* [PATCH] [PATCH v1]: sched/fair: Revise comment about lb decision matrix
@ 2022-04-14 23:46 Tao Zhou
0 siblings, 0 replies; only message in thread
From: Tao Zhou @ 2022-04-14 23:46 UTC (permalink / raw)
To: LKML, Tao Zhou
Cc: Ingo Molnar, Peter Zijlstra, Lelli, Vincent Guittot,
Dietmar Eggemann, Ben Segall, Mel Gorman,
Daniel Bristot de Oliveira
If busiest group type is group_misfit_task, the local
group type must be group_has_spare according to below
code in update_sd_pick_busiest():
if (sgs->group_type == group_misfit_task &&
(!capacity_greater(capacity_of(env->dst_cpu), sg->sgc->max_capacity) ||
sds->local_stat.group_type != group_has_spare))
return false;
group type imbalanced and overloaded and fully_busy are filtered in here.
misfit and asym are filtered before in update_sg_lb_stats().
So, change the decision matrix to:
busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
has_spare nr_idle balanced N/A N/A balanced balanced
fully_busy nr_idle nr_idle N/A N/A balanced balanced
misfit_task force N/A N/A N/A *N/A* *N/A*
asym_packing force force N/A N/A force force
imbalanced force force N/A N/A force force
overloaded force force N/A N/A force avg_load
Fixes: 0b0695f2b34a ("sched/fair: Rework load_balance()")
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Tao Zhou <tao.zhou@linux.dev>
---
v1 changelog:
(1) Send to MAINTAINERS/REVIEWS get from `./scripts/get_maintainer.pl`
suggested by Dietmar Eggemann.
(2) Based on v5.18-rc2
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d4bd299d67ab..b8c67e7c8cf3 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9495,7 +9495,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
* busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
* has_spare nr_idle balanced N/A N/A balanced balanced
* fully_busy nr_idle nr_idle N/A N/A balanced balanced
- * misfit_task force N/A N/A N/A force force
+ * misfit_task force N/A N/A N/A N/A N/A
* asym_packing force force N/A N/A force force
* imbalanced force force N/A N/A force force
* overloaded force force N/A N/A force avg_load
--
2.35.2
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