From: Tejun Heo <tj@kernel.org>
To: Laurent Vivier <lvivier@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
Jens Axboe <axboe@kernel.dk>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Michael Ellerman <mpe@ellerman.id.au>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 2/2] blk-mq: don't use WORK_CPU_UNBOUND
Date: Mon, 21 Aug 2017 07:48:56 -0700 [thread overview]
Message-ID: <20170821144855.GF491396@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <20170821134951.18848-2-lvivier@redhat.com>
On Mon, Aug 21, 2017 at 03:49:51PM +0200, Laurent Vivier wrote:
> cpumask is the list of CPUs present when the queue is built.
> If a new CPU is hotplugged, this list is not updated,
> and when the scheduler asks for a CPU id, blk_mq_hctx_next_cpu()
> can return WORK_CPU_UNBOUND.
> And in this case _blk_mq_run_hw_queue() can be executed by the new CPU
> (that is not present in cpumask) and raises the following warning:
>
> WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) &&
> cpu_online(hctx->next_cpu));
>
> To fix this problem, this patch modifies blk_mq_hctx_next_cpu()
> to only return a CPU id present in cpumask.
So, this one isn't needed either.
Thanks.
--
tejun
next prev parent reply other threads:[~2017-08-21 14:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-21 13:49 [PATCH 1/2] powerpc/workqueue: update list of possible CPUs Laurent Vivier
2017-08-21 13:49 ` [PATCH 2/2] blk-mq: don't use WORK_CPU_UNBOUND Laurent Vivier
2017-08-21 14:48 ` Tejun Heo [this message]
2017-08-21 14:48 ` [PATCH 1/2] powerpc/workqueue: update list of possible CPUs Tejun Heo
2017-08-22 1:41 ` Michael Ellerman
2017-08-22 16:54 ` Tejun Heo
2017-08-23 11:00 ` Michael Ellerman
2017-08-23 11:17 ` Laurent Vivier
2017-08-23 13:26 ` Tejun Heo
2017-08-24 12:10 ` Laurent Vivier
2017-08-24 13:51 ` Tejun Heo
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