From: Juri Lelli <juri.lelli@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>,
Ingo Molnar <mingo@kernel.org>,
Luca Abeni <luca.abeni@santannapisa.it>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Valentin Schneider <Valentin.Schneider@arm.com>,
Qais Yousef <Qais.Yousef@arm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/5] sched/deadline: Cleanup on_dl_rq() handling
Date: Tue, 30 Jul 2019 08:41:15 +0200 [thread overview]
Message-ID: <20190730064115.GC8927@localhost.localdomain> (raw)
In-Reply-To: <20190729164932.GN31398@hirez.programming.kicks-ass.net>
On 29/07/19 18:49, Peter Zijlstra wrote:
> On Fri, Jul 26, 2019 at 09:27:55AM +0100, Dietmar Eggemann wrote:
> > Remove BUG_ON() in __enqueue_dl_entity() since there is already one in
> > enqueue_dl_entity().
> >
> > Move the check that the dl_se is not on the dl_rq from
> > __dequeue_dl_entity() to dequeue_dl_entity() to align with the enqueue
> > side and use the on_dl_rq() helper function.
> >
> > Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> > ---
> > kernel/sched/deadline.c | 8 +++-----
> > 1 file changed, 3 insertions(+), 5 deletions(-)
> >
> > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> > index 1fa005f79307..a9cb52ceb761 100644
> > --- a/kernel/sched/deadline.c
> > +++ b/kernel/sched/deadline.c
> > @@ -1407,8 +1407,6 @@ static void __enqueue_dl_entity(struct sched_dl_entity *dl_se)
> > struct sched_dl_entity *entry;
> > int leftmost = 1;
> >
> > - BUG_ON(!RB_EMPTY_NODE(&dl_se->rb_node));
> > -
> > while (*link) {
> > parent = *link;
> > entry = rb_entry(parent, struct sched_dl_entity, rb_node);
> > @@ -1430,9 +1428,6 @@ static void __dequeue_dl_entity(struct sched_dl_entity *dl_se)
> > {
> > struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
> >
> > - if (RB_EMPTY_NODE(&dl_se->rb_node))
> > - return;
> > -
> > rb_erase_cached(&dl_se->rb_node, &dl_rq->root);
> > RB_CLEAR_NODE(&dl_se->rb_node);
> >
> > @@ -1466,6 +1461,9 @@ enqueue_dl_entity(struct sched_dl_entity *dl_se,
> >
> > static void dequeue_dl_entity(struct sched_dl_entity *dl_se)
> > {
> > + if (!on_dl_rq(dl_se))
> > + return;
>
> Why allow double dequeue instead of WARN?
As I was saying to Valentin, it can currently happen that a task could
have already been dequeued by update_curr_dl()->throttle called by
dequeue_task_dl() before calling __dequeue_task_dl(). Do you think we
should check for this condition before calling into dequeue_dl_entity()?
next prev parent reply other threads:[~2019-07-30 6:41 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-26 8:27 [PATCH 0/5] sched/deadline: Fix double accounting in push_dl_task() & some cleanups Dietmar Eggemann
2019-07-26 8:27 ` [PATCH 1/5] sched/deadline: Fix double accounting of rq/running bw in push_dl_task() Dietmar Eggemann
2019-07-26 10:11 ` luca abeni
2019-07-29 8:59 ` Dietmar Eggemann
2019-07-29 16:10 ` Peter Zijlstra
2019-07-26 13:30 ` luca abeni
2019-07-29 9:00 ` Dietmar Eggemann
2019-07-31 10:32 ` Dietmar Eggemann
2019-07-26 8:27 ` [PATCH 2/5] sched/deadline: Remove unused int flags from __dequeue_task_dl() Dietmar Eggemann
2019-07-29 16:35 ` Peter Zijlstra
2019-07-29 17:12 ` Dietmar Eggemann
2019-07-26 8:27 ` [PATCH 3/5] sched/deadline: Use __sub_running_bw() throughout dl_change_utilization() Dietmar Eggemann
2019-07-29 16:47 ` Peter Zijlstra
2019-07-29 17:21 ` Dietmar Eggemann
2019-07-26 8:27 ` [PATCH 4/5] sched/deadline: Cleanup on_dl_rq() handling Dietmar Eggemann
2019-07-26 8:37 ` Valentin Schneider
2019-07-26 8:58 ` Qais Yousef
2019-07-26 9:20 ` Juri Lelli
2019-07-26 9:32 ` Valentin Schneider
2019-07-29 16:49 ` Peter Zijlstra
2019-07-30 6:41 ` Juri Lelli [this message]
2019-07-30 8:21 ` Peter Zijlstra
2019-07-31 17:32 ` Dietmar Eggemann
2019-07-31 20:20 ` luca abeni
2019-08-01 16:01 ` Dietmar Eggemann
2019-07-26 8:27 ` [PATCH 5/5] sched/deadline: Use return value of SCHED_WARN_ON() in bw accounting Dietmar Eggemann
2019-07-26 10:18 ` luca abeni
2019-07-29 16:54 ` Peter Zijlstra
2019-07-29 16:59 ` Dietmar Eggemann
2019-07-30 8:23 ` Peter Zijlstra
2019-07-30 16:08 ` Dietmar Eggemann
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190730064115.GC8927@localhost.localdomain \
--to=juri.lelli@redhat.com \
--cc=Qais.Yousef@arm.com \
--cc=Valentin.Schneider@arm.com \
--cc=bristot@redhat.com \
--cc=dietmar.eggemann@arm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luca.abeni@santannapisa.it \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).