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| author | Brendan Jackman <brendan.jackman@arm.com> | 2017-10-05 13:45:16 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-10-10 11:45:36 +0200 |
| commit | 93f50f90247e3e926bbe9830df089c64a5cec236 (patch) | |
| tree | a7b31f40fa439b4ee9b43c208d38fcc7f73bba0d /kernel | |
| parent | sched/fair: Fix usage of find_idlest_group() when no groups are allowed (diff) | |
| download | linux-93f50f90247e3e926bbe9830df089c64a5cec236.tar.xz linux-93f50f90247e3e926bbe9830df089c64a5cec236.zip | |
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 <brendan.jackman@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20171005114516.18617-6-brendan.jackman@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/fair.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ed80d6bd76c8..56f343b8e749 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; |