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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2019-04-23 14:26:36 (GMT)
committerIngo Molnar <mingo@kernel.org>2019-06-03 09:49:37 (GMT)
commit3bd3706251ee8ab67e69d9340ac2abdca217e733 (patch)
tree4431aa630d095905d840ace6a0b86e266395f71a /samples
parentf2c7c76c5d0a443053e94adb9f0918fa2fb85c3a (diff)
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sched/core: Provide a pointer to the valid CPU mask
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>
Diffstat (limited to 'samples')
-rw-r--r--samples/trace_events/trace-events-sample.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
index 1da597a..1a72b7d 100644
--- a/samples/trace_events/trace-events-sample.c
+++ b/samples/trace_events/trace-events-sample.c
@@ -34,7 +34,7 @@ static void simple_thread_func(int cnt)
/* Silly tracepoints */
trace_foo_bar("hello", cnt, array, random_strings[len],
- &current->cpus_allowed);
+ current->cpus_ptr);
trace_foo_with_template_simple("HELLO", cnt);