lkml.org 
[lkml]   [2019]   [Dec]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] sched/fair: fix sgc->{min,max}_capacity miscalculate
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
\
 
 \ /
  Last update: 2019-12-31 04:52    [W:0.045 / U:29.184 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site