From: Peter Zijlstra <peterz@infradead.org>
To: Tejun Heo <tj@kernel.org>
Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org,
mingo@redhat.com, axboe@kernel.dk, tytso@mit.edu, jack@suse.com,
adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com, mingbo@fb.com
Subject: Re: [PATCH 1/4] sched: move IO scheduling accounting from io_schedule_timeout() to __schedule()
Date: Fri, 28 Oct 2016 20:27:12 +0200 [thread overview]
Message-ID: <20161028182712.GM3142@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1477673892-28940-2-git-send-email-tj@kernel.org>
On Fri, Oct 28, 2016 at 12:58:09PM -0400, Tejun Heo wrote:
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -3336,11 +3336,17 @@ static void __sched notrace __schedule(bool preempt)
> unsigned long *switch_count;
> struct pin_cookie cookie;
> struct rq *rq;
> - int cpu;
> + int cpu, in_iowait;
>
> cpu = smp_processor_id();
> rq = cpu_rq(cpu);
> prev = rq->curr;
> + in_iowait = prev->in_iowait;
> +
> + if (in_iowait) {
> + delayacct_blkio_start();
> + atomic_inc(&rq->nr_iowait);
> + }
>
> schedule_debug(prev);
>
> @@ -3406,6 +3412,11 @@ static void __sched notrace __schedule(bool preempt)
> }
>
> balance_callback(rq);
> +
> + if (in_iowait) {
> + atomic_dec(&rq->nr_iowait);
> + delayacct_blkio_end();
> + }
> }
>
> void __noreturn do_task_dead(void)
Urgh, can't say I like this much. It moves two branches into the
schedule path.
Nor do I really like the idea of having to annotate special mutexes for
the iowait crap.
I'll think more after KS/LPC etc..
next prev parent reply other threads:[~2016-10-28 18:27 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-28 16:58 [PATCHSET RFC] sched, jbd2: mark sleeps on journal->j_checkpoint_mutex as iowait Tejun Heo
2016-10-28 16:58 ` [PATCH 1/4] sched: move IO scheduling accounting from io_schedule_timeout() to __schedule() Tejun Heo
2016-10-28 18:27 ` Peter Zijlstra [this message]
2016-10-28 19:07 ` Peter Zijlstra
2016-10-28 19:12 ` Tejun Heo
2016-10-29 3:21 ` Peter Zijlstra
2016-10-31 16:45 ` Tejun Heo
2016-12-06 21:30 ` Tejun Heo
2016-11-03 15:33 ` Pavan Kondeti
2016-11-08 22:51 ` Tejun Heo
2016-12-06 21:29 ` [PATCH v2 " Tejun Heo
2016-12-07 9:35 ` Peter Zijlstra
2016-12-07 20:48 ` [PATCH v3 1/4] sched: move IO scheduling accounting from io_schedule_timeout() into scheduler Tejun Heo
2017-01-14 12:49 ` [tip:sched/core] sched/core: " tip-bot for Tejun Heo
2016-10-28 16:58 ` [PATCH 2/4] sched: separate out io_schedule_prepare() and io_schedule_finish() Tejun Heo
2017-01-14 12:49 ` [tip:sched/core] sched/core: Separate " tip-bot for Tejun Heo
2016-10-28 16:58 ` [PATCH 3/4] mutex: add mutex_lock_io() Tejun Heo
2017-01-14 12:50 ` [tip:sched/core] locking/mutex, sched/wait: Add mutex_lock_io() tip-bot for Tejun Heo
2017-01-14 14:13 ` Mike Galbraith
2017-01-14 16:10 ` Ingo Molnar
2016-10-28 16:58 ` [PATCH 4/4] jbd2: use mutex_lock_io() for journal->j_checkpoint_mutex Tejun Heo
2017-01-14 12:51 ` [tip:sched/core] fs/jbd2, locking/mutex, sched/wait: Use " tip-bot for Tejun Heo
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