[git pull] scheduler fixes

Ingo Molnar
2009-02-11T14:42:00Z

Linus,

Please pull the latest sched-fixes-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git sched-fixes-for-linus

Thanks,

Ingo

------------------>
Peter Zijlstra (1):
sched: revert recent sync wakeup changes

Suresh Siddha (1):
sched: fix nohz load balancer on cpu offline

kernel/sched.c | 27 +++++++++++----------------
kernel/sched_fair.c | 11 +++++++++--
2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index 242d0d4..f11c02b 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2266,16 +2266,6 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
if (!sched_feat(SYNC_WAKEUPS))
sync = 0;

- if (!sync) {
- if (current->se.avg_overlap < sysctl_sched_migration_cost &&
- p->se.avg_overlap < sysctl_sched_migration_cost)
- sync = 1;
- } else {
- if (current->se.avg_overlap >= sysctl_sched_migration_cost ||
- p->se.avg_overlap >= sysctl_sched_migration_cost)
- sync = 0;
- }
-
#ifdef CONFIG_SMP
if (sched_feat(LB_WAKEUP_UPDATE)) {
struct sched_domain *sd;
@@ -3890,19 +3880,24 @@ int select_nohz_load_balancer(int stop_tick)
int cpu = smp_processor_id();

if (stop_tick) {
- cpumask_set_cpu(cpu, nohz.cpu_mask);
cpu_rq(cpu)->in_nohz_recently = 1;

- /*
- * If we are going offline and still the leader, give up!
- */
- if (!cpu_active(cpu) &&
- atomic_read(&nohz.load_balancer) == cpu) {
+ if (!cpu_active(cpu)) {
+ if (atomic_read(&nohz.load_balancer) != cpu)
+ return 0;
+
+ /*
+ * If we are going offline and still the leader,
+ * give up!
+ */
if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
BUG();
+
return 0;
}

+ cpumask_set_cpu(cpu, nohz.cpu_mask);
+
/* time for ilb owner also to sleep */
if (cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
if (atomic_read(&nohz.load_balancer) == cpu)
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index a7e50ba..0566f2a 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1191,15 +1191,20 @@ wake_affine(struct sched_domain *this_sd, struct rq *this_rq,
int idx, unsigned long load, unsigned long this_load,
unsigned int imbalance)
{
+ struct task_struct *curr = this_rq->curr;
+ struct task_group *tg;
unsigned long tl = this_load;
unsigned long tl_per_task;
- struct task_group *tg;
unsigned long weight;
int balanced;

if (!(this_sd->flags & SD_WAKE_AFFINE) || !sched_feat(AFFINE_WAKEUPS))
return 0;

+ if (sync && (curr->se.avg_overlap > sysctl_sched_migration_cost ||
+ p->se.avg_overlap > sysctl_sched_migration_cost))
+ sync = 0;
+
/*
* If sync wakeup then subtract the (maximum possible)
* effect of the currently running task from the load
@@ -1426,7 +1431,9 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
if (!sched_feat(WAKEUP_PREEMPT))
return;

- if (sched_feat(WAKEUP_OVERLAP) && sync) {
+ if (sched_feat(WAKEUP_OVERLAP) && (sync ||
+ (se->avg_overlap < sysctl_sched_migration_cost &&
+ pse->avg_overlap < sysctl_sched_migration_cost))) {
resched_task(curr);
return;
}