From: Peter Zijlstra <peterz@infradead.org>
To: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jens Axboe <axboe@kernel.dk>, Ingo Molnar <mingo@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Stefano Garzarella <sgarzare@redhat.com>
Subject: Re: [PATCH] sched/fair: don't NUMA balance for kthreads
Date: Tue, 26 May 2020 22:00:15 +0200 [thread overview]
Message-ID: <20200526200015.GG325280@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <jhjpnaqtztl.mognet@arm.com>
On Tue, May 26, 2020 at 05:40:06PM +0100, Valentin Schneider wrote:
> > Change the task_tick_numa() check to exclude kernel threads in general,
> > as it doesn't make sense to attempt ot balance for kthreads anyway.
> >
>
> Does it? (this isn't a rethorical question)
>
> Suppose a given kthread ends up doing more accesses to some pages
> (via use_mm()) than the other threads that access them, wouldn't it make
> sense to take that into account when it comes to NUMA balancing?
Well, task_tick_numa() tries and farm off a bunch of actual work to
task_work_add(), and there's so very little userspace for a kernel
thread to return to... :-)
next prev parent reply other threads:[~2020-05-26 20:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-26 15:38 [PATCH] sched/fair: don't NUMA balance for kthreads Jens Axboe
2020-05-26 16:37 ` [tip: sched/urgent] sched/fair: Don't " tip-bot2 for Jens Axboe
2020-05-26 16:40 ` [PATCH] sched/fair: don't " Valentin Schneider
2020-05-26 20:00 ` Peter Zijlstra [this message]
2020-05-26 23:42 ` Valentin Schneider
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