path: root/samples/trace_events/trace-events-sample.c (follow)
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2019-06-03sched/core: Provide a pointer to the valid CPU maskSebastian Andrzej Siewior1-1/+1
In commit: 4b53a3412d66 ("sched/core: Remove the tsk_nr_cpus_allowed() wrapper") the tsk_nr_cpus_allowed() wrapper was removed. There was not much difference in !RT but in RT we used this to implement migrate_disable(). Within a migrate_disable() section the CPU mask is restricted to single CPU while the "normal" CPU mask remains untouched. As an alternative implementation Ingo suggested to use: struct task_struct { const cpumask_t *cpus_ptr; cpumask_t cpus_mask; }; with t->cpus_ptr = &t->cpus_mask; In -RT we then can switch the cpus_ptr to: t->cpus_ptr = &cpumask_of(task_cpu(p)); in a migration disabled region. The rules are simple: - Code that 'uses' ->cpus_allowed would use the pointer. - Code that 'modifies' ->cpus_allowed would use the direct mask. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/20190423142636.14347-1-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-05-21treewide: Add SPDX license identifier for more missed filesThomas Gleixner1-0/+1
Add SPDX license identifiers to all files which: - Have no license information of any form - Have MODULE_LICENCE("GPL*") inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-27Fix tracing sample code warning.Linus Torvalds1-1/+1
Commit 6575257c60e1 ("tracing/samples: Fix creation and deletion of simple_thread_fn creation") introduced a new warning due to using a boolean as a counter. Just make it "int". Fixes: 6575257c60e1 ("tracing/samples: Fix creation and deletion of simple_thread_fn creation") Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-17tracing/samples: Fix creation and deletion of simple_thread_fn creationSteven Rostedt (VMware)1-3/+11
Commit 7496946a8 ("tracing: Add samples of DECLARE_EVENT_CLASS() and DEFINE_EVENT()") added template examples for all the events. It created a DEFINE_EVENT_FN() example which reused the foo_bar_reg and foo_bar_unreg functions. Enabling both the TRACE_EVENT_FN() and DEFINE_EVENT_FN() example trace events caused the foo_bar_reg to be called twice, creating the test thread twice. The foo_bar_unreg would remove it only once, even if it was called multiple times, leaving a thread existing when the module is unloaded, causing an oops. Add a ref count and allow foo_bar_reg() and foo_bar_unreg() be called by multiple trace events. Cc: stable@vger.kernel.org Fixes: 7496946a8 ("tracing: Add samples of DECLARE_EVENT_CLASS() and DEFINE_EVENT()") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-03-02sched/core: Remove the tsk_cpus_allowed() wrapperIngo Molnar1-1/+1
So the original intention of tsk_cpus_allowed() was to 'future-proof' the field - but it's pretty ineffectual at that, because half of the code uses ->cpus_allowed directly ... Also, the wrapper makes the code longer than the original expression! So just get rid of it. This also shrinks <linux/sched.h> a bit. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-09tracing: Have the reg function allow to failSteven Rostedt (Red Hat)1-1/+2
Some tracepoints have a registration function that gets enabled when the tracepoint is enabled. There may be cases that the registraction function must fail (for example, can't allocate enough memory). In this case, the tracepoint should also fail to register, otherwise the user would not know why the tracepoint is not working. Cc: David Howells <dhowells@redhat.com> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Anton Blanchard <anton@samba.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-02-09tracing: Add samples of DECLARE_EVENT_CLASS() and DEFINE_EVENT()Steven Rostedt (Red Hat)1-0/+7
Add to samples/trace_events/ the macros DECLARE_EVENT_CLASS() and DEFINE_EVENT() and recommend using them over multiple TRACE_EVENT() macros if the multiple events have the same format. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-02-09tracing: Add TRACE_EVENT_FN exampleSteven Rostedt (Red Hat)1-0/+51
If a function should be called before a tracepoint is enabled and/or after it is disabled, the TRACE_EVENT_FN() serves this purpose. But it is not well documented. Having it as a sample would help developers to know how to use it. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-02-09tracing: Add TRACE_EVENT_CONDITION sampleSteven Rostedt (Red Hat)1-0/+3
The sample code lacks an example of TRACE_EVENT_CONDITION, and it has been expressed to me that this feature for TRACE_EVENT is not well known and not used when it could be. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-02-09tracing: Update the TRACE_EVENT fields available in the sample codeSteven Rostedt (Red Hat)1-1/+18
The sample code in samples/trace_events/ is extremely out of date and does not show all the new fields that have been added since the sample code was written. As most people are unaware of these new fields, adding sample code and explanations of those fields should help out. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-05-06tracing/events: don't say hi when loading the trace event sampleLi Zefan1-4/+0
The sample is useful for testing, and I'm using it. But after loading the module, it keeps saying hi every 10 seconds, this may be disturbing. Also Steven said commenting out the "hi" helped in causing races. :) [ Impact: make testing a bit easier ] Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A00F6AD.2070008@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-14tracing/events: add trace-events-sampleSteven Rostedt1-0/+56
This patch adds a sample to the samples directory on how to create and use TRACE_EVENT trace points. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>