Messages in this thread Patch in this message | | | Date | Mon, 6 Feb 2017 11:04:26 -0500 | From | Steven Rostedt <> | Subject | [PATCH v2] sched: Remove unlikely annotation from sched_move_task() running check |
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From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
The check for running in sched_move_task() has an unlikely() around it. That is, it is unlikely that the task being moved is running. That use to be true. But with a couple of recent updates, it is now likely that the task will be running.
The first change came from ea86cb4b7621 ("sched/cgroup: Fix cpu_cgroup_fork() handling") that moved around the use case of sched_move_task() in do_fork() where the call is now done after the task is woken (hence it is running).
The second change came from 8e5bfa8c1f84 ("sched/autogroup: Do not use autogroup->tg in zombie threads") where sched_move_task() is called by the exit path, by the task that is exiting. Hence it too is running.
Cc: Oleg Nesterov <oleg@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> --- Changes from v1.
Removed annotation entirely, instead of inversing it.
Changed the subject from:
sched: Update unlikely to now likely in sched_move_task()
kernel/sched/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index c56fb57..dbb295f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7989,14 +7989,14 @@ void sched_move_task(struct task_struct *tsk) if (queued) dequeue_task(rq, tsk, DEQUEUE_SAVE | DEQUEUE_MOVE); - if (unlikely(running)) + if (running) put_prev_task(rq, tsk); sched_change_group(tsk, TASK_MOVE_GROUP); if (queued) enqueue_task(rq, tsk, ENQUEUE_RESTORE | ENQUEUE_MOVE); - if (unlikely(running)) + if (running) set_curr_task(rq, tsk); task_rq_unlock(rq, tsk, &rf); -- 2.9.3
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