linux-kernel - [tip:sched/core] sched: Remove FAIR

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Date:	Thu, 11 Mar 2010 18:32:33 GMT
From:	tip-bot for Mike Galbraith <efault@....de>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
	a.p.zijlstra@...llo.nl, efault@....de, tglx@...utronix.de,
	mingo@...e.hu
Subject: [tip:sched/core] sched: Remove FAIR_SLEEPERS feature

Commit-ID:  5ca9880c6f4ba4c84b517bc2fed5366adf63d191
Gitweb:     http://git.kernel.org/tip/5ca9880c6f4ba4c84b517bc2fed5366adf63d191
Author:     Mike Galbraith <efault@....de>
AuthorDate: Thu, 11 Mar 2010 17:17:17 +0100
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Thu, 11 Mar 2010 18:32:52 +0100

sched: Remove FAIR_SLEEPERS feature

Our preemption model relies too heavily on sleeper fairness to disable it
without dire consequences.  Remove the feature, and save a branch or two.

Signed-off-by: Mike Galbraith <efault@....de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
LKML-Reference: <1268301520.6785.40.camel@...ge.simson.net>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 kernel/sched_fair.c     |    2 +-
 kernel/sched_features.h |    7 -------
 2 files changed, 1 insertions(+), 8 deletions(-)

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index de98e2e..97682f9 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -738,7 +738,7 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
 		vruntime += sched_vslice(cfs_rq, se);
 
 	/* sleeps up to a single latency don't count. */
-	if (!initial && sched_feat(FAIR_SLEEPERS)) {
+	if (!initial) {
 		unsigned long thresh = sysctl_sched_latency;
 
 		/*
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index 4042883..850f980 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -1,11 +1,4 @@
 /*
- * Disregards a certain amount of sleep time (sched_latency_ns) and
- * considers the task to be running during that period. This gives it
- * a service deficit on wakeup, allowing it to run sooner.
- */
-SCHED_FEAT(FAIR_SLEEPERS, 1)
-
-/*
  * Only give sleepers 50% of their service deficit. This allows
  * them to run sooner, but does not allow tons of sleepers to
  * rip the spread apart.
--
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