From: Jens Axboe <axboe@kernel.dk>
To: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>, Robert Elliott <elliott@hp.com>,
Ming Lei <ming.lei@canonical.com>,
Alexander Gordeev <agordeev@redhat.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/6] blk-mq: Avoid that I/O hangs in bt_get()
Date: Tue, 09 Dec 2014 09:10:10 -0700 [thread overview]
Message-ID: <54871EE2.3070502@kernel.dk> (raw)
In-Reply-To: <54871C41.5040500@acm.org>
On 12/09/2014 08:58 AM, Bart Van Assche wrote:
> Avoid that if there are fewer hardware queues than CPU threads that
> bt_get() can hang. The symptoms of the hang were as follows:
> * All tags allocated for a particular hardware queue.
> * (nr_tags) pending commands for that hardware queue.
> * No pending commands for the software queues associated with that
> hardware queue.
I already queued up the previous one, and added the extra tag get myself.
--
Jens Axboe
next prev parent reply other threads:[~2014-12-09 16:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-09 15:57 [PATCH 0/6] Six blk-mq patches Bart Van Assche
2014-12-09 15:57 ` [PATCH 1/6] blk-mq: Fix a use-after-free Bart Van Assche
2014-12-09 15:58 ` [PATCH 2/6] blk-mq: Avoid that __bt_get_word() wraps multiple times Bart Van Assche
2014-12-09 15:58 ` [PATCH 3/6] blk-mq: Fix a race between bt_clear_tag() and bt_get() Bart Van Assche
2014-12-09 15:58 ` [PATCH 4/6] blk-mq: Avoid that I/O hangs in bt_get() Bart Van Assche
2014-12-09 16:10 ` Jens Axboe [this message]
2014-12-09 15:59 ` [PATCH 5/6] blk-mq: Use all available hardware queues Bart Van Assche
2014-12-09 16:10 ` Jens Axboe
2014-12-09 15:59 ` [PATCH 6/6] blk-mq: Micro-optimize bt_get() Bart Van Assche
2014-12-09 16:06 ` Jens Axboe
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