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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2015-05-12 16:41:49 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-05-19 08:39:12 +0200 |
| commit | b30f0e3ffedfa52b1d67a302ae5860c49998e5e2 (patch) | |
| tree | 939884115ae2a9658da6e962833f00eb197d349a /include/linux/preempt.h | |
| parent | 90b62b5129d5cb50f62f40e684de7a1961e57197 (diff) | |
| download | lwn-b30f0e3ffedfa52b1d67a302ae5860c49998e5e2.tar.gz lwn-b30f0e3ffedfa52b1d67a302ae5860c49998e5e2.zip | |
sched/preempt: Optimize preemption operations on __schedule() callers
__schedule() disables preemption and some of its callers
(the preempt_schedule*() family) also set PREEMPT_ACTIVE.
So we have two preempt_count() modifications that could be performed
at once.
Lets remove the preemption disablement from __schedule() and pull
this responsibility to its callers in order to optimize preempt_count()
operations in a single place.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431441711-29753-5-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/preempt.h')
| -rw-r--r-- | include/linux/preempt.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/linux/preempt.h b/include/linux/preempt.h index 4689ef210a13..45da394f2779 100644 --- a/include/linux/preempt.h +++ b/include/linux/preempt.h @@ -137,6 +137,18 @@ extern void preempt_count_sub(int val); #define preempt_count_inc() preempt_count_add(1) #define preempt_count_dec() preempt_count_sub(1) +#define preempt_active_enter() \ +do { \ + preempt_count_add(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET); \ + barrier(); \ +} while (0) + +#define preempt_active_exit() \ +do { \ + barrier(); \ + preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET); \ +} while (0) + #ifdef CONFIG_PREEMPT_COUNT #define preempt_disable() \ |