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authorPeter Zijlstra <peterz@infradead.org>2021-02-24 13:15:23 +0300
committerIngo Molnar <mingo@kernel.org>2021-03-06 14:40:21 +0300
commit58b1a45086b5f80f2b2842aa7ed0da51a64a302b (patch)
tree763139498bda05d3827770839028f5acce5a0c67 /kernel
parentc20cf065d4a619d394d23290093b1002e27dff86 (diff)
downloadlinux-58b1a45086b5f80f2b2842aa7ed0da51a64a302b.tar.xz
sched: Collate affine_move_task() stoppers
The SCA_MIGRATE_ENABLE and task_running() cases are almost identical, collapse them to avoid further duplication. Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()") Cc: stable@kernel.org Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Link: https://lkml.kernel.org/r/20210224131355.500108964@infradead.org
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/core.c23
1 files changed, 8 insertions, 15 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 088e8f492271..84b657f05625 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2239,30 +2239,23 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
return -EINVAL;
}
- if (flags & SCA_MIGRATE_ENABLE) {
-
- refcount_inc(&pending->refs); /* pending->{arg,stop_work} */
- p->migration_flags &= ~MDF_PUSH;
- task_rq_unlock(rq, p, rf);
-
- stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
- &pending->arg, &pending->stop_work);
-
- return 0;
- }
-
if (task_running(rq, p) || p->state == TASK_WAKING) {
/*
- * Lessen races (and headaches) by delegating
- * is_migration_disabled(p) checks to the stopper, which will
- * run on the same CPU as said p.
+ * MIGRATE_ENABLE gets here because 'p == current', but for
+ * anything else we cannot do is_migration_disabled(), punt
+ * and have the stopper function handle it all race-free.
*/
+
refcount_inc(&pending->refs); /* pending->{arg,stop_work} */
+ if (flags & SCA_MIGRATE_ENABLE)
+ p->migration_flags &= ~MDF_PUSH;
task_rq_unlock(rq, p, rf);
stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
&pending->arg, &pending->stop_work);
+ if (flags & SCA_MIGRATE_ENABLE)
+ return 0;
} else {
if (!is_migration_disabled(p)) {