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authorPeter Zijlstra <peterz@infradead.org>2013-11-20 15:22:37 +0400
committerIngo Molnar <mingo@kernel.org>2014-01-13 20:38:55 +0400
commit8cb75e0c4ec9786b81439761eac1d18d4a931af3 (patch)
tree9d13e6c3580a36cd76d1b3a96827795949519409 /include/linux/preempt.h
parentc9c8986847d2f4fc474c10ee08afa57e7474096d (diff)
downloadlinux-8cb75e0c4ec9786b81439761eac1d18d4a931af3.tar.xz
sched/preempt: Fix up missed PREEMPT_NEED_RESCHED folding
With various drivers wanting to inject idle time; we get people calling idle routines outside of the idle loop proper. Therefore we need to be extra careful about not missing TIF_NEED_RESCHED -> PREEMPT_NEED_RESCHED propagations. While looking at this, I also realized there's a small window in the existing idle loop where we can miss TIF_NEED_RESCHED; when it hits right after the tif_need_resched() test at the end of the loop but right before the need_resched() test at the start of the loop. So move preempt_fold_need_resched() out of the loop where we're guaranteed to have TIF_NEED_RESCHED set. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-x9jgh45oeayzajz2mjt0y7d6@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/preempt.h')
-rw-r--r--include/linux/preempt.h15
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index dd9ddf8af205..59749fc48328 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -134,6 +134,21 @@ do { \
#undef preempt_check_resched
#endif
+#ifdef CONFIG_PREEMPT
+#define preempt_set_need_resched() \
+do { \
+ set_preempt_need_resched(); \
+} while (0)
+#define preempt_fold_need_resched() \
+do { \
+ if (tif_need_resched()) \
+ set_preempt_need_resched(); \
+} while (0)
+#else
+#define preempt_set_need_resched() do { } while (0)
+#define preempt_fold_need_resched() do { } while (0)
+#endif
+
#ifdef CONFIG_PREEMPT_NOTIFIERS
struct preempt_notifier;