk rcu_bh_ctrlblk = { - .rcucblist = NULL, - .donetail = &rcu_bh_ctrlblk.rcucblist, - .curtail = &rcu_bh_ctrlblk.rcucblist, + .donetail = &rcu_bh_ctrlblk.rcucblist, + .curtail = &rcu_bh_ctrlblk.rcucblist, }; #ifdef CONFIG_NO_HZ @@ -84,8 +82,8 @@ void rcu_exit_nohz(void) /* * Helper function for rcu_qsctr_inc() and rcu_bh_qsctr_inc(). - * Also disable irqs to avoid confusion due to interrupt handlers invoking - * call_rcu(). + * Also disable irqs to avoid confusion due to interrupt handlers + * invoking call_rcu(). */ static int rcu_qsctr_help(struct rcu_ctrlblk *rcp) { @@ -99,6 +97,7 @@ static int rcu_qsctr_help(struct rcu_ctrlblk *rcp) return 1; } local_irq_restore(flags); + return 0; } @@ -143,8 +142,8 @@ void rcu_check_callbacks(int cpu, int user) */ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp) { - unsigned long flags; struct rcu_head *next, *list; + unsigned long flags; /* If no RCU callbacks ready to invoke, just return. */ if (&rcp->rcucblist == rcp->donetail) @@ -182,8 +181,7 @@ static void rcu_process_callbacks(struct softirq_action *unused) * Null function to handle CPU being onlined. Longer term, we want to * make TINY_RCU avoid using rcupdate.c, but later... */ -int rcu_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu) +int rcu_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { return NOTIFY_OK; } @@ -223,6 +221,7 @@ static void __call_rcu(struct rcu_head *head, head->func = func; head->next = NULL; + local_irq_save(flags); *rcp->curtail = head; rcp->curtail = &head->next; @@ -234,8 +233,7 @@ static void __call_rcu(struct rcu_head *head, * period. But since we have but one CPU, that would be after any * quiescent state. */ -void call_rcu(struct rcu_head *head, - void (*func)(struct rcu_head *rcu)) +void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) { __call_rcu(head, func, &rcu_ctrlblk); } @@ -245,8 +243,7 @@ EXPORT_SYMBOL_GPL(call_rcu); * Post an RCU bottom-half callback to be invoked after any subsequent * quiescent state. */ -void call_rcu_bh(struct rcu_head *head, - void (*func)(struct rcu_head *rcu)) +void call_rcu_bh(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) { __call_rcu(head, func, &rcu_bh_ctrlblk); } -- cgit v1.2.3 From 88b91c7ca49bc8600cf1106eb891d08c1965b9ce Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 26 Oct 2009 10:24:31 -0700 Subject: rcu: Simplify creating of lockdep class for root rcu_node Use lockdep_set_class() to simplify the code and to avoid any additional overhead in the !LOCKDEP case. Also move the definition of rcu_root_class into kernel/rcutree.c, as suggested by Lai Jiangshan. Signed-off-by: Peter Zijlstra Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1256577871443-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index ddbf111e9e18..055f1a941a9e 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -51,6 +51,8 @@ /* Data structures. */ +static struct lock_class_key rcu_root_class; + #define RCU_STATE_INITIALIZER(name) { \ .level = { &name.node[0] }, \ .levelcnt = { \ @@ -1666,8 +1668,7 @@ static void __init rcu_init_one(struct rcu_state *rsp) cpustride *= rsp->levelspread[i]; rnp = rsp->level[i]; for (j = 0; j < rsp->levelcnt[i]; j++, rnp++) { - if (rnp != rcu_get_root(rsp)) - spin_lock_init(&rnp->lock); + spin_lock_init(&rnp->lock); rnp->gpnum = 0; rnp->qsmask = 0; rnp->qsmaskinit = 0; @@ -1690,7 +1691,7 @@ static void __init rcu_init_one(struct rcu_state *rsp) INIT_LIST_HEAD(&rnp->blocked_tasks[1]); } } - spin_lock_init(&rcu_get_root(rsp)->lock); + lockdep_set_class(&rcu_get_root(rsp)->lock, &rcu_root_class); } /* -- cgit v1.2.3 From 5e9b397292ca0b9409dced33e3a22ec993377064 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 2 Nov 2009 08:51:13 +0800 Subject: tracing: Fix to use __always_unused attribute ____ftrace_check_##name() is used for compile-time check on F_printk() only, so it should be marked as __unused instead of __used. Signed-off-by: Li Zefan Cc: Steven Rostedt Cc: Frederic Weisbecker Cc: Linus Torvalds LKML-Reference: <4AEE2D01.4010305@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- kernel/trace/trace_export.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c index 9753fcc61bc5..c74848ddb85a 100644 --- a/kernel/trace/trace_export.c +++ b/kernel/trace/trace_export.c @@ -48,11 +48,11 @@ struct ____ftrace_##name { \ tstruct \ }; \ -static void __used ____ftrace_check_##name(void) \ +static void __always_unused ____ftrace_check_##name(void) \ { \ struct ____ftrace_##name *__entry = NULL; \ \ - /* force cmpile-time check on F_printk() */ \ + /* force compile-time check on F_printk() */ \ printk(print); \ } -- cgit v1.2.3 From c5e0cb3ddc5f14cedcfc50c0fb3b5fc6b56576da Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Wed, 28 Oct 2009 08:14:48 -0700 Subject: rcu: Cleanup: balance rcu_irq_enter()/rcu_irq_exit() calls Currently, rcu_irq_exit() is invoked only for CONFIG_NO_HZ, while rcu_irq_enter() is invoked unconditionally. This patch moves rcu_irq_exit() out from under CONFIG_NO_HZ so that the calls are balanced. This patch has no effect on the behavior of the kernel because both rcu_irq_enter() and rcu_irq_exit() are empty for !CONFIG_NO_HZ, but the code is easier to understand if the calls are obviously balanced in all cases. Signed-off-by: Lai Jiangshan Signed-off-by: Paul E. McKenney Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12567428891605-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/softirq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/softirq.c b/kernel/softirq.c index f8749e5216e0..21939d9e830e 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -302,9 +302,9 @@ void irq_exit(void) if (!in_interrupt() && local_softirq_pending()) invoke_softirq(); + rcu_irq_exit(); #ifdef CONFIG_NO_HZ /* Make sure that timer wheel updates are propagated */ - rcu_irq_exit(); if (idle_cpu(smp_processor_id()) && !in_interrupt() && !need_resched()) tick_nohz_stop_sched_tick(0); #endif -- cgit v1.2.3 From 4dae560f97fa438f373b53e14b30149c9e44a600 Mon Sep 17 00:00:00 2001 From: Ananth N Mavinakayanahalli Date: Fri, 30 Oct 2009 19:23:10 +0530 Subject: kprobes: Sanitize struct kretprobe_instance allocations For as long as kretprobes have existed, we've allocated NR_CPUS instances of kretprobe_instance structures. With the default value of CONFIG_NR_CPUS increasing on certain architectures, we are potentially wasting kernel memory. See http://sourceware.org/bugzilla/show_bug.cgi?id=10839#c3 for more details. Use a saner num_possible_cpus() instead of NR_CPUS for allocation. Signed-off-by: Ananth N Mavinakayanahalli Acked-by: Masami Hiramatsu Cc: Jim Keniston Cc: fweisbec@gmail.com LKML-Reference: <20091030135310.GA22230@in.ibm.com> Signed-off-by: Ingo Molnar --- kernel/kprobes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 5240d75f4c60..1494e85b35f2 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1014,9 +1014,9 @@ int __kprobes register_kretprobe(struct kretprobe *rp) /* Pre-allocate memory for max kretprobe instances */ if (rp->maxactive <= 0) { #ifdef CONFIG_PREEMPT - rp->maxactive = max(10, 2 * NR_CPUS); + rp->maxactive = max(10, 2 * num_possible_cpus()); #else - rp->maxactive = NR_CPUS; + rp->maxactive = num_possible_cpus(); #endif } spin_lock_init(&rp->lock); -- cgit v1.2.3 From 24b26d4211130b6455692804c14d537158855cd7 Mon Sep 17 00:00:00 2001 From: Liuweni Date: Wed, 4 Nov 2009 20:11:05 +0800 Subject: irq: Fix docbook comments Fix docbook comments to match the actual function names (set_irq_msi, handle_percpu_irq). Signed-off-by: Liuwenyi Signed-off-by: Thomas Gleixner --- kernel/irq/chip.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index c1660194d115..ba566c261adc 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -166,11 +166,11 @@ int set_irq_data(unsigned int irq, void *data) EXPORT_SYMBOL(set_irq_data); /** - * set_irq_data - set irq type data for an irq + * set_irq_msi - set MSI descriptor data for an irq * @irq: Interrupt number * @entry: Pointer to MSI descriptor data * - * Set the hardware irq controller data for an irq + * Set the MSI descriptor entry for an irq */ int set_irq_msi(unsigned int irq, struct msi_desc *entry) { @@ -590,7 +590,7 @@ out_unlock: } /** - * handle_percpu_IRQ - Per CPU local irq handler + * handle_percpu_irq - Per CPU local irq handler * @irq: the interrupt number * @desc: the interrupt description structure for this irq * -- cgit v1.2.3 From 663e69592856df53ef52969482ef413a96bc4e06 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 4 Nov 2009 14:22:21 +0100 Subject: irq: Remove unused debug_poll_all_shared_irqs() commit 74296a8ed added this function for debug purposes, but it was never used for anything. Remove it. Signed-off-by: Thomas Gleixner --- include/linux/interrupt.h | 6 ------ kernel/irq/spurious.c | 14 +------------- 2 files changed, 1 insertion(+), 19 deletions(-) (limited to 'kernel') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 7ca72b74eec7..75f3f00ac1e5 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -603,12 +603,6 @@ static inline void init_irq_proc(void) } #endif -#if defined(CONFIG_GENERIC_HARDIRQS) && defined(CONFIG_DEBUG_SHIRQ) -extern void debug_poll_all_shared_irqs(void); -#else -static inline void debug_poll_all_shared_irqs(void) { } -#endif - struct seq_file; int show_interrupts(struct seq_file *p, void *v); diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c index 114e704760fe..8996b98f9eb2 100644 --- a/kernel/irq/spurious.c +++ b/kernel/irq/spurious.c @@ -104,7 +104,7 @@ static int misrouted_irq(int irq) return ok; } -static void poll_all_shared_irqs(void) +static void poll_spurious_irqs(unsigned long dummy) { struct irq_desc *desc; int i; @@ -123,23 +123,11 @@ static void poll_all_shared_irqs(void) try_one_irq(i, desc); } -} - -static void poll_spurious_irqs(unsigned long dummy) -{ - poll_all_shared_irqs(); mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL); } -#ifdef CONFIG_DEBUG_SHIRQ -void debug_poll_all_shared_irqs(void) -{ - poll_all_shared_irqs(); -} -#endif - /* * If 99,900 of the previous 100,000 interrupts have not been handled * then assume that the IRQ is stuck in some manner. Drop a diagnostic -- cgit v1.2.3 From c82a43d40b93200a10a9fec0a489791e65e135ca Mon Sep 17 00:00:00 2001 From: Cyrill Gorcunov Date: Mon, 26 Oct 2009 23:28:11 +0300 Subject: irq: Do not attempt to create subdirectories if /proc/irq/ failed If a parent directory (ie /proc/irq/) could not be created we should not attempt to create subdirectories. Otherwise it would lead that "smp_affinity" and "spurious" entries are may be registered under /proc root instead of a proper place. Signed-off-by: Cyrill Gorcunov Cc: Rusty Russell Cc: Yinghai Lu LKML-Reference: <20091026202811.GD5321@lenovo> Signed-off-by: Ingo Molnar --- kernel/irq/proc.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 692363dd591f..dfef5b9f3845 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -214,6 +214,8 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc) /* create /proc/irq/1234 */ desc->dir = proc_mkdir(name, root_irq_dir); + if (!desc->dir) + return; #ifdef CONFIG_SMP /* create /proc/irq//smp_affinity */ -- cgit v1.2.3 From f84d49b218b7d4c6cba2e0b41f24bd4045403962 Mon Sep 17 00:00:00 2001 From: Naohiro Ooiwa Date: Mon, 9 Nov 2009 00:46:42 +0900 Subject: signal: Print warning message when dropping signals When the system has too many timers or too many aggregate queued signals, the EAGAIN error is returned to application from kernel, including timer_create() [POSIX.1b]. It means that the app exceeded the limit of pending signals, but in general application writers do not expect this outcome and the current silent failure can cause rare app failures under very high load. This patch adds a new message when we reach the limit and if print_fatal_signals is enabled: task/1234: reached RLIMIT_SIGPENDING, dropping signal If you see this message and your system behaved unexpectedly, you can run following command to lift the limit: # ulimit -i unlimited With help from Hiroshi Shimamoto . Signed-off-by: Naohiro Ooiwa Cc: Andrew Morton Cc: Hiroshi Shimamoto Cc: Roland McGrath Cc: Peter Zijlstra Cc: oleg@redhat.com LKML-Reference: <4AF6E7E2.9080406@miraclelinux.com> [ Modified a few small details, gave surrounding code some love. ] Signed-off-by: Ingo Molnar --- Documentation/kernel-parameters.txt | 11 +++++++-- kernel/signal.c | 46 ++++++++++++++++++++++++++----------- 2 files changed, 42 insertions(+), 15 deletions(-) (limited to 'kernel') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 9107b387e91f..3bbd92f805a6 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2032,8 +2032,15 @@ and is between 256 and 4096 characters. It is defined in the file print-fatal-signals= [KNL] debug: print fatal signals - print-fatal-signals=1: print segfault info to - the kernel console. + + If enabled, warn about various signal handling + related application anomalies: too many signals, + too many POSIX.1 timers, fatal signals causing a + coredump - etc. + + If you hit the warning due to signal overflow, + you might want to try "ulimit -i unlimited". + default: off. printk.time= Show timing data prefixed to each printk message line diff --git a/kernel/signal.c b/kernel/signal.c index 6705320784fd..fe08008133da 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -41,6 +42,8 @@ static struct kmem_cache *sigqueue_cachep; +int print_fatal_signals __read_mostly; + static void __user *sig_handler(struct task_struct *t, int sig) { return t->sighand->action[sig - 1].sa.sa_handler; @@ -159,7 +162,7 @@ int next_signal(struct sigpending *pending, sigset_t *mask) { unsigned long i, *s, *m, x; int sig = 0; - + s = pending->signal.sig; m = mask->sig; switch (_NSIG_WORDS) { @@ -184,17 +187,31 @@ int next_signal(struct sigpending *pending, sigset_t *mask) sig = ffz(~x) + 1; break; } - + return sig; } +static inline void print_dropped_signal(int sig) +{ + static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); + + if (!print_fatal_signals) + return; + + if (!__ratelimit(&ratelimit_state)) + return; + + printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n", + current->comm, current->pid, sig); +} + /* * allocate a new signal queue record * - this may be called without locks if and only if t == current, otherwise an * appopriate lock must be held to stop the target task from exiting */ -static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, - int override_rlimit) +static struct sigqueue * +__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit) { struct sigqueue *q = NULL; struct user_struct *user; @@ -207,10 +224,15 @@ static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, */ user = get_uid(__task_cred(t)->user); atomic_inc(&user->sigpending); + if (override_rlimit || atomic_read(&user->sigpending) <= - t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) + t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) { q = kmem_cache_alloc(sigqueue_cachep, flags); + } else { + print_dropped_signal(sig); + } + if (unlikely(q == NULL)) { atomic_dec(&user->sigpending); free_uid(user); @@ -869,7 +891,7 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, else override_rlimit = 0; - q = __sigqueue_alloc(t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, + q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE, override_rlimit); if (q) { list_add_tail(&q->list, &pending->list); @@ -925,8 +947,6 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t, return __send_signal(sig, info, t, group, from_ancestor_ns); } -int print_fatal_signals; - static void print_fatal_signal(struct pt_regs *regs, int signr) { printk("%s/%d: potentially unexpected fatal signal %d.\n", @@ -1293,19 +1313,19 @@ EXPORT_SYMBOL(kill_pid); * These functions support sending signals using preallocated sigqueue * structures. This is needed "because realtime applications cannot * afford to lose notifications of asynchronous events, like timer - * expirations or I/O completions". In the case of Posix Timers + * expirations or I/O completions". In the case of Posix Timers * we allocate the sigqueue structure from the timer_create. If this * allocation fails we are able to report the failure to the application * with an EAGAIN error. */ - struct sigqueue *sigqueue_alloc(void) { - struct sigqueue *q; + struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0); - if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0))) + if (q) q->flags |= SIGQUEUE_PREALLOC; - return(q); + + return q; } void sigqueue_free(struct sigqueue *q) -- cgit v1.2.3 From dd8dbf2e6880e30c00b18600c962d0cb5a03c555 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 3 Nov 2009 16:35:32 +1100 Subject: security: report the module name to security_module_request For SELinux to do better filtering in userspace we send the name of the module along with the AVC denial when a program is denied module_request. Example output: type=SYSCALL msg=audit(11/03/2009 10:59:43.510:9) : arch=x86_64 syscall=write success=yes exit=2 a0=3 a1=7fc28c0d56c0 a2=2 a3=7fffca0d7440 items=0 ppid=1727 pid=1729 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=unset comm=rpc.nfsd exe=/usr/sbin/rpc.nfsd subj=system_u:system_r:nfsd_t:s0 key=(null) type=AVC msg=audit(11/03/2009 10:59:43.510:9) : avc: denied { module_request } for pid=1729 comm=rpc.nfsd kmod="net-pf-10" scontext=system_u:system_r:nfsd_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=system Signed-off-by: Eric Paris Signed-off-by: James Morris --- include/linux/lsm_audit.h | 18 ++++++++++-------- include/linux/security.h | 7 ++++--- kernel/kmod.c | 8 ++++---- security/capability.c | 2 +- security/lsm_audit.c | 4 ++++ security/security.c | 4 ++-- security/selinux/hooks.c | 13 +++++++++++-- 7 files changed, 36 insertions(+), 20 deletions(-) (limited to 'kernel') diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h index 190c37854870..f78f83d7663f 100644 --- a/include/linux/lsm_audit.h +++ b/include/linux/lsm_audit.h @@ -26,14 +26,15 @@ /* Auxiliary data to use in generating the audit record. */ struct common_audit_data { - char type; -#define LSM_AUDIT_DATA_FS 1 -#define LSM_AUDIT_DATA_NET 2 -#define LSM_AUDIT_DATA_CAP 3 -#define LSM_AUDIT_DATA_IPC 4 -#define LSM_AUDIT_DATA_TASK 5 -#define LSM_AUDIT_DATA_KEY 6 -#define LSM_AUDIT_NO_AUDIT 7 + char type; +#define LSM_AUDIT_DATA_FS 1 +#define LSM_AUDIT_DATA_NET 2 +#define LSM_AUDIT_DATA_CAP 3 +#define LSM_AUDIT_DATA_IPC 4 +#define LSM_AUDIT_DATA_TASK 5 +#define LSM_AUDIT_DATA_KEY 6 +#define LSM_AUDIT_NO_AUDIT 7 +#define LSM_AUDIT_DATA_KMOD 8 struct task_struct *tsk; union { struct { @@ -66,6 +67,7 @@ struct common_audit_data { char *key_desc; } key_struct; #endif + char *kmod_name; } u; /* this union contains LSM specific data */ union { diff --git a/include/linux/security.h b/include/linux/security.h index ed0faea60b82..466cbadbd1ef 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -706,6 +706,7 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @kernel_module_request: * Ability to trigger the kernel to automatically upcall to userspace for * userspace to load a kernel module with the given name. + * @kmod_name name of the module requested by the kernel * Return 0 if successful. * @task_setuid: * Check permission before setting one or more of the user identity @@ -1577,7 +1578,7 @@ struct security_operations { void (*cred_transfer)(struct cred *new, const struct cred *old); int (*kernel_act_as)(struct cred *new, u32 secid); int (*kernel_create_files_as)(struct cred *new, struct inode *inode); - int (*kernel_module_request)(void); + int (*kernel_module_request)(char *kmod_name); int (*task_setuid) (uid_t id0, uid_t id1, uid_t id2, int flags); int (*task_fix_setuid) (struct cred *new, const struct cred *old, int flags); @@ -1842,7 +1843,7 @@ void security_commit_creds(struct cred *new, const struct cred *old); void security_transfer_creds(struct cred *new, const struct cred *old); int security_kernel_act_as(struct cred *new, u32 secid); int security_kernel_create_files_as(struct cred *new, struct inode *inode); -int security_kernel_module_request(void); +int security_kernel_module_request(char *kmod_name); int security_task_setuid(uid_t id0, uid_t id1, uid_t id2, int flags); int security_task_fix_setuid(struct cred *new, const struct cred *old, int flags); @@ -2407,7 +2408,7 @@ static inline int security_kernel_create_files_as(struct cred *cred, return 0; } -static inline int security_kernel_module_request(void) +static inline int security_kernel_module_request(char *kmod_name) { return 0; } diff --git a/kernel/kmod.c b/kernel/kmod.c index 9fcb53a11f87..25b103190364 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -80,16 +80,16 @@ int __request_module(bool wait, const char *fmt, ...) #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ static int kmod_loop_msg; - ret = security_kernel_module_request(); - if (ret) - return ret; - va_start(args, fmt); ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); va_end(args); if (ret >= MODULE_NAME_LEN) return -ENAMETOOLONG; + ret = security_kernel_module_request(module_name); + if (ret) + return ret; + /* If modprobe needs a service that is in a module, we get a recursive * loop. Limit the number of running kmod threads to max_threads/2 or * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method diff --git a/security/capability.c b/security/capability.c index 4f3ab476937f..5c700e1a4fd3 100644 --- a/security/capability.c +++ b/security/capability.c @@ -421,7 +421,7 @@ static int cap_kernel_create_files_as(struct cred *new, struct inode *inode) return 0; } -static int cap_kernel_module_request(void) +static int cap_kernel_module_request(char *kmod_name) { return 0; } diff --git a/security/lsm_audit.c b/security/lsm_audit.c index 3bb90b6f1dd3..51bd0fd9c9f0 100644 --- a/security/lsm_audit.c +++ b/security/lsm_audit.c @@ -354,6 +354,10 @@ static void dump_common_audit_data(struct audit_buffer *ab, } break; #endif + case LSM_AUDIT_DATA_KMOD: + audit_log_format(ab, " kmod="); + audit_log_untrustedstring(ab, a->u.kmod_name); + break; } /* switch (a->type) */ } diff --git a/security/security.c b/security/security.c index aad71b2ca195..24e060be9fa5 100644 --- a/security/security.c +++ b/security/security.c @@ -764,9 +764,9 @@ int security_kernel_create_files_as(struct cred *new, struct inode *inode) return security_ops->kernel_create_files_as(new, inode); } -int security_kernel_module_request(void) +int security_kernel_module_request(char *kmod_name) { - return security_ops->kernel_module_request(); + return security_ops->kernel_module_request(kmod_name); } int security_task_setuid(uid_t id0, uid_t id1, uid_t id2, int flags) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index a29d6612a328..c96d63ec4753 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3337,9 +3337,18 @@ static int selinux_kernel_create_files_as(struct cred *new, struct inode *inode) return 0; } -static int selinux_kernel_module_request(void) +static int selinux_kernel_module_request(char *kmod_name) { - return task_has_system(current, SYSTEM__MODULE_REQUEST); + u32 sid; + struct common_audit_data ad; + + sid = task_sid(current); + + COMMON_AUDIT_DATA_INIT(&ad, KMOD); + ad.u.kmod_name = kmod_name; + + return avc_has_perm(sid, SECINITSID_KERNEL, SECCLASS_SYSTEM, + SYSTEM__MODULE_REQUEST, &ad); } static int selinux_task_setpgid(struct task_struct *p, pid_t pgid) -- cgit v1.2.3 From 281d150c5f8892f158747594ab49ce2823fd8b8c Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 2 Nov 2009 13:52:27 -0800 Subject: rcu: Prepare for synchronization fixes: clean up for non-NO_HZ handling of ->completed counter Impose a clear locking design on non-NO_HZ handling of the ->completed counter. This increases the distance between the RCU and the CPU-hotplug mechanisms. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com Cc: # .32.x LKML-Reference: <12571987491353-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 67 +++++++++++++++++++++++++------------------------------- kernel/rcutree.h | 8 +++---- 2 files changed, 34 insertions(+), 41 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 69f4efec3449..26249abf24dc 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -178,8 +178,28 @@ static struct rcu_node *rcu_get_root(struct rcu_state *rsp) return &rsp->node[0]; } +/* + * Record the specified "completed" value, which is later used to validate + * dynticks counter manipulations and CPU-offline checks. Specify + * "rsp->completed - 1" to unconditionally invalidate any future dynticks + * manipulations and CPU-offline checks. Such invalidation is useful at + * the beginning of a grace period. + */ +static void dyntick_record_completed(struct rcu_state *rsp, long comp) +{ + rsp->dynticks_completed = comp; +} + #ifdef CONFIG_SMP +/* + * Recall the previously recorded value of the completion for dynticks. + */ +static long dyntick_recall_completed(struct rcu_state *rsp) +{ + return rsp->dynticks_completed; +} + /* * If the specified CPU is offline, tell the caller that it is in * a quiescent state. Otherwise, whack it with a reschedule IPI. @@ -337,27 +357,8 @@ void rcu_irq_exit(void) set_need_resched(); } -/* - * Record the specified "completed" value, which is later used to validate - * dynticks counter manipulations. Specify "rsp->completed - 1" to - * unconditionally invalidate any future dynticks manipulations (which is - * useful at the beginning of a grace period). - */ -static void dyntick_record_completed(struct rcu_state *rsp, long comp) -{ - rsp->dynticks_completed = comp; -} - #ifdef CONFIG_SMP -/* - * Recall the previously recorded value of the completion for dynticks. - */ -static long dyntick_recall_completed(struct rcu_state *rsp) -{ - return rsp->dynticks_completed; -} - /* * Snapshot the specified CPU's dynticks counter so that we can later * credit them with an implicit quiescent state. Return 1 if this CPU @@ -421,24 +422,8 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) #else /* #ifdef CONFIG_NO_HZ */ -static void dyntick_record_completed(struct rcu_state *rsp, long comp) -{ -} - #ifdef CONFIG_SMP -/* - * If there are no dynticks, then the only way that a CPU can passively - * be in a quiescent state is to be offline. Unlike dynticks idle, which - * is a point in time during the prior (already finished) grace period, - * an offline CPU is always in a quiescent state, and thus can be - * unconditionally applied. So just return the current value of completed. - */ -static long dyntick_recall_completed(struct rcu_state *rsp) -{ - return rsp->completed; -} - static int dyntick_save_progress_counter(struct rcu_data *rdp) { return 0; @@ -1146,6 +1131,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) long lastcomp; struct rcu_node *rnp = rcu_get_root(rsp); u8 signaled; + u8 forcenow; if (!rcu_gp_in_progress(rsp)) return; /* No grace period in progress, nothing to force. */ @@ -1182,16 +1168,23 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) if (rcu_process_dyntick(rsp, lastcomp, dyntick_save_progress_counter)) goto unlock_ret; + /* fall into next case. */ + + case RCU_SAVE_COMPLETED: /* Update state, record completion counter. */ + forcenow = 0; spin_lock(&rnp->lock); if (lastcomp == rsp->completed && - rsp->signaled == RCU_SAVE_DYNTICK) { + rsp->signaled == signaled) { rsp->signaled = RCU_FORCE_QS; dyntick_record_completed(rsp, lastcomp); + forcenow = signaled == RCU_SAVE_COMPLETED; } spin_unlock(&rnp->lock); - break; + if (!forcenow) + break; + /* fall into next case. */ case RCU_FORCE_QS: diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 1899023b0962..8a4c1650ad8d 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -204,11 +204,12 @@ struct rcu_data { #define RCU_GP_IDLE 0 /* No grace period in progress. */ #define RCU_GP_INIT 1 /* Grace period being initialized. */ #define RCU_SAVE_DYNTICK 2 /* Need to scan dyntick state. */ -#define RCU_FORCE_QS 3 /* Need to force quiescent state. */ +#define RCU_SAVE_COMPLETED 3 /* Need to save rsp->completed. */ +#define RCU_FORCE_QS 4 /* Need to force quiescent state. */ #ifdef CONFIG_NO_HZ #define RCU_SIGNAL_INIT RCU_SAVE_DYNTICK #else /* #ifdef CONFIG_NO_HZ */ -#define RCU_SIGNAL_INIT RCU_FORCE_QS +#define RCU_SIGNAL_INIT RCU_SAVE_COMPLETED #endif /* #else #ifdef CONFIG_NO_HZ */ #define RCU_JIFFIES_TILL_FORCE_QS 3 /* for rsp->jiffies_force_qs */ @@ -274,9 +275,8 @@ struct rcu_state { unsigned long jiffies_stall; /* Time at which to check */ /* for CPU stalls. */ #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ -#ifdef CONFIG_NO_HZ long dynticks_completed; /* Value of completed @ snap. */ -#endif /* #ifdef CONFIG_NO_HZ */ + /* Protected by fqslock. */ }; #ifdef RCU_TREE_NONCORE -- cgit v1.2.3 From d09b62dfa336447c52a5ec9bb88adbc479b0f3b8 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 2 Nov 2009 13:52:28 -0800 Subject: rcu: Fix synchronization for rcu_process_gp_end() uses of ->completed counter Impose a clear locking design on the rcu_process_gp_end() function's use of the ->completed counter. This is done by creating a ->completed field in the rcu_node structure, which can safely be accessed under the protection of that structure's lock. Performance and scalability are maintained by using a form of double-checked locking, so that rcu_process_gp_end() only acquires the leaf rcu_node structure's ->lock if a grace period has recently ended. This fix reduces rcutorture failure rate by at least two orders of magnitude under heavy stress with force_quiescent_state() being invoked artificially often. Without this fix, unsynchronized access to the ->completed field can cause rcu_process_gp_end() to advance callbacks whose grace period has not yet expired. (Bad idea!) Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com Cc: # .32.x LKML-Reference: <12571987494069-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 128 ++++++++++++++++++++++++++++++++++--------------------- kernel/rcutree.h | 3 ++ 2 files changed, 83 insertions(+), 48 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 26249abf24dc..9e068d112153 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -569,6 +569,76 @@ check_for_new_grace_period(struct rcu_state *rsp, struct rcu_data *rdp) return ret; } +/* + * Advance this CPU's callbacks, but only if the current grace period + * has ended. This may be called only from the CPU to whom the rdp + * belongs. In addition, the corresponding leaf rcu_node structure's + * ->lock must be held by the caller, with irqs disabled. + */ +static void +__rcu_process_gp_end(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) +{ + /* Did another grace period end? */ + if (rdp->completed != rnp->completed) { + + /* Advance callbacks. No harm if list empty. */ + rdp->nxttail[RCU_DONE_TAIL] = rdp->nxttail[RCU_WAIT_TAIL]; + rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_READY_TAIL]; + rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; + + /* Remember that we saw this grace-period completion. */ + rdp->completed = rnp->completed; + } +} + +/* + * Advance this CPU's callbacks, but only if the current grace period + * has ended. This may be called only from the CPU to whom the rdp + * belongs. + */ +static void +rcu_process_gp_end(struct rcu_state *rsp, struct rcu_data *rdp) +{ + unsigned long flags; + struct rcu_node *rnp; + + local_irq_save(flags); + rnp = rdp->mynode; + if (rdp->completed == ACCESS_ONCE(rnp->completed) || /* outside lock. */ + !spin_trylock(&rnp->lock)) { /* irqs already off, retry later. */ + local_irq_restore(flags); + return; + } + __rcu_process_gp_end(rsp, rnp, rdp); + spin_unlock_irqrestore(&rnp->lock, flags); +} + +/* + * Do per-CPU grace-period initialization for running CPU. The caller + * must hold the lock of the leaf rcu_node structure corresponding to + * this CPU. + */ +static void +rcu_start_gp_per_cpu(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) +{ + /* Prior grace period ended, so advance callbacks for current CPU. */ + __rcu_process_gp_end(rsp, rnp, rdp); + + /* + * Because this CPU just now started the new grace period, we know + * that all of its callbacks will be covered by this upcoming grace + * period, even the ones that were registered arbitrarily recently. + * Therefore, advance all outstanding callbacks to RCU_WAIT_TAIL. + * + * Other CPUs cannot be sure exactly when the grace period started. + * Therefore, their recently registered callbacks must pass through + * an additional RCU_NEXT_READY stage, so that they will be handled + * by the next RCU grace period. + */ + rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; + rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; +} + /* * Start a new RCU grace period if warranted, re-initializing the hierarchy * in preparation for detecting the next grace period. The caller must hold @@ -596,26 +666,14 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) dyntick_record_completed(rsp, rsp->completed - 1); note_new_gpnum(rsp, rdp); - /* - * Because this CPU just now started the new grace period, we know - * that all of its callbacks will be covered by this upcoming grace - * period, even the ones that were registered arbitrarily recently. - * Therefore, advance all outstanding callbacks to RCU_WAIT_TAIL. - * - * Other CPUs cannot be sure exactly when the grace period started. - * Therefore, their recently registered callbacks must pass through - * an additional RCU_NEXT_READY stage, so that they will be handled - * by the next RCU grace period. - */ - rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; - rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; - /* Special-case the common single-level case. */ if (NUM_RCU_NODES == 1) { rcu_preempt_check_blocked_tasks(rnp); rnp->qsmask = rnp->qsmaskinit; rnp->gpnum = rsp->gpnum; + rnp->completed = rsp->completed; rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state OK. */ + rcu_start_gp_per_cpu(rsp, rnp, rdp); spin_unlock_irqrestore(&rnp->lock, flags); return; } @@ -648,6 +706,9 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) rcu_preempt_check_blocked_tasks(rnp); rnp->qsmask = rnp->qsmaskinit; rnp->gpnum = rsp->gpnum; + rnp->completed = rsp->completed; + if (rnp == rdp->mynode) + rcu_start_gp_per_cpu(rsp, rnp, rdp); spin_unlock(&rnp->lock); /* irqs remain disabled. */ } @@ -658,34 +719,6 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) spin_unlock_irqrestore(&rsp->onofflock, flags); } -/* - * Advance this CPU's callbacks, but only if the current grace period - * has ended. This may be called only from the CPU to whom the rdp - * belongs. - */ -static void -rcu_process_gp_end(struct rcu_state *rsp, struct rcu_data *rdp) -{ - long completed_snap; - unsigned long flags; - - local_irq_save(flags); - completed_snap = ACCESS_ONCE(rsp->completed); /* outside of lock. */ - - /* Did another grace period end? */ - if (rdp->completed != completed_snap) { - - /* Advance callbacks. No harm if list empty. */ - rdp->nxttail[RCU_DONE_TAIL] = rdp->nxttail[RCU_WAIT_TAIL]; - rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_READY_TAIL]; - rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; - - /* Remember that we saw this grace-period completion. */ - rdp->completed = completed_snap; - } - local_irq_restore(flags); -} - /* * Clean up after the prior grace period and let rcu_start_gp() start up * the next grace period if one is needed. Note that the caller must @@ -697,7 +730,6 @@ static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags) WARN_ON_ONCE(!rcu_gp_in_progress(rsp)); rsp->completed = rsp->gpnum; rsp->signaled = RCU_GP_IDLE; - rcu_process_gp_end(rsp, rsp->rda[smp_processor_id()]); rcu_start_gp(rsp, flags); /* releases root node's rnp->lock. */ } @@ -1539,21 +1571,16 @@ static void __cpuinit rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable) { unsigned long flags; - long lastcomp; unsigned long mask; struct rcu_data *rdp = rsp->rda[cpu]; struct rcu_node *rnp = rcu_get_root(rsp); /* Set up local state, ensuring consistent view of global state. */ spin_lock_irqsave(&rnp->lock, flags); - lastcomp = rsp->completed; - rdp->completed = lastcomp; - rdp->gpnum = lastcomp; rdp->passed_quiesc = 0; /* We could be racing with new GP, */ rdp->qs_pending = 1; /* so set up to respond to current GP. */ rdp->beenonline = 1; /* We have now been online. */ rdp->preemptable = preemptable; - rdp->passed_quiesc_completed = lastcomp - 1; rdp->qlen_last_fqs_check = 0; rdp->n_force_qs_snap = rsp->n_force_qs; rdp->blimit = blimit; @@ -1575,6 +1602,11 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable) spin_lock(&rnp->lock); /* irqs already disabled. */ rnp->qsmaskinit |= mask; mask = rnp->grpmask; + if (rnp == rdp->mynode) { + rdp->gpnum = rnp->completed; /* if GP in progress... */ + rdp->completed = rnp->completed; + rdp->passed_quiesc_completed = rnp->completed - 1; + } spin_unlock(&rnp->lock); /* irqs already disabled. */ rnp = rnp->parent; } while (rnp != NULL && !(rnp->qsmaskinit & mask)); diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 8a4c1650ad8d..c1891c3cae63 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -84,6 +84,9 @@ struct rcu_node { long gpnum; /* Current grace period for this node. */ /* This will either be equal to or one */ /* behind the root rcu_node's gpnum. */ + long completed; /* Last grace period completed for this node. */ + /* This will either be equal to or one */ + /* behind the root rcu_node's gpnum. */ unsigned long qsmask; /* CPUs or groups that need to switch in */ /* order for current grace period to proceed.*/ /* In leaf rcu_node, each bit corresponds to */ -- cgit v1.2.3 From 9160306e6f5b68bb64630c9031c517ca1cf463db Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 2 Nov 2009 13:52:29 -0800 Subject: rcu: Fix note_new_gpnum() uses of ->gpnum Impose a clear locking design on the note_new_gpnum() function's use of the ->gpnum counter. This is done by updating rdp->gpnum only from the corresponding leaf rcu_node structure's rnp->gpnum field, and even then only under the protection of that same rcu_node structure's ->lock field. Performance and scalability are maintained using a form of double-checked locking, and excessive spinning is avoided by use of the spin_trylock() function. The use of spin_trylock() is safe due to the fact that CPUs who fail to acquire this lock will try again later. The hierarchical nature of the rcu_node data structure limits contention (which could be limited further if need be using the RCU_FANOUT kernel parameter). Without this patch, obscure but quite possible races could result in a quiescent state that occurred during one grace period to be accounted to the following grace period, causing this following grace period to end prematurely. Not good! Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com Cc: # .32.x LKML-Reference: <12571987492350-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 9e068d112153..ec007dd22632 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -540,13 +540,33 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) /* * Update CPU-local rcu_data state to record the newly noticed grace period. * This is used both when we started the grace period and when we notice - * that someone else started the grace period. + * that someone else started the grace period. The caller must hold the + * ->lock of the leaf rcu_node structure corresponding to the current CPU, + * and must have irqs disabled. */ +static void __note_new_gpnum(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_data *rdp) +{ + if (rdp->gpnum != rnp->gpnum) { + rdp->qs_pending = 1; + rdp->passed_quiesc = 0; + rdp->gpnum = rnp->gpnum; + } +} + static void note_new_gpnum(struct rcu_state *rsp, struct rcu_data *rdp) { - rdp->qs_pending = 1; - rdp->passed_quiesc = 0; - rdp->gpnum = rsp->gpnum; + unsigned long flags; + struct rcu_node *rnp; + + local_irq_save(flags); + rnp = rdp->mynode; + if (rdp->gpnum == ACCESS_ONCE(rnp->gpnum) || /* outside lock. */ + !spin_trylock(&rnp->lock)) { /* irqs already off, retry later. */ + local_irq_restore(flags); + return; + } + __note_new_gpnum(rsp, rnp, rdp); + spin_unlock_irqrestore(&rnp->lock, flags); } /* @@ -637,6 +657,9 @@ rcu_start_gp_per_cpu(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_dat */ rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; + + /* Set state so that this CPU will detect the next quiescent state. */ + __note_new_gpnum(rsp, rnp, rdp); } /* @@ -664,7 +687,6 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; record_gp_stall_check_time(rsp); dyntick_record_completed(rsp, rsp->completed - 1); - note_new_gpnum(rsp, rdp); /* Special-case the common single-level case. */ if (NUM_RCU_NODES == 1) { -- cgit v1.2.3 From dbe01350fa8ce0c11948ab7d6be71a4d901be151 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 10 Nov 2009 13:37:19 -0800 Subject: rcu: Remove inline from forward-referenced functions Some variants of gcc are reputed to dislike forward references to functions declared "inline". Remove the "inline" keyword from such functions. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12578890422402-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.h | 2 +- kernel/rcutree_plugin.h | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.h b/kernel/rcutree.h index c1891c3cae63..ddb79ece05eb 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -301,7 +301,7 @@ DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data); #else /* #ifdef RCU_TREE_NONCORE */ /* Forward declarations for rcutree_plugin.h */ -static inline void rcu_bootup_announce(void); +static void rcu_bootup_announce(void); long rcu_batches_completed(void); static void rcu_preempt_note_context_switch(int cpu); static int rcu_preempted_readers(struct rcu_node *rnp); diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index ef2a58c2b9d5..c03edf766357 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -33,7 +33,7 @@ DEFINE_PER_CPU(struct rcu_data, rcu_preempt_data); /* * Tell them what RCU they are running. */ -static inline void rcu_bootup_announce(void) +static void rcu_bootup_announce(void) { printk(KERN_INFO "Experimental preemptable hierarchical RCU implementation.\n"); @@ -481,7 +481,7 @@ void exit_rcu(void) /* * Tell them what RCU they are running. */ -static inline void rcu_bootup_announce(void) +static void rcu_bootup_announce(void) { printk(KERN_INFO "Hierarchical RCU implementation.\n"); } -- cgit v1.2.3 From 956539b75921f561c0956c22d37320780e8b4ba1 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 10 Nov 2009 13:37:20 -0800 Subject: rcu: Enable synchronize_sched_expedited() fastpath This patch adds a counter increment to enable tasks to actually take the synchronize_sched_expedited() function's fastpath. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1257889042435-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/sched.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 76c0e9691fc0..e69fee4544bd 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -10865,6 +10865,7 @@ void synchronize_sched_expedited(void) spin_unlock_irqrestore(&rq->lock, flags); } rcu_expedited_state = RCU_EXPEDITED_STATE_IDLE; + synchronize_sched_expedited_count++; mutex_unlock(&rcu_sched_expedited_mutex); put_online_cpus(); if (need_full_sync) -- cgit v1.2.3 From 4bcfe055030d9e953945def3864f7e6997b27782 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 10 Nov 2009 13:37:21 -0800 Subject: rcu: Rename dynticks_completed to completed_fqs This field is used whether or not CONFIG_NO_HZ is set, so the old name of ->dynticks_completed is quite misleading. Change to ->completed_fqs, given that it the value that force_quiescent_state() is trying to drive the ->completed field away from. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12578890423298-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 4 ++-- kernel/rcutree.h | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index ec007dd22632..26fc7807761d 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -187,7 +187,7 @@ static struct rcu_node *rcu_get_root(struct rcu_state *rsp) */ static void dyntick_record_completed(struct rcu_state *rsp, long comp) { - rsp->dynticks_completed = comp; + rsp->completed_fqs = comp; } #ifdef CONFIG_SMP @@ -197,7 +197,7 @@ static void dyntick_record_completed(struct rcu_state *rsp, long comp) */ static long dyntick_recall_completed(struct rcu_state *rsp) { - return rsp->dynticks_completed; + return rsp->completed_fqs; } /* diff --git a/kernel/rcutree.h b/kernel/rcutree.h index ddb79ece05eb..17a28a08b559 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -264,6 +264,8 @@ struct rcu_state { long orphan_qlen; /* Number of orphaned cbs. */ spinlock_t fqslock; /* Only one task forcing */ /* quiescent states. */ + long completed_fqs; /* Value of completed @ snap. */ + /* Protected by fqslock. */ unsigned long jiffies_force_qs; /* Time at which to invoke */ /* force_quiescent_state(). */ unsigned long n_force_qs; /* Number of calls to */ @@ -278,8 +280,6 @@ struct rcu_state { unsigned long jiffies_stall; /* Time at which to check */ /* for CPU stalls. */ #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ - long dynticks_completed; /* Value of completed @ snap. */ - /* Protected by fqslock. */ }; #ifdef RCU_TREE_NONCORE -- cgit v1.2.3 From c64ac3ce06558e534aec62b1fadeb0a3f111dac1 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 10 Nov 2009 13:37:22 -0800 Subject: rcu: Simplify association of quiescent states with grace periods The rdp->passed_quiesc_completed fields are used to properly associate the recorded quiescent state with a grace period. It is OK to wrongly associate a given quiescent state with a preceding grace period, but it is fatal to associate a given quiescent state with a grace period that begins after the quiescent state occurred. Grace periods are numbered, and the following fields track them: o ->gpnum is the number of the grace period currently in progress, or the number of the last grace period to complete if no grace period is currently in progress. o ->completed is the number of the last grace period to have completed. These two fields are equal if there is no grace period in progress, otherwise ->gpnum is one greater than ->completed. But the rdp->passed_quiesc_completed field compared against ->completed, and if equal, the quiescent state is presumed to count against the current grace period. The earlier code copied rdp->completed to rdp->passed_quiesc_completed, which has been made to work, but is error-prone. In contrast, copying one less than rdp->gpnum is guaranteed safe, because rdp->gpnum is not incremented until after the start of the corresponding grace period. At the end of the grace period, when ->completed has incremented, then any quiescent periods recorded previously will be discarded. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12578890421011-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 4 ++-- kernel/rcutree_plugin.h | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 26fc7807761d..d8024192c73b 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -100,7 +100,7 @@ void rcu_sched_qs(int cpu) struct rcu_data *rdp; rdp = &per_cpu(rcu_sched_data, cpu); - rdp->passed_quiesc_completed = rdp->completed; + rdp->passed_quiesc_completed = rdp->gpnum - 1; barrier(); rdp->passed_quiesc = 1; rcu_preempt_note_context_switch(cpu); @@ -111,7 +111,7 @@ void rcu_bh_qs(int cpu) struct rcu_data *rdp; rdp = &per_cpu(rcu_bh_data, cpu); - rdp->passed_quiesc_completed = rdp->completed; + rdp->passed_quiesc_completed = rdp->gpnum - 1; barrier(); rdp->passed_quiesc = 1; } diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index c03edf766357..52075da70549 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -67,7 +67,7 @@ EXPORT_SYMBOL_GPL(rcu_batches_completed); static void rcu_preempt_qs(int cpu) { struct rcu_data *rdp = &per_cpu(rcu_preempt_data, cpu); - rdp->passed_quiesc_completed = rdp->completed; + rdp->passed_quiesc_completed = rdp->gpnum - 1; barrier(); rdp->passed_quiesc = 1; } -- cgit v1.2.3 From 0e0fc1c23e04c15e814763f2b366e92d87d8b95d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 11 Nov 2009 11:28:06 -0800 Subject: rcu: Mark init-time-only rcu_bootup_announce() as __init Because rcu_bootup_announce() is used only at boot time, mark it as __init, presumably so that its memory can be reclaimed. Suggested-by: Joe Perches Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <20091111192806.GA10073@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/rcutree_plugin.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 52075da70549..5ca2d26c5971 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -33,7 +33,7 @@ DEFINE_PER_CPU(struct rcu_data, rcu_preempt_data); /* * Tell them what RCU they are running. */ -static void rcu_bootup_announce(void) +static void __init rcu_bootup_announce(void) { printk(KERN_INFO "Experimental preemptable hierarchical RCU implementation.\n"); @@ -481,7 +481,7 @@ void exit_rcu(void) /* * Tell them what RCU they are running. */ -static void rcu_bootup_announce(void) +static void __init rcu_bootup_announce(void) { printk(KERN_INFO "Hierarchical RCU implementation.\n"); } -- cgit v1.2.3 From a646365cc330b5aaf4452c91f61b1e0d1acf68d0 Mon Sep 17 00:00:00 2001 From: Roel Kluin Date: Wed, 11 Nov 2009 22:26:35 +0100 Subject: tracing: Fix return value of tracing_stats_read() The function tracing_stats_read() mistakenly returns ENOMEM instead of the negative value -ENOMEM. Signed-off-by: Roel Kluin LKML-Reference: <4AFB2C0B.50605@gmail.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b20d3ec75de9..03c7fd55c5f9 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3730,7 +3730,7 @@ tracing_stats_read(struct file *filp, char __user *ubuf, s = kmalloc(sizeof(*s), GFP_KERNEL); if (!s) - return ENOMEM; + return -ENOMEM; trace_seq_init(s); -- cgit v1.2.3 From a6f0eb6adc42e5eed3f35af99c61c0e411b16f8e Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 11 Nov 2009 17:14:07 -0500 Subject: ring-buffer: Add multiple iterations between benchmark timestamps The ring_buffer_benchmark does a gettimeofday after every write to the ring buffer in its measurements. This adds the overhead of the call to gettimeofday to the measurements and does not give an accurate picture of the length of time it takes to record a trace. This was first noticed with perf top: ------------------------------------------------------------------------------ PerfTop: 679 irqs/sec kernel:99.9% [1000Hz cpu-clock-msecs], (all, 4 CPUs) ------------------------------------------------------------------------------ samples pcnt kernel function _______ _____ _______________ 1673.00 - 27.8% : trace_clock_local 806.00 - 13.4% : do_gettimeofday 590.00 - 9.8% : rb_reserve_next_event 554.00 - 9.2% : native_read_tsc 431.00 - 7.2% : ring_buffer_lock_reserve 365.00 - 6.1% : __rb_reserve_next 355.00 - 5.9% : rb_end_commit 322.00 - 5.4% : getnstimeofday 268.00 - 4.5% : ring_buffer_unlock_commit 262.00 - 4.4% : ring_buffer_producer_thread [ring_buffer_benchmark] 113.00 - 1.9% : read_tsc 91.00 - 1.5% : debug_smp_processor_id 69.00 - 1.1% : trace_recursive_unlock 66.00 - 1.1% : ring_buffer_event_data 25.00 - 0.4% : _spin_unlock_irq And the length of each write to the ring buffer measured at 310ns. This patch adds a new module parameter called "write_interval" which is defaulted to 50. This is the number of writes performed between timestamps. After this patch perf top shows: ------------------------------------------------------------------------------ PerfTop: 244 irqs/sec kernel:100.0% [1000Hz cpu-clock-msecs], (all, 4 CPUs) ------------------------------------------------------------------------------ samples pcnt kernel function _______ _____ _______________ 2842.00 - 40.4% : trace_clock_local 1043.00 - 14.8% : rb_reserve_next_event 784.00 - 11.1% : ring_buffer_lock_reserve 600.00 - 8.5% : __rb_reserve_next 579.00 - 8.2% : rb_end_commit 440.00 - 6.3% : ring_buffer_unlock_commit 290.00 - 4.1% : ring_buffer_producer_thread [ring_buffer_benchmark] 155.00 - 2.2% : debug_smp_processor_id 117.00 - 1.7% : trace_recursive_unlock 103.00 - 1.5% : ring_buffer_event_data 28.00 - 0.4% : do_gettimeofday 22.00 - 0.3% : _spin_unlock_irq 14.00 - 0.2% : native_read_tsc 11.00 - 0.2% : getnstimeofday do_gettimeofday dropped from 13% usage to a mere 0.4%! (using the default 50 interval) The measurement for each timestamp went from 310ns to 210ns. That's 100ns (1/3rd) overhead that the gettimeofday call was introducing. Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer_benchmark.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c index 573d3cc762c3..70df73e4ff21 100644 --- a/kernel/trace/ring_buffer_benchmark.c +++ b/kernel/trace/ring_buffer_benchmark.c @@ -35,6 +35,10 @@ static int disable_reader; module_param(disable_reader, uint, 0644); MODULE_PARM_DESC(disable_reader, "only run producer"); +static int write_iteration = 50; +module_param(write_iteration, uint, 0644); +MODULE_PARM_DESC(write_iteration, "# of writes between timestamp readings"); + static int read_events; static int kill_test; @@ -208,15 +212,18 @@ static void ring_buffer_producer(void) do { struct ring_buffer_event *event; int *entry; - - event = ring_buffer_lock_reserve(buffer, 10); - if (!event) { - missed++; - } else { - hit++; - entry = ring_buffer_event_data(event); - *entry = smp_processor_id(); - ring_buffer_unlock_commit(buffer, event); + int i; + + for (i = 0; i < write_iteration; i++) { + event = ring_buffer_lock_reserve(buffer, 10); + if (!event) { + missed++; + } else { + hit++; + entry = ring_buffer_event_data(event); + *entry = smp_processor_id(); + ring_buffer_unlock_commit(buffer, event); + } } do_gettimeofday(&end_tv); -- cgit v1.2.3 From 8b2a5dac7859dd1954095fce8b6445c3ceb36ef6 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 11 Nov 2009 19:36:03 -0500 Subject: tracing: do not disable interrupts for trace_clock_local Disabling interrupts in trace_clock_local takes quite a performance hit to the recording of traces. Using perf top we see: ------------------------------------------------------------------------------ PerfTop: 244 irqs/sec kernel:100.0% [1000Hz cpu-clock-msecs], (all, 4 CPUs) ------------------------------------------------------------------------------ samples pcnt kernel function _______ _____ _______________ 2842.00 - 40.4% : trace_clock_local 1043.00 - 14.8% : rb_reserve_next_event 784.00 - 11.1% : ring_buffer_lock_reserve 600.00 - 8.5% : __rb_reserve_next 579.00 - 8.2% : rb_end_commit 440.00 - 6.3% : ring_buffer_unlock_commit 290.00 - 4.1% : ring_buffer_producer_thread [ring_buffer_benchmark] 155.00 - 2.2% : debug_smp_processor_id 117.00 - 1.7% : trace_recursive_unlock 103.00 - 1.5% : ring_buffer_event_data 28.00 - 0.4% : do_gettimeofday 22.00 - 0.3% : _spin_unlock_irq 14.00 - 0.2% : native_read_tsc 11.00 - 0.2% : getnstimeofday Where trace_clock_local is 40% of the tracing, and the time for recording a trace according to ring_buffer_benchmark is 210ns. After converting the interrupts to preemption disabling we have from perf top: ------------------------------------------------------------------------------ PerfTop: 1084 irqs/sec kernel:99.9% [1000Hz cpu-clock-msecs], (all, 4 CPUs) ------------------------------------------------------------------------------ samples pcnt kernel function _______ _____ _______________ 1277.00 - 16.8% : native_read_tsc 1148.00 - 15.1% : rb_reserve_next_event 896.00 - 11.8% : ring_buffer_lock_reserve 688.00 - 9.1% : __rb_reserve_next 664.00 - 8.8% : rb_end_commit 563.00 - 7.4% : ring_buffer_unlock_commit 508.00 - 6.7% : _spin_unlock_irq 365.00 - 4.8% : debug_smp_processor_id 321.00 - 4.2% : trace_clock_local 303.00 - 4.0% : ring_buffer_producer_thread [ring_buffer_benchmark] 273.00 - 3.6% : native_sched_clock 122.00 - 1.6% : trace_recursive_unlock 113.00 - 1.5% : sched_clock 101.00 - 1.3% : ring_buffer_event_data 53.00 - 0.7% : tick_nohz_stop_sched_tick Where trace_clock_local drops from 40% to only taking 4% of the total time. The trace time also goes from 210ns down to 179ns (31ns). I talked with Peter Zijlstra about the impact that sched_clock may have without having interrupts disabled, and he told me that if a timer interrupt comes in, sched_clock may report a wrong time. Balancing a seldom incorrect timestamp with a 15% performance boost, I'll take the performance boost. Acked-by: Peter Zijlstra Signed-off-by: Steven Rostedt --- kernel/trace/trace_clock.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_clock.c b/kernel/trace/trace_clock.c index 20c5f92e28a8..878c03f386ba 100644 --- a/kernel/trace/trace_clock.c +++ b/kernel/trace/trace_clock.c @@ -20,6 +20,8 @@ #include #include +#include "trace.h" + /* * trace_clock_local(): the simplest and least coherent tracing clock. * @@ -28,17 +30,17 @@ */ u64 notrace trace_clock_local(void) { - unsigned long flags; u64 clock; + int resched; /* * sched_clock() is an architecture implemented, fast, scalable, * lockless clock. It is not guaranteed to be coherent across * CPUs, nor across CPU idle events. */ - raw_local_irq_save(flags); + resched = ftrace_preempt_disable(); clock = sched_clock(); - raw_local_irq_restore(flags); + ftrace_preempt_enable(resched); return clock; } -- cgit v1.2.3 From b32e9eb6ad29572b4451847d0e8227c9be2b6d69 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 12 Nov 2009 22:35:03 -0800 Subject: rcu: Accelerate callback processing on CPUs not detecting GP end An earlier fix for a race resulted in a situation where the CPUs other than the CPU that detected the end of the grace period would not process their callbacks until the next grace period started. This means that these other CPUs would unnecessarily demand that an extra grace period be started. This patch eliminates this extra grace period and speeds callback processing by propagating rsp->completed to the rcu_node structures in the case where the CPU detecting the end of the grace period sees no reason to start a new grace period. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1258094104417-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index d8024192c73b..b4efb9e36680 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -676,7 +676,23 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) struct rcu_node *rnp = rcu_get_root(rsp); if (!cpu_needs_another_gp(rsp, rdp)) { - spin_unlock_irqrestore(&rnp->lock, flags); + if (rnp->completed == rsp->completed) { + spin_unlock_irqrestore(&rnp->lock, flags); + return; + } + spin_unlock(&rnp->lock); /* irqs remain disabled. */ + + /* + * Propagate new ->completed value to rcu_node structures + * so that other CPUs don't have to wait until the start + * of the next grace period to process their callbacks. + */ + rcu_for_each_node_breadth_first(rsp, rnp) { + spin_lock(&rnp->lock); /* irqs already disabled. */ + rnp->completed = rsp->completed; + spin_unlock(&rnp->lock); /* irqs remain disabled. */ + } + local_irq_restore(flags); return; } -- cgit v1.2.3 From 8e9aa8f067d2dcd9457980ced618e1cffbcfba46 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 12 Nov 2009 22:35:04 -0800 Subject: rcu: Simplify association of forced quiescent states with grace periods The force_quiescent_state() function also took a snapshot of the ->completed field, which was as obnoxious as it was in rcu_sched_qs() and friends. So snapshot ->gpnum-1. Also, since the dyntick_record_completed() and dyntick_recall_completed() functions are now simple assignments that are independent of CONFIG_NO_HZ, and since their names are now misleading, get rid of them. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12580941042308-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 27 +++------------------------ 1 file changed, 3 insertions(+), 24 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index b4efb9e36680..3df04381ea3e 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -178,28 +178,8 @@ static struct rcu_node *rcu_get_root(struct rcu_state *rsp) return &rsp->node[0]; } -/* - * Record the specified "completed" value, which is later used to validate - * dynticks counter manipulations and CPU-offline checks. Specify - * "rsp->completed - 1" to unconditionally invalidate any future dynticks - * manipulations and CPU-offline checks. Such invalidation is useful at - * the beginning of a grace period. - */ -static void dyntick_record_completed(struct rcu_state *rsp, long comp) -{ - rsp->completed_fqs = comp; -} - #ifdef CONFIG_SMP -/* - * Recall the previously recorded value of the completion for dynticks. - */ -static long dyntick_recall_completed(struct rcu_state *rsp) -{ - return rsp->completed_fqs; -} - /* * If the specified CPU is offline, tell the caller that it is in * a quiescent state. Otherwise, whack it with a reschedule IPI. @@ -702,7 +682,6 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) rsp->signaled = RCU_GP_INIT; /* Hold off force_quiescent_state. */ rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; record_gp_stall_check_time(rsp); - dyntick_record_completed(rsp, rsp->completed - 1); /* Special-case the common single-level case. */ if (NUM_RCU_NODES == 1) { @@ -1214,7 +1193,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) goto unlock_ret; /* no emergency and done recently. */ rsp->n_force_qs++; spin_lock(&rnp->lock); - lastcomp = rsp->completed; + lastcomp = rsp->gpnum - 1; signaled = rsp->signaled; rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; if (lastcomp == rsp->gpnum) { @@ -1248,7 +1227,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) if (lastcomp == rsp->completed && rsp->signaled == signaled) { rsp->signaled = RCU_FORCE_QS; - dyntick_record_completed(rsp, lastcomp); + rsp->completed_fqs = lastcomp; forcenow = signaled == RCU_SAVE_COMPLETED; } spin_unlock(&rnp->lock); @@ -1259,7 +1238,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) case RCU_FORCE_QS: /* Check dyntick-idle state, send IPI to laggarts. */ - if (rcu_process_dyntick(rsp, dyntick_recall_completed(rsp), + if (rcu_process_dyntick(rsp, rsp->completed_fqs, rcu_implicit_dynticks_qs)) goto unlock_ret; -- cgit v1.2.3 From 6beb000923882f6204ea2cfcd932e568e900803f Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 9 Nov 2009 15:21:34 +0000 Subject: locking: Make inlining decision Kconfig based commit 892a7c67 (locking: Allow arch-inlined spinlocks) implements the selection of which lock functions are inlined based on defines in arch/.../spinlock.h: #define __always_inline__LOCK_FUNCTION Despite of the name __always_inline__* the lock functions can be built out of line depending on config options. Also if the arch does not set some inline defines the generic code might set them; again depending on config options. This makes it unnecessary hard to figure out when and which lock functions are inlined. Aside of that it makes it way harder and messier for -rt to manipulate the lock functions. Convert the inlining decision to CONFIG switches. Each lock function is inlined depending on CONFIG_INLINE_*. The configs implement the existing dependencies. The architecture code can select ARCH_INLINE_* to signal that it wants the corresponding lock function inlined. ARCH_INLINE_* is necessary as Kconfig ignores "depends on" restrictions when a config element is selected. No functional change. Signed-off-by: Thomas Gleixner LKML-Reference: <20091109151428.504477141@linutronix.de> Acked-by: Heiko Carstens Reviewed-by: Ingo Molnar Acked-by: Peter Zijlstra --- arch/s390/Kconfig | 28 ++++++ arch/s390/include/asm/spinlock.h | 29 ------ include/linux/spinlock_api_smp.h | 75 ++++++--------- init/Kconfig | 1 + kernel/Kconfig.locks | 199 +++++++++++++++++++++++++++++++++++++++ kernel/spinlock.c | 56 +++++------ 6 files changed, 284 insertions(+), 104 deletions(-) create mode 100644 kernel/Kconfig.locks (limited to 'kernel') diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 43c0acad7160..16c673096a22 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -95,6 +95,34 @@ config S390 select HAVE_ARCH_TRACEHOOK select INIT_ALL_POSSIBLE select HAVE_PERF_EVENTS + select ARCH_INLINE_SPIN_TRYLOCK + select ARCH_INLINE_SPIN_TRYLOCK_BH + select ARCH_INLINE_SPIN_LOCK + select ARCH_INLINE_SPIN_LOCK_BH + select ARCH_INLINE_SPIN_LOCK_IRQ + select ARCH_INLINE_SPIN_LOCK_IRQSAVE + select ARCH_INLINE_SPIN_UNLOCK + select ARCH_INLINE_SPIN_UNLOCK_BH + select ARCH_INLINE_SPIN_UNLOCK_IRQ + select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE + select ARCH_INLINE_READ_TRYLOCK + select ARCH_INLINE_READ_LOCK + select ARCH_INLINE_READ_LOCK_BH + select ARCH_INLINE_READ_LOCK_IRQ + select ARCH_INLINE_READ_LOCK_IRQSAVE + select ARCH_INLINE_READ_UNLOCK + select ARCH_INLINE_READ_UNLOCK_BH + select ARCH_INLINE_READ_UNLOCK_IRQ + select ARCH_INLINE_READ_UNLOCK_IRQRESTORE + select ARCH_INLINE_WRITE_TRYLOCK + select ARCH_INLINE_WRITE_LOCK + select ARCH_INLINE_WRITE_LOCK_BH + select ARCH_INLINE_WRITE_LOCK_IRQ + select ARCH_INLINE_WRITE_LOCK_IRQSAVE + select ARCH_INLINE_WRITE_UNLOCK + select ARCH_INLINE_WRITE_UNLOCK_BH + select ARCH_INLINE_WRITE_UNLOCK_IRQ + select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE config SCHED_OMIT_FRAME_POINTER bool diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h index 41ce6861174e..c9af0d19c7ab 100644 --- a/arch/s390/include/asm/spinlock.h +++ b/arch/s390/include/asm/spinlock.h @@ -191,33 +191,4 @@ static inline int __raw_write_trylock(raw_rwlock_t *rw) #define _raw_read_relax(lock) cpu_relax() #define _raw_write_relax(lock) cpu_relax() -#define __always_inline__spin_lock -#define __always_inline__read_lock -#define __always_inline__write_lock -#define __always_inline__spin_lock_bh -#define __always_inline__read_lock_bh -#define __always_inline__write_lock_bh -#define __always_inline__spin_lock_irq -#define __always_inline__read_lock_irq -#define __always_inline__write_lock_irq -#define __always_inline__spin_lock_irqsave -#define __always_inline__read_lock_irqsave -#define __always_inline__write_lock_irqsave -#define __always_inline__spin_trylock -#define __always_inline__read_trylock -#define __always_inline__write_trylock -#define __always_inline__spin_trylock_bh -#define __always_inline__spin_unlock -#define __always_inline__read_unlock -#define __always_inline__write_unlock -#define __always_inline__spin_unlock_bh -#define __always_inline__read_unlock_bh -#define __always_inline__write_unlock_bh -#define __always_inline__spin_unlock_irq -#define __always_inline__read_unlock_irq -#define __always_inline__write_unlock_irq -#define __always_inline__spin_unlock_irqrestore -#define __always_inline__read_unlock_irqrestore -#define __always_inline__write_unlock_irqrestore - #endif /* __ASM_SPINLOCK_H */ diff --git a/include/linux/spinlock_api_smp.h b/include/linux/spinlock_api_smp.h index 7a7e18fc2415..8264a7f459bc 100644 --- a/include/linux/spinlock_api_smp.h +++ b/include/linux/spinlock_api_smp.h @@ -60,137 +60,118 @@ void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags) void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags) __releases(lock); -/* - * We inline the unlock functions in the nondebug case: - */ -#if !defined(CONFIG_DEBUG_SPINLOCK) && !defined(CONFIG_PREEMPT) -#define __always_inline__spin_unlock -#define __always_inline__read_unlock -#define __always_inline__write_unlock -#define __always_inline__spin_unlock_irq -#define __always_inline__read_unlock_irq -#define __always_inline__write_unlock_irq -#endif - -#ifndef CONFIG_DEBUG_SPINLOCK -#ifndef CONFIG_GENERIC_LOCKBREAK - -#ifdef __always_inline__spin_lock +#ifdef CONFIG_INLINE_SPIN_LOCK #define _spin_lock(lock) __spin_lock(lock) #endif -#ifdef __always_inline__read_lock +#ifdef CONFIG_INLINE_READ_LOCK #define _read_lock(lock) __read_lock(lock) #endif -#ifdef __always_inline__write_lock +#ifdef CONFIG_INLINE_WRITE_LOCK #define _write_lock(lock) __write_lock(lock) #endif -#ifdef __always_inline__spin_lock_bh +#ifdef CONFIG_INLINE_SPIN_LOCK_BH #define _spin_lock_bh(lock) __spin_lock_bh(lock) #endif -#ifdef __always_inline__read_lock_bh +#ifdef CONFIG_INLINE_READ_LOCK_BH #define _read_lock_bh(lock) __read_lock_bh(lock) #endif -#ifdef __always_inline__write_lock_bh +#ifdef CONFIG_INLINE_WRITE_LOCK_BH #define _write_lock_bh(lock) __write_lock_bh(lock) #endif -#ifdef __always_inline__spin_lock_irq +#ifdef CONFIG_INLINE_SPIN_LOCK_IRQ #define _spin_lock_irq(lock) __spin_lock_irq(lock) #endif -#ifdef __always_inline__read_lock_irq +#ifdef CONFIG_INLINE_READ_LOCK_IRQ #define _read_lock_irq(lock) __read_lock_irq(lock) #endif -#ifdef __always_inline__write_lock_irq +#ifdef CONFIG_INLINE_WRITE_LOCK_IRQ #define _write_lock_irq(lock) __write_lock_irq(lock) #endif -#ifdef __always_inline__spin_lock_irqsave +#ifdef CONFIG_INLINE_SPIN_LOCK_IRQSAVE #define _spin_lock_irqsave(lock) __spin_lock_irqsave(lock) #endif -#ifdef __always_inline__read_lock_irqsave +#ifdef CONFIG_INLINE_READ_LOCK_IRQSAVE #define _read_lock_irqsave(lock) __read_lock_irqsave(lock) #endif -#ifdef __always_inline__write_lock_irqsave +#ifdef CONFIG_INLINE_WRITE_LOCK_IRQSAVE #define _write_lock_irqsave(lock) __write_lock_irqsave(lock) #endif -#endif /* !CONFIG_GENERIC_LOCKBREAK */ - -#ifdef __always_inline__spin_trylock +#ifdef CONFIG_INLINE_SPIN_TRYLOCK #define _spin_trylock(lock) __spin_trylock(lock) #endif -#ifdef __always_inline__read_trylock +#ifdef CONFIG_INLINE_READ_TRYLOCK #define _read_trylock(lock) __read_trylock(lock) #endif -#ifdef __always_inline__write_trylock +#ifdef CONFIG_INLINE_WRITE_TRYLOCK #define _write_trylock(lock) __write_trylock(lock) #endif -#ifdef __always_inline__spin_trylock_bh +#ifdef CONFIG_INLINE_SPIN_TRYLOCK_BH #define _spin_trylock_bh(lock) __spin_trylock_bh(lock) #endif -#ifdef __always_inline__spin_unlock +#ifdef CONFIG_INLINE_SPIN_UNLOCK #define _spin_unlock(lock) __spin_unlock(lock) #endif -#ifdef __always_inline__read_unlock +#ifdef CONFIG_INLINE_READ_UNLOCK #define _read_unlock(lock) __read_unlock(lock) #endif -#ifdef __always_inline__write_unlock +#ifdef CONFIG_INLINE_WRITE_UNLOCK #define _write_unlock(lock) __write_unlock(lock) #endif -#ifdef __always_inline__spin_unlock_bh +#ifdef CONFIG_INLINE_SPIN_UNLOCK_BH #define _spin_unlock_bh(lock) __spin_unlock_bh(lock) #endif -#ifdef __always_inline__read_unlock_bh +#ifdef CONFIG_INLINE_READ_UNLOCK_BH #define _read_unlock_bh(lock) __read_unlock_bh(lock) #endif -#ifdef __always_inline__write_unlock_bh +#ifdef CONFIG_INLINE_WRITE_UNLOCK_BH #define _write_unlock_bh(lock) __write_unlock_bh(lock) #endif -#ifdef __always_inline__spin_unlock_irq +#ifdef CONFIG_INLINE_SPIN_UNLOCK_IRQ #define _spin_unlock_irq(lock) __spin_unlock_irq(lock) #endif -#ifdef __always_inline__read_unlock_irq +#ifdef CONFIG_INLINE_READ_UNLOCK_IRQ #define _read_unlock_irq(lock) __read_unlock_irq(lock) #endif -#ifdef __always_inline__write_unlock_irq +#ifdef CONFIG_INLINE_WRITE_UNLOCK_IRQ #define _write_unlock_irq(lock) __write_unlock_irq(lock) #endif -#ifdef __always_inline__spin_unlock_irqrestore +#ifdef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE #define _spin_unlock_irqrestore(lock, flags) __spin_unlock_irqrestore(lock, flags) #endif -#ifdef __always_inline__read_unlock_irqrestore +#ifdef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE #define _read_unlock_irqrestore(lock, flags) __read_unlock_irqrestore(lock, flags) #endif -#ifdef __always_inline__write_unlock_irqrestore +#ifdef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE #define _write_unlock_irqrestore(lock, flags) __write_unlock_irqrestore(lock, flags) #endif -#endif /* CONFIG_DEBUG_SPINLOCK */ - static inline int __spin_trylock(spinlock_t *lock) { preempt_disable(); diff --git a/init/Kconfig b/init/Kconfig index 9e03ef8b311e..06863dd7bf49 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1210,3 +1210,4 @@ source "block/Kconfig" config PREEMPT_NOTIFIERS bool +source "kernel/Kconfig.locks" diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks new file mode 100644 index 000000000000..d1f86db71451 --- /dev/null +++ b/kernel/Kconfig.locks @@ -0,0 +1,199 @@ +# +# The ARCH_INLINE foo is necessary because select ignores "depends on" +# +config ARCH_INLINE_SPIN_TRYLOCK + bool + +config ARCH_INLINE_SPIN_TRYLOCK_BH + bool + +config ARCH_INLINE_SPIN_LOCK + bool + +config ARCH_INLINE_SPIN_LOCK_BH + bool + +config ARCH_INLINE_SPIN_LOCK_IRQ + bool + +config ARCH_INLINE_SPIN_LOCK_IRQSAVE + bool + +config ARCH_INLINE_SPIN_UNLOCK + bool + +config ARCH_INLINE_SPIN_UNLOCK_BH + bool + +config ARCH_INLINE_SPIN_UNLOCK_IRQ + bool + +config ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE + bool + + +config ARCH_INLINE_READ_TRYLOCK + bool + +config ARCH_INLINE_READ_LOCK + bool + +config ARCH_INLINE_READ_LOCK_BH + bool + +config ARCH_INLINE_READ_LOCK_IRQ + bool + +config ARCH_INLINE_READ_LOCK_IRQSAVE + bool + +config ARCH_INLINE_READ_UNLOCK + bool + +config ARCH_INLINE_READ_UNLOCK_BH + bool + +config ARCH_INLINE_READ_UNLOCK_IRQ + bool + +config ARCH_INLINE_READ_UNLOCK_IRQRESTORE + bool + + +config ARCH_INLINE_WRITE_TRYLOCK + bool + +config ARCH_INLINE_WRITE_LOCK + bool + +config ARCH_INLINE_WRITE_LOCK_BH + bool + +config ARCH_INLINE_WRITE_LOCK_IRQ + bool + +config ARCH_INLINE_WRITE_LOCK_IRQSAVE + bool + +config ARCH_INLINE_WRITE_UNLOCK + bool + +config ARCH_INLINE_WRITE_UNLOCK_BH + bool + +config ARCH_INLINE_WRITE_UNLOCK_IRQ + bool + +config ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE + bool + +# +# lock_* functions are inlined when: +# - DEBUG_SPINLOCK=n and GENERIC_LOCKBREAK=n and ARCH_INLINE_*LOCK=y +# +# trylock_* functions are inlined when: +# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y +# +# unlock and unlock_irq functions are inlined when: +# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y +# or +# - DEBUG_SPINLOCK=n and PREEMPT=n +# +# unlock_bh and unlock_irqrestore functions are inlined when: +# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y +# + +config INLINE_SPIN_TRYLOCK + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_TRYLOCK + +config INLINE_SPIN_TRYLOCK_BH + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_TRYLOCK_BH + +config INLINE_SPIN_LOCK + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK + +config INLINE_SPIN_LOCK_BH + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_SPIN_LOCK_BH + +config INLINE_SPIN_LOCK_IRQ + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_SPIN_LOCK_IRQ + +config INLINE_SPIN_LOCK_IRQSAVE + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_SPIN_LOCK_IRQSAVE + +config INLINE_SPIN_UNLOCK + def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_SPIN_UNLOCK) + +config INLINE_SPIN_UNLOCK_BH + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_UNLOCK_BH + +config INLINE_SPIN_UNLOCK_IRQ + def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_SPIN_UNLOCK_BH) + +config INLINE_SPIN_UNLOCK_IRQRESTORE + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE + + +config INLINE_READ_TRYLOCK + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_READ_TRYLOCK + +config INLINE_READ_LOCK + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK + +config INLINE_READ_LOCK_BH + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_READ_LOCK_BH + +config INLINE_READ_LOCK_IRQ + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_READ_LOCK_IRQ + +config INLINE_READ_LOCK_IRQSAVE + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_READ_LOCK_IRQSAVE + +config INLINE_READ_UNLOCK + def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_READ_UNLOCK) + +config INLINE_READ_UNLOCK_BH + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_READ_UNLOCK_BH + +config INLINE_READ_UNLOCK_IRQ + def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_READ_UNLOCK_BH) + +config INLINE_READ_UNLOCK_IRQRESTORE + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_READ_UNLOCK_IRQRESTORE + + +config INLINE_WRITE_TRYLOCK + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_TRYLOCK + +config INLINE_WRITE_LOCK + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK + +config INLINE_WRITE_LOCK_BH + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_WRITE_LOCK_BH + +config INLINE_WRITE_LOCK_IRQ + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_WRITE_LOCK_IRQ + +config INLINE_WRITE_LOCK_IRQSAVE + def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \ + ARCH_INLINE_WRITE_LOCK_IRQSAVE + +config INLINE_WRITE_UNLOCK + def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_WRITE_UNLOCK) + +config INLINE_WRITE_UNLOCK_BH + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_UNLOCK_BH + +config INLINE_WRITE_UNLOCK_IRQ + def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_WRITE_UNLOCK_BH) + +config INLINE_WRITE_UNLOCK_IRQRESTORE + def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE diff --git a/kernel/spinlock.c b/kernel/spinlock.c index 5ddab730cb2f..235a9579a875 100644 --- a/kernel/spinlock.c +++ b/kernel/spinlock.c @@ -21,7 +21,7 @@ #include #include -#ifndef _spin_trylock +#ifndef CONFIG_INLINE_SPIN_TRYLOCK int __lockfunc _spin_trylock(spinlock_t *lock) { return __spin_trylock(lock); @@ -29,7 +29,7 @@ int __lockfunc _spin_trylock(spinlock_t *lock) EXPORT_SYMBOL(_spin_trylock); #endif -#ifndef _read_trylock +#ifndef CONFIG_INLINE_READ_TRYLOCK int __lockfunc _read_trylock(rwlock_t *lock) { return __read_trylock(lock); @@ -37,7 +37,7 @@ int __lockfunc _read_trylock(rwlock_t *lock) EXPORT_SYMBOL(_read_trylock); #endif -#ifndef _write_trylock +#ifndef CONFIG_INLINE_WRITE_TRYLOCK int __lockfunc _write_trylock(rwlock_t *lock) { return __write_trylock(lock); @@ -52,7 +52,7 @@ EXPORT_SYMBOL(_write_trylock); */ #if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC) -#ifndef _read_lock +#ifndef CONFIG_INLINE_READ_LOCK void __lockfunc _read_lock(rwlock_t *lock) { __read_lock(lock); @@ -60,7 +60,7 @@ void __lockfunc _read_lock(rwlock_t *lock) EXPORT_SYMBOL(_read_lock); #endif -#ifndef _spin_lock_irqsave +#ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock) { return __spin_lock_irqsave(lock); @@ -68,7 +68,7 @@ unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock) EXPORT_SYMBOL(_spin_lock_irqsave); #endif -#ifndef _spin_lock_irq +#ifndef CONFIG_INLINE_SPIN_LOCK_IRQ void __lockfunc _spin_lock_irq(spinlock_t *lock) { __spin_lock_irq(lock); @@ -76,7 +76,7 @@ void __lockfunc _spin_lock_irq(spinlock_t *lock) EXPORT_SYMBOL(_spin_lock_irq); #endif -#ifndef _spin_lock_bh +#ifndef CONFIG_INLINE_SPIN_LOCK_BH void __lockfunc _spin_lock_bh(spinlock_t *lock) { __spin_lock_bh(lock); @@ -84,7 +84,7 @@ void __lockfunc _spin_lock_bh(spinlock_t *lock) EXPORT_SYMBOL(_spin_lock_bh); #endif -#ifndef _read_lock_irqsave +#ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock) { return __read_lock_irqsave(lock); @@ -92,7 +92,7 @@ unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock) EXPORT_SYMBOL(_read_lock_irqsave); #endif -#ifndef _read_lock_irq +#ifndef CONFIG_INLINE_READ_LOCK_IRQ void __lockfunc _read_lock_irq(rwlock_t *lock) { __read_lock_irq(lock); @@ -100,7 +100,7 @@ void __lockfunc _read_lock_irq(rwlock_t *lock) EXPORT_SYMBOL(_read_lock_irq); #endif -#ifndef _read_lock_bh +#ifndef CONFIG_INLINE_READ_LOCK_BH void __lockfunc _read_lock_bh(rwlock_t *lock) { __read_lock_bh(lock); @@ -108,7 +108,7 @@ void __lockfunc _read_lock_bh(rwlock_t *lock) EXPORT_SYMBOL(_read_lock_bh); #endif -#ifndef _write_lock_irqsave +#ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock) { return __write_lock_irqsave(lock); @@ -116,7 +116,7 @@ unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock) EXPORT_SYMBOL(_write_lock_irqsave); #endif -#ifndef _write_lock_irq +#ifndef CONFIG_INLINE_WRITE_LOCK_IRQ void __lockfunc _write_lock_irq(rwlock_t *lock) { __write_lock_irq(lock); @@ -124,7 +124,7 @@ void __lockfunc _write_lock_irq(rwlock_t *lock) EXPORT_SYMBOL(_write_lock_irq); #endif -#ifndef _write_lock_bh +#ifndef CONFIG_INLINE_WRITE_LOCK_BH void __lockfunc _write_lock_bh(rwlock_t *lock) { __write_lock_bh(lock); @@ -132,7 +132,7 @@ void __lockfunc _write_lock_bh(rwlock_t *lock) EXPORT_SYMBOL(_write_lock_bh); #endif -#ifndef _spin_lock +#ifndef CONFIG_INLINE_SPIN_LOCK void __lockfunc _spin_lock(spinlock_t *lock) { __spin_lock(lock); @@ -140,7 +140,7 @@ void __lockfunc _spin_lock(spinlock_t *lock) EXPORT_SYMBOL(_spin_lock); #endif -#ifndef _write_lock +#ifndef CONFIG_INLINE_WRITE_LOCK void __lockfunc _write_lock(rwlock_t *lock) { __write_lock(lock); @@ -272,7 +272,7 @@ EXPORT_SYMBOL(_spin_lock_nest_lock); #endif -#ifndef _spin_unlock +#ifndef CONFIG_INLINE_SPIN_UNLOCK void __lockfunc _spin_unlock(spinlock_t *lock) { __spin_unlock(lock); @@ -280,7 +280,7 @@ void __lockfunc _spin_unlock(spinlock_t *lock) EXPORT_SYMBOL(_spin_unlock); #endif -#ifndef _write_unlock +#ifndef CONFIG_INLINE_WRITE_UNLOCK void __lockfunc _write_unlock(rwlock_t *lock) { __write_unlock(lock); @@ -288,7 +288,7 @@ void __lockfunc _write_unlock(rwlock_t *lock) EXPORT_SYMBOL(_write_unlock); #endif -#ifndef _read_unlock +#ifndef CONFIG_INLINE_READ_UNLOCK void __lockfunc _read_unlock(rwlock_t *lock) { __read_unlock(lock); @@ -296,7 +296,7 @@ void __lockfunc _read_unlock(rwlock_t *lock) EXPORT_SYMBOL(_read_unlock); #endif -#ifndef _spin_unlock_irqrestore +#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) { __spin_unlock_irqrestore(lock, flags); @@ -304,7 +304,7 @@ void __lockfunc _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) EXPORT_SYMBOL(_spin_unlock_irqrestore); #endif -#ifndef _spin_unlock_irq +#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ void __lockfunc _spin_unlock_irq(spinlock_t *lock) { __spin_unlock_irq(lock); @@ -312,7 +312,7 @@ void __lockfunc _spin_unlock_irq(spinlock_t *lock) EXPORT_SYMBOL(_spin_unlock_irq); #endif -#ifndef _spin_unlock_bh +#ifndef CONFIG_INLINE_SPIN_UNLOCK_BH void __lockfunc _spin_unlock_bh(spinlock_t *lock) { __spin_unlock_bh(lock); @@ -320,7 +320,7 @@ void __lockfunc _spin_unlock_bh(spinlock_t *lock) EXPORT_SYMBOL(_spin_unlock_bh); #endif -#ifndef _read_unlock_irqrestore +#ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags) { __read_unlock_irqrestore(lock, flags); @@ -328,7 +328,7 @@ void __lockfunc _read_unlock_irqrestore(rwlock_t *lock, unsigned long flags) EXPORT_SYMBOL(_read_unlock_irqrestore); #endif -#ifndef _read_unlock_irq +#ifndef CONFIG_INLINE_READ_UNLOCK_IRQ void __lockfunc _read_unlock_irq(rwlock_t *lock) { __read_unlock_irq(lock); @@ -336,7 +336,7 @@ void __lockfunc _read_unlock_irq(rwlock_t *lock) EXPORT_SYMBOL(_read_unlock_irq); #endif -#ifndef _read_unlock_bh +#ifndef CONFIG_INLINE_READ_UNLOCK_BH void __lockfunc _read_unlock_bh(rwlock_t *lock) { __read_unlock_bh(lock); @@ -344,7 +344,7 @@ void __lockfunc _read_unlock_bh(rwlock_t *lock) EXPORT_SYMBOL(_read_unlock_bh); #endif -#ifndef _write_unlock_irqrestore +#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags) { __write_unlock_irqrestore(lock, flags); @@ -352,7 +352,7 @@ void __lockfunc _write_unlock_irqrestore(rwlock_t *lock, unsigned long flags) EXPORT_SYMBOL(_write_unlock_irqrestore); #endif -#ifndef _write_unlock_irq +#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ void __lockfunc _write_unlock_irq(rwlock_t *lock) { __write_unlock_irq(lock); @@ -360,7 +360,7 @@ void __lockfunc _write_unlock_irq(rwlock_t *lock) EXPORT_SYMBOL(_write_unlock_irq); #endif -#ifndef _write_unlock_bh +#ifndef CONFIG_INLINE_WRITE_UNLOCK_BH void __lockfunc _write_unlock_bh(rwlock_t *lock) { __write_unlock_bh(lock); @@ -368,7 +368,7 @@ void __lockfunc _write_unlock_bh(rwlock_t *lock) EXPORT_SYMBOL(_write_unlock_bh); #endif -#ifndef _spin_trylock_bh +#ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH int __lockfunc _spin_trylock_bh(spinlock_t *lock) { return __spin_trylock_bh(lock); -- cgit v1.2.3 From 8e13c7b772387f55dc05c6a0e5b30010c3c46ff9 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 9 Nov 2009 15:21:41 +0000 Subject: locking: Reduce ifdefs in kernel/spinlock.c With the Kconfig based inline decisions we can remove extra ifdefs in kernel/spinlock.c by creating the complex lockbreak functions as inlines which are inserted into the non inlined lock functions. No functional change. Signed-off-by: Thomas Gleixner LKML-Reference: <20091109151428.548614772@linutronix.de> Acked-by: Heiko Carstens Reviewed-by: Ingo Molnar Acked-by: Peter Zijlstra --- kernel/spinlock.c | 258 +++++++++++++++++++++++++++--------------------------- 1 file changed, 127 insertions(+), 131 deletions(-) (limited to 'kernel') diff --git a/kernel/spinlock.c b/kernel/spinlock.c index 235a9579a875..41e042219ff6 100644 --- a/kernel/spinlock.c +++ b/kernel/spinlock.c @@ -21,6 +21,133 @@ #include #include +/* + * If lockdep is enabled then we use the non-preemption spin-ops + * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are + * not re-enabled during lock-acquire (which the preempt-spin-ops do): + */ +#if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC) +/* + * The __lock_function inlines are taken from + * include/linux/spinlock_api_smp.h + */ +#else +/* + * We build the __lock_function inlines here. They are too large for + * inlining all over the place, but here is only one user per function + * which embedds them into the calling _lock_function below. + * + * This could be a long-held lock. We both prepare to spin for a long + * time (making _this_ CPU preemptable if possible), and we also signal + * towards that other CPU that it should break the lock ASAP. + */ +#define BUILD_LOCK_OPS(op, locktype) \ +void __lockfunc __##op##_lock(locktype##_t *lock) \ +{ \ + for (;;) { \ + preempt_disable(); \ + if (likely(_raw_##op##_trylock(lock))) \ + break; \ + preempt_enable(); \ + \ + if (!(lock)->break_lock) \ + (lock)->break_lock = 1; \ + while (!op##_can_lock(lock) && (lock)->break_lock) \ + _raw_##op##_relax(&lock->raw_lock); \ + } \ + (lock)->break_lock = 0; \ +} \ + \ +unsigned long __lockfunc __##op##_lock_irqsave(locktype##_t *lock) \ +{ \ + unsigned long flags; \ + \ + for (;;) { \ + preempt_disable(); \ + local_irq_save(flags); \ + if (likely(_raw_##op##_trylock(lock))) \ + break; \ + local_irq_restore(flags); \ + preempt_enable(); \ + \ + if (!(lock)->break_lock) \ + (lock)->break_lock = 1; \ + while (!op##_can_lock(lock) && (lock)->break_lock) \ + _raw_##op##_relax(&lock->raw_lock); \ + } \ + (lock)->break_lock = 0; \ + return flags; \ +} \ + \ +void __lockfunc __##op##_lock_irq(locktype##_t *lock) \ +{ \ + _##op##_lock_irqsave(lock); \ +} \ + \ +void __lockfunc __##op##_lock_bh(locktype##_t *lock) \ +{ \ + unsigned long flags; \ + \ + /* */ \ + /* Careful: we must exclude softirqs too, hence the */ \ + /* irq-disabling. We use the generic preemption-aware */ \ + /* function: */ \ + /**/ \ + flags = _##op##_lock_irqsave(lock); \ + local_bh_disable(); \ + local_irq_restore(flags); \ +} \ + +/* + * Build preemption-friendly versions of the following + * lock-spinning functions: + * + * __[spin|read|write]_lock() + * __[spin|read|write]_lock_irq() + * __[spin|read|write]_lock_irqsave() + * __[spin|read|write]_lock_bh() + */ +BUILD_LOCK_OPS(spin, spinlock); +BUILD_LOCK_OPS(read, rwlock); +BUILD_LOCK_OPS(write, rwlock); + +#endif + +#ifdef CONFIG_DEBUG_LOCK_ALLOC + +void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass) +{ + preempt_disable(); + spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); + LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); +} +EXPORT_SYMBOL(_spin_lock_nested); + +unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, + int subclass) +{ + unsigned long flags; + + local_irq_save(flags); + preempt_disable(); + spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); + LOCK_CONTENDED_FLAGS(lock, _raw_spin_trylock, _raw_spin_lock, + _raw_spin_lock_flags, &flags); + return flags; +} +EXPORT_SYMBOL(_spin_lock_irqsave_nested); + +void __lockfunc _spin_lock_nest_lock(spinlock_t *lock, + struct lockdep_map *nest_lock) +{ + preempt_disable(); + spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_); + LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); +} +EXPORT_SYMBOL(_spin_lock_nest_lock); + +#endif + #ifndef CONFIG_INLINE_SPIN_TRYLOCK int __lockfunc _spin_trylock(spinlock_t *lock) { @@ -45,13 +172,6 @@ int __lockfunc _write_trylock(rwlock_t *lock) EXPORT_SYMBOL(_write_trylock); #endif -/* - * If lockdep is enabled then we use the non-preemption spin-ops - * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are - * not re-enabled during lock-acquire (which the preempt-spin-ops do): - */ -#if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC) - #ifndef CONFIG_INLINE_READ_LOCK void __lockfunc _read_lock(rwlock_t *lock) { @@ -148,130 +268,6 @@ void __lockfunc _write_lock(rwlock_t *lock) EXPORT_SYMBOL(_write_lock); #endif -#else /* CONFIG_PREEMPT: */ - -/* - * This could be a long-held lock. We both prepare to spin for a long - * time (making _this_ CPU preemptable if possible), and we also signal - * towards that other CPU that it should break the lock ASAP. - * - * (We do this in a function because inlining it would be excessive.) - */ - -#define BUILD_LOCK_OPS(op, locktype) \ -void __lockfunc _##op##_lock(locktype##_t *lock) \ -{ \ - for (;;) { \ - preempt_disable(); \ - if (likely(_raw_##op##_trylock(lock))) \ - break; \ - preempt_enable(); \ - \ - if (!(lock)->break_lock) \ - (lock)->break_lock = 1; \ - while (!op##_can_lock(lock) && (lock)->break_lock) \ - _raw_##op##_relax(&lock->raw_lock); \ - } \ - (lock)->break_lock = 0; \ -} \ - \ -EXPORT_SYMBOL(_##op##_lock); \ - \ -unsigned long __lockfunc _##op##_lock_irqsave(locktype##_t *lock) \ -{ \ - unsigned long flags; \ - \ - for (;;) { \ - preempt_disable(); \ - local_irq_save(flags); \ - if (likely(_raw_##op##_trylock(lock))) \ - break; \ - local_irq_restore(flags); \ - preempt_enable(); \ - \ - if (!(lock)->break_lock) \ - (lock)->break_lock = 1; \ - while (!op##_can_lock(lock) && (lock)->break_lock) \ - _raw_##op##_relax(&lock->raw_lock); \ - } \ - (lock)->break_lock = 0; \ - return flags; \ -} \ - \ -EXPORT_SYMBOL(_##op##_lock_irqsave); \ - \ -void __lockfunc _##op##_lock_irq(locktype##_t *lock) \ -{ \ - _##op##_lock_irqsave(lock); \ -} \ - \ -EXPORT_SYMBOL(_##op##_lock_irq); \ - \ -void __lockfunc _##op##_lock_bh(locktype##_t *lock) \ -{ \ - unsigned long flags; \ - \ - /* */ \ - /* Careful: we must exclude softirqs too, hence the */ \ - /* irq-disabling. We use the generic preemption-aware */ \ - /* function: */ \ - /**/ \ - flags = _##op##_lock_irqsave(lock); \ - local_bh_disable(); \ - local_irq_restore(flags); \ -} \ - \ -EXPORT_SYMBOL(_##op##_lock_bh) - -/* - * Build preemption-friendly versions of the following - * lock-spinning functions: - * - * _[spin|read|write]_lock() - * _[spin|read|write]_lock_irq() - * _[spin|read|write]_lock_irqsave() - * _[spin|read|write]_lock_bh() - */ -BUILD_LOCK_OPS(spin, spinlock); -BUILD_LOCK_OPS(read, rwlock); -BUILD_LOCK_OPS(write, rwlock); - -#endif /* CONFIG_PREEMPT */ - -#ifdef CONFIG_DEBUG_LOCK_ALLOC - -void __lockfunc _spin_lock_nested(spinlock_t *lock, int subclass) -{ - preempt_disable(); - spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); - LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); -} -EXPORT_SYMBOL(_spin_lock_nested); - -unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass) -{ - unsigned long flags; - - local_irq_save(flags); - preempt_disable(); - spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); - LOCK_CONTENDED_FLAGS(lock, _raw_spin_trylock, _raw_spin_lock, - _raw_spin_lock_flags, &flags); - return flags; -} -EXPORT_SYMBOL(_spin_lock_irqsave_nested); - -void __lockfunc _spin_lock_nest_lock(spinlock_t *lock, - struct lockdep_map *nest_lock) -{ - preempt_disable(); - spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_); - LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock); -} -EXPORT_SYMBOL(_spin_lock_nest_lock); - -#endif - #ifndef CONFIG_INLINE_SPIN_UNLOCK void __lockfunc _spin_unlock(spinlock_t *lock) { -- cgit v1.2.3 From 560d4bc0df9a5e63b980432282d8c2bd3559ec74 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 13 Nov 2009 19:51:38 -0800 Subject: rcu: Further cleanups of use of lastcomp Now that a copy of the rsp->completed flag is available in all rcu_node structures, make full use of it. It is still legitimate to access rsp->completed while holding the root rcu_node structure's lock, however. Also, tighten up force_quiescent_state()'s checks for end of current grace period. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1258170699933-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 3df04381ea3e..24bbf2ce0605 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -817,7 +817,7 @@ cpu_quiet(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) rnp = rdp->mynode; spin_lock_irqsave(&rnp->lock, flags); - if (lastcomp != ACCESS_ONCE(rsp->completed)) { + if (lastcomp != rnp->completed) { /* * Someone beat us to it for this grace period, so leave. @@ -935,7 +935,6 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp) static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) { unsigned long flags; - long lastcomp; unsigned long mask; struct rcu_data *rdp = rsp->rda[cpu]; struct rcu_node *rnp; @@ -971,7 +970,6 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) spin_unlock(&rnp->lock); /* irqs remain disabled. */ rnp = rnp->parent; } while (rnp != NULL); - lastcomp = rsp->completed; spin_unlock_irqrestore(&rsp->onofflock, flags); @@ -1145,7 +1143,7 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp, rcu_for_each_leaf_node(rsp, rnp) { mask = 0; spin_lock_irqsave(&rnp->lock, flags); - if (rsp->completed != lastcomp) { + if (rnp->completed != lastcomp) { spin_unlock_irqrestore(&rnp->lock, flags); return 1; } @@ -1159,7 +1157,7 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp, if ((rnp->qsmask & bit) != 0 && f(rsp->rda[cpu])) mask |= bit; } - if (mask != 0 && rsp->completed == lastcomp) { + if (mask != 0 && rnp->completed == lastcomp) { /* cpu_quiet_msk() releases rnp->lock. */ cpu_quiet_msk(mask, rsp, rnp, flags); @@ -1196,7 +1194,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) lastcomp = rsp->gpnum - 1; signaled = rsp->signaled; rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; - if (lastcomp == rsp->gpnum) { + if(!rcu_gp_in_progress(rsp)) { rsp->n_force_qs_ngp++; spin_unlock(&rnp->lock); goto unlock_ret; /* no GP in progress, time updated. */ @@ -1224,7 +1222,8 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) /* Update state, record completion counter. */ forcenow = 0; spin_lock(&rnp->lock); - if (lastcomp == rsp->completed && + if (lastcomp + 1 == rsp->gpnum && + lastcomp == rsp->completed && rsp->signaled == signaled) { rsp->signaled = RCU_FORCE_QS; rsp->completed_fqs = lastcomp; -- cgit v1.2.3 From 2f51f9884f6a36b0fe9636d5a1937e5cbd25723b Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 13 Nov 2009 19:51:39 -0800 Subject: rcu: Eliminate __rcu_pending() false positives Now that there are both ->gpnum and ->completed fields in the rcu_node structure, __rcu_pending() should check rdp->gpnum and rdp->completed against rnp->gpnum and rdp->completed, respectively, instead of the prior comparison against the rcu_state fields rsp->gpnum and rsp->completed. Given the old comparison, __rcu_pending() could return 1, resulting in a needless raise_softirq(RCU_SOFTIRQ). This useless work would happen if RCU responded to a scheduling-clock interrupt after the rcu_state fields had been updated, but before the rcu_node fields had been updated. Changing the comparison from the rcu_state fields to the rcu_node fields prevents this useless work from happening. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12581706991966-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 24bbf2ce0605..9b36d6d7fb97 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1403,6 +1403,8 @@ EXPORT_SYMBOL_GPL(call_rcu_bh); */ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) { + struct rcu_node *rnp = rdp->mynode; + rdp->n_rcu_pending++; /* Check for CPU stalls, if enabled. */ @@ -1427,13 +1429,13 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) } /* Has another RCU grace period completed? */ - if (ACCESS_ONCE(rsp->completed) != rdp->completed) { /* outside lock */ + if (ACCESS_ONCE(rnp->completed) != rdp->completed) { /* outside lock */ rdp->n_rp_gp_completed++; return 1; } /* Has a new RCU grace period started? */ - if (ACCESS_ONCE(rsp->gpnum) != rdp->gpnum) { /* outside lock */ + if (ACCESS_ONCE(rnp->gpnum) != rdp->gpnum) { /* outside lock */ rdp->n_rp_gp_started++; return 1; } -- cgit v1.2.3 From 5a50e33cc916f6a81cb96f0f24f6a88c9ab78b79 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 17 Nov 2009 08:43:01 -0500 Subject: ring-buffer: Move access to commit_page up into function used With the change of the way we process commits. Where a commit only happens at the outer most level, and that we don't need to worry about a commit ending after the rb_start_commit() has been called, the code use to grab the commit page before the tail page to prevent a possible race. But this race no longer exists with the rb_start_commit() rb_end_commit() interface. Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 3ffa502fb243..4b8293fa545e 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1785,9 +1785,9 @@ rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer, static struct ring_buffer_event * rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer, unsigned long length, unsigned long tail, - struct buffer_page *commit_page, struct buffer_page *tail_page, u64 *ts) { + struct buffer_page *commit_page = cpu_buffer->commit_page; struct ring_buffer *buffer = cpu_buffer->buffer; struct buffer_page *next_page; int ret; @@ -1890,13 +1890,10 @@ static struct ring_buffer_event * __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, unsigned type, unsigned long length, u64 *ts) { - struct buffer_page *tail_page, *commit_page; + struct buffer_page *tail_page; struct ring_buffer_event *event; unsigned long tail, write; - commit_page = cpu_buffer->commit_page; - /* we just need to protect against interrupts */ - barrier(); tail_page = cpu_buffer->tail_page; write = local_add_return(length, &tail_page->write); @@ -1907,7 +1904,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, /* See if we shot pass the end of this buffer page */ if (write > BUF_PAGE_SIZE) return rb_move_tail(cpu_buffer, length, tail, - commit_page, tail_page, ts); + tail_page, ts); /* We reserved something on the buffer */ -- cgit v1.2.3 From c13d2f7c3231e873f30db92b96c8caa48f100f33 Mon Sep 17 00:00:00 2001 From: Carsten Emde Date: Mon, 16 Nov 2009 20:56:13 +0100 Subject: tracing: Fix trace_marker output When a string was written to /tracing/trace_marker, some strange characters appeared in the trace output instead of the string, since a vprint function erroneously called a vararg print function with a va_list argument. This patch fixes the problem and simplifies the related code. Signed-off-by: Carsten Emde LKML-Reference: <4B01AE5D.1010801@osadl.org> Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 39 ++++++++++++++------------------------- 1 file changed, 14 insertions(+), 25 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 03c7fd55c5f9..12b49caedf82 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1361,10 +1361,11 @@ int trace_array_vprintk(struct trace_array *tr, pause_graph_tracing(); raw_local_irq_save(irq_flags); __raw_spin_lock(&trace_buf_lock); - len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args); - - len = min(len, TRACE_BUF_SIZE-1); - trace_buf[len] = 0; + if (args == NULL) { + strncpy(trace_buf, fmt, TRACE_BUF_SIZE); + len = strlen(trace_buf); + } else + len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args); size = sizeof(*entry) + len + 1; buffer = tr->buffer; @@ -1373,10 +1374,10 @@ int trace_array_vprintk(struct trace_array *tr, if (!event) goto out_unlock; entry = ring_buffer_event_data(event); - entry->ip = ip; + entry->ip = ip; memcpy(&entry->buf, trace_buf, len); - entry->buf[len] = 0; + entry->buf[len] = '\0'; if (!filter_check_discard(call, entry, buffer, event)) ring_buffer_unlock_commit(buffer, event); @@ -3319,22 +3320,11 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, return cnt; } -static int mark_printk(const char *fmt, ...) -{ - int ret; - va_list args; - va_start(args, fmt); - ret = trace_vprintk(0, fmt, args); - va_end(args); - return ret; -} - static ssize_t tracing_mark_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *fpos) { char *buf; - char *end; if (tracing_disabled) return -EINVAL; @@ -3342,7 +3332,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, if (cnt > TRACE_BUF_SIZE) cnt = TRACE_BUF_SIZE; - buf = kmalloc(cnt + 1, GFP_KERNEL); + buf = kmalloc(cnt + 2, GFP_KERNEL); if (buf == NULL) return -ENOMEM; @@ -3350,14 +3340,13 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, kfree(buf); return -EFAULT; } + if (buf[cnt-1] != '\n') { + buf[cnt] = '\n'; + buf[cnt+1] = '\0'; + } else + buf[cnt] = '\0'; - /* Cut from the first nil or newline. */ - buf[cnt] = '\0'; - end = strchr(buf, '\n'); - if (end) - *end = '\0'; - - cnt = mark_printk("%s\n", buf); + cnt = trace_vprintk(0, buf, NULL); kfree(buf); *fpos += cnt; -- cgit v1.2.3 From f6060f46819f313d34a8c8151390cda509c23389 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Thu, 5 Nov 2009 11:16:17 +0800 Subject: tracing: Prevent build warning: 'ftrace_graph_buf' defined but not used Prevent build warning when CONFIG_FUNCTION_GRAPH_TRACER is not set. Signed-off-by: Lai Jiangshan LKML-Reference: <4AF24381.5060307@cn.fujitsu.com> Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1ed514fe3a30..7f9b51e8184b 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2274,7 +2274,6 @@ void ftrace_set_notrace(unsigned char *buf, int len, int reset) #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata; static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata; -static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; static int __init set_ftrace_notrace(char *str) { @@ -2291,6 +2290,7 @@ static int __init set_ftrace_filter(char *str) __setup("ftrace_filter=", set_ftrace_filter); #ifdef CONFIG_FUNCTION_GRAPH_TRACER +static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; static int __init set_graph_function(char *str) { strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); -- cgit v1.2.3 From a1afb6371bb5341057056194d1168753f6d77242 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Fri, 28 Aug 2009 22:19:33 +0400 Subject: genirq: switch /proc/irq/*/spurious to seq_file [ tglx: compacted it a bit ] Signed-off-by: Alexey Dobriyan LKML-Reference: <20090828181743.GA14050@x200.localdomain> Signed-off-by: Andrew Morton Signed-off-by: Thomas Gleixner --- kernel/irq/proc.c | 36 +++++++++++++++++++++--------------- 1 file changed, 21 insertions(+), 15 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index dfef5b9f3845..4e47f11da6a7 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -148,18 +148,28 @@ static const struct file_operations default_affinity_proc_fops = { }; #endif -static int irq_spurious_read(char *page, char **start, off_t off, - int count, int *eof, void *data) +static int irq_spurious_proc_show(struct seq_file *m, void *v) { - struct irq_desc *desc = irq_to_desc((long) data); - return sprintf(page, "count %u\n" - "unhandled %u\n" - "last_unhandled %u ms\n", - desc->irq_count, - desc->irqs_unhandled, - jiffies_to_msecs(desc->last_unhandled)); + struct irq_desc *desc = irq_to_desc((long) m->private); + + seq_printf(m, "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n", + desc->irq_count, desc->irqs_unhandled, + jiffies_to_msecs(desc->last_unhandled)); + return 0; +} + +static int irq_spurious_proc_open(struct inode *inode, struct file *file) +{ + return single_open(file, irq_spurious_proc_show, NULL); } +static const struct file_operations irq_spurious_proc_fops = { + .open = irq_spurious_proc_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + #define MAX_NAMELEN 128 static int name_unique(unsigned int irq, struct irqaction *new_action) @@ -204,7 +214,6 @@ void register_handler_proc(unsigned int irq, struct irqaction *action) void register_irq_proc(unsigned int irq, struct irq_desc *desc) { char name [MAX_NAMELEN]; - struct proc_dir_entry *entry; if (!root_irq_dir || (desc->chip == &no_irq_chip) || desc->dir) return; @@ -223,11 +232,8 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc) &irq_affinity_proc_fops, (void *)(long)irq); #endif - entry = create_proc_entry("spurious", 0444, desc->dir); - if (entry) { - entry->data = (void *)(long)irq; - entry->read_proc = irq_spurious_read; - } + proc_create_data("spurious", 0444, desc->dir, + &irq_spurious_proc_fops, (void *)(long)irq); } #undef MAX_NAMELEN -- cgit v1.2.3 From 2ea6dec4a22a6f66f6633876212fd4d195cf8277 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 17 Nov 2009 14:27:27 -0800 Subject: generic-ipi: Add smp_call_function_any() Andrew points out that acpi-cpufreq uses cpumask_any, when it really would prefer to use the same CPU if possible (to avoid an IPI). In general, this seems a good idea to offer. [ tglx: Documented selection preference and Inlined the UP case to avoid the copy of smp_call_function_single() and the extra EXPORT ] Signed-off-by: Rusty Russell Cc: Ingo Molnar Cc: Venkatesh Pallipadi Cc: Len Brown Cc: Zhao Yakui Cc: Dave Jones Cc: Thomas Gleixner Cc: Mike Galbraith Cc: "Zhang, Yanmin" Signed-off-by: Andrew Morton Signed-off-by: Thomas Gleixner --- include/linux/smp.h | 11 ++++++++++- kernel/smp.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/include/linux/smp.h b/include/linux/smp.h index 39c64bae776d..7a0570e6a596 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -76,6 +76,9 @@ void smp_call_function_many(const struct cpumask *mask, void __smp_call_function_single(int cpuid, struct call_single_data *data, int wait); +int smp_call_function_any(const struct cpumask *mask, + void (*func)(void *info), void *info, int wait); + /* * Generic and arch helpers */ @@ -137,9 +140,15 @@ static inline void smp_send_reschedule(int cpu) { } #define smp_prepare_boot_cpu() do {} while (0) #define smp_call_function_many(mask, func, info, wait) \ (up_smp_call_function(func, info)) -static inline void init_call_single_data(void) +static inline void init_call_single_data(void) { } + +static inline int +smp_call_function_any(const struct cpumask *mask, void (*func)(void *info), + void *info, int wait) { + return smp_call_function_single(0, func, info, wait); } + #endif /* !SMP */ /* diff --git a/kernel/smp.c b/kernel/smp.c index 8bd618f0364d..a8c76069cf50 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -319,6 +319,51 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info, } EXPORT_SYMBOL(smp_call_function_single); +/* + * smp_call_function_any - Run a function on any of the given cpus + * @mask: The mask of cpus it can run on. + * @func: The function to run. This must be fast and non-blocking. + * @info: An arbitrary pointer to pass to the function. + * @wait: If true, wait until function has completed. + * + * Returns 0 on success, else a negative status code (if no cpus were online). + * Note that @wait will be implicitly turned on in case of allocation failures, + * since we fall back to on-stack allocation. + * + * Selection preference: + * 1) current cpu if in @mask + * 2) any cpu of current node if in @mask + * 3) any other online cpu in @mask + */ +int smp_call_function_any(const struct cpumask *mask, + void (*func)(void *info), void *info, int wait) +{ + unsigned int cpu; + const struct cpumask *nodemask; + int ret; + + /* Try for same CPU (cheapest) */ + cpu = get_cpu(); + if (cpumask_test_cpu(cpu, mask)) + goto call; + + /* Try for same node. */ + nodemask = cpumask_of_node(cpu); + for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids; + cpu = cpumask_next_and(cpu, nodemask, mask)) { + if (cpu_online(cpu)) + goto call; + } + + /* Any online will do: smp_call_function_single handles nr_cpu_ids. */ + cpu = cpumask_any_and(mask, cpu_online_mask); +call: + ret = smp_call_function_single(cpu, func, info, wait); + put_cpu(); + return ret; +} +EXPORT_SYMBOL_GPL(smp_call_function_any); + /** * __smp_call_function_single(): Run a function on another CPU * @cpu: The CPU to run on. -- cgit v1.2.3 From 34769945f7cd9ab470413ffe64426e3ad069f49e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 20 Nov 2009 11:46:21 +0100 Subject: genirq: Fix spurious irq seqfile conversion single_open data argument must be PDE(inode)->data instead of NULL otherwise seq_file->private is always NULL and we always read the spurious data of irq 0. Reported-by: Alexey Dobriyan Signed-off-by: Thomas Gleixner --- kernel/irq/proc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 4e47f11da6a7..0832145fea97 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -136,7 +136,7 @@ out: static int default_affinity_open(struct inode *inode, struct file *file) { - return single_open(file, default_affinity_show, NULL); + return single_open(file, default_affinity_show, PDE(inode)->data); } static const struct file_operations default_affinity_proc_fops = { -- cgit v1.2.3 From b668c9cf3e58739dac54a1d6f42f2b4bdd980b3e Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 22 Nov 2009 08:53:48 -0800 Subject: rcu: Fix grace-period-stall bug on large systems with CPU hotplug When the last CPU of a given leaf rcu_node structure goes offline, all of the tasks queued on that leaf rcu_node structure (due to having blocked in their current RCU read-side critical sections) are requeued onto the root rcu_node structure. This requeuing is carried out by rcu_preempt_offline_tasks(). However, it is possible that these queued tasks are the only thing preventing the leaf rcu_node structure from reporting a quiescent state up the rcu_node hierarchy. Unfortunately, the old code would fail to do this reporting, resulting in a grace-period stall given the following sequence of events: 1. Kernel built for more than 32 CPUs on 32-bit systems or for more than 64 CPUs on 64-bit systems, so that there is more than one rcu_node structure. (Or CONFIG_RCU_FANOUT is artificially set to a number smaller than CONFIG_NR_CPUS.) 2. The kernel is built with CONFIG_TREE_PREEMPT_RCU. 3. A task running on a CPU associated with a given leaf rcu_node structure blocks while in an RCU read-side critical section -and- that CPU has not yet passed through a quiescent state for the current RCU grace period. This will cause the task to be queued on the leaf rcu_node's blocked_tasks[] array, in particular, on the element of this array corresponding to the current grace period. 4. Each of the remaining CPUs corresponding to this same leaf rcu_node structure pass through a quiescent state. However, the task is still in its RCU read-side critical section, so these quiescent states cannot be reported further up the rcu_node hierarchy. Nevertheless, all bits in the leaf rcu_node structure's ->qsmask field are now zero. 5. Each of the remaining CPUs go offline. (The events in step #4 and #5 can happen in any order as long as each CPU passes through a quiescent state before going offline.) 6. When the last CPU goes offline, __rcu_offline_cpu() will invoke rcu_preempt_offline_tasks(), which will move the task to the root rcu_node structure, but without reporting a quiescent state up the rcu_node hierarchy (and this failure to report a quiescent state is the bug). But because this leaf rcu_node structure's ->qsmask field is already zero and its ->block_tasks[] entries are all empty, force_quiescent_state() will skip this rcu_node structure. Therefore, grace periods are now hung. This patch abstracts some code out of rcu_read_unlock_special(), calling the result task_quiet() by analogy with cpu_quiet(), and invokes task_quiet() from both rcu_read_lock_special() and __rcu_offline_cpu(). Invoking task_quiet() from __rcu_offline_cpu() reports the quiescent state up the rcu_node hierarchy, fixing the bug. This ends up requiring a separate lock_class_key per level of the rcu_node hierarchy, which this patch also provides. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12589088301770-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 40 ++++++++++++----------- kernel/rcutree.h | 3 ++ kernel/rcutree_plugin.h | 85 +++++++++++++++++++++++++++++++++++-------------- 3 files changed, 85 insertions(+), 43 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 9b36d6d7fb97..b79bfcd28e95 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -51,7 +51,7 @@ /* Data structures. */ -static struct lock_class_key rcu_root_class; +static struct lock_class_key rcu_node_class[NUM_RCU_LVLS]; #define RCU_STATE_INITIALIZER(name) { \ .level = { &name.node[0] }, \ @@ -936,6 +936,7 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) { unsigned long flags; unsigned long mask; + int need_quiet = 0; struct rcu_data *rdp = rsp->rda[cpu]; struct rcu_node *rnp; @@ -949,29 +950,30 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) spin_lock(&rnp->lock); /* irqs already disabled. */ rnp->qsmaskinit &= ~mask; if (rnp->qsmaskinit != 0) { - spin_unlock(&rnp->lock); /* irqs remain disabled. */ + if (rnp != rdp->mynode) + spin_unlock(&rnp->lock); /* irqs remain disabled. */ break; } - - /* - * If there was a task blocking the current grace period, - * and if all CPUs have checked in, we need to propagate - * the quiescent state up the rcu_node hierarchy. But that - * is inconvenient at the moment due to deadlock issues if - * this should end the current grace period. So set the - * offlined CPU's bit in ->qsmask in order to force the - * next force_quiescent_state() invocation to clean up this - * mess in a deadlock-free manner. - */ - if (rcu_preempt_offline_tasks(rsp, rnp, rdp) && !rnp->qsmask) - rnp->qsmask |= mask; - + if (rnp == rdp->mynode) + need_quiet = rcu_preempt_offline_tasks(rsp, rnp, rdp); + else + spin_unlock(&rnp->lock); /* irqs remain disabled. */ mask = rnp->grpmask; - spin_unlock(&rnp->lock); /* irqs remain disabled. */ rnp = rnp->parent; } while (rnp != NULL); - spin_unlock_irqrestore(&rsp->onofflock, flags); + /* + * We still hold the leaf rcu_node structure lock here, and + * irqs are still disabled. The reason for this subterfuge is + * because invoking task_quiet() with ->onofflock held leads + * to deadlock. + */ + spin_unlock(&rsp->onofflock); /* irqs remain disabled. */ + rnp = rdp->mynode; + if (need_quiet) + task_quiet(rnp, flags); + else + spin_unlock_irqrestore(&rnp->lock, flags); rcu_adopt_orphan_cbs(rsp); } @@ -1731,6 +1733,7 @@ static void __init rcu_init_one(struct rcu_state *rsp) rnp = rsp->level[i]; for (j = 0; j < rsp->levelcnt[i]; j++, rnp++) { spin_lock_init(&rnp->lock); + lockdep_set_class(&rnp->lock, &rcu_node_class[i]); rnp->gpnum = 0; rnp->qsmask = 0; rnp->qsmaskinit = 0; @@ -1753,7 +1756,6 @@ static void __init rcu_init_one(struct rcu_state *rsp) INIT_LIST_HEAD(&rnp->blocked_tasks[1]); } } - lockdep_set_class(&rcu_get_root(rsp)->lock, &rcu_root_class); } /* diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 17a28a08b559..a81188c42929 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -305,6 +305,9 @@ static void rcu_bootup_announce(void); long rcu_batches_completed(void); static void rcu_preempt_note_context_switch(int cpu); static int rcu_preempted_readers(struct rcu_node *rnp); +#ifdef CONFIG_HOTPLUG_CPU +static void task_quiet(struct rcu_node *rnp, unsigned long flags); +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ #ifdef CONFIG_RCU_CPU_STALL_DETECTOR static void rcu_print_task_stall(struct rcu_node *rnp); #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 5ca2d26c5971..0bdb592eee66 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -160,11 +160,51 @@ static int rcu_preempted_readers(struct rcu_node *rnp) return !list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x1]); } +/* + * Record a quiescent state for all tasks that were previously queued + * on the specified rcu_node structure and that were blocking the current + * RCU grace period. The caller must hold the specified rnp->lock with + * irqs disabled, and this lock is released upon return, but irqs remain + * disabled. + */ +static void task_quiet(struct rcu_node *rnp, unsigned long flags) + __releases(rnp->lock) +{ + unsigned long mask; + struct rcu_node *rnp_p; + + if (rnp->qsmask != 0 || rcu_preempted_readers(rnp)) { + spin_unlock_irqrestore(&rnp->lock, flags); + return; /* Still need more quiescent states! */ + } + + rnp_p = rnp->parent; + if (rnp_p == NULL) { + /* + * Either there is only one rcu_node in the tree, + * or tasks were kicked up to root rcu_node due to + * CPUs going offline. + */ + cpu_quiet_msk_finish(&rcu_preempt_state, flags); + return; + } + + /* Report up the rest of the hierarchy. */ + mask = rnp->grpmask; + spin_unlock(&rnp->lock); /* irqs remain disabled. */ + spin_lock(&rnp_p->lock); /* irqs already disabled. */ + cpu_quiet_msk(mask, &rcu_preempt_state, rnp_p, flags); +} + +/* + * Handle special cases during rcu_read_unlock(), such as needing to + * notify RCU core processing or task having blocked during the RCU + * read-side critical section. + */ static void rcu_read_unlock_special(struct task_struct *t) { int empty; unsigned long flags; - unsigned long mask; struct rcu_node *rnp; int special; @@ -213,30 +253,15 @@ static void rcu_read_unlock_special(struct task_struct *t) /* * If this was the last task on the current list, and if * we aren't waiting on any CPUs, report the quiescent state. - * Note that both cpu_quiet_msk_finish() and cpu_quiet_msk() - * drop rnp->lock and restore irq. + * Note that task_quiet() releases rnp->lock. */ - if (!empty && rnp->qsmask == 0 && - !rcu_preempted_readers(rnp)) { - struct rcu_node *rnp_p; - - if (rnp->parent == NULL) { - /* Only one rcu_node in the tree. */ - cpu_quiet_msk_finish(&rcu_preempt_state, flags); - return; - } - /* Report up the rest of the hierarchy. */ - mask = rnp->grpmask; + if (empty) spin_unlock_irqrestore(&rnp->lock, flags); - rnp_p = rnp->parent; - spin_lock_irqsave(&rnp_p->lock, flags); - WARN_ON_ONCE(rnp->qsmask); - cpu_quiet_msk(mask, &rcu_preempt_state, rnp_p, flags); - return; - } - spin_unlock(&rnp->lock); + else + task_quiet(rnp, flags); + } else { + local_irq_restore(flags); } - local_irq_restore(flags); } /* @@ -303,6 +328,8 @@ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp) * rcu_node. The reason for not just moving them to the immediate * parent is to remove the need for rcu_read_unlock_special() to * make more than two attempts to acquire the target rcu_node's lock. + * Returns true if there were tasks blocking the current RCU grace + * period. * * Returns 1 if there was previously a task blocking the current grace * period on the specified rcu_node structure. @@ -316,7 +343,7 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp, int i; struct list_head *lp; struct list_head *lp_root; - int retval = rcu_preempted_readers(rnp); + int retval; struct rcu_node *rnp_root = rcu_get_root(rsp); struct task_struct *tp; @@ -334,6 +361,7 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp, * rcu_nodes in terms of gp_num value. This fact allows us to * move the blocked_tasks[] array directly, element by element. */ + retval = rcu_preempted_readers(rnp); for (i = 0; i < 2; i++) { lp = &rnp->blocked_tasks[i]; lp_root = &rnp_root->blocked_tasks[i]; @@ -346,7 +374,6 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp, spin_unlock(&rnp_root->lock); /* irqs remain disabled */ } } - return retval; } @@ -512,6 +539,16 @@ static int rcu_preempted_readers(struct rcu_node *rnp) return 0; } +#ifdef CONFIG_HOTPLUG_CPU + +/* Because preemptible RCU does not exist, no quieting of tasks. */ +static void task_quiet(struct rcu_node *rnp, unsigned long flags) +{ + spin_unlock_irqrestore(&rnp->lock, flags); +} + +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ + #ifdef CONFIG_RCU_CPU_STALL_DETECTOR /* -- cgit v1.2.3 From 9f680ab41485edfdc96331b70afa7513aa0a7720 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 22 Nov 2009 08:53:49 -0800 Subject: rcu: Eliminate unneeded function wrapping The functions rcu_init() is a wrapper for __rcu_init(), and also sets up the CPU-hotplug notifier for rcu_barrier_cpu_hotplug(). But TINY_RCU doesn't need CPU-hotplug notification, and the rcu_barrier_cpu_hotplug() is a simple wrapper for rcu_cpu_notify(). So push rcu_init() out to kernel/rcutree.c and kernel/rcutiny.c and get rid of the wrapper function rcu_barrier_cpu_hotplug(). Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12589088302320-git-send-email-> Signed-off-by: Ingo Molnar --- include/linux/rcutiny.h | 2 -- include/linux/rcutree.h | 3 --- kernel/rcupdate.c | 22 ---------------------- kernel/rcutiny.c | 11 +---------- kernel/rcutree.c | 17 ++++++++++++++--- 5 files changed, 15 insertions(+), 40 deletions(-) (limited to 'kernel') diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 2c1fe8373e71..a3b6272af2dd 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -38,7 +38,6 @@ void rcu_bh_qs(int cpu); #define rcu_init_sched() do { } while (0) extern void rcu_check_callbacks(int cpu, int user); -extern void __rcu_init(void); /* * Return the number of grace periods. @@ -69,7 +68,6 @@ static inline void synchronize_rcu_bh_expedited(void) } struct notifier_block; -extern int rcu_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu); #ifdef CONFIG_NO_HZ diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 9642c6bcb399..111a65257350 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -34,8 +34,6 @@ struct notifier_block; extern void rcu_sched_qs(int cpu); extern void rcu_bh_qs(int cpu); -extern int rcu_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu); extern int rcu_needs_cpu(int cpu); extern int rcu_expedited_torture_stats(char *page); @@ -83,7 +81,6 @@ static inline void synchronize_rcu_bh_expedited(void) synchronize_sched_expedited(); } -extern void __rcu_init(void); extern void rcu_check_callbacks(int cpu, int user); extern long rcu_batches_completed(void); diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 7625f207f65e..eb6b534db318 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -161,28 +161,6 @@ EXPORT_SYMBOL_GPL(synchronize_rcu_bh); #endif /* #ifndef CONFIG_TINY_RCU */ -static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self, - unsigned long action, void *hcpu) -{ - return rcu_cpu_notify(self, action, hcpu); -} - -void __init rcu_init(void) -{ - int i; - - __rcu_init(); - cpu_notifier(rcu_barrier_cpu_hotplug, 0); - - /* - * We don't need protection against CPU-hotplug here because - * this is called early in boot, before either interrupts - * or the scheduler are operational. - */ - for_each_online_cpu(i) - rcu_barrier_cpu_hotplug(NULL, CPU_UP_PREPARE, (void *)(long)i); -} - void rcu_scheduler_starting(void) { WARN_ON(num_online_cpus() != 1); diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c index b33ec3aa377a..9f6d9ff2572c 100644 --- a/kernel/rcutiny.c +++ b/kernel/rcutiny.c @@ -177,15 +177,6 @@ static void rcu_process_callbacks(struct softirq_action *unused) __rcu_process_callbacks(&rcu_bh_ctrlblk); } -/* - * Null function to handle CPU being onlined. Longer term, we want to - * make TINY_RCU avoid using rcupdate.c, but later... - */ -int rcu_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) -{ - return NOTIFY_OK; -} - /* * Wait for a grace period to elapse. But it is illegal to invoke * synchronize_sched() from within an RCU read-side critical section. @@ -285,7 +276,7 @@ void rcu_barrier_sched(void) } EXPORT_SYMBOL_GPL(rcu_barrier_sched); -void __rcu_init(void) +void __init rcu_init(void) { open_softirq(RCU_SOFTIRQ, rcu_process_callbacks); } diff --git a/kernel/rcutree.c b/kernel/rcutree.c index b79bfcd28e95..e3d3bbddbcd5 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1644,8 +1644,8 @@ static void __cpuinit rcu_online_cpu(int cpu) /* * Handle CPU online/offline notification events. */ -int __cpuinit rcu_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu) +static int __cpuinit rcu_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) { long cpu = (long)hcpu; @@ -1781,8 +1781,10 @@ do { \ } \ } while (0) -void __init __rcu_init(void) +void __init rcu_init(void) { + int i; + rcu_bootup_announce(); #ifdef CONFIG_RCU_CPU_STALL_DETECTOR printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n"); @@ -1791,6 +1793,15 @@ void __init __rcu_init(void) RCU_INIT_FLAVOR(&rcu_bh_state, rcu_bh_data); __rcu_init_preempt(); open_softirq(RCU_SOFTIRQ, rcu_process_callbacks); + + /* + * We don't need protection against CPU-hotplug here because + * this is called early in boot, before either interrupts + * or the scheduler are operational. + */ + cpu_notifier(rcu_cpu_notify, 0); + for_each_online_cpu(i) + rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)i); } #include "rcutree_plugin.h" -- cgit v1.2.3 From 6ebb237bece23275d1da149b61a342f0d4d06a08 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 22 Nov 2009 08:53:50 -0800 Subject: rcu: Re-arrange code to reduce #ifdef pain Remove #ifdefs from kernel/rcupdate.c and include/linux/rcupdate.h by moving code to include/linux/rcutiny.h, include/linux/rcutree.h, and kernel/rcutree.c. Also remove some definitions that are no longer used. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1258908830885-git-send-email-> Signed-off-by: Ingo Molnar --- include/linux/rcupdate.h | 12 ------ include/linux/rcutiny.h | 11 +++++ include/linux/rcutree.h | 4 +- kernel/rcupdate.c | 104 ----------------------------------------------- kernel/rcutree.c | 80 ++++++++++++++++++++++++++++++++++++ kernel/rcutree_plugin.h | 24 +++++++++++ 6 files changed, 118 insertions(+), 117 deletions(-) (limited to 'kernel') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 2f1bc42a3b82..24440f4bf476 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -52,11 +52,6 @@ struct rcu_head { }; /* Exported common interfaces */ -#ifdef CONFIG_TREE_PREEMPT_RCU -extern void synchronize_rcu(void); -#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */ -#define synchronize_rcu synchronize_sched -#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */ extern void synchronize_rcu_bh(void); extern void synchronize_sched(void); extern void rcu_barrier(void); @@ -67,13 +62,6 @@ extern int sched_expedited_torture_stats(char *page); /* Internal to kernel */ extern void rcu_init(void); -extern void rcu_scheduler_starting(void); -#ifndef CONFIG_TINY_RCU -extern int rcu_needs_cpu(int cpu); -#else -static inline int rcu_needs_cpu(int cpu) { return 0; } -#endif -extern int rcu_scheduler_active; #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU) #include diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index a3b6272af2dd..c4ba9a78721e 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -39,6 +39,11 @@ void rcu_bh_qs(int cpu); #define rcu_init_sched() do { } while (0) extern void rcu_check_callbacks(int cpu, int user); +static inline int rcu_needs_cpu(int cpu) +{ + return 0; +} + /* * Return the number of grace periods. */ @@ -57,6 +62,8 @@ static inline long rcu_batches_completed_bh(void) extern int rcu_expedited_torture_stats(char *page); +#define synchronize_rcu synchronize_sched + static inline void synchronize_rcu_expedited(void) { synchronize_sched(); @@ -86,6 +93,10 @@ static inline void rcu_exit_nohz(void) #endif /* #else #ifdef CONFIG_NO_HZ */ +static inline void rcu_scheduler_starting(void) +{ +} + static inline void exit_rcu(void) { } diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 111a65257350..c93eee5911b0 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -35,12 +35,14 @@ struct notifier_block; extern void rcu_sched_qs(int cpu); extern void rcu_bh_qs(int cpu); extern int rcu_needs_cpu(int cpu); +extern void rcu_scheduler_starting(void); extern int rcu_expedited_torture_stats(char *page); #ifdef CONFIG_TREE_PREEMPT_RCU extern void __rcu_read_lock(void); extern void __rcu_read_unlock(void); +extern void synchronize_rcu(void); extern void exit_rcu(void); #else /* #ifdef CONFIG_TREE_PREEMPT_RCU */ @@ -55,7 +57,7 @@ static inline void __rcu_read_unlock(void) preempt_enable(); } -#define __synchronize_sched() synchronize_rcu() +#define synchronize_rcu synchronize_sched static inline void exit_rcu(void) { diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index eb6b534db318..9b7fd4723878 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -44,7 +44,6 @@ #include #include #include -#include #ifdef CONFIG_DEBUG_LOCK_ALLOC static struct lock_class_key rcu_lock_key; @@ -53,8 +52,6 @@ struct lockdep_map rcu_lock_map = EXPORT_SYMBOL_GPL(rcu_lock_map); #endif -int rcu_scheduler_active __read_mostly; - /* * Awaken the corresponding synchronize_rcu() instance now that a * grace period has elapsed. @@ -66,104 +63,3 @@ void wakeme_after_rcu(struct rcu_head *head) rcu = container_of(head, struct rcu_synchronize, head); complete(&rcu->completion); } - -#ifndef CONFIG_TINY_RCU - -#ifdef CONFIG_TREE_PREEMPT_RCU - -/** - * synchronize_rcu - wait until a grace period has elapsed. - * - * Control will return to the caller some time after a full grace - * period has elapsed, in other words after all currently executing RCU - * read-side critical sections have completed. RCU read-side critical - * sections are delimited by rcu_read_lock() and rcu_read_unlock(), - * and may be nested. - */ -void synchronize_rcu(void) -{ - struct rcu_synchronize rcu; - - if (!rcu_scheduler_active) - return; - - init_completion(&rcu.completion); - /* Will wake me after RCU finished. */ - call_rcu(&rcu.head, wakeme_after_rcu); - /* Wait for it. */ - wait_for_completion(&rcu.completion); -} -EXPORT_SYMBOL_GPL(synchronize_rcu); - -#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ - -/** - * synchronize_sched - wait until an rcu-sched grace period has elapsed. - * - * Control will return to the caller some time after a full rcu-sched - * grace period has elapsed, in other words after all currently executing - * rcu-sched read-side critical sections have completed. These read-side - * critical sections are delimited by rcu_read_lock_sched() and - * rcu_read_unlock_sched(), and may be nested. Note that preempt_disable(), - * local_irq_disable(), and so on may be used in place of - * rcu_read_lock_sched(). - * - * This means that all preempt_disable code sequences, including NMI and - * hardware-interrupt handlers, in progress on entry will have completed - * before this primitive returns. However, this does not guarantee that - * softirq handlers will have completed, since in some kernels, these - * handlers can run in process context, and can block. - * - * This primitive provides the guarantees made by the (now removed) - * synchronize_kernel() API. In contrast, synchronize_rcu() only - * guarantees that rcu_read_lock() sections will have completed. - * In "classic RCU", these two guarantees happen to be one and - * the same, but can differ in realtime RCU implementations. - */ -void synchronize_sched(void) -{ - struct rcu_synchronize rcu; - - if (rcu_blocking_is_gp()) - return; - - init_completion(&rcu.completion); - /* Will wake me after RCU finished. */ - call_rcu_sched(&rcu.head, wakeme_after_rcu); - /* Wait for it. */ - wait_for_completion(&rcu.completion); -} -EXPORT_SYMBOL_GPL(synchronize_sched); - -/** - * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed. - * - * Control will return to the caller some time after a full rcu_bh grace - * period has elapsed, in other words after all currently executing rcu_bh - * read-side critical sections have completed. RCU read-side critical - * sections are delimited by rcu_read_lock_bh() and rcu_read_unlock_bh(), - * and may be nested. - */ -void synchronize_rcu_bh(void) -{ - struct rcu_synchronize rcu; - - if (rcu_blocking_is_gp()) - return; - - init_completion(&rcu.completion); - /* Will wake me after RCU finished. */ - call_rcu_bh(&rcu.head, wakeme_after_rcu); - /* Wait for it. */ - wait_for_completion(&rcu.completion); -} -EXPORT_SYMBOL_GPL(synchronize_rcu_bh); - -#endif /* #ifndef CONFIG_TINY_RCU */ - -void rcu_scheduler_starting(void) -{ - WARN_ON(num_online_cpus() != 1); - WARN_ON(nr_context_switches() > 0); - rcu_scheduler_active = 1; -} diff --git a/kernel/rcutree.c b/kernel/rcutree.c index e3d3bbddbcd5..4ca7e0292fd8 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -46,6 +46,7 @@ #include #include #include +#include #include "rcutree.h" @@ -79,6 +80,8 @@ DEFINE_PER_CPU(struct rcu_data, rcu_sched_data); struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state); DEFINE_PER_CPU(struct rcu_data, rcu_bh_data); +static int rcu_scheduler_active __read_mostly; + /* * Return true if an RCU grace period is in progress. The ACCESS_ONCE()s @@ -1396,6 +1399,68 @@ void call_rcu_bh(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) } EXPORT_SYMBOL_GPL(call_rcu_bh); +/** + * synchronize_sched - wait until an rcu-sched grace period has elapsed. + * + * Control will return to the caller some time after a full rcu-sched + * grace period has elapsed, in other words after all currently executing + * rcu-sched read-side critical sections have completed. These read-side + * critical sections are delimited by rcu_read_lock_sched() and + * rcu_read_unlock_sched(), and may be nested. Note that preempt_disable(), + * local_irq_disable(), and so on may be used in place of + * rcu_read_lock_sched(). + * + * This means that all preempt_disable code sequences, including NMI and + * hardware-interrupt handlers, in progress on entry will have completed + * before this primitive returns. However, this does not guarantee that + * softirq handlers will have completed, since in some kernels, these + * handlers can run in process context, and can block. + * + * This primitive provides the guarantees made by the (now removed) + * synchronize_kernel() API. In contrast, synchronize_rcu() only + * guarantees that rcu_read_lock() sections will have completed. + * In "classic RCU", these two guarantees happen to be one and + * the same, but can differ in realtime RCU implementations. + */ +void synchronize_sched(void) +{ + struct rcu_synchronize rcu; + + if (rcu_blocking_is_gp()) + return; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu_sched(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(synchronize_sched); + +/** + * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed. + * + * Control will return to the caller some time after a full rcu_bh grace + * period has elapsed, in other words after all currently executing rcu_bh + * read-side critical sections have completed. RCU read-side critical + * sections are delimited by rcu_read_lock_bh() and rcu_read_unlock_bh(), + * and may be nested. + */ +void synchronize_rcu_bh(void) +{ + struct rcu_synchronize rcu; + + if (rcu_blocking_is_gp()) + return; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu_bh(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(synchronize_rcu_bh); + /* * Check to see if there is any immediate RCU-related work to be done * by the current CPU, for the specified type of RCU, returning 1 if so. @@ -1480,6 +1545,21 @@ int rcu_needs_cpu(int cpu) rcu_preempt_needs_cpu(cpu); } +/* + * This function is invoked towards the end of the scheduler's initialization + * process. Before this is called, the idle task might contain + * RCU read-side critical sections (during which time, this idle + * task is booting the system). After this function is called, the + * idle tasks are prohibited from containing RCU read-side critical + * sections. + */ +void rcu_scheduler_starting(void) +{ + WARN_ON(num_online_cpus() != 1); + WARN_ON(nr_context_switches() > 0); + rcu_scheduler_active = 1; +} + static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL}; static atomic_t rcu_barrier_cpu_count; static DEFINE_MUTEX(rcu_barrier_mutex); diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 0bdb592eee66..1d295c789d3d 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -425,6 +425,30 @@ void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) } EXPORT_SYMBOL_GPL(call_rcu); +/** + * synchronize_rcu - wait until a grace period has elapsed. + * + * Control will return to the caller some time after a full grace + * period has elapsed, in other words after all currently executing RCU + * read-side critical sections have completed. RCU read-side critical + * sections are delimited by rcu_read_lock() and rcu_read_unlock(), + * and may be nested. + */ +void synchronize_rcu(void) +{ + struct rcu_synchronize rcu; + + if (!rcu_scheduler_active) + return; + + init_completion(&rcu.completion); + /* Will wake me after RCU finished. */ + call_rcu(&rcu.head, wakeme_after_rcu); + /* Wait for it. */ + wait_for_completion(&rcu.completion); +} +EXPORT_SYMBOL_GPL(synchronize_rcu); + /* * Wait for an rcu-preempt grace period. We are supposed to expedite the * grace period, but this is the crude slow compatability hack, so just -- cgit v1.2.3 From 98e4833ba3c314c99dc364012fba6ac894230ad0 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 23 Nov 2009 08:03:09 +0100 Subject: ring-buffer benchmark: Run producer/consumer threads at nice +19 The ring-buffer benchmark threads run on nice 0 by default, using up a lot of CPU time and slowing down the system: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1024 root 20 0 0 0 0 D 95.3 0.0 4:01.67 rb_producer 1023 root 20 0 0 0 0 R 93.5 0.0 2:54.33 rb_consumer 21569 mingo 40 0 14852 1048 772 R 3.6 0.1 0:00.05 top 1 root 40 0 4080 928 668 S 0.0 0.0 0:23.98 init Renice them to +19 to make them less intrusive. Cc: Steven Rostedt Cc: Frederic Weisbecker Cc: Peter Zijlstra Cc: Mike Galbraith LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/trace/ring_buffer_benchmark.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c index 70df73e4ff21..3875d49da990 100644 --- a/kernel/trace/ring_buffer_benchmark.c +++ b/kernel/trace/ring_buffer_benchmark.c @@ -399,6 +399,12 @@ static int __init ring_buffer_benchmark_init(void) if (IS_ERR(producer)) goto out_kill; + /* + * Run them as low-prio background tasks by default: + */ + set_user_nice(consumer, 19); + set_user_nice(producer, 19); + return 0; out_kill: -- cgit v1.2.3 From 457dc928f586f3f4b930206965e6db270034e97e Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 23 Nov 2009 11:03:28 +0100 Subject: tracing, function tracer: Clean up strstrip() usage Clean up strstrip() usage - which also addresses this build warning: kernel/trace/ftrace.c: In function 'ftrace_pid_write': kernel/trace/ftrace.c:3004: warning: ignoring return value of 'strstrip', declared with attribute warn_unused_result Cc: Steven Rostedt Cc: Frederic Weisbecker Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 7f9b51e8184b..1dc101d09765 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2985,7 +2985,7 @@ static ssize_t ftrace_pid_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { - char buf[64]; + char buf[64], *tmp; long val; int ret; @@ -3001,11 +3001,11 @@ ftrace_pid_write(struct file *filp, const char __user *ubuf, * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid" * to clean the filter quietly. */ - strstrip(buf); - if (strlen(buf) == 0) + tmp = strstrip(buf); + if (strlen(tmp) == 0) return 1; - ret = strict_strtol(buf, 10, &val); + ret = strict_strtol(tmp, 10, &val); if (ret < 0) return ret; @@ -3391,4 +3391,3 @@ void ftrace_graph_stop(void) ftrace_stop(); } #endif - -- cgit v1.2.3 From c4a5af54c8ef277a59189fc9358e190f3c1b8206 Mon Sep 17 00:00:00 2001 From: "Andrew G. Morgan" Date: Mon, 23 Nov 2009 04:57:52 +0000 Subject: Silence the existing API for capability version compatibility check. When libcap, or other libraries attempt to confirm/determine the supported capability version magic, they generally supply a NULL dataptr to capget(). In this case, while returning the supported/preferred magic (via a modified header content), the return code of this system call may be 0, -EINVAL, or -EFAULT. No libcap code depends on the previous -EINVAL etc. return code, and all of the above three return codes can accompany a valid (successful) attempt to determine the requested magic value. This patch cleans up the system call to return 0, if the call is successfully being used to determine the supported/preferred capability magic value. Signed-off-by: Andrew G. Morgan Acked-by: Steve Grubb Acked-by: Serge Hallyn Signed-off-by: James Morris --- kernel/capability.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/capability.c b/kernel/capability.c index c2316d3fa094..c450375e855f 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -169,8 +169,8 @@ SYSCALL_DEFINE2(capget, cap_user_header_t, header, cap_user_data_t, dataptr) kernel_cap_t pE, pI, pP; ret = cap_validate_magic(header, &tocopy); - if (ret != 0) - return ret; + if ((dataptr == NULL) || (ret != 0)) + return ((dataptr == NULL) && (ret == -EINVAL)) ? 0 : ret; if (get_user(pid, &header->pid)) return -EFAULT; -- cgit v1.2.3 From b3a222e52e4d4be77cc4520a57af1a4a0d8222d1 Mon Sep 17 00:00:00 2001 From: "Serge E. Hallyn" Date: Mon, 23 Nov 2009 16:21:30 -0600 Subject: remove CONFIG_SECURITY_FILE_CAPABILITIES compile option As far as I know, all distros currently ship kernels with default CONFIG_SECURITY_FILE_CAPABILITIES=y. Since having the option on leaves a 'no_file_caps' option to boot without file capabilities, the main reason to keep the option is that turning it off saves you (on my s390x partition) 5k. In particular, vmlinux sizes came to: without patch fscaps=n: 53598392 without patch fscaps=y: 53603406 with this patch applied: 53603342 with the security-next tree. Against this we must weigh the fact that there is no simple way for userspace to figure out whether file capabilities are supported, while things like per-process securebits, capability bounding sets, and adding bits to pI if CAP_SETPCAP is in pE are not supported with SECURITY_FILE_CAPABILITIES=n, leaving a bit of a problem for applications wanting to know whether they can use them and/or why something failed. It also adds another subtly different set of semantics which we must maintain at the risk of severe security regressions. So this patch removes the SECURITY_FILE_CAPABILITIES compile option. It drops the kernel size by about 50k over the stock SECURITY_FILE_CAPABILITIES=y kernel, by removing the cap_limit_ptraced_target() function. Changelog: Nov 20: remove cap_limit_ptraced_target() as it's logic was ifndef'ed. Signed-off-by: Serge E. Hallyn Acked-by: Andrew G. Morgan" Signed-off-by: James Morris --- include/linux/capability.h | 2 -- include/linux/init_task.h | 4 --- kernel/capability.c | 2 -- security/Kconfig | 9 ------ security/commoncap.c | 72 ++-------------------------------------------- 5 files changed, 2 insertions(+), 87 deletions(-) (limited to 'kernel') diff --git a/include/linux/capability.h b/include/linux/capability.h index c8f2a5f70ed5..39e5ff512fbe 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -92,9 +92,7 @@ struct vfs_cap_data { #define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3 #define _KERNEL_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3 -#ifdef CONFIG_SECURITY_FILE_CAPABILITIES extern int file_caps_enabled; -#endif typedef struct kernel_cap_struct { __u32 cap[_KERNEL_CAPABILITY_U32S]; diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 21a6f5d9af22..8d10aa7fd4c9 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -83,16 +83,12 @@ extern struct group_info init_groups; #define INIT_IDS #endif -#ifdef CONFIG_SECURITY_FILE_CAPABILITIES /* * Because of the reduced scope of CAP_SETPCAP when filesystem * capabilities are in effect, it is safe to allow CAP_SETPCAP to * be available in the default configuration. */ # define CAP_INIT_BSET CAP_FULL_SET -#else -# define CAP_INIT_BSET CAP_INIT_EFF_SET -#endif #ifdef CONFIG_TREE_PREEMPT_RCU #define INIT_TASK_RCU_PREEMPT(tsk) \ diff --git a/kernel/capability.c b/kernel/capability.c index c450375e855f..7f876e60521f 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -29,7 +29,6 @@ EXPORT_SYMBOL(__cap_empty_set); EXPORT_SYMBOL(__cap_full_set); EXPORT_SYMBOL(__cap_init_eff_set); -#ifdef CONFIG_SECURITY_FILE_CAPABILITIES int file_caps_enabled = 1; static int __init file_caps_disable(char *str) @@ -38,7 +37,6 @@ static int __init file_caps_disable(char *str) return 1; } __setup("no_file_caps", file_caps_disable); -#endif /* * More recent versions of libcap are available from: diff --git a/security/Kconfig b/security/Kconfig index 95cc08913ca1..226b9556b25f 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -91,15 +91,6 @@ config SECURITY_PATH implement pathname based access controls. If you are unsure how to answer this question, answer N. -config SECURITY_FILE_CAPABILITIES - bool "File POSIX Capabilities" - default n - help - This enables filesystem capabilities, allowing you to give - binaries a subset of root's powers without using setuid 0. - - If in doubt, answer N. - config INTEL_TXT bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)" depends on HAVE_INTEL_TXT diff --git a/security/commoncap.c b/security/commoncap.c index 45b87af4ae5d..f800fdb3de94 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -173,7 +173,6 @@ int cap_capget(struct task_struct *target, kernel_cap_t *effective, */ static inline int cap_inh_is_capped(void) { -#ifdef CONFIG_SECURITY_FILE_CAPABILITIES /* they are so limited unless the current task has the CAP_SETPCAP * capability @@ -181,7 +180,6 @@ static inline int cap_inh_is_capped(void) if (cap_capable(current, current_cred(), CAP_SETPCAP, SECURITY_CAP_AUDIT) == 0) return 0; -#endif return 1; } @@ -239,8 +237,6 @@ static inline void bprm_clear_caps(struct linux_binprm *bprm) bprm->cap_effective = false; } -#ifdef CONFIG_SECURITY_FILE_CAPABILITIES - /** * cap_inode_need_killpriv - Determine if inode change affects privileges * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV @@ -421,49 +417,6 @@ out: return rc; } -#else -int cap_inode_need_killpriv(struct dentry *dentry) -{ - return 0; -} - -int cap_inode_killpriv(struct dentry *dentry) -{ - return 0; -} - -int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps) -{ - memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data)); - return -ENODATA; -} - -static inline int get_file_caps(struct linux_binprm *bprm, bool *effective) -{ - bprm_clear_caps(bprm); - return 0; -} -#endif - -/* - * Determine whether a exec'ing process's new permitted capabilities should be - * limited to just what it already has. - * - * This prevents processes that are being ptraced from gaining access to - * CAP_SETPCAP, unless the process they're tracing already has it, and the - * binary they're executing has filecaps that elevate it. - * - * Returns 1 if they should be limited, 0 if they are not. - */ -static inline int cap_limit_ptraced_target(void) -{ -#ifndef CONFIG_SECURITY_FILE_CAPABILITIES - if (capable(CAP_SETPCAP)) - return 0; -#endif - return 1; -} - /** * cap_bprm_set_creds - Set up the proposed credentials for execve(). * @bprm: The execution parameters, including the proposed creds @@ -523,9 +476,8 @@ skip: new->euid = new->uid; new->egid = new->gid; } - if (cap_limit_ptraced_target()) - new->cap_permitted = cap_intersect(new->cap_permitted, - old->cap_permitted); + new->cap_permitted = cap_intersect(new->cap_permitted, + old->cap_permitted); } new->suid = new->fsuid = new->euid; @@ -739,7 +691,6 @@ int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags) return 0; } -#ifdef CONFIG_SECURITY_FILE_CAPABILITIES /* * Rationale: code calling task_setscheduler, task_setioprio, and * task_setnice, assumes that @@ -820,22 +771,6 @@ static long cap_prctl_drop(struct cred *new, unsigned long cap) return 0; } -#else -int cap_task_setscheduler (struct task_struct *p, int policy, - struct sched_param *lp) -{ - return 0; -} -int cap_task_setioprio (struct task_struct *p, int ioprio) -{ - return 0; -} -int cap_task_setnice (struct task_struct *p, int nice) -{ - return 0; -} -#endif - /** * cap_task_prctl - Implement process control functions for this security module * @option: The process control function requested @@ -866,7 +801,6 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, error = !!cap_raised(new->cap_bset, arg2); goto no_change; -#ifdef CONFIG_SECURITY_FILE_CAPABILITIES case PR_CAPBSET_DROP: error = cap_prctl_drop(new, arg2); if (error < 0) @@ -917,8 +851,6 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, error = new->securebits; goto no_change; -#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */ - case PR_GET_KEEPCAPS: if (issecure(SECURE_KEEP_CAPS)) error = 1; -- cgit v1.2.3 From 7ac074340480018681a0d72b324d4487543bdc0e Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 25 Nov 2009 13:22:21 -0500 Subject: ring-buffer-benchmark: Add parameters to set produce/consumer priorities Running the ring-buffer-benchmark's threads at the lowest priority may work well for keeping it in the background, but it is not appropriate for the benchmarks. This patch adds 4 parameters to the module: consumer_fifo consumer_nice producer_fifo producer_nice By default the consumer and producer still run at nice +19. If the *_fifo options are set, they will override the *_nice values. modprobe ring_buffer_benchmark consumer_nice=0 producer_fifo=10 The above will set the consumer thread to a nice value of 0, and the producer thread to a RT SCHED_FIFO priority of 10. Note, this patch also fixes a bug where calling set_user_nice on the consumer thread would oops the kernel when the parameter "disable_reader" is set. Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer_benchmark.c | 58 ++++++++++++++++++++++++++++++++++-- 1 file changed, 56 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c index 3875d49da990..b2477caf09c2 100644 --- a/kernel/trace/ring_buffer_benchmark.c +++ b/kernel/trace/ring_buffer_benchmark.c @@ -39,6 +39,24 @@ static int write_iteration = 50; module_param(write_iteration, uint, 0644); MODULE_PARM_DESC(write_iteration, "# of writes between timestamp readings"); +static int producer_nice = 19; +static int consumer_nice = 19; + +static int producer_fifo = -1; +static int consumer_fifo = -1; + +module_param(producer_nice, uint, 0644); +MODULE_PARM_DESC(producer_nice, "nice prio for producer"); + +module_param(consumer_nice, uint, 0644); +MODULE_PARM_DESC(consumer_nice, "nice prio for consumer"); + +module_param(producer_fifo, uint, 0644); +MODULE_PARM_DESC(producer_fifo, "fifo prio for producer"); + +module_param(consumer_fifo, uint, 0644); +MODULE_PARM_DESC(consumer_fifo, "fifo prio for consumer"); + static int read_events; static int kill_test; @@ -270,6 +288,27 @@ static void ring_buffer_producer(void) if (kill_test) trace_printk("ERROR!\n"); + + if (!disable_reader) { + if (consumer_fifo < 0) + trace_printk("Running Consumer at nice: %d\n", + consumer_nice); + else + trace_printk("Running Consumer at SCHED_FIFO %d\n", + consumer_fifo); + } + if (producer_fifo < 0) + trace_printk("Running Producer at nice: %d\n", + producer_nice); + else + trace_printk("Running Producer at SCHED_FIFO %d\n", + producer_fifo); + + /* Let the user know that the test is running at low priority */ + if (producer_fifo < 0 && consumer_fifo < 0 && + producer_nice == 19 && consumer_nice == 19) + trace_printk("WARNING!!! This test is running at lowest priority.\n"); + trace_printk("Time: %lld (usecs)\n", time); trace_printk("Overruns: %lld\n", overruns); if (disable_reader) @@ -402,8 +441,23 @@ static int __init ring_buffer_benchmark_init(void) /* * Run them as low-prio background tasks by default: */ - set_user_nice(consumer, 19); - set_user_nice(producer, 19); + if (!disable_reader) { + if (consumer_fifo >= 0) { + struct sched_param param = { + .sched_priority = consumer_fifo + }; + sched_setscheduler(consumer, SCHED_FIFO, ¶m); + } else + set_user_nice(consumer, consumer_nice); + } + + if (producer_fifo >= 0) { + struct sched_param param = { + .sched_priority = consumer_fifo + }; + sched_setscheduler(producer, SCHED_FIFO, ¶m); + } else + set_user_nice(producer, producer_nice); return 0; -- cgit v1.2.3 From e5af02261668350b43eb7381648930bde8e872f7 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Fri, 27 Nov 2009 13:28:20 +1100 Subject: softlockup: Fix hung_task_check_count sysctl I'm seeing spikes of up to 0.5ms in khungtaskd on a large machine. To reduce this source of jitter I tried setting hung_task_check_count to 0: # echo 0 > /proc/sys/kernel/hung_task_check_count which didn't have the intended response. Change to a post increment of max_count, so a value of 0 means check 0 tasks. Signed-off-by: Anton Blanchard Acked-by: Frederic Weisbecker Cc: msb@google.com LKML-Reference: <20091127022820.GU32182@kryten> Signed-off-by: Ingo Molnar --- kernel/hung_task.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/hung_task.c b/kernel/hung_task.c index d4e841747400..0c642d51aac2 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -144,7 +144,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) rcu_read_lock(); do_each_thread(g, t) { - if (!--max_count) + if (!max_count--) goto unlock; if (!--batch_count) { batch_count = HUNG_TASK_BATCHING; -- cgit v1.2.3 From 35dead4235e2b67da7275b4122fed37099c2f462 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Thu, 3 Dec 2009 00:29:15 +0100 Subject: modules: don't export section names of empty sections via sysfs On the parisc architecture we face for each and every loaded kernel module this kernel "badness warning": sysfs: cannot create duplicate filename '/module/ac97_bus/sections/.text' Badness at fs/sysfs/dir.c:487 Reason for that is, that on parisc all kernel modules do have multiple .text sections due to the usage of the -ffunction-sections compiler flag which is needed to reach all jump targets on this platform. An objdump on such a kernel module gives: Sections: Idx Name Size VMA LMA File off Algn 0 .note.gnu.build-id 00000024 00000000 00000000 00000034 2**2 CONTENTS, ALLOC, LOAD, READONLY, DATA 1 .text 00000000 00000000 00000000 00000058 2**0 CONTENTS, ALLOC, LOAD, READONLY, CODE 2 .text.ac97_bus_match 0000001c 00000000 00000000 00000058 2**2 CONTENTS, ALLOC, LOAD, READONLY, CODE 3 .text 00000000 00000000 00000000 000000d4 2**0 CONTENTS, ALLOC, LOAD, READONLY, CODE ... Since the .text sections are empty (size of 0 bytes) and won't be loaded by the kernel module loader anyway, I don't see a reason why such sections need to be listed under /sys/module//sections/ either. The attached patch does solve this issue by not exporting section names which are empty. This fixes bugzilla http://bugzilla.kernel.org/show_bug.cgi?id=14703 Signed-off-by: Helge Deller CC: rusty@rustcorp.com.au CC: akpm@linux-foundation.org CC: James.Bottomley@HansenPartnership.com CC: roland@redhat.com CC: dave@hiauly1.hia.nrc.ca Signed-off-by: Linus Torvalds --- kernel/module.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index 8b7d8805819d..5842a71cf052 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1187,7 +1187,8 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect, /* Count loaded sections and allocate structures */ for (i = 0; i < nsect; i++) - if (sechdrs[i].sh_flags & SHF_ALLOC) + if (sechdrs[i].sh_flags & SHF_ALLOC + && sechdrs[i].sh_size) nloaded++; size[0] = ALIGN(sizeof(*sect_attrs) + nloaded * sizeof(sect_attrs->attrs[0]), @@ -1207,6 +1208,8 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect, for (i = 0; i < nsect; i++) { if (! (sechdrs[i].sh_flags & SHF_ALLOC)) continue; + if (!sechdrs[i].sh_size) + continue; sattr->address = sechdrs[i].sh_addr; sattr->name = kstrdup(secstrings + sechdrs[i].sh_name, GFP_KERNEL); -- cgit v1.2.3 From d3f6bad3911736e44ba11f3f3f6ac4e8c837fdfc Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 2 Dec 2009 12:10:13 -0800 Subject: rcu: Rename "quiet" functions The number of "quiet" functions has grown recently, and the names are no longer very descriptive. The point of all of these functions is to do some portion of the task of reporting a quiescent state, so rename them accordingly: o cpu_quiet() becomes rcu_report_qs_rdp(), which reports a quiescent state to the per-CPU rcu_data structure. If this turns out to be a new quiescent state for this grace period, then rcu_report_qs_rnp() will be invoked to propagate the quiescent state up the rcu_node hierarchy. o cpu_quiet_msk() becomes rcu_report_qs_rnp(), which reports a quiescent state for a given CPU (or possibly a set of CPUs) up the rcu_node hierarchy. o cpu_quiet_msk_finish() becomes rcu_report_qs_rsp(), which reports a full set of quiescent states to the global rcu_state structure. o task_quiet() becomes rcu_report_unblock_qs_rnp(), which reports a quiescent state due to a task exiting an RCU read-side critical section that had previously blocked in that same critical section. As indicated by the new name, this type of quiescent state is reported up the rcu_node hierarchy (using rcu_report_qs_rnp() to do so). Signed-off-by: Paul E. McKenney Acked-by: Josh Triplett Acked-by: Lai Jiangshan Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12597846163698-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 66 +++++++++++++++++++++++++++---------------------- kernel/rcutree.h | 3 ++- kernel/rcutree_plugin.h | 12 ++++----- 3 files changed, 45 insertions(+), 36 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 4ca7e0292fd8..a9f51031d3e8 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -740,11 +740,13 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) } /* - * Clean up after the prior grace period and let rcu_start_gp() start up - * the next grace period if one is needed. Note that the caller must - * hold rnp->lock, as required by rcu_start_gp(), which will release it. + * Report a full set of quiescent states to the specified rcu_state + * data structure. This involves cleaning up after the prior grace + * period and letting rcu_start_gp() start up the next grace period + * if one is needed. Note that the caller must hold rnp->lock, as + * required by rcu_start_gp(), which will release it. */ -static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags) +static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags) __releases(rcu_get_root(rsp)->lock) { WARN_ON_ONCE(!rcu_gp_in_progress(rsp)); @@ -754,15 +756,16 @@ static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags) } /* - * Similar to cpu_quiet(), for which it is a helper function. Allows - * a group of CPUs to be quieted at one go, though all the CPUs in the - * group must be represented by the same leaf rcu_node structure. - * That structure's lock must be held upon entry, and it is released - * before return. + * Similar to rcu_report_qs_rdp(), for which it is a helper function. + * Allows quiescent states for a group of CPUs to be reported at one go + * to the specified rcu_node structure, though all the CPUs in the group + * must be represented by the same rcu_node structure (which need not be + * a leaf rcu_node structure, though it often will be). That structure's + * lock must be held upon entry, and it is released before return. */ static void -cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp, struct rcu_node *rnp, - unsigned long flags) +rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp, + struct rcu_node *rnp, unsigned long flags) __releases(rnp->lock) { struct rcu_node *rnp_c; @@ -798,21 +801,23 @@ cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp, struct rcu_node *rnp, /* * Get here if we are the last CPU to pass through a quiescent - * state for this grace period. Invoke cpu_quiet_msk_finish() + * state for this grace period. Invoke rcu_report_qs_rsp() * to clean up and start the next grace period if one is needed. */ - cpu_quiet_msk_finish(rsp, flags); /* releases rnp->lock. */ + rcu_report_qs_rsp(rsp, flags); /* releases rnp->lock. */ } /* - * Record a quiescent state for the specified CPU, which must either be - * the current CPU. The lastcomp argument is used to make sure we are - * still in the grace period of interest. We don't want to end the current - * grace period based on quiescent states detected in an earlier grace - * period! + * Record a quiescent state for the specified CPU to that CPU's rcu_data + * structure. This must be either called from the specified CPU, or + * called when the specified CPU is known to be offline (and when it is + * also known that no other CPU is concurrently trying to help the offline + * CPU). The lastcomp argument is used to make sure we are still in the + * grace period of interest. We don't want to end the current grace period + * based on quiescent states detected in an earlier grace period! */ static void -cpu_quiet(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) +rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) { unsigned long flags; unsigned long mask; @@ -827,8 +832,8 @@ cpu_quiet(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) * The race with GP start is resolved by the fact that we * hold the leaf rcu_node lock, so that the per-CPU bits * cannot yet be initialized -- so we would simply find our - * CPU's bit already cleared in cpu_quiet_msk() if this race - * occurred. + * CPU's bit already cleared in rcu_report_qs_rnp() if this + * race occurred. */ rdp->passed_quiesc = 0; /* try again later! */ spin_unlock_irqrestore(&rnp->lock, flags); @@ -846,7 +851,7 @@ cpu_quiet(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) */ rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; - cpu_quiet_msk(mask, rsp, rnp, flags); /* releases rnp->lock */ + rcu_report_qs_rnp(mask, rsp, rnp, flags); /* rlses rnp->lock */ } } @@ -877,8 +882,11 @@ rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp) if (!rdp->passed_quiesc) return; - /* Tell RCU we are done (but cpu_quiet() will be the judge of that). */ - cpu_quiet(rdp->cpu, rsp, rdp, rdp->passed_quiesc_completed); + /* + * Tell RCU we are done (but rcu_report_qs_rdp() will be the + * judge of that). + */ + rcu_report_qs_rdp(rdp->cpu, rsp, rdp, rdp->passed_quiesc_completed); } #ifdef CONFIG_HOTPLUG_CPU @@ -968,13 +976,13 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) /* * We still hold the leaf rcu_node structure lock here, and * irqs are still disabled. The reason for this subterfuge is - * because invoking task_quiet() with ->onofflock held leads - * to deadlock. + * because invoking rcu_report_unblock_qs_rnp() with ->onofflock + * held leads to deadlock. */ spin_unlock(&rsp->onofflock); /* irqs remain disabled. */ rnp = rdp->mynode; if (need_quiet) - task_quiet(rnp, flags); + rcu_report_unblock_qs_rnp(rnp, flags); else spin_unlock_irqrestore(&rnp->lock, flags); @@ -1164,8 +1172,8 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp, } if (mask != 0 && rnp->completed == lastcomp) { - /* cpu_quiet_msk() releases rnp->lock. */ - cpu_quiet_msk(mask, rsp, rnp, flags); + /* rcu_report_qs_rnp() releases rnp->lock. */ + rcu_report_qs_rnp(mask, rsp, rnp, flags); continue; } spin_unlock_irqrestore(&rnp->lock, flags); diff --git a/kernel/rcutree.h b/kernel/rcutree.h index a81188c42929..8bb03cb07447 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -306,7 +306,8 @@ long rcu_batches_completed(void); static void rcu_preempt_note_context_switch(int cpu); static int rcu_preempted_readers(struct rcu_node *rnp); #ifdef CONFIG_HOTPLUG_CPU -static void task_quiet(struct rcu_node *rnp, unsigned long flags); +static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, + unsigned long flags); #endif /* #ifdef CONFIG_HOTPLUG_CPU */ #ifdef CONFIG_RCU_CPU_STALL_DETECTOR static void rcu_print_task_stall(struct rcu_node *rnp); diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 1d295c789d3d..c9f0c975c003 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -167,7 +167,7 @@ static int rcu_preempted_readers(struct rcu_node *rnp) * irqs disabled, and this lock is released upon return, but irqs remain * disabled. */ -static void task_quiet(struct rcu_node *rnp, unsigned long flags) +static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) __releases(rnp->lock) { unsigned long mask; @@ -185,7 +185,7 @@ static void task_quiet(struct rcu_node *rnp, unsigned long flags) * or tasks were kicked up to root rcu_node due to * CPUs going offline. */ - cpu_quiet_msk_finish(&rcu_preempt_state, flags); + rcu_report_qs_rsp(&rcu_preempt_state, flags); return; } @@ -193,7 +193,7 @@ static void task_quiet(struct rcu_node *rnp, unsigned long flags) mask = rnp->grpmask; spin_unlock(&rnp->lock); /* irqs remain disabled. */ spin_lock(&rnp_p->lock); /* irqs already disabled. */ - cpu_quiet_msk(mask, &rcu_preempt_state, rnp_p, flags); + rcu_report_qs_rnp(mask, &rcu_preempt_state, rnp_p, flags); } /* @@ -253,12 +253,12 @@ static void rcu_read_unlock_special(struct task_struct *t) /* * If this was the last task on the current list, and if * we aren't waiting on any CPUs, report the quiescent state. - * Note that task_quiet() releases rnp->lock. + * Note that rcu_report_unblock_qs_rnp() releases rnp->lock. */ if (empty) spin_unlock_irqrestore(&rnp->lock, flags); else - task_quiet(rnp, flags); + rcu_report_unblock_qs_rnp(rnp, flags); } else { local_irq_restore(flags); } @@ -566,7 +566,7 @@ static int rcu_preempted_readers(struct rcu_node *rnp) #ifdef CONFIG_HOTPLUG_CPU /* Because preemptible RCU does not exist, no quieting of tasks. */ -static void task_quiet(struct rcu_node *rnp, unsigned long flags) +static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) { spin_unlock_irqrestore(&rnp->lock, flags); } -- cgit v1.2.3 From cf244dc01bf68e1ad338b82447f8686d24ea4435 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 2 Dec 2009 12:10:14 -0800 Subject: rcu: Enable fourth level of TREE_RCU hierarchy Enable a fourth level of rcu_node hierarchy for TREE_RCU and TREE_PREEMPT_RCU. This is for stress-testing and experiemental purposes only, although in theory this would enable 16,777,216 CPUs on 64-bit systems, though only 1,048,576 CPUs on 32-bit systems. Normal experimental use of this fourth level will normally set CONFIG_RCU_FANOUT=2, requiring a 16-CPU system, though the more adventurous (and more fortunate) experimenters may wish to chose CONFIG_RCU_FANOUT=3 for 81-CPU systems or even CONFIG_RCU_FANOUT=4 for 256-CPU systems. Signed-off-by: Paul E. McKenney Acked-by: Josh Triplett Acked-by: Lai Jiangshan Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12597846161257-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 6 +++++- kernel/rcutree.h | 15 +++++++++++++-- 2 files changed, 18 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index a9f51031d3e8..d47e03e5792a 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -60,7 +60,8 @@ static struct lock_class_key rcu_node_class[NUM_RCU_LVLS]; NUM_RCU_LVL_0, /* root of hierarchy. */ \ NUM_RCU_LVL_1, \ NUM_RCU_LVL_2, \ - NUM_RCU_LVL_3, /* == MAX_RCU_LVLS */ \ + NUM_RCU_LVL_3, \ + NUM_RCU_LVL_4, /* == MAX_RCU_LVLS */ \ }, \ .signaled = RCU_GP_IDLE, \ .gpnum = -300, \ @@ -1877,6 +1878,9 @@ void __init rcu_init(void) #ifdef CONFIG_RCU_CPU_STALL_DETECTOR printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n"); #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ +#if NUM_RCU_LVL_4 != 0 + printk(KERN_INFO "Experimental four-level hierarchy is enabled.\n"); +#endif /* #if NUM_RCU_LVL_4 != 0 */ RCU_INIT_FLAVOR(&rcu_sched_state, rcu_sched_data); RCU_INIT_FLAVOR(&rcu_bh_state, rcu_bh_data); __rcu_init_preempt(); diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 8bb03cb07447..df2e0b694744 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -34,10 +34,11 @@ * In practice, this has not been tested, so there is probably some * bug somewhere. */ -#define MAX_RCU_LVLS 3 +#define MAX_RCU_LVLS 4 #define RCU_FANOUT (CONFIG_RCU_FANOUT) #define RCU_FANOUT_SQ (RCU_FANOUT * RCU_FANOUT) #define RCU_FANOUT_CUBE (RCU_FANOUT_SQ * RCU_FANOUT) +#define RCU_FANOUT_FOURTH (RCU_FANOUT_CUBE * RCU_FANOUT) #if NR_CPUS <= RCU_FANOUT # define NUM_RCU_LVLS 1 @@ -45,23 +46,33 @@ # define NUM_RCU_LVL_1 (NR_CPUS) # define NUM_RCU_LVL_2 0 # define NUM_RCU_LVL_3 0 +# define NUM_RCU_LVL_4 0 #elif NR_CPUS <= RCU_FANOUT_SQ # define NUM_RCU_LVLS 2 # define NUM_RCU_LVL_0 1 # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT) # define NUM_RCU_LVL_2 (NR_CPUS) # define NUM_RCU_LVL_3 0 +# define NUM_RCU_LVL_4 0 #elif NR_CPUS <= RCU_FANOUT_CUBE # define NUM_RCU_LVLS 3 # define NUM_RCU_LVL_0 1 # define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_SQ) # define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT) # define NUM_RCU_LVL_3 NR_CPUS +# define NUM_RCU_LVL_4 0 +#elif NR_CPUS <= RCU_FANOUT_FOURTH +# define NUM_RCU_LVLS 4 +# define NUM_RCU_LVL_0 1 +# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_CUBE) +# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_SQ) +# define NUM_RCU_LVL_3 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT) +# define NUM_RCU_LVL_4 NR_CPUS #else # error "CONFIG_RCU_FANOUT insufficient for NR_CPUS" #endif /* #if (NR_CPUS) <= RCU_FANOUT */ -#define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3) +#define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3 + NUM_RCU_LVL_4) #define NUM_RCU_NODES (RCU_SUM - NR_CPUS) /* -- cgit v1.2.3 From d9a3da0699b24a589b27a61e1a5b5bd30d9db669 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 2 Dec 2009 12:10:15 -0800 Subject: rcu: Add expedited grace-period support for preemptible RCU Implement an synchronize_rcu_expedited() for preemptible RCU that actually is expedited. This uses synchronize_sched_expedited() to force all threads currently running in a preemptible-RCU read-side critical section onto the appropriate ->blocked_tasks[] list, then takes a snapshot of all of these lists and waits for them to drain. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1259784616158-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutorture.c | 34 ++++++--- kernel/rcutree.c | 10 ++- kernel/rcutree.h | 35 ++++++++- kernel/rcutree_plugin.h | 198 +++++++++++++++++++++++++++++++++++++++++++++--- kernel/rcutree_trace.c | 10 ++- 5 files changed, 260 insertions(+), 27 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 3dd0ca23e191..a621a67ef4e3 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -327,6 +327,11 @@ rcu_torture_cb(struct rcu_head *p) cur_ops->deferred_free(rp); } +static int rcu_no_completed(void) +{ + return 0; +} + static void rcu_torture_deferred_free(struct rcu_torture *p) { call_rcu(&p->rtort_rcu, rcu_torture_cb); @@ -388,6 +393,21 @@ static struct rcu_torture_ops rcu_sync_ops = { .name = "rcu_sync" }; +static struct rcu_torture_ops rcu_expedited_ops = { + .init = rcu_sync_torture_init, + .cleanup = NULL, + .readlock = rcu_torture_read_lock, + .read_delay = rcu_read_delay, /* just reuse rcu's version. */ + .readunlock = rcu_torture_read_unlock, + .completed = rcu_no_completed, + .deferred_free = rcu_sync_torture_deferred_free, + .sync = synchronize_rcu_expedited, + .cb_barrier = NULL, + .stats = NULL, + .irq_capable = 1, + .name = "rcu_expedited" +}; + /* * Definitions for rcu_bh torture testing. */ @@ -581,11 +601,6 @@ static void sched_torture_read_unlock(int idx) preempt_enable(); } -static int sched_torture_completed(void) -{ - return 0; -} - static void rcu_sched_torture_deferred_free(struct rcu_torture *p) { call_rcu_sched(&p->rtort_rcu, rcu_torture_cb); @@ -602,7 +617,7 @@ static struct rcu_torture_ops sched_ops = { .readlock = sched_torture_read_lock, .read_delay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = sched_torture_read_unlock, - .completed = sched_torture_completed, + .completed = rcu_no_completed, .deferred_free = rcu_sched_torture_deferred_free, .sync = sched_torture_synchronize, .cb_barrier = rcu_barrier_sched, @@ -617,7 +632,7 @@ static struct rcu_torture_ops sched_sync_ops = { .readlock = sched_torture_read_lock, .read_delay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = sched_torture_read_unlock, - .completed = sched_torture_completed, + .completed = rcu_no_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = sched_torture_synchronize, .cb_barrier = NULL, @@ -631,7 +646,7 @@ static struct rcu_torture_ops sched_expedited_ops = { .readlock = sched_torture_read_lock, .read_delay = rcu_read_delay, /* just reuse rcu's version. */ .readunlock = sched_torture_read_unlock, - .completed = sched_torture_completed, + .completed = rcu_no_completed, .deferred_free = rcu_sync_torture_deferred_free, .sync = synchronize_sched_expedited, .cb_barrier = NULL, @@ -1116,7 +1131,8 @@ rcu_torture_init(void) int cpu; int firsterr = 0; static struct rcu_torture_ops *torture_ops[] = - { &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops, + { &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops, + &rcu_bh_ops, &rcu_bh_sync_ops, &srcu_ops, &srcu_expedited_ops, &sched_ops, &sched_sync_ops, &sched_expedited_ops, }; diff --git a/kernel/rcutree.c b/kernel/rcutree.c index d47e03e5792a..53ae9598f798 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -948,7 +948,7 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) { unsigned long flags; unsigned long mask; - int need_quiet = 0; + int need_report = 0; struct rcu_data *rdp = rsp->rda[cpu]; struct rcu_node *rnp; @@ -967,7 +967,7 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) break; } if (rnp == rdp->mynode) - need_quiet = rcu_preempt_offline_tasks(rsp, rnp, rdp); + need_report = rcu_preempt_offline_tasks(rsp, rnp, rdp); else spin_unlock(&rnp->lock); /* irqs remain disabled. */ mask = rnp->grpmask; @@ -982,10 +982,12 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) */ spin_unlock(&rsp->onofflock); /* irqs remain disabled. */ rnp = rdp->mynode; - if (need_quiet) + if (need_report & RCU_OFL_TASKS_NORM_GP) rcu_report_unblock_qs_rnp(rnp, flags); else spin_unlock_irqrestore(&rnp->lock, flags); + if (need_report & RCU_OFL_TASKS_EXP_GP) + rcu_report_exp_rnp(rsp, rnp); rcu_adopt_orphan_cbs(rsp); } @@ -1843,6 +1845,8 @@ static void __init rcu_init_one(struct rcu_state *rsp) rnp->level = i; INIT_LIST_HEAD(&rnp->blocked_tasks[0]); INIT_LIST_HEAD(&rnp->blocked_tasks[1]); + INIT_LIST_HEAD(&rnp->blocked_tasks[2]); + INIT_LIST_HEAD(&rnp->blocked_tasks[3]); } } } diff --git a/kernel/rcutree.h b/kernel/rcutree.h index df2e0b694744..d2a0046f63b2 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -104,8 +104,12 @@ struct rcu_node { /* an rcu_data structure, otherwise, each */ /* bit corresponds to a child rcu_node */ /* structure. */ + unsigned long expmask; /* Groups that have ->blocked_tasks[] */ + /* elements that need to drain to allow the */ + /* current expedited grace period to */ + /* complete (only for TREE_PREEMPT_RCU). */ unsigned long qsmaskinit; - /* Per-GP initialization for qsmask. */ + /* Per-GP initial value for qsmask & expmask. */ unsigned long grpmask; /* Mask to apply to parent qsmask. */ /* Only one bit will be set in this mask. */ int grplo; /* lowest-numbered CPU or group here. */ @@ -113,7 +117,7 @@ struct rcu_node { u8 grpnum; /* CPU/group number for next level up. */ u8 level; /* root is at level 0. */ struct rcu_node *parent; - struct list_head blocked_tasks[2]; + struct list_head blocked_tasks[4]; /* Tasks blocked in RCU read-side critsect. */ /* Grace period number (->gpnum) x blocked */ /* by tasks on the (x & 0x1) element of the */ @@ -128,6 +132,21 @@ struct rcu_node { for ((rnp) = &(rsp)->node[0]; \ (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++) +/* + * Do a breadth-first scan of the non-leaf rcu_node structures for the + * specified rcu_state structure. Note that if there is a singleton + * rcu_node tree with but one rcu_node structure, this loop is a no-op. + */ +#define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \ + for ((rnp) = &(rsp)->node[0]; \ + (rnp) < (rsp)->level[NUM_RCU_LVLS - 1]; (rnp)++) + +/* + * Scan the leaves of the rcu_node hierarchy for the specified rcu_state + * structure. Note that if there is a singleton rcu_node tree with but + * one rcu_node structure, this loop -will- visit the rcu_node structure. + * It is still a leaf node, even if it is also the root node. + */ #define rcu_for_each_leaf_node(rsp, rnp) \ for ((rnp) = (rsp)->level[NUM_RCU_LVLS - 1]; \ (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++) @@ -261,7 +280,7 @@ struct rcu_state { long gpnum; /* Current gp number. */ long completed; /* # of last completed gp. */ - /* End of fields guarded by root rcu_node's lock. */ + /* End of fields guarded by root rcu_node's lock. */ spinlock_t onofflock; /* exclude on/offline and */ /* starting new GP. Also */ @@ -293,6 +312,13 @@ struct rcu_state { #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ }; +/* Return values for rcu_preempt_offline_tasks(). */ + +#define RCU_OFL_TASKS_NORM_GP 0x1 /* Tasks blocking normal */ + /* GP were moved to root. */ +#define RCU_OFL_TASKS_EXP_GP 0x2 /* Tasks blocking expedited */ + /* GP were moved to root. */ + #ifdef RCU_TREE_NONCORE /* @@ -333,6 +359,9 @@ static void rcu_preempt_offline_cpu(int cpu); static void rcu_preempt_check_callbacks(int cpu); static void rcu_preempt_process_callbacks(void); void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)); +#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) +static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp); +#endif /* #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU) */ static int rcu_preempt_pending(int cpu); static int rcu_preempt_needs_cpu(int cpu); static void __cpuinit rcu_preempt_init_percpu_data(int cpu); diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index c9f0c975c003..37fbccdf41d5 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -24,12 +24,15 @@ * Paul E. McKenney */ +#include #ifdef CONFIG_TREE_PREEMPT_RCU struct rcu_state rcu_preempt_state = RCU_STATE_INITIALIZER(rcu_preempt_state); DEFINE_PER_CPU(struct rcu_data, rcu_preempt_data); +static int rcu_preempted_readers_exp(struct rcu_node *rnp); + /* * Tell them what RCU they are running. */ @@ -157,7 +160,10 @@ EXPORT_SYMBOL_GPL(__rcu_read_lock); */ static int rcu_preempted_readers(struct rcu_node *rnp) { - return !list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x1]); + int phase = rnp->gpnum & 0x1; + + return !list_empty(&rnp->blocked_tasks[phase]) || + !list_empty(&rnp->blocked_tasks[phase + 2]); } /* @@ -204,6 +210,7 @@ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) static void rcu_read_unlock_special(struct task_struct *t) { int empty; + int empty_exp; unsigned long flags; struct rcu_node *rnp; int special; @@ -247,6 +254,8 @@ static void rcu_read_unlock_special(struct task_struct *t) spin_unlock(&rnp->lock); /* irqs remain disabled. */ } empty = !rcu_preempted_readers(rnp); + empty_exp = !rcu_preempted_readers_exp(rnp); + smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */ list_del_init(&t->rcu_node_entry); t->rcu_blocked_node = NULL; @@ -259,6 +268,13 @@ static void rcu_read_unlock_special(struct task_struct *t) spin_unlock_irqrestore(&rnp->lock, flags); else rcu_report_unblock_qs_rnp(rnp, flags); + + /* + * If this was the last task on the expedited lists, + * then we need to report up the rcu_node hierarchy. + */ + if (!empty_exp && !rcu_preempted_readers_exp(rnp)) + rcu_report_exp_rnp(&rcu_preempt_state, rnp); } else { local_irq_restore(flags); } @@ -343,7 +359,7 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp, int i; struct list_head *lp; struct list_head *lp_root; - int retval; + int retval = 0; struct rcu_node *rnp_root = rcu_get_root(rsp); struct task_struct *tp; @@ -353,7 +369,9 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp, } WARN_ON_ONCE(rnp != rdp->mynode && (!list_empty(&rnp->blocked_tasks[0]) || - !list_empty(&rnp->blocked_tasks[1]))); + !list_empty(&rnp->blocked_tasks[1]) || + !list_empty(&rnp->blocked_tasks[2]) || + !list_empty(&rnp->blocked_tasks[3]))); /* * Move tasks up to root rcu_node. Rely on the fact that the @@ -361,8 +379,11 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp, * rcu_nodes in terms of gp_num value. This fact allows us to * move the blocked_tasks[] array directly, element by element. */ - retval = rcu_preempted_readers(rnp); - for (i = 0; i < 2; i++) { + if (rcu_preempted_readers(rnp)) + retval |= RCU_OFL_TASKS_NORM_GP; + if (rcu_preempted_readers_exp(rnp)) + retval |= RCU_OFL_TASKS_EXP_GP; + for (i = 0; i < 4; i++) { lp = &rnp->blocked_tasks[i]; lp_root = &rnp_root->blocked_tasks[i]; while (!list_empty(lp)) { @@ -449,14 +470,159 @@ void synchronize_rcu(void) } EXPORT_SYMBOL_GPL(synchronize_rcu); +static DECLARE_WAIT_QUEUE_HEAD(sync_rcu_preempt_exp_wq); +static long sync_rcu_preempt_exp_count; +static DEFINE_MUTEX(sync_rcu_preempt_exp_mutex); + +/* + * Return non-zero if there are any tasks in RCU read-side critical + * sections blocking the current preemptible-RCU expedited grace period. + * If there is no preemptible-RCU expedited grace period currently in + * progress, returns zero unconditionally. + */ +static int rcu_preempted_readers_exp(struct rcu_node *rnp) +{ + return !list_empty(&rnp->blocked_tasks[2]) || + !list_empty(&rnp->blocked_tasks[3]); +} + +/* + * return non-zero if there is no RCU expedited grace period in progress + * for the specified rcu_node structure, in other words, if all CPUs and + * tasks covered by the specified rcu_node structure have done their bit + * for the current expedited grace period. Works only for preemptible + * RCU -- other RCU implementation use other means. + * + * Caller must hold sync_rcu_preempt_exp_mutex. + */ +static int sync_rcu_preempt_exp_done(struct rcu_node *rnp) +{ + return !rcu_preempted_readers_exp(rnp) && + ACCESS_ONCE(rnp->expmask) == 0; +} + +/* + * Report the exit from RCU read-side critical section for the last task + * that queued itself during or before the current expedited preemptible-RCU + * grace period. This event is reported either to the rcu_node structure on + * which the task was queued or to one of that rcu_node structure's ancestors, + * recursively up the tree. (Calm down, calm down, we do the recursion + * iteratively!) + * + * Caller must hold sync_rcu_preempt_exp_mutex. + */ +static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp) +{ + unsigned long flags; + unsigned long mask; + + spin_lock_irqsave(&rnp->lock, flags); + for (;;) { + if (!sync_rcu_preempt_exp_done(rnp)) + break; + if (rnp->parent == NULL) { + wake_up(&sync_rcu_preempt_exp_wq); + break; + } + mask = rnp->grpmask; + spin_unlock(&rnp->lock); /* irqs remain disabled */ + rnp = rnp->parent; + spin_lock(&rnp->lock); /* irqs already disabled */ + rnp->expmask &= ~mask; + } + spin_unlock_irqrestore(&rnp->lock, flags); +} + +/* + * Snapshot the tasks blocking the newly started preemptible-RCU expedited + * grace period for the specified rcu_node structure. If there are no such + * tasks, report it up the rcu_node hierarchy. + * + * Caller must hold sync_rcu_preempt_exp_mutex and rsp->onofflock. + */ +static void +sync_rcu_preempt_exp_init(struct rcu_state *rsp, struct rcu_node *rnp) +{ + int must_wait; + + spin_lock(&rnp->lock); /* irqs already disabled */ + list_splice_init(&rnp->blocked_tasks[0], &rnp->blocked_tasks[2]); + list_splice_init(&rnp->blocked_tasks[1], &rnp->blocked_tasks[3]); + must_wait = rcu_preempted_readers_exp(rnp); + spin_unlock(&rnp->lock); /* irqs remain disabled */ + if (!must_wait) + rcu_report_exp_rnp(rsp, rnp); +} + /* - * Wait for an rcu-preempt grace period. We are supposed to expedite the - * grace period, but this is the crude slow compatability hack, so just - * invoke synchronize_rcu(). + * Wait for an rcu-preempt grace period, but expedite it. The basic idea + * is to invoke synchronize_sched_expedited() to push all the tasks to + * the ->blocked_tasks[] lists, move all entries from the first set of + * ->blocked_tasks[] lists to the second set, and finally wait for this + * second set to drain. */ void synchronize_rcu_expedited(void) { - synchronize_rcu(); + unsigned long flags; + struct rcu_node *rnp; + struct rcu_state *rsp = &rcu_preempt_state; + long snap; + int trycount = 0; + + smp_mb(); /* Caller's modifications seen first by other CPUs. */ + snap = ACCESS_ONCE(sync_rcu_preempt_exp_count) + 1; + smp_mb(); /* Above access cannot bleed into critical section. */ + + /* + * Acquire lock, falling back to synchronize_rcu() if too many + * lock-acquisition failures. Of course, if someone does the + * expedited grace period for us, just leave. + */ + while (!mutex_trylock(&sync_rcu_preempt_exp_mutex)) { + if (trycount++ < 10) + udelay(trycount * num_online_cpus()); + else { + synchronize_rcu(); + return; + } + if ((ACCESS_ONCE(sync_rcu_preempt_exp_count) - snap) > 0) + goto mb_ret; /* Others did our work for us. */ + } + if ((ACCESS_ONCE(sync_rcu_preempt_exp_count) - snap) > 0) + goto unlock_mb_ret; /* Others did our work for us. */ + + /* force all RCU readers onto blocked_tasks[]. */ + synchronize_sched_expedited(); + + spin_lock_irqsave(&rsp->onofflock, flags); + + /* Initialize ->expmask for all non-leaf rcu_node structures. */ + rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) { + spin_lock(&rnp->lock); /* irqs already disabled. */ + rnp->expmask = rnp->qsmaskinit; + spin_unlock(&rnp->lock); /* irqs remain disabled. */ + } + + /* Snapshot current state of ->blocked_tasks[] lists. */ + rcu_for_each_leaf_node(rsp, rnp) + sync_rcu_preempt_exp_init(rsp, rnp); + if (NUM_RCU_NODES > 1) + sync_rcu_preempt_exp_init(rsp, rcu_get_root(rsp)); + + spin_unlock_irqrestore(&rsp->onofflock, flags); + + /* Wait for snapshotted ->blocked_tasks[] lists to drain. */ + rnp = rcu_get_root(rsp); + wait_event(sync_rcu_preempt_exp_wq, + sync_rcu_preempt_exp_done(rnp)); + + /* Clean up and exit. */ + smp_mb(); /* ensure expedited GP seen before counter increment. */ + ACCESS_ONCE(sync_rcu_preempt_exp_count)++; +unlock_mb_ret: + mutex_unlock(&sync_rcu_preempt_exp_mutex); +mb_ret: + smp_mb(); /* ensure subsequent action seen after grace period. */ } EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); @@ -655,6 +821,20 @@ void synchronize_rcu_expedited(void) } EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); +#ifdef CONFIG_HOTPLUG_CPU + +/* + * Because preemptable RCU does not exist, there is never any need to + * report on tasks preempted in RCU read-side critical sections during + * expedited RCU grace periods. + */ +static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp) +{ + return; +} + +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ + /* * Because preemptable RCU does not exist, it never has any work to do. */ diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index 1984cdc51e9a..9d2c88423b31 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -157,6 +157,7 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) { long gpnum; int level = 0; + int phase; struct rcu_node *rnp; gpnum = rsp->gpnum; @@ -173,10 +174,13 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) seq_puts(m, "\n"); level = rnp->level; } - seq_printf(m, "%lx/%lx %c>%c %d:%d ^%d ", + phase = gpnum & 0x1; + seq_printf(m, "%lx/%lx %c%c>%c%c %d:%d ^%d ", rnp->qsmask, rnp->qsmaskinit, - "T."[list_empty(&rnp->blocked_tasks[gpnum & 1])], - "T."[list_empty(&rnp->blocked_tasks[!(gpnum & 1)])], + "T."[list_empty(&rnp->blocked_tasks[phase])], + "E."[list_empty(&rnp->blocked_tasks[phase + 2])], + "T."[list_empty(&rnp->blocked_tasks[!phase])], + "E."[list_empty(&rnp->blocked_tasks[!phase + 2])], rnp->grplo, rnp->grphi, rnp->grpnum); } seq_puts(m, "\n"); -- cgit v1.2.3 From c02260277e472095ffb3ad893be5eeab9dcefde3 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 2 Dec 2009 20:49:16 +0100 Subject: mutex: Better control mutex adaptive spinning config Introduce CONFIG_MUTEX_SPIN_ON_OWNER so that we can centralize in a single place the conditions that determine its definition and use. Signed-off-by: Frederic Weisbecker Acked-by: Peter Zijlstra LKML-Reference: <1259783357-8542-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar Cc: Peter Zijlstra --- kernel/Kconfig.locks | 3 +++ kernel/mutex.c | 4 ++-- 2 files changed, 5 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks index d1f86db71451..88c92fb44618 100644 --- a/kernel/Kconfig.locks +++ b/kernel/Kconfig.locks @@ -197,3 +197,6 @@ config INLINE_WRITE_UNLOCK_IRQ config INLINE_WRITE_UNLOCK_IRQRESTORE def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE + +config MUTEX_SPIN_ON_OWNER + def_bool SMP && !DEBUG_MUTEXES && !HAVE_DEFAULT_NO_SPIN_MUTEXES diff --git a/kernel/mutex.c b/kernel/mutex.c index 947b3ad551f8..632f04c57d82 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -148,8 +148,8 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, preempt_disable(); mutex_acquire(&lock->dep_map, subclass, 0, ip); -#if defined(CONFIG_SMP) && !defined(CONFIG_DEBUG_MUTEXES) && \ - !defined(CONFIG_HAVE_DEFAULT_NO_SPIN_MUTEXES) + +#ifdef CONFIG_MUTEX_SPIN_ON_OWNER /* * Optimistic spinning. * -- cgit v1.2.3 From c08f782985eed9959438368e84ce1d7f2ed03d95 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 2 Dec 2009 20:49:17 +0100 Subject: mutex: Fix missing conditions to build mutex_spin_on_owner() We don't need to build mutex_spin_on_owner() if we have CONFIG_DEBUG_MUTEXES or CONFIG_HAVE_DEFAULT_NO_SPIN_MUTEXES as it won't be used under such configs. Use CONFIG_MUTEX_SPIN_ON_OWNER as it gathers all the necessary checks before building it. Signed-off-by: Frederic Weisbecker Acked-by: Peter Zijlstra LKML-Reference: <1259783357-8542-2-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar Cc: Peter Zijlstra --- kernel/sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 3c11ae0a948d..ec0af1fcb195 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5481,7 +5481,7 @@ need_resched_nonpreemptible: } EXPORT_SYMBOL(schedule); -#ifdef CONFIG_SMP +#ifdef CONFIG_MUTEX_SPIN_ON_OWNER /* * Look out! "owner" is an entirely speculative pointer * access and not reliable. -- cgit v1.2.3