From 8230f27b1ccc4b8976c137e3d6d690f9d4ffca8d Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Fri, 14 Oct 2022 08:04:56 -0400 Subject: tracing: Add __cpumask to denote a trace event field that is a cpumask_t The trace events have a __bitmask field that can be used for anything that requires bitmasks. Although currently it is only used for CPU masks, it could be used in the future for any type of bitmasks. There is some user space tooling that wants to know if a field is a CPU mask and not just some random unsigned long bitmask. Introduce "__cpumask()" helper functions that work the same as the current __bitmask() helpers but displays in the format file: field:__data_loc cpumask_t *[] mask; offset:36; size:4; signed:0; Instead of: field:__data_loc unsigned long[] mask; offset:32; size:4; signed:0; The main difference is the type. Instead of "unsigned long" it is "cpumask_t *". Note, this type field needs to be a real type in the __dynamic_array() logic that both __cpumask and__bitmask use, but the comparison field requires it to be a scalar type whereas cpumask_t is a structure (non-scalar). But everything works when making it a pointer. Valentin added changes to remove the need of passing in "nr_bits" and the __cpumask will always use nr_cpumask_bits as its size. Link: https://lkml.kernel.org/r/20221014080456.1d32b989@rorschach.local.home Requested-by: Valentin Schneider Reviewed-by: Valentin Schneider Signed-off-by: Valentin Schneider Signed-off-by: Steven Rostedt (Google) --- samples/trace_events/trace-events-sample.c | 2 +- samples/trace_events/trace-events-sample.h | 34 +++++++++++++++++++++++------- 2 files changed, 27 insertions(+), 9 deletions(-) (limited to 'samples') diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c index 608c4ae3b08a..ecc7db237f2e 100644 --- a/samples/trace_events/trace-events-sample.c +++ b/samples/trace_events/trace-events-sample.c @@ -50,7 +50,7 @@ static void do_simple_thread_func(int cnt, const char *fmt, ...) trace_foo_with_template_print("I have to be different", cnt); - trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask); + trace_foo_rel_loc("Hello __rel_loc", cnt, bitmask, current->cpus_ptr); } static void simple_thread_func(int cnt) diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h index 1a92226202fc..fb4548a44153 100644 --- a/samples/trace_events/trace-events-sample.h +++ b/samples/trace_events/trace-events-sample.h @@ -200,6 +200,16 @@ * * __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits); * + * __cpumask: This is pretty much the same as __bitmask but is specific for + * CPU masks. The type displayed to the user via the format files will + * be "cpumaks_t" such that user space may deal with them differently + * if they choose to do so, and the bits is always set to nr_cpumask_bits. + * + * __cpumask(target_cpu) + * + * To assign a cpumask, use the __assign_cpumask() helper macro. + * + * __assign_cpumask(target_cpus, cpumask_bits(bar)); * * fast_assign: This is a C like function that is used to store the items * into the ring buffer. A special variable called "__entry" will be the @@ -212,8 +222,8 @@ * This is also used to print out the data from the trace files. * Again, the __entry macro is used to access the data from the ring buffer. * - * Note, __dynamic_array, __string, and __bitmask require special helpers - * to access the data. + * Note, __dynamic_array, __string, __bitmask and __cpumask require special + * helpers to access the data. * * For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo) * Use __get_dynamic_array_len(foo) to get the length of the array @@ -226,6 +236,8 @@ * * For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus) * + * For __cpumask(target_cpus) use __get_cpumask(target_cpus) + * * * Note, that for both the assign and the printk, __entry is the handler * to the data structure in the ring buffer, and is defined by the @@ -288,6 +300,7 @@ TRACE_EVENT(foo_bar, __dynamic_array(int, list, __length_of(lst)) __string( str, string ) __bitmask( cpus, num_possible_cpus() ) + __cpumask( cpum ) __vstring( vstr, fmt, va ) ), @@ -299,9 +312,10 @@ TRACE_EVENT(foo_bar, __assign_str(str, string); __assign_vstr(vstr, fmt, va); __assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus()); + __assign_cpumask(cpum, cpumask_bits(mask)); ), - TP_printk("foo %s %d %s %s %s %s (%s) %s", __entry->foo, __entry->bar, + TP_printk("foo %s %d %s %s %s %s (%s) (%s) %s", __entry->foo, __entry->bar, /* * Notice here the use of some helper functions. This includes: @@ -345,7 +359,8 @@ TRACE_EVENT(foo_bar, __print_array(__get_dynamic_array(list), __get_dynamic_array_len(list) / sizeof(int), sizeof(int)), - __get_str(str), __get_bitmask(cpus), __get_str(vstr)) + __get_str(str), __get_bitmask(cpus), __get_cpumask(cpus), + __get_str(vstr)) ); /* @@ -542,15 +557,16 @@ DEFINE_EVENT_PRINT(foo_template, foo_with_template_print, TRACE_EVENT(foo_rel_loc, - TP_PROTO(const char *foo, int bar, unsigned long *mask), + TP_PROTO(const char *foo, int bar, unsigned long *mask, const cpumask_t *cpus), - TP_ARGS(foo, bar, mask), + TP_ARGS(foo, bar, mask, cpus), TP_STRUCT__entry( __rel_string( foo, foo ) __field( int, bar ) __rel_bitmask( bitmask, BITS_PER_BYTE * sizeof(unsigned long) ) + __rel_cpumask( cpumask ) ), TP_fast_assign( @@ -558,10 +574,12 @@ TRACE_EVENT(foo_rel_loc, __entry->bar = bar; __assign_rel_bitmask(bitmask, mask, BITS_PER_BYTE * sizeof(unsigned long)); + __assign_rel_cpumask(cpumask, cpus); ), - TP_printk("foo_rel_loc %s, %d, %s", __get_rel_str(foo), __entry->bar, - __get_rel_bitmask(bitmask)) + TP_printk("foo_rel_loc %s, %d, %s, %s", __get_rel_str(foo), __entry->bar, + __get_rel_bitmask(bitmask), + __get_rel_cpumask(cpumask)) ); #endif -- cgit v1.2.3 From eb9d58947d40699d93e5e69e1ddc54e41da7e132 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Tue, 13 Dec 2022 22:12:27 -0500 Subject: tracing: Fix cpumask() example typo The sample code for using cpumask used the wrong field for the __get_cpumask() helper. It used "cpus" which is the bitmask (but would still give a proper example) instead of the "cpum" that was there to be used. Although it produces the same output, fix it, because it's an example and is confusing in how to properly use the cpumask() macro. Link: https://lore.kernel.org/linux-trace-kernel/20221213221227.56560374@gandalf.local.home Cc: Andrew Morton Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- samples/trace_events/trace-events-sample.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'samples') diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h index fb4548a44153..1c6b843b8c4e 100644 --- a/samples/trace_events/trace-events-sample.h +++ b/samples/trace_events/trace-events-sample.h @@ -359,7 +359,7 @@ TRACE_EVENT(foo_bar, __print_array(__get_dynamic_array(list), __get_dynamic_array_len(list) / sizeof(int), sizeof(int)), - __get_str(str), __get_bitmask(cpus), __get_cpumask(cpus), + __get_str(str), __get_bitmask(cpus), __get_cpumask(cpum), __get_str(vstr)) ); -- cgit v1.2.3