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authorIngo Molnar <mingo@elte.hu>2008-03-16 20:03:22 +0100
committerIngo Molnar <mingo@elte.hu>2008-04-19 19:44:57 +0200
commitb85d0667268320072ccdeb07c27c25b300ab3724 (patch)
tree34bc3926e6524d82d450df5531744fff6b4df560 /kernel/sched.c
parentsched: fix wakeup granularity for buddies (diff)
downloadlinux-b85d0667268320072ccdeb07c27c25b300ab3724.tar.xz
linux-b85d0667268320072ccdeb07c27c25b300ab3724.zip
sched: introduce SCHED_FEAT_SYNC_WAKEUPS, turn it off
turn off sync wakeups by default. They are not needed anymore - the buddy logic should be smart enough to keep the system from overscheduling. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to '')
-rw-r--r--kernel/sched.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index d8456a9ac9af..263e25e10204 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -627,6 +627,7 @@ enum {
SCHED_FEAT_START_DEBIT = 4,
SCHED_FEAT_HRTICK = 8,
SCHED_FEAT_DOUBLE_TICK = 16,
+ SCHED_FEAT_SYNC_WAKEUPS = 32,
};
const_debug unsigned int sysctl_sched_features =
@@ -634,7 +635,8 @@ const_debug unsigned int sysctl_sched_features =
SCHED_FEAT_WAKEUP_PREEMPT * 1 |
SCHED_FEAT_START_DEBIT * 1 |
SCHED_FEAT_HRTICK * 1 |
- SCHED_FEAT_DOUBLE_TICK * 0;
+ SCHED_FEAT_DOUBLE_TICK * 0 |
+ SCHED_FEAT_SYNC_WAKEUPS * 0;
#define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
@@ -1916,6 +1918,9 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
long old_state;
struct rq *rq;
+ if (!sched_feat(SYNC_WAKEUPS))
+ sync = 0;
+
smp_wmb();
rq = task_rq_lock(p, &flags);
old_state = p->state;