sched: Remove SYNC_WAKEUPS feature

Sync wakeups are critical functionality with a long history.  Remove it, we don't
need the branch or icache footprint.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1268301817.6785.47.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched.c b/kernel/sched.c
index 16559de4edeafbe0d51542c934ced7951ee2bff8..cc6dc8caa3809f6e73e8780a39b8f6a3c29e715e 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2369,9 +2369,6 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
        unsigned long flags;
        struct rq *rq;
 
-       if (!sched_feat(SYNC_WAKEUPS))
-               wake_flags &= ~WF_SYNC;
-
        this_cpu = get_cpu();
 
        smp_wmb();

diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index 1cb7c4701bf3c4de517345de2be8c6a09d4c72a7..f54b6f9cc3ddb814eb21c19326caf463bce0f0e5 100644 (file)
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -22,14 +22,6 @@ SCHED_FEAT(WAKEUP_PREEMPT, 1)
  */
 SCHED_FEAT(ASYM_GRAN, 1)
 
-/*
- * Use the SYNC wakeup hint, pipes and the likes use this to indicate
- * the remote end is likely to consume the data we just wrote, and
- * therefore has cache benefit from being placed on the same cpu, see
- * also AFFINE_WAKEUPS.
- */
-SCHED_FEAT(SYNC_WAKEUPS, 1)
-
 /*
  * Based on load and program behaviour, see if it makes sense to place
  * a newly woken task on the same cpu as the task that woke it --