From: Christoph Hellwig <hch@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>,
Dave Chinner <david@fromorbit.com>,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
linux-mm@kvack.org, John Hubbard <jhubbard@nvidia.com>,
David Howells <dhowells@redhat.com>,
David Hildenbrand <david@redhat.com>
Subject: Re: [PATCH 4/5] block: Add support for bouncing pinned pages
Date: Sun, 19 Feb 2023 22:22:32 -0800 [thread overview]
Message-ID: <Y/MRqLbA2g7I0xgp@infradead.org> (raw)
In-Reply-To: <20230216123316.vkmtucazg33vidzg@quack3>
On Thu, Feb 16, 2023 at 01:33:16PM +0100, Jan Kara wrote:
> I'm a bit skeptical we can reasonably assess that (as much as I would love
> to just not write these pages and be done with it) because a lot of
> FOLL_LONGTERM users just pin passed userspace address range, then allow
> userspace to manipulate it with other operations, and finally unpin it with
> another call. Who knows whether shared pagecache pages are passed in and
> what userspace is doing with them while they are pinned?
True.
So what other sensible thing could we do at a higher level?
Treat MAP_SHARED buffers that are long term registered as MAP_PRIVATE
while registered, and just do writeback using in-kernel O_DIRECT on
fsync?
next prev parent reply other threads:[~2023-02-20 6:22 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-09 12:31 [PATCH RFC 0/5] Writeback handling of pinned pages Jan Kara
2023-02-09 12:31 ` [PATCH 1/5] mm: Do not reclaim private data from pinned page Jan Kara
2023-02-09 16:17 ` Matthew Wilcox
2023-02-10 11:29 ` Jan Kara
2023-02-13 9:55 ` Christoph Hellwig
2023-02-14 13:06 ` Jan Kara
2023-02-14 21:40 ` John Hubbard
2023-02-16 11:56 ` Jan Kara
2023-02-13 9:01 ` David Hildenbrand
2023-02-14 13:00 ` Jan Kara
2023-02-09 12:31 ` [PATCH 2/5] ext4: Drop workaround for mm reclaiming fs private page data Jan Kara
2023-02-09 12:31 ` [PATCH 3/5] mm: Do not try to write pinned folio during memory cleaning writeback Jan Kara
2023-02-10 1:54 ` John Hubbard
2023-02-10 2:10 ` John Hubbard
2023-02-10 10:42 ` Jan Kara
2023-02-10 10:54 ` Jan Kara
2023-02-09 12:31 ` [PATCH 4/5] block: Add support for bouncing pinned pages Jan Kara
2023-02-13 9:59 ` Christoph Hellwig
2023-02-14 13:56 ` Jan Kara
2023-02-15 4:59 ` Dave Chinner
2023-02-15 6:24 ` Christoph Hellwig
2023-02-16 12:33 ` Jan Kara
2023-02-20 6:22 ` Christoph Hellwig [this message]
2023-02-27 11:39 ` Jan Kara
2023-02-27 13:36 ` Christoph Hellwig
2023-02-09 12:31 ` [PATCH 5/5] iomap: Bounce pinned pages during writeback Jan Kara
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