From: Christoph Hellwig <hch@lst.de>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Zachary Hays <zhays@lexmark.com>, Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@lst.de>,
Adrian Hunter <adrian.hunter@intel.com>,
Linus Walleij <linus.walleij@linaro.org>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
linux-block <linux-block@vger.kernel.org>
Subject: Re: [PATCH] mmc: block: handle complete_work on the system_highpri workqueue
Date: Mon, 4 Feb 2019 09:25:27 +0100 [thread overview]
Message-ID: <20190204082527.GA5953@lst.de> (raw)
In-Reply-To: <CAPDyKFpcmyKnF-QPBV1vbTfGdSYN30GayZSA5O9Gm_EbZjfdAw@mail.gmail.com>
On Mon, Feb 04, 2019 at 07:24:43AM +0100, Ulf Hansson wrote:
> > The above results in multiple hung tasks that lead to failures to boot.
> >
> > Switching complete_work to the system_highpri queue avoids this
> > because system_highpri is not flagged with WQ_MEM_RECLAIM. This allows
> > the host to be released without getting blocked by other claims tasks.
> >
>
> Thanks for fix and the detailed description to the problem!
I don't think this is correct, though. If you think of the swap
(or memory reclaim of file backed pages) case on mmc, completing
a mmc request can very much be critical for completing that memory
reclaim. Thus we absolutely do need a WQ_MEM_RECLAIM workqueue.
You probably want to create a private WQ_MEM_RECLAIM workqueue in the
mmc code for that.
next prev parent reply other threads:[~2019-02-04 8:25 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1548965800-3080-1-git-send-email-zhays@lexmark.com>
2019-02-04 6:24 ` [PATCH] mmc: block: handle complete_work on the system_highpri workqueue Ulf Hansson
2019-02-04 8:02 ` Adrian Hunter
2019-02-04 14:30 ` Christoph Hellwig
2019-02-04 8:25 ` Christoph Hellwig [this message]
2019-02-04 12:30 ` Ulf Hansson
2019-02-04 14:28 ` Christoph Hellwig
2019-02-05 14:41 ` Zak Hays
2019-02-04 12:52 ` Ulf Hansson
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