From: Omar Sandoval <osandov@osandov.com>
To: Jens Axboe <axboe@fb.com>, linux-block@vger.kernel.org
Cc: Christoph Hellwig <hch@lst.de>,
Keith Busch <keith.busch@intel.com>, Josef Bacik <jbacik@fb.com>,
kernel-team@fb.com
Subject: Re: [PATCH] blk-mq: remap queues when adding/removing hardware queues
Date: Fri, 31 Mar 2017 12:01:08 -0700 [thread overview]
Message-ID: <20170331190032.GA10042@vader> (raw)
In-Reply-To: <52fb0623a8496808622c718f0f6372d37574dbe1.1490986618.git.osandov@fb.com>
On Fri, Mar 31, 2017 at 11:59:24AM -0700, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
>
> blk_mq_update_nr_hw_queues() used to remap hardware queues, which is the
> behavior that drivers expect. However, commit 4e68a011428a changed
> blk_mq_queue_reinit() to not remap queues for the case of CPU
> hotplugging, inadvertently making blk_mq_update_nr_hw_queues() not remap
> queues as well. This breaks, for example, NBD's multi-connection mode,
> leaving the added hardware queues unused. Fix it by making
> blk_mq_queue_reinit() optionally remap queues, which we do when updating
> the number of hardware queues but not when hotplugging.
>
> Fixes: 4e68a011428a ("blk-mq: don't redistribute hardware queues on a CPU hotplug event")
> Signed-off-by: Omar Sandoval <osandov@fb.com>
> ---
> The only callers of blk_mq_update_nr_hw_queues() are nbd and nbd. I *think*
> nbd_dev_add() also wants this remap behavior.
Uh, I meant nbd and nvme, and nvme_dev_add().
next prev parent reply other threads:[~2017-03-31 19:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-31 18:59 [PATCH] blk-mq: remap queues when adding/removing hardware queues Omar Sandoval
2017-03-31 19:01 ` Omar Sandoval [this message]
2017-03-31 20:30 ` Keith Busch
2017-03-31 20:30 ` Omar Sandoval
2017-03-31 20:44 ` Keith Busch
2017-03-31 20:43 ` [PATCH v2] " Omar Sandoval
2017-03-31 20:46 ` Omar Sandoval
2017-03-31 20:48 ` [PATCH v3] " Omar Sandoval
2017-03-31 21:09 ` Keith Busch
2017-04-04 6:24 ` Christoph Hellwig
2017-04-05 12:01 ` Sagi Grimberg
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