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| author | Luis Henriques <henrix@sapo.pt> | 2009-03-16 19:59:02 +0000 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-03-17 12:04:41 +0100 |
| commit | 708dc5125309cd33c5daaad3026cc4ae6ef39c8b (patch) | |
| tree | 7a99f6b210ebba4b42123a933345e464e3052eef /kernel/sched.c | |
| parent | 80dd99b368cf6501be88ab517bbbb5bf352b75b8 (diff) | |
| download | lwn-708dc5125309cd33c5daaad3026cc4ae6ef39c8b.tar.gz lwn-708dc5125309cd33c5daaad3026cc4ae6ef39c8b.zip | |
sched: small optimisation of can_migrate_task()
There were 3 invocations of task_hot() in can_migrate_task().
Replace these 3 invocations by only one invocation, cached in
a local variable.
Signed-off-by: Luis Henriques <henrix@sapo.pt>
LKML-Reference: <20090316195902.GA6197@hades.domain.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 489e7d926408..d2dfe4c1a225 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3002,6 +3002,7 @@ 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 @@ -3025,10 +3026,11 @@ 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); } @@ -3036,7 +3038,7 @@ 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; } |