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>

2 files changed, 0 insertions, 11 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 16559de4edea..cc6dc8caa380 100644
--- 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 1cb7c4701bf3..f54b6f9cc3dd 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -23,14 +23,6 @@ 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 --
  * improve cache locality. Typically used with SYNC wakeups as