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authorFrederic Weisbecker <fweisbec@gmail.com>2015-05-12 17:41:49 +0300
committerIngo Molnar <mingo@kernel.org>2015-05-19 09:39:12 +0300
commitb30f0e3ffedfa52b1d67a302ae5860c49998e5e2 (patch)
tree939884115ae2a9658da6e962833f00eb197d349a /include/linux/preempt.h
parent90b62b5129d5cb50f62f40e684de7a1961e57197 (diff)
downloadlinux-b30f0e3ffedfa52b1d67a302ae5860c49998e5e2.tar.xz
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.h12
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() \