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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2008-06-27 13:41:19 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-06-27 14:31:33 +0200 |
| commit | 4d8d595dfa69e1c807bf928f364668a7f30da5dc (patch) | |
| tree | af61c1d6d53aea66fac272e7dad67ae93a832a66 | |
| parent | sched: fix sched_domain aggregation (diff) | |
| download | linux-4d8d595dfa69e1c807bf928f364668a7f30da5dc.tar.xz linux-4d8d595dfa69e1c807bf928f364668a7f30da5dc.zip | |
sched: update aggregate when holding the RQs
It was observed that in __update_group_shares_cpu()
rq_weight > aggregate()->rq_weight
This is caused by forks/wakeups in between the initial aggregate pass and
locking of the RQs for load balance. To avoid this situation partially re-do
the aggregation once we have the RQs locked (which avoids new tasks from
appearing).
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/sched.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 160d3c209b8f..dae20199dc9c 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1721,6 +1721,11 @@ aggregate_get_up(struct task_group *tg, int cpu, struct sched_domain *sd) aggregate_group_set_shares(tg, cpu, sd); } +static void +aggregate_get_nop(struct task_group *tg, int cpu, struct sched_domain *sd) +{ +} + static DEFINE_PER_CPU(spinlock_t, aggregate_lock); static void __init init_aggregate(void) @@ -1740,6 +1745,11 @@ static int get_aggregate(int cpu, struct sched_domain *sd) return 1; } +static void update_aggregate(int cpu, struct sched_domain *sd) +{ + aggregate_walk_tree(aggregate_get_down, aggregate_get_nop, cpu, sd); +} + static void put_aggregate(int cpu, struct sched_domain *sd) { spin_unlock(&per_cpu(aggregate_lock, cpu)); @@ -1761,6 +1771,10 @@ static inline int get_aggregate(int cpu, struct sched_domain *sd) return 0; } +static inline void update_aggregate(int cpu, struct sched_domain *sd) +{ +} + static inline void put_aggregate(int cpu, struct sched_domain *sd) { } @@ -2192,6 +2206,12 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) int load_idx = sd->forkexec_idx; int imbalance = 100 + (sd->imbalance_pct-100)/2; + /* + * now that we have both rqs locked the rq weight won't change + * anymore - so update the stats. + */ + update_aggregate(this_cpu, sd); + do { unsigned long load, avg_load; int local_group; |