lkml.org 
[lkml]   [2009]   [Mar]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 2/2 -tip] sched: small optimisation on can_migrate_task
There were 3 invocation to task_hot() in function can_migrate_task().  These 3
invocations have been replaced by only one invocation, cached in a local
variable.

Signed-off-by: Luis Henriques <henrix@sapo.pt>
---
kernel/sched.c | 10 ++++++----
1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index 0a5d929..4000304 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3072,6 +3072,7 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
struct sched_domain *sd, enum cpu_idle_type idle,
int *all_pinned)
{
+ int tsk_cache_hot = 0;
/*
* We do not migrate tasks that are:
* 1) running (obviously), or
@@ -3095,10 +3096,11 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
* 2) too many balance attempts have failed.
*/

- if (!task_hot(p, rq->clock, sd) ||
- sd->nr_balance_failed > sd->cache_nice_tries) {
+ tsk_cache_hot = task_hot(p, rq->clock, sd);
+ if (!tsk_cache_hot ||
+ sd->nr_balance_failed > sd->cache_nice_tries) {
#ifdef CONFIG_SCHEDSTATS
- if (task_hot(p, rq->clock, sd)) {
+ if (tsk_cache_hot) {
schedstat_inc(sd, lb_hot_gained[idle]);
schedstat_inc(p, se.nr_forced_migrations);
}
@@ -3106,7 +3108,7 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
return 1;
}

- if (task_hot(p, rq->clock, sd)) {
+ if (tsk_cache_hot) {
schedstat_inc(p, se.nr_failed_migrations_hot);
return 0;
}
--
1.6.2


\
 
 \ /
  Last update: 2009-03-16 21:03    [W:0.032 / U:1.096 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site