diff options
| author | Vincent Guittot <vincent.guittot@linaro.org> | 2019-10-18 16:26:32 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-10-21 10:40:54 +0300 |
| commit | 5e23e474431529b7d1480f649ce33d0e9c1b2e48 (patch) | |
| tree | 593f33b072f7eeee7c3d7a9313729897aa111ec7 /kernel/sched | |
| parent | 0b0695f2b34a4afa3f6e9aa1ff0e5336d8dad912 (diff) | |
| download | linux-5e23e474431529b7d1480f649ce33d0e9c1b2e48.tar.xz | |
sched/fair: Use rq->nr_running when balancing load
CFS load_balance() only takes care of CFS tasks whereas CPUs can be used by
other scheduling classes. Typically, a CFS task preempted by an RT or deadline
task will not get a chance to be pulled by another CPU because
load_balance() doesn't take into account tasks from other classes.
Add sum of nr_running in the statistics and use it to detect such
situations.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten.Rasmussen@arm.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: hdanton@sina.com
Cc: parth@linux.ibm.com
Cc: pauld@redhat.com
Cc: quentin.perret@arm.com
Cc: riel@surriel.com
Cc: srikar@linux.vnet.ibm.com
Cc: valentin.schneider@arm.com
Link: https://lkml.kernel.org/r/1571405198-27570-6-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/fair.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 76a2aa8db471..4e7396c97239 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7694,6 +7694,7 @@ struct sg_lb_stats { unsigned long group_load; /* Total load over the CPUs of the group */ unsigned long group_capacity; unsigned long group_util; /* Total utilization of the group */ + unsigned int sum_nr_running; /* Nr of tasks running in the group */ unsigned int sum_h_nr_running; /* Nr of CFS tasks running in the group */ unsigned int idle_cpus; unsigned int group_weight; @@ -7928,7 +7929,7 @@ static inline int sg_imbalanced(struct sched_group *group) static inline bool group_has_capacity(struct lb_env *env, struct sg_lb_stats *sgs) { - if (sgs->sum_h_nr_running < sgs->group_weight) + if (sgs->sum_nr_running < sgs->group_weight) return true; if ((sgs->group_capacity * 100) > @@ -7949,7 +7950,7 @@ group_has_capacity(struct lb_env *env, struct sg_lb_stats *sgs) static inline bool group_is_overloaded(struct lb_env *env, struct sg_lb_stats *sgs) { - if (sgs->sum_h_nr_running <= sgs->group_weight) + if (sgs->sum_nr_running <= sgs->group_weight) return false; if ((sgs->group_capacity * 100) < @@ -8053,6 +8054,8 @@ static inline void update_sg_lb_stats(struct lb_env *env, sgs->sum_h_nr_running += rq->cfs.h_nr_running; nr_running = rq->nr_running; + sgs->sum_nr_running += nr_running; + if (nr_running > 1) *sg_status |= SG_OVERLOAD; @@ -8410,13 +8413,13 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s } if (busiest->group_weight == 1 || sds->prefer_sibling) { - unsigned int nr_diff = busiest->sum_h_nr_running; + unsigned int nr_diff = busiest->sum_nr_running; /* * When prefer sibling, evenly spread running tasks on * groups. */ env->migration_type = migrate_task; - lsub_positive(&nr_diff, local->sum_h_nr_running); + lsub_positive(&nr_diff, local->sum_nr_running); env->imbalance = nr_diff >> 1; return; } @@ -8580,7 +8583,7 @@ static struct sched_group *find_busiest_group(struct lb_env *env) /* Try to move all excess tasks to child's sibling domain */ if (sds.prefer_sibling && local->group_type == group_has_spare && - busiest->sum_h_nr_running > local->sum_h_nr_running + 1) + busiest->sum_nr_running > local->sum_nr_running + 1) goto force_balance; if (busiest->group_type != group_overloaded && |