From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>, Ming Lei <ming.lei@redhat.com>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
linux-block@vger.kernel.org, John Garry <john.garry@huawei.com>,
Bart Van Assche <bvanassche@acm.org>,
Hannes Reinecke <hare@suse.com>,
io-uring@vger.kernel.org
Subject: Re: io_uring vs CPU hotplug, was Re: [PATCH 5/9] blk-mq: don't set data->ctx and data->hctx in blk_mq_alloc_request_hctx
Date: Wed, 20 May 2020 17:31:23 +0200 [thread overview]
Message-ID: <20200520153123.GA2340@lst.de> (raw)
In-Reply-To: <448d3660-0d83-889b-001f-a09ea53fa117@kernel.dk>
On Wed, May 20, 2020 at 09:20:50AM -0600, Jens Axboe wrote:
> Just checked, and it works fine for me. If I create an SQPOLL ring with
> SQ_AFF set and bound to CPU 3, if CPU 3 goes offline, then the kthread
> just appears unbound but runs just fine. When CPU 3 comes online again,
> the mask appears correct.
>
> So don't think there's anything wrong on that side. The affinity is a
> performance optimization, not a correctness issue. Really not much we
> can do if the chosen CPU is offlined, apart from continue to chug along.
Ok, that sounds pretty sensible.
next prev parent reply other threads:[~2020-05-20 15:31 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200518093155.GB35380@T590>
[not found] ` <87imgty15d.fsf@nanos.tec.linutronix.de>
[not found] ` <20200518115454.GA46364@T590>
[not found] ` <20200518131634.GA645@lst.de>
[not found] ` <20200518141107.GA50374@T590>
[not found] ` <20200518165619.GA17465@lst.de>
[not found] ` <20200519015420.GA70957@T590>
[not found] ` <20200519153000.GB22286@lst.de>
[not found] ` <20200520011823.GA415158@T590>
[not found] ` <20200520030424.GI416136@T590>
2020-05-20 8:03 ` io_uring vs CPU hotplug, was Re: [PATCH 5/9] blk-mq: don't set data->ctx and data->hctx in blk_mq_alloc_request_hctx Christoph Hellwig
2020-05-20 14:45 ` Jens Axboe
2020-05-20 15:20 ` Jens Axboe
2020-05-20 15:31 ` Christoph Hellwig [this message]
2020-05-20 19:41 ` Thomas Gleixner
2020-05-20 20:18 ` Jens Axboe
2020-05-20 22:14 ` Thomas Gleixner
2020-05-20 22:40 ` Jens Axboe
2020-05-21 2:27 ` Ming Lei
2020-05-21 8:13 ` Thomas Gleixner
2020-05-21 9:23 ` Ming Lei
2020-05-21 18:39 ` Thomas Gleixner
2020-05-21 18:45 ` Jens Axboe
2020-05-21 20:00 ` Thomas Gleixner
2020-05-22 1:57 ` Ming Lei
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