Patch "sched/fair: Allow disabling sched_balance_newidle with sched_relax_domain_level" has been added to the 6.8-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    sched/fair: Allow disabling sched_balance_newidle with sched_relax_domain_level

to the 6.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sched-fair-allow-disabling-sched_balance_newidle-wit.patch
and it can be found in the queue-6.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit b8d37e1981c3ad96f9b367fd53b7e8eb26f1fcc6
Author: Vitalii Bursov <vitaly@xxxxxxxxxx>
Date:   Tue Apr 30 18:05:23 2024 +0300

    sched/fair: Allow disabling sched_balance_newidle with sched_relax_domain_level
    
    [ Upstream commit a1fd0b9d751f840df23ef0e75b691fc00cfd4743 ]
    
    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@xxxxxxxxxx>
    Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
    Tested-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
    Reviewed-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
    Reviewed-by: Valentin Schneider <vschneid@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/bd6de28e80073c79466ec6401cdeae78f0d4423d.1714488502.git.vitaly@xxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 927bef3a598ad..6d6e540bacbfb 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 10d1391e74161..4fdab14953fc9 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1468,7 +1468,7 @@ 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);
 	}