From: "hch@lst.de" <hch@lst.de>
To: Bart Van Assche <Bart.VanAssche@wdc.com>
Cc: "hch@lst.de" <hch@lst.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"israelr@mellanox.com" <israelr@mellanox.com>,
"sagi@grimberg.me" <sagi@grimberg.me>,
"sebott@linux.ibm.com" <sebott@linux.ibm.com>,
"ming.lei@redhat.com" <ming.lei@redhat.com>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"jianchao.w.wang@oracle.com" <jianchao.w.wang@oracle.com>,
"maxg@mellanox.com" <maxg@mellanox.com>,
"tj@kernel.org" <tj@kernel.org>
Subject: Re: [PATCH v9 2/2] blk-mq: Rework blk-mq timeout handling again
Date: Wed, 16 May 2018 18:24:32 +0200 [thread overview]
Message-ID: <20180516162432.GA4398@lst.de> (raw)
In-Reply-To: <8058d72fef475caffa78c962bc4220f5f8fa3dde.camel@wdc.com>
On Wed, May 16, 2018 at 04:17:42PM +0000, Bart Van Assche wrote:
> There is another reason the deadline is included in the atomic operation,
> namely to handle races between the BLK_EH_RESET_TIMER case in blk_mq_rq_timed_out()
> and blk_mq_complete_request(). I don't think that race is addressed properly by
> your patch. I will see what I can do to address that race without using 64-bit
> atomic operations.
I might be missing something here, so please help me understand
what is missing.
If we restart the timer in blk_mq_rq_timed_out we also bump the
generation at the same time as we reset the deadline in your old
patch. With this patch we only bump the generation, but that should
be enough to address the rest, or not?
next prev parent reply other threads:[~2018-05-16 16:24 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-15 22:51 [PATCH v10 0/2] blk-mq: Rework blk-mq timeout handling again Bart Van Assche
2018-05-15 22:51 ` [PATCH v10 1/2] arch/*: Add CONFIG_ARCH_HAVE_CMPXCHG64 Bart Van Assche
2018-05-16 4:15 ` Michael Ellerman
2018-05-18 20:33 ` Palmer Dabbelt
2018-05-15 22:51 ` [PATCH v10 2/2] blk-mq: Rework blk-mq timeout handling again Bart Van Assche
2018-05-15 22:51 ` [PATCH v9 0/2] " Bart Van Assche
2018-05-15 22:51 ` [PATCH v9 1/2] arch/*: Add CONFIG_ARCH_HAVE_CMPXCHG64 Bart Van Assche
2018-05-16 6:07 ` Christoph Hellwig
2018-05-15 22:51 ` [PATCH v9 2/2] blk-mq: Rework blk-mq timeout handling again Bart Van Assche
2018-05-16 12:51 ` Christoph Hellwig
2018-05-16 16:17 ` Bart Van Assche
2018-05-16 16:24 ` hch [this message]
2018-05-16 16:47 ` Bart Van Assche
2018-05-16 17:31 ` hch
2018-05-16 18:06 ` Bart Van Assche
-- strict thread matches above, loose matches on Subject: below --
2018-05-14 18:46 [PATCH v9 0/2] " Bart Van Assche
2018-05-14 18:46 ` [PATCH v9 2/2] " Bart Van Assche
2018-05-15 13:49 ` Sebastian Ott
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