From: Michal Hocko <mhocko@kernel.org>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org,
linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org,
Johannes Weiner <hannes@cmpxchg.org>,
Rik van Riel <riel@surriel.com>
Subject: Re: [LSF/MM TOPIC] few MM topics
Date: Wed, 31 Jan 2018 21:24:38 +0100 [thread overview]
Message-ID: <20180131202438.GA21609@dhcp22.suse.cz> (raw)
In-Reply-To: <20180131192104.GD4841@magnolia>
On Wed 31-01-18 11:21:04, Darrick J. Wong wrote:
> On Wed, Jan 24, 2018 at 10:26:49AM +0100, Michal Hocko wrote:
[...]
> > - I would also love to talk to some FS people and convince them to move
> > away from GFP_NOFS in favor of the new scope API. I know this just
> > means to send patches but the existing code is quite complex and it
> > really requires somebody familiar with the specific FS to do that
> > work.
>
> Hm, are you talking about setting PF_MEMALLOC_NOFS instead of passing
> *_NOFS to allocation functions and whatnot?
yes memalloc_nofs_{save,restore}
> Right now XFS will set it
> on any thread which has a transaction open, but that doesn't help for
> fs operations that don't have transactions (e.g. reading metadata,
> opening files). I suppose we could just set the flag any time someone
> stumbles into the fs code from userspace, though you're right that seems
> daunting.
I would really love to see the code to take the nofs scope
(memalloc_nofs_save) at the point where the FS "critical" section starts
(from the reclaim recursion POV). This would both document the context
and also limit NOFS allocations to bare minumum.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2018-01-31 20:24 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-24 9:26 [LSF/MM TOPIC] few MM topics Michal Hocko
2018-01-24 18:23 ` Mike Kravetz
2018-01-25 10:02 ` Michal Hocko
2018-01-25 9:37 ` Jan Kara
2018-01-31 19:21 ` Darrick J. Wong
2018-01-31 20:24 ` Michal Hocko [this message]
2018-01-31 23:41 ` Dave Chinner
2018-02-01 15:46 ` [Lsf-pc] " Michal Hocko
2018-02-01 22:47 ` Dave Chinner
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