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authorLinus Torvalds <torvalds@linux-foundation.org>2008-10-23 18:37:16 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-23 18:37:16 +0200
commit133e887f90208d339088dd60cb1d08a72ba27288 (patch)
tree4f6bab9d13df7fac50bc7d699d8486f441deb428 /kernel/sched.c
parentMerge branch 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kern... (diff)
parentsched: disable the hrtick for now (diff)
downloadlinux-133e887f90208d339088dd60cb1d08a72ba27288.tar.xz
linux-133e887f90208d339088dd60cb1d08a72ba27288.zip
Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: disable the hrtick for now sched: revert back to per-rq vruntime sched: fair scheduler should not resched rt tasks sched: optimize group load balancer sched: minor fast-path overhead reduction sched: fix the wrong mask_len, cleanup sched: kill unused scheduler decl. sched: fix the wrong mask_len sched: only update rq->clock while holding rq->lock
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c51
1 files changed, 26 insertions, 25 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index d906f72b42d2..945a97b9600d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -819,6 +819,13 @@ const_debug unsigned int sysctl_sched_nr_migrate = 32;
unsigned int sysctl_sched_shares_ratelimit = 250000;
/*
+ * Inject some fuzzyness into changing the per-cpu group shares
+ * this avoids remote rq-locks at the expense of fairness.
+ * default: 4
+ */
+unsigned int sysctl_sched_shares_thresh = 4;
+
+/*
* period over which we measure -rt task cpu usage in us.
* default: 1s
*/
@@ -1454,8 +1461,8 @@ static void __set_se_shares(struct sched_entity *se, unsigned long shares);
* Calculate and set the cpu's group shares.
*/
static void
-__update_group_shares_cpu(struct task_group *tg, int cpu,
- unsigned long sd_shares, unsigned long sd_rq_weight)
+update_group_shares_cpu(struct task_group *tg, int cpu,
+ unsigned long sd_shares, unsigned long sd_rq_weight)
{
int boost = 0;
unsigned long shares;
@@ -1486,19 +1493,23 @@ __update_group_shares_cpu(struct task_group *tg, int cpu,
*
*/
shares = (sd_shares * rq_weight) / (sd_rq_weight + 1);
+ shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES);
- /*
- * record the actual number of shares, not the boosted amount.
- */
- tg->cfs_rq[cpu]->shares = boost ? 0 : shares;
- tg->cfs_rq[cpu]->rq_weight = rq_weight;
+ if (abs(shares - tg->se[cpu]->load.weight) >
+ sysctl_sched_shares_thresh) {
+ struct rq *rq = cpu_rq(cpu);
+ unsigned long flags;
- if (shares < MIN_SHARES)
- shares = MIN_SHARES;
- else if (shares > MAX_SHARES)
- shares = MAX_SHARES;
+ spin_lock_irqsave(&rq->lock, flags);
+ /*
+ * record the actual number of shares, not the boosted amount.
+ */
+ tg->cfs_rq[cpu]->shares = boost ? 0 : shares;
+ tg->cfs_rq[cpu]->rq_weight = rq_weight;
- __set_se_shares(tg->se[cpu], shares);
+ __set_se_shares(tg->se[cpu], shares);
+ spin_unlock_irqrestore(&rq->lock, flags);
+ }
}
/*
@@ -1527,14 +1538,8 @@ static int tg_shares_up(struct task_group *tg, void *data)
if (!rq_weight)
rq_weight = cpus_weight(sd->span) * NICE_0_LOAD;
- for_each_cpu_mask(i, sd->span) {
- struct rq *rq = cpu_rq(i);
- unsigned long flags;
-
- spin_lock_irqsave(&rq->lock, flags);
- __update_group_shares_cpu(tg, i, shares, rq_weight);
- spin_unlock_irqrestore(&rq->lock, flags);
- }
+ for_each_cpu_mask(i, sd->span)
+ update_group_shares_cpu(tg, i, shares, rq_weight);
return 0;
}
@@ -4443,12 +4448,8 @@ need_resched_nonpreemptible:
if (sched_feat(HRTICK))
hrtick_clear(rq);
- /*
- * Do the rq-clock update outside the rq lock:
- */
- local_irq_disable();
+ spin_lock_irq(&rq->lock);
update_rq_clock(rq);
- spin_lock(&rq->lock);
clear_tsk_need_resched(prev);
if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {