From f488e1057bb97b881ed317557dc5e62ff8747393 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 8 Nov 2019 14:15:56 +0100 Subject: [PATCH] sched/core: Make pick_next_task_idle() more consistent Only pick_next_task_fair() needs the @prev and @rf argument; these are required to implement the cpu-cgroup optimization. None of the other pick_next_task() methods need this. Make pick_next_task_idle() more consistent. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: juri.lelli@redhat.com Cc: ktkhai@virtuozzo.com Cc: mgorman@suse.de Cc: qais.yousef@arm.com Cc: qperret@google.com Cc: rostedt@goodmis.org Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Link: https://lkml.kernel.org/r/20191108131909.545730862@infradead.org Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 6 ++++-- kernel/sched/idle.c | 3 +-- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0f2eb3629070..59c4f2963417 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3922,8 +3922,10 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) goto restart; /* Assumes fair_sched_class->next == idle_sched_class */ - if (unlikely(!p)) - p = idle_sched_class.pick_next_task(rq, prev, rf); + if (unlikely(!p)) { + put_prev_task(rq, prev); + p = idle_sched_class.pick_next_task(rq, NULL, NULL); + } return p; } diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index f65ef1e2f204..179d1d4ac5a6 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -396,8 +396,7 @@ pick_next_task_idle(struct rq *rq, struct task_struct *prev, struct rq_flags *rf { struct task_struct *next = rq->idle; - if (prev) - put_prev_task(rq, prev); + WARN_ON_ONCE(prev || rf); set_next_task_idle(rq, next); -- 2.30.2