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| author | Peter Zijlstra <peterz@infradead.org> | 2013-08-19 15:22:57 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-09-02 08:27:35 +0200 |
| commit | 147c5fc2bad780d8093b547f2baa204e78107faf (patch) | |
| tree | d3edc50c11c47dc03d405275adffd116d5d5c480 /kernel/sched | |
| parent | 56cf515b4b1567c4e8fa9926175b40c66b9ec472 (diff) | |
| download | linux-147c5fc2bad780d8093b547f2baa204e78107faf.tar.bz2 | |
sched/fair: Shrink sg_lb_stats and play memset games
We can shrink sg_lb_stats because rq::nr_running is an unsigned int
and cpu numbers are 'int'
Before:
sgs: /* size: 72, cachelines: 2, members: 10 */
sds: /* size: 184, cachelines: 3, members: 7 */
After:
sgs: /* size: 56, cachelines: 1, members: 10 */
sds: /* size: 152, cachelines: 3, members: 7 */
Further we can avoid clearing all of sds since we do a total
clear/assignment of sg_stats in update_sg_lb_stats() with exception of
busiest_stat.avg_load which is referenced in update_sd_pick_busiest().
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-0klzmz9okll8wc0nsudguc9p@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/fair.c | 33 |
1 files changed, 26 insertions, 7 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 2da80a55827b..4c6a8a5a789a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4237,12 +4237,12 @@ static unsigned long task_h_load(struct task_struct *p) struct sg_lb_stats { unsigned long avg_load; /*Avg load across the CPUs of the group */ unsigned long group_load; /* Total load over the CPUs of the group */ - unsigned long sum_nr_running; /* Nr tasks running in the group */ unsigned long sum_weighted_load; /* Weighted load of group's tasks */ unsigned long load_per_task; - unsigned long group_capacity; - unsigned long idle_cpus; - unsigned long group_weight; + unsigned int sum_nr_running; /* Nr tasks running in the group */ + unsigned int group_capacity; + unsigned int idle_cpus; + unsigned int group_weight; int group_imb; /* Is there an imbalance in the group ? */ int group_has_capacity; /* Is there extra capacity in the group? */ }; @@ -4258,10 +4258,29 @@ struct sd_lb_stats { unsigned long total_pwr; /* Total power of all groups in sd */ unsigned long avg_load; /* Average load across all groups in sd */ - struct sg_lb_stats local_stat; /* Statistics of the local group */ struct sg_lb_stats busiest_stat;/* Statistics of the busiest group */ + struct sg_lb_stats local_stat; /* Statistics of the local group */ }; +static inline void init_sd_lb_stats(struct sd_lb_stats *sds) +{ + /* + * Skimp on the clearing to avoid duplicate work. We can avoid clearing + * local_stat because update_sg_lb_stats() does a full clear/assignment. + * We must however clear busiest_stat::avg_load because + * update_sd_pick_busiest() reads this before assignment. + */ + *sds = (struct sd_lb_stats){ + .busiest = NULL, + .local = NULL, + .total_load = 0UL, + .total_pwr = 0UL, + .busiest_stat = { + .avg_load = 0UL, + }, + }; +} + /** * get_sd_load_idx - Obtain the load index for a given sched domain. * @sd: The sched_domain whose load_idx is to be obtained. @@ -4615,7 +4634,7 @@ static inline void update_sd_lb_stats(struct lb_env *env, */ if (prefer_sibling && !local_group && sds->local && sds->local_stat.group_has_capacity) - sgs->group_capacity = min(sgs->group_capacity, 1UL); + sgs->group_capacity = min(sgs->group_capacity, 1U); /* Now, start updating sd_lb_stats */ sds->total_load += sgs->group_load; @@ -4846,7 +4865,7 @@ static struct sched_group *find_busiest_group(struct lb_env *env) struct sg_lb_stats *local, *busiest; struct sd_lb_stats sds; - memset(&sds, 0, sizeof(sds)); + init_sd_lb_stats(&sds); /* * Compute the various statistics relavent for load balancing at |