linux-kernel - [tip: sched/urgent] sched/fair: Allow disabling sched_balance_newidle with sched_relax_domain

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Date: Fri, 17 May 2024 08:06:11 -0000
From: "tip-bot2 for Vitalii Bursov" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Vitalii Bursov <vitaly@...sov.com>, Ingo Molnar <mingo@...nel.org>,
 Dietmar Eggemann <dietmar.eggemann@....com>,
 Vincent Guittot <vincent.guittot@...aro.org>,
 Valentin Schneider <vschneid@...hat.com>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: sched/urgent] sched/fair: Allow disabling sched_balance_newidle
 with sched_relax_domain_level

The following commit has been merged into the sched/urgent branch of tip:

Commit-ID:     a1fd0b9d751f840df23ef0e75b691fc00cfd4743
Gitweb:        https://git.kernel.org/tip/a1fd0b9d751f840df23ef0e75b691fc00cfd4743
Author:        Vitalii Bursov <vitaly@...sov.com>
AuthorDate:    Tue, 30 Apr 2024 18:05:23 +03:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Fri, 17 May 2024 09:48:24 +02:00

sched/fair: Allow disabling sched_balance_newidle with sched_relax_domain_level

Change relax_domain_level checks so that it would be possible
to include or exclude all domains from newidle balancing.

This matches the behavior described in the documentation:

  -1   no request. use system default or follow request of others.
   0   no search.
   1   search siblings (hyperthreads in a core).

"2" enables levels 0 and 1, level_max excludes the last (level_max)
level, and level_max+1 includes all levels.

Fixes: 1d3504fcf560 ("sched, cpuset: customize sched domains, core")
Signed-off-by: Vitalii Bursov <vitaly@...sov.com>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Tested-by: Dietmar Eggemann <dietmar.eggemann@....com>
Reviewed-by: Vincent Guittot <vincent.guittot@...aro.org>
Reviewed-by: Valentin Schneider <vschneid@...hat.com>
Link: https://lore.kernel.org/r/bd6de28e80073c79466ec6401cdeae78f0d4423d.1714488502.git.vitaly@bursov.com
---
 kernel/cgroup/cpuset.c  | 2 +-
 kernel/sched/topology.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 4237c87..da24187 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -2948,7 +2948,7 @@ bool current_cpuset_is_being_rebound(void)
 static int update_relax_domain_level(struct cpuset *cs, s64 val)
 {
 #ifdef CONFIG_SMP
-	if (val < -1 || val >= sched_domain_level_max)
+	if (val < -1 || val > sched_domain_level_max + 1)
 		return -EINVAL;
 #endif
 
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 63aecd2..67a777b 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1475,7 +1475,7 @@ static void set_domain_attribute(struct sched_domain *sd,
 	} else
 		request = attr->relax_domain_level;
 
-	if (sd->level > request) {
+	if (sd->level >= request) {
 		/* Turn off idle balance on this domain: */
 		sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
 	}