[tip:sched/core] sched: Kill WAKEUP_PREEMPT

From: tip-bot for Yong Zhang
Date: Sun Aug 14 2011 - 11:57:55 EST


Commit-ID: 2c2efaed9bc973e3aeab1385c618017b56c8f6d7
Gitweb: http://git.kernel.org/tip/2c2efaed9bc973e3aeab1385c618017b56c8f6d7
Author: Yong Zhang <yong.zhang0@xxxxxxxxx>
AuthorDate: Fri, 29 Jul 2011 16:20:33 +0800
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Sun, 14 Aug 2011 12:00:41 +0200

sched: Kill WAKEUP_PREEMPT

Remove the WAKEUP_PREEMPT feature, disabling it doesn't make any sense
and its outlived its use by a long long while.

Signed-off-by: Yong Zhang <yong.zhang0@xxxxxxxxx>
Acked-by: Mike Galbraith <efault@xxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20110729082033.GB12106@zhy
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
kernel/sched_fair.c | 9 +--------
kernel/sched_features.h | 5 -----
2 files changed, 1 insertions(+), 13 deletions(-)

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index bc8ee99..241fc86 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1095,9 +1095,6 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
* narrow margin doesn't have to wait for a full slice.
* This also mitigates buddy induced latencies under load.
*/
- if (!sched_feat(WAKEUP_PREEMPT))
- return;
-
if (delta_exec < sysctl_sched_min_granularity)
return;

@@ -1233,7 +1230,7 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
return;
#endif

- if (cfs_rq->nr_running > 1 || !sched_feat(WAKEUP_PREEMPT))
+ if (cfs_rq->nr_running > 1)
check_preempt_tick(cfs_rq, curr);
}

@@ -1899,10 +1896,6 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
if (unlikely(p->policy != SCHED_NORMAL))
return;

-
- if (!sched_feat(WAKEUP_PREEMPT))
- return;
-
find_matching_se(&se, &pse);
update_curr(cfs_rq_of(se));
BUG_ON(!pse);
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index 2e74677..efa0a7b 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -12,11 +12,6 @@ SCHED_FEAT(GENTLE_FAIR_SLEEPERS, 1)
SCHED_FEAT(START_DEBIT, 1)

/*
- * Should wakeups try to preempt running tasks.
- */
-SCHED_FEAT(WAKEUP_PREEMPT, 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
--
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