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Groups > linux.kernel > #1579570
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v2 8/9] sched: Don't reinvent the wheel but use existing llist API |
| Date | 2017-02-13 11:10 +0100 |
| Message-ID | <talK2-2iF-13@gated-at.bofh.it> (permalink) |
| References | <tajfc-zU-3@gated-at.bofh.it> <tajfc-zU-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Mon, Feb 13, 2017 at 04:21:08PM +0900, Byungchul Park wrote:
> Although llist provides proper APIs, they are not used. Make them used.
>
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> ---
> kernel/sched/core.c | 13 ++-----------
> 1 file changed, 2 insertions(+), 11 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index d01f9d0..417060b 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -1783,17 +1783,8 @@ void sched_ttwu_pending(void)
> raw_spin_lock_irqsave(&rq->lock, flags);
> rq_pin_lock(rq, &rf);
>
> - while (llist) {
> - int wake_flags = 0;
> -
> - p = llist_entry(llist, struct task_struct, wake_entry);
> - llist = llist_next(llist);
> -
> - if (p->sched_remote_wakeup)
> - wake_flags = WF_MIGRATED;
> -
> - ttwu_do_activate(rq, p, wake_flags, &rf);
> - }
> + llist_for_each_entry(p, llist, wake_entry)
> + ttwu_do_activate(rq, p, p->sched_remote_wakeup ? WF_MIGRATED : 0, &rf);
I think this suffers the exact same problem the others did. After
ttwu_do_activate() the llist entry can be reused, so doing list_next()
after it is flaky.
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[PATCH v2 8/9] sched: Don't reinvent the wheel but use existing llist API Byungchul Park <byungchul.park@lge.com> - 2017-02-13 08:30 +0100
Re: [PATCH v2 8/9] sched: Don't reinvent the wheel but use existing llist API Peter Zijlstra <peterz@infradead.org> - 2017-02-13 11:10 +0100
Re: [PATCH v2 8/9] sched: Don't reinvent the wheel but use existing llist API Oleg Nesterov <oleg@redhat.com> - 2017-02-13 17:00 +0100
Re: [PATCH v2 8/9] sched: Don't reinvent the wheel but use existing llist API Byungchul Park <byungchul.park@lge.com> - 2017-02-14 00:10 +0100
Re: [PATCH v2 8/9] sched: Don't reinvent the wheel but use existing llist API Byungchul Park <byungchul.park@lge.com> - 2017-02-14 00:10 +0100
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