summaryrefslogtreecommitdiffstats
path: root/kernel/trace/tracing_map.c
AgeCommit message (Collapse)AuthorFilesLines
2022-10-03tracing: Remove unused variable 'dups'Chen Zhongjin1-3/+2
Reported by Clang [-Wunused-but-set-variable] 'commit c193707dde77 ("tracing: Remove code which merges duplicates")' This commit removed the code which merges duplicates in detect_dups(), but forgot to delete the variable 'dups' which used to merge duplicates in the loop. Now only 'total_dups' is needed, remove 'dups' for clean code. Link: https://lkml.kernel.org/r/20220930103236.253985-1-chenzhongjin@huawei.com Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26tracing: Fix tracing_map_sort_entries() kernel-doc commentYang Li1-1/+2
Add the description of @n_sort_keys and make @sort_key -> @sort_keys in tracing_map_sort_entries() kernel-doc comment to remove warnings found by running scripts/kernel-doc, which is caused by using 'make W=1'. kernel/trace/tracing_map.c:1073: warning: Function parameter or member 'sort_keys' not described in 'tracing_map_sort_entries' kernel/trace/tracing_map.c:1073: warning: Function parameter or member 'n_sort_keys' not described in 'tracing_map_sort_entries' kernel/trace/tracing_map.c:1073: warning: Excess function parameter 'sort_key' description in 'tracing_map_sort_entries' Link: https://lkml.kernel.org/r/20220402072015.45864-1-yang.lee@linux.alibaba.com Reported-by: Abaci Robot <abaci@linux.alibaba.com> Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2021-12-01tracing: Fix a kmemleak false positive in tracing_mapChen Jun1-0/+3
Doing the command: echo 'hist:key=common_pid.execname,common_timestamp' > /sys/kernel/debug/tracing/events/xxx/trigger Triggers many kmemleak reports: unreferenced object 0xffff0000c7ea4980 (size 128): comm "bash", pid 338, jiffies 4294912626 (age 9339.324s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000f3469921>] kmem_cache_alloc_trace+0x4c0/0x6f0 [<0000000054ca40c3>] hist_trigger_elt_data_alloc+0x140/0x178 [<00000000633bd154>] tracing_map_init+0x1f8/0x268 [<000000007e814ab9>] event_hist_trigger_func+0xca0/0x1ad0 [<00000000bf8520ed>] trigger_process_regex+0xd4/0x128 [<00000000f549355a>] event_trigger_write+0x7c/0x120 [<00000000b80f898d>] vfs_write+0xc4/0x380 [<00000000823e1055>] ksys_write+0x74/0xf8 [<000000008a9374aa>] __arm64_sys_write+0x24/0x30 [<0000000087124017>] do_el0_svc+0x88/0x1c0 [<00000000efd0dcd1>] el0_svc+0x1c/0x28 [<00000000dbfba9b3>] el0_sync_handler+0x88/0xc0 [<00000000e7399680>] el0_sync+0x148/0x180 unreferenced object 0xffff0000c7ea4980 (size 128): comm "bash", pid 338, jiffies 4294912626 (age 9339.324s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000f3469921>] kmem_cache_alloc_trace+0x4c0/0x6f0 [<0000000054ca40c3>] hist_trigger_elt_data_alloc+0x140/0x178 [<00000000633bd154>] tracing_map_init+0x1f8/0x268 [<000000007e814ab9>] event_hist_trigger_func+0xca0/0x1ad0 [<00000000bf8520ed>] trigger_process_regex+0xd4/0x128 [<00000000f549355a>] event_trigger_write+0x7c/0x120 [<00000000b80f898d>] vfs_write+0xc4/0x380 [<00000000823e1055>] ksys_write+0x74/0xf8 [<000000008a9374aa>] __arm64_sys_write+0x24/0x30 [<0000000087124017>] do_el0_svc+0x88/0x1c0 [<00000000efd0dcd1>] el0_svc+0x1c/0x28 [<00000000dbfba9b3>] el0_sync_handler+0x88/0xc0 [<00000000e7399680>] el0_sync+0x148/0x180 The reason is elts->pages[i] is alloced by get_zeroed_page. and kmemleak will not scan the area alloced by get_zeroed_page. The address stored in elts->pages will be regarded as leaked. That is, the elts->pages[i] will have pointers loaded onto it as well, and without telling kmemleak about it, those pointers will look like memory without a reference. To fix this, call kmemleak_alloc to tell kmemleak to scan elts->pages[i] Link: https://lkml.kernel.org/r/20211124140801.87121-1-chenjun102@huawei.com Signed-off-by: Chen Jun <chenjun102@huawei.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-10-19tracing/cfi: Fix cmp_entries_* functions signature mismatchKalesh Singh1-17/+23
If CONFIG_CFI_CLANG=y, attempting to read an event histogram will cause the kernel to panic due to failed CFI check. 1. echo 'hist:keys=common_pid' >> events/sched/sched_switch/trigger 2. cat events/sched/sched_switch/hist 3. kernel panics on attempting to read hist This happens because the sort() function expects a generic int (*)(const void *, const void *) pointer for the compare function. To prevent this CFI failure, change tracing map cmp_entries_* function signatures to match this. Also, fix the build error reported by the kernel test robot [1]. [1] https://lore.kernel.org/r/202110141140.zzi4dRh4-lkp@intel.com/ Link: https://lkml.kernel.org/r/20211014045217.3265162-1-kaleshsingh@google.com Signed-off-by: Kalesh Singh <kaleshsingh@google.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-11-10tracing: Fix some typos in commentsQiujun Huang1-3/+3
s/detetector/detector/ s/enfoced/enforced/ s/writen/written/ s/actualy/actually/ s/bascially/basically/ s/Regarldess/Regardless/ s/zeroes/zeros/ s/followd/followed/ s/incrememented/incremented/ s/separatelly/separately/ s/accesible/accessible/ s/sythetic/synthetic/ s/enabed/enabled/ s/heurisitc/heuristic/ s/assocated/associated/ s/otherwides/otherwise/ s/specfied/specified/ s/seaching/searching/ s/hierachry/hierarchy/ s/internel/internal/ s/Thise/This/ Link: https://lkml.kernel.org/r/20201029150554.3354-1-hqjagain@gmail.com Signed-off-by: Qiujun Huang <hqjagain@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-09-21tracing: Delete repeated words in commentsRandy Dunlap1-1/+1
Drop repeated words in kernel/trace/. {and, the, not} Link: https://lkml.kernel.org/r/20200807033259.13778-1-rdunlap@infradead.org Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-04-22tracing: Convert local functions in tracing_map.c to staticJason Yan1-3/+3
Fix the following sparse warning: kernel/trace/tracing_map.c:286:6: warning: symbol 'tracing_map_array_clear' was not declared. Should it be static? kernel/trace/tracing_map.c:297:6: warning: symbol 'tracing_map_array_free' was not declared. Should it be static? kernel/trace/tracing_map.c:319:26: warning: symbol 'tracing_map_array_alloc' was not declared. Should it be static? Link: http://lkml.kernel.org/r/20200410073312.38855-1-yanaijie@huawei.com Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-12-19tracing: Have the histogram compare functions convert to u64 firstSteven Rostedt (VMware)1-2/+2
The compare functions of the histogram code would be specific for the size of the value being compared (byte, short, int, long long). It would reference the value from the array via the type of the compare, but the value was stored in a 64 bit number. This is fine for little endian machines, but for big endian machines, it would end up comparing zeros or all ones (depending on the sign) for anything but 64 bit numbers. To fix this, first derference the value as a u64 then convert it to the type being compared. Link: http://lkml.kernel.org/r/20191211103557.7bed6928@gandalf.local.home Cc: stable@vger.kernel.org Fixes: 08d43a5fa063e ("tracing: Add lock-free tracing_map") Acked-by: Tom Zanussi <zanussi@kernel.org> Reported-by: Sven Schnelle <svens@stackframe.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-08-16tracing: Add SPDX License format tags to tracing filesSteven Rostedt (VMware)1-10/+1
Add the SPDX License header to ease license compliance management. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-06-12treewide: Use array_size() in vmalloc()Kees Cook1-1/+1
The vmalloc() function has no 2-factor argument form, so multiplication factors need to be wrapped in array_size(). This patch replaces cases of: vmalloc(a * b) with: vmalloc(array_size(a, b)) as well as handling cases of: vmalloc(a * b * c) with: vmalloc(array3_size(a, b, c)) This does, however, attempt to ignore constant size factors like: vmalloc(4 * 1024) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( vmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | vmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( vmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(u8) * COUNT + COUNT , ...) | vmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | vmalloc( - sizeof(char) * COUNT + COUNT , ...) | vmalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( vmalloc( - sizeof(TYPE) * (COUNT_ID) + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT_ID + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT_CONST + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vmalloc( - sizeof(THING) * (COUNT_ID) + array_size(COUNT_ID, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT_ID + array_size(COUNT_ID, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT_CONST + array_size(COUNT_CONST, sizeof(THING)) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ vmalloc( - SIZE * COUNT + array_size(COUNT, SIZE) , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( vmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( vmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( vmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( vmalloc(C1 * C2 * C3, ...) | vmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants. @@ expression E1, E2; constant C1, C2; @@ ( vmalloc(C1 * C2, ...) | vmalloc( - E1 * E2 + array_size(E1, E2) , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-03-10tracing: Add per-element variable support to tracing_mapTom Zanussi1-0/+108
In order to allow information to be passed between trace events, add support for per-element variables to tracing_map. This provides a means for histograms to associate a value or values with an entry when it's saved or updated, and retrieved by a subsequent event occurrences. Variables can be set using tracing_map_set_var() and read using tracing_map_read_var(). tracing_map_var_set() returns true or false depending on whether or not the variable has been set or not, which is important for event-matching applications. tracing_map_read_var_once() reads the variable and resets it to the 'unset' state, implementing read-once variables, which are also important for event-matching uses. Link: http://lkml.kernel.org/r/7fa001108252556f0c6dd9d63145eabfe3370d1a.1516069914.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-03-10tracing: Remove code which merges duplicatesVedang Patel1-77/+6
We now have the logic to detect and remove duplicates in the tracing_map hash table. The code which merges duplicates in the histogram is redundant now. So, modify this code just to detect duplicates. The duplication detection code is still kept to ensure that any rare race condition which might cause duplicates does not go unnoticed. Link: http://lkml.kernel.org/r/55215cf59e2674391bdaf772fdafc4c393352b03.1516069914.git.tom.zanussi@linux.intel.com Signed-off-by: Vedang Patel <vedang.patel@intel.com> Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-03-10tracing: Add support to detect and avoid duplicatesVedang Patel1-5/+36
A duplicate in the tracing_map hash table is when 2 different entries have the same key and, as a result, the key_hash. This is possible due to a race condition in the algorithm. This race condition is inherent to the algorithm and not a bug. This was fine because, until now, we were only interested in the sum of all the values related to a particular key (the duplicates are dealt with in tracing_map_sort_entries()). But, with the inclusion of variables[1], we are interested in individual values. So, it will not be clear what value to choose when there are duplicates. So, the duplicates need to be removed. The duplicates can occur in the code in the following scenarios: - A thread is in the process of adding a new element. It has successfully executed cmpxchg() and inserted the key. But, it is still not done acquiring the trace_map_elt struct, populating it and storing the pointer to the struct in the value field of tracing_map hash table. If another thread comes in at this time and wants to add an element with the same key, it will not see the current element and add a new one. - There are multiple threads trying to execute cmpxchg at the same time, one of the threads will succeed and the others will fail. The ones which fail will go ahead increment 'idx' and add a new element there creating a duplicate. This patch detects and avoids the first condition by asking the thread which detects the duplicate to loop one more time. There is also a possibility of infinite loop if the thread which is trying to insert goes to sleep indefinitely and the one which is trying to insert a new element detects a duplicate. Which is why, the thread loops for map_size iterations before returning NULL. The second scenario is avoided by preventing the threads which failed cmpxchg() from incrementing idx. This way, they will loop around and check if the thread which succeeded in executing cmpxchg() had the same key. [1] http://lkml.kernel.org/r/cover.1498510759.git.tom.zanussi@linux.intel.com Link: http://lkml.kernel.org/r/e178e89ec399240331d383bd5913d649713110f4.1516069914.git.tom.zanussi@linux.intel.com Signed-off-by: Vedang Patel <vedang.patel@intel.com> Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-10-04tracing: Remove lookups from tracing_map hitcountTom Zanussi1-1/+2
Lookups inflate the hitcount, making it essentially useless. Only inserts and updates should really affect the hitcount anyway, so explicitly filter lookups out. Link: http://lkml.kernel.org/r/c8d9dc39d269a8abf88bf4102d0dfc65deb0fc7f.1506105045.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-08-24tracing: Fix kmemleak in tracing_map_array_free()Chunyu Hu1-4/+7
kmemleak reported the below leak when I was doing clear of the hist trigger. With this patch, the kmeamleak is gone. unreferenced object 0xffff94322b63d760 (size 32): comm "bash", pid 1522, jiffies 4403687962 (age 2442.311s) hex dump (first 32 bytes): 00 01 00 00 04 00 00 00 08 00 00 00 ff 00 00 00 ................ 10 00 00 00 00 00 00 00 80 a8 7a f2 31 94 ff ff ..........z.1... backtrace: [<ffffffff9e96c27a>] kmemleak_alloc+0x4a/0xa0 [<ffffffff9e424cba>] kmem_cache_alloc_trace+0xca/0x1d0 [<ffffffff9e377736>] tracing_map_array_alloc+0x26/0x140 [<ffffffff9e261be0>] kretprobe_trampoline+0x0/0x50 [<ffffffff9e38b935>] create_hist_data+0x535/0x750 [<ffffffff9e38bd47>] event_hist_trigger_func+0x1f7/0x420 [<ffffffff9e38893d>] event_trigger_write+0xfd/0x1a0 [<ffffffff9e44dfc7>] __vfs_write+0x37/0x170 [<ffffffff9e44f552>] vfs_write+0xb2/0x1b0 [<ffffffff9e450b85>] SyS_write+0x55/0xc0 [<ffffffff9e203857>] do_syscall_64+0x67/0x150 [<ffffffff9e977ce7>] return_from_SYSCALL_64+0x0/0x6a [<ffffffffffffffff>] 0xffffffffffffffff unreferenced object 0xffff9431f27aa880 (size 128): comm "bash", pid 1522, jiffies 4403687962 (age 2442.311s) hex dump (first 32 bytes): 00 00 8c 2a 32 94 ff ff 00 f0 8b 2a 32 94 ff ff ...*2......*2... 00 e0 8b 2a 32 94 ff ff 00 d0 8b 2a 32 94 ff ff ...*2......*2... backtrace: [<ffffffff9e96c27a>] kmemleak_alloc+0x4a/0xa0 [<ffffffff9e425348>] __kmalloc+0xe8/0x220 [<ffffffff9e3777c1>] tracing_map_array_alloc+0xb1/0x140 [<ffffffff9e261be0>] kretprobe_trampoline+0x0/0x50 [<ffffffff9e38b935>] create_hist_data+0x535/0x750 [<ffffffff9e38bd47>] event_hist_trigger_func+0x1f7/0x420 [<ffffffff9e38893d>] event_trigger_write+0xfd/0x1a0 [<ffffffff9e44dfc7>] __vfs_write+0x37/0x170 [<ffffffff9e44f552>] vfs_write+0xb2/0x1b0 [<ffffffff9e450b85>] SyS_write+0x55/0xc0 [<ffffffff9e203857>] do_syscall_64+0x67/0x150 [<ffffffff9e977ce7>] return_from_SYSCALL_64+0x0/0x6a [<ffffffffffffffff>] 0xffffffffffffffff Link: http://lkml.kernel.org/r/1502705898-27571-1-git-send-email-chuhu@redhat.com Cc: stable@vger.kernel.org Fixes: 08d43a5fa063 ("tracing: Add lock-free tracing_map") Signed-off-by: Chunyu Hu <chuhu@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2016-04-26tracing: Handle tracing_map_alloc_elts() error path correctlyTom Zanussi1-2/+6
If tracing_map_elt_alloc() fails, it will return ERR_PTR() instead of NULL, so change the check to IS_ERROR(). We also need to set the failed entry in the map->elts array to NULL instead of ERR_PTR() so tracing_map_free_elts() doesn't try freeing an ERR_PTR(). tracing_map_free_elts() should also zero out what it frees so a reentrant call won't find previously freed elements. Link: http://lkml.kernel.org/r/f29d03b00bce3aac8cf151a8a30e6c83e5fee66d.1461610073.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-26tracing: checking for NULL instead of IS_ERR()Dan Carpenter1-1/+1
tracing_map_elt_alloc() returns ERR_PTRs on error, never NULL. Fixes: 08d43a5fa063 ('tracing: Add lock-free tracing_map') Link: http://lkml.kernel.org/r/20160423102347.GA11136@mwanda Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19tracing: Update some tracing_map constants and commentsTom Zanussi1-2/+2
Make it clear exactly how many keys and values are supported through better defines, and add 1 to the vals count, since normally clients want support for at least a hitcount and two other values. Also, note the error return value for tracing_map_add_key/val_field() in the comments. Link: http://lkml.kernel.org/r/6696fa02ebc716aa344c27a571a2afaa25e5b4d4.1457029949.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19tracing: Add lock-free tracing_mapTom Zanussi1-0/+1058
Add tracing_map, a special-purpose lock-free map for tracing. tracing_map is designed to aggregate or 'sum' one or more values associated with a specific object of type tracing_map_elt, which is associated by the map to a given key. It provides various hooks allowing per-tracer customization and is separated out into a separate file in order to allow it to be shared between multiple tracers, but isn't meant to be generally used outside of that context. The tracing_map implementation was inspired by lock-free map algorithms originated by Dr. Cliff Click: http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf Link: http://lkml.kernel.org/r/b43d68d1add33582a396f553c8ef705a33a6a748.1449767187.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-07 04:49:29 +0000