Commit-ID: 93f50f90247e3e926bbe9830df089c64a5cec236 Gitweb: https://git.kernel.org/tip/93f50f90247e3e926bbe9830df089c64a5cec236 Author: Brendan Jackman <[email protected]> AuthorDate: Thu, 5 Oct 2017 12:45:16 +0100 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 10 Oct 2017 11:45:36 +0200
sched/fair: Fix usage of find_idlest_group() when the local group is idlest find_idlest_group() returns NULL when the local group is idlest. The caller then continues the find_idlest_group() search at a lower level of the current CPU's sched_domain hierarchy. find_idlest_group_cpu() is not consulted and, crucially, @new_cpu is not updated. This means the search is pointless and we return @prev_cpu from select_task_rq_fair(). This is fixed by initialising @new_cpu to @cpu instead of @prev_cpu. Signed-off-by: Brendan Jackman <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Reviewed-by: Josef Bacik <[email protected]> Reviewed-by: Vincent Guittot <[email protected]> Cc: Dietmar Eggemann <[email protected]> Cc: Josef Bacik <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Mike Galbraith <[email protected]> Cc: Morten Rasmussen <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- 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 ed80d6b..56f343b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5917,7 +5917,7 @@ find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p, int cpu, int prev_cpu, int sd_flag) { - int new_cpu = prev_cpu; + int new_cpu = cpu; if (!cpumask_intersects(sched_domain_span(sd), &p->cpus_allowed)) return prev_cpu;
