[tip:sched/core] sched: Remove FAIR_SLEEPERS feature

From: tip-bot for Mike Galbraith
Date: Thu Mar 11 2010 - 13:33:19 EST


Commit-ID: 5ca9880c6f4ba4c84b517bc2fed5366adf63d191
Gitweb: http://git.kernel.org/tip/5ca9880c6f4ba4c84b517bc2fed5366adf63d191
Author: Mike Galbraith <efault@xxxxxx>
AuthorDate: Thu, 11 Mar 2010 17:17:17 +0100
Committer: Ingo Molnar <mingo@xxxxxxx>
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@xxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
LKML-Reference: <1268301520.6785.40.camel@xxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
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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