From: Damien Le Moal <Damien.LeMoal@wdc.com>
To: Dave Chinner <david@fromorbit.com>
Cc: Andreas Dilger <adilger@dilger.ca>,
"Theodore Y. Ts'o" <tytso@mit.edu>,
Christoph Hellwig <hch@infradead.org>,
"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>,
Johannes Thumshirn <jthumshirn@suse.de>,
Naohiro Aota <Naohiro.Aota@wdc.com>,
Masato Suzuki <masato.suzuki@wdc.com>
Subject: Re: [PATCH] ext4: Fix deadlock on page reclaim
Date: Wed, 31 Jul 2019 04:37:57 +0000 [thread overview]
Message-ID: <BN8PR04MB581229D9A42D3323077AF823E7DF0@BN8PR04MB5812.namprd04.prod.outlook.com> (raw)
In-Reply-To: 20190730234716.GY7689@dread.disaster.area
Dave,
On 2019/07/31 8:48, Dave Chinner wrote:
> On Tue, Jul 30, 2019 at 02:06:33AM +0000, Damien Le Moal wrote:
>> If we had a pread_nofs()/pwrite_nofs(), that would work. Or we could define a
>> RWF_NORECLAIM flag for pwritev2()/preadv2(). This last one could actually be the
>> cleanest approach.
>
> Clean, yes, but I'm not sure we want to expose kernel memory reclaim
> capabilities to userspace... It would be misleading, too, because we
> still want to allow reclaim to occur, just not have reclaim recurse
> into other filesystems....
When I wrote RWF_NORECLAIM, I was really thinking of RWF_NOFSRECLAIM. So
suppressing direct reclaim recursing into another FS rather than completely
disabling reclaim. Sorry for the confusion.
Would this be better ? This is still application controlled, so debatable if
control should be given. Most likely this would need to be limited to CAP_SYS
capable user processes (e.g. root processes).
I still need to check on FUSE if anything at all along these lines exists there.
I will dig.
Best regards.
--
Damien Le Moal
Western Digital Research
prev parent reply other threads:[~2019-07-31 4:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 9:33 [PATCH] ext4: Fix deadlock on page reclaim Damien Le Moal
2019-07-25 11:54 ` Christoph Hellwig
2019-07-25 19:57 ` Andreas Dilger
2019-07-26 2:24 ` Damien Le Moal
2019-07-26 22:44 ` Dave Chinner
2019-07-26 22:55 ` Theodore Y. Ts'o
2019-07-27 2:59 ` Damien Le Moal
2019-07-28 23:41 ` Dave Chinner
2019-07-29 1:07 ` Damien Le Moal
2019-07-29 18:40 ` Andreas Dilger
2019-07-30 2:06 ` Damien Le Moal
2019-07-30 23:47 ` Dave Chinner
2019-07-31 4:37 ` Damien Le Moal [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=BN8PR04MB581229D9A42D3323077AF823E7DF0@BN8PR04MB5812.namprd04.prod.outlook.com \
--to=damien.lemoal@wdc.com \
--cc=Naohiro.Aota@wdc.com \
--cc=adilger@dilger.ca \
--cc=david@fromorbit.com \
--cc=hch@infradead.org \
--cc=hch@lst.de \
--cc=jthumshirn@suse.de \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=masato.suzuki@wdc.com \
--cc=tytso@mit.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).