From: Jens Axboe <axboe@kernel.dk>
To: Rik van Riel <riel@redhat.com>, Frederic Weisbecker <fweisbec@gmail.com>
Cc: axboe@kernel.org, fweisbec@redhat.com, mingo@kernel.org,
linux-kernel@vger.kernel.org, lcapitulino@redhat.com,
mtosatti@redhat.com
Subject: Re: [PATCH RFC] nohz,blk-mq: do not create blk-mq workqueues on nohz dedicated CPUs
Date: Thu, 02 Apr 2015 19:15:32 -0600 [thread overview]
Message-ID: <551DE9B4.2000403@kernel.dk> (raw)
In-Reply-To: <551C18F4.2090407@redhat.com>
On 04/01/2015 10:12 AM, Rik van Riel wrote:
> On 03/31/2015 11:43 AM, Jens Axboe wrote:
>
>> That'd be easy enough to do, that's how blk-mq handles offline CPUs as
>> well. The attached patch is completely untested, but will handle offline
>> or nohz CPUs in the same fashion - they will punt to hardware queue 0,
>> which is mapped to CPU0 (and others, depending on the queue vs CPU ratio).
>
> I have done some sanity testing with your patch,
> starting a KVM guest with vcpus and emulator threads
> all pinned to nohz_full cpus.
>
> The guest is still able to do disk IO, so things
> appear to work...
>
> Thanks for looking into this, Jens.
>
> Tested-by: Rik van Riel <riel@redhat.com>
Great thanks, I'll do some sanity testing here too and get it applied
for 4.1.
--
Jens Axboe
next prev parent reply other threads:[~2015-04-03 1:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-31 14:27 [PATCH RFC] nohz,blk-mq: do not create blk-mq workqueues on nohz dedicated CPUs Rik van Riel
2015-03-31 15:02 ` Frederic Weisbecker
2015-03-31 23:18 ` Marcelo Tosatti
2015-04-07 13:14 ` Luiz Capitulino
2015-03-31 15:07 ` Jens Axboe
2015-03-31 15:33 ` Frederic Weisbecker
2015-03-31 15:43 ` Jens Axboe
2015-04-01 16:12 ` Rik van Riel
2015-04-03 1:15 ` Jens Axboe [this message]
2015-03-31 23:17 ` Marcelo Tosatti
2015-04-01 14:36 ` Jens Axboe
2015-04-01 14:45 ` Rik van Riel
2015-04-01 14:46 ` Jens Axboe
2015-04-05 5:31 ` Mike Galbraith
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