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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-09-01 10:34:38 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-09-04 10:09:55 +0200 |
| commit | bdb94aa5dbd8b55e75f5a50b61312fe589e2c2d1 (patch) | |
| tree | 388da3774a3c69f4a0a74285478226311ec41c90 /kernel/sched.c | |
| parent | e9e9250bc78e7f6342517214c0178a529807964b (diff) | |
| download | linux-bdb94aa5dbd8b55e75f5a50b61312fe589e2c2d1.tar.gz linux-bdb94aa5dbd8b55e75f5a50b61312fe589e2c2d1.tar.bz2 linux-bdb94aa5dbd8b55e75f5a50b61312fe589e2c2d1.zip | |
sched: Try to deal with low capacity
When the capacity drops low, we want to migrate load away.
Allow the load-balancer to remove all tasks when we hit rock
bottom.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Acked-by: Gautham R Shenoy <ego@in.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
LKML-Reference: <20090901083826.342231003@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 33 |
1 files changed, 28 insertions, 5 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index ab532b5de40e..5f5b359b01b8 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3908,8 +3908,8 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task) sgs->group_imb = 1; - sgs->group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; - + sgs->group_capacity = + DIV_ROUND_CLOSEST(group->__cpu_power, SCHED_LOAD_SCALE); } /** @@ -3959,7 +3959,7 @@ static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu, * and move all the excess tasks away. */ if (prefer_sibling) - sgs.group_capacity = 1; + sgs.group_capacity = min(sgs.group_capacity, 1UL); if (local_group) { sds->this_load = sgs.avg_load; @@ -4191,6 +4191,26 @@ ret: return NULL; } +static struct sched_group *group_of(int cpu) +{ + struct sched_domain *sd = rcu_dereference(cpu_rq(cpu)->sd); + + if (!sd) + return NULL; + + return sd->groups; +} + +static unsigned long power_of(int cpu) +{ + struct sched_group *group = group_of(cpu); + + if (!group) + return SCHED_LOAD_SCALE; + + return group->__cpu_power; +} + /* * find_busiest_queue - find the busiest runqueue among the cpus in group. */ @@ -4203,15 +4223,18 @@ find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, int i; for_each_cpu(i, sched_group_cpus(group)) { + unsigned long power = power_of(i); + unsigned long capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE); unsigned long wl; if (!cpumask_test_cpu(i, cpus)) continue; rq = cpu_rq(i); - wl = weighted_cpuload(i); + wl = weighted_cpuload(i) * SCHED_LOAD_SCALE; + wl /= power; - if (rq->nr_running == 1 && wl > imbalance) + if (capacity && rq->nr_running == 1 && wl > imbalance) continue; if (wl > max_load) { |