From 2137d07adba02ce2e243c3bbf582efe60eeff643 Mon Sep 17 00:00:00 2001 From: Valentin Schneider Date: Mon, 14 Oct 2019 17:44:08 +0100 Subject: [PATCH] sched/topology: Don't set SD_BALANCE_WAKE on cpuset domain relax [ Upstream commit 9ae7ab20b4835dbea0e5fc6a5c70171dc354a72e ] As pointed out in commit 182a85f8a119 ("sched: Disable wakeup balancing") SD_BALANCE_WAKE is a tad too aggressive, and is usually left unset. However, it turns out cpuset domain relaxation will unconditionally set it on domains below the relaxation level. This made sense back when SD_BALANCE_WAKE was set unconditionally, but it no longer is the case. We can improve things slightly by noticing that set_domain_attribute() is always called after sd_init(), so rather than setting flags we can rely on whatever sd_init() is doing and only clear certain flags when above the relaxation level. While at it, slightly clean up the function and flip the relax level check to be more human readable. Signed-off-by: Valentin Schneider Signed-off-by: Peter Zijlstra (Intel) Cc: mingo@kernel.org Cc: vincent.guittot@linaro.org Cc: juri.lelli@redhat.com Cc: seto.hidetoshi@jp.fujitsu.com Cc: qperret@google.com Cc: Dietmar.Eggemann@arm.com Cc: morten.rasmussen@arm.com Link: https://lkml.kernel.org/r/20191014164408.32596-1-valentin.schneider@arm.com Stable-dep-of: a1fd0b9d751f ("sched/fair: Allow disabling sched_balance_newidle with sched_relax_domain_level") Signed-off-by: Sasha Levin --- kernel/sched/topology.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index e5ebaffc4fef..844dc30fc559 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -1201,16 +1201,13 @@ static void set_domain_attribute(struct sched_domain *sd, if (!attr || attr->relax_domain_level < 0) { if (default_relax_domain_level < 0) return; - else - request = default_relax_domain_level; + request = default_relax_domain_level; } else request = attr->relax_domain_level; - if (request < sd->level) { + + if (sd->level > request) { /* Turn off idle balance on this domain: */ sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); - } else { - /* Turn on idle balance on this domain: */ - sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); } }