Messages in this thread Patch in this message | | | Date | Tue, 31 Dec 2019 11:51:22 +0800 | From | Peng Liu <> | Subject | [PATCH] sched/fair: fix sgc->{min,max}_capacity miscalculate |
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commit bf475ce0a3dd ("sched/fair: Add per-CPU min capacity to sched_group_capacity") introduced per-cpu min_capacity.
commit e3d6d0cb66f2 ("sched/fair: Add sched_group per-CPU max capacity") introduced per-cpu max_capacity.
sgc->capacity is the *SUM* of all CPU's capacity in the group. sgc->{min,max}_capacity are the sg per-cpu variables. Compare with sgc->capacity to get sgc->{min,max}_capacity makes no sense. Instead, we should compare one by one in each iteration to get sgc->{min,max}_capacity of the group.
Signed-off-by: Peng Liu <iwtbavbm@gmail.com> --- kernel/sched/fair.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 2d170b5da0e3..97b164fcda93 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7795,6 +7795,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu) for_each_cpu(cpu, sched_group_span(sdg)) { struct sched_group_capacity *sgc; struct rq *rq = cpu_rq(cpu); + unsigned long cap; /* * build_sched_domains() -> init_sched_groups_capacity() @@ -7808,14 +7809,16 @@ void update_group_capacity(struct sched_domain *sd, int cpu) * causing divide-by-zero issues on boot. */ if (unlikely(!rq->sd)) { - capacity += capacity_of(cpu); + cap = capacity_of(cpu); + capacity += cap; + min_capacity = min(cap, min_capacity); + max_capacity = max(cap, max_capacity); } else { sgc = rq->sd->groups->sgc; capacity += sgc->capacity; + min_capacity = min(sgc->min_capacity, min_capacity); + max_capacity = max(sgc->max_capacity, max_capacity); } - - min_capacity = min(capacity, min_capacity); - max_capacity = max(capacity, max_capacity); } } else { /* -- 2.17.1
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