From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Jan Kara <jack@suse.cz>,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [PATCH 2/3] mm: Provide address_space operation for filling pages for read
Date: Wed, 20 Jan 2021 17:56:24 +0000 [thread overview]
Message-ID: <20210120175624.GL2260413@casper.infradead.org> (raw)
In-Reply-To: <20210120172836.GA3809508@infradead.org>
On Wed, Jan 20, 2021 at 05:28:36PM +0000, Christoph Hellwig wrote:
> On Wed, Jan 20, 2021 at 06:27:05PM +0100, Jan Kara wrote:
> > This would mean pulling i_mmap_sem out from ext4/XFS/F2FS private inode
> > into the VFS inode. Which is fine by me but it would grow struct inode for
> > proc / tmpfs / btrfs (although for btrfs I'm not convinced it isn't
> > actually prone to the race and doesn't need similar protection as xfs /
> > ext4) so some people may object.
>
> The btrfs folks are already looking into lifting it to common code.
>
> Also I have a patch pending to remove a list_head from the inode to
> counter the size increase :)
We can get rid of nrexceptional as well:
https://lore.kernel.org/linux-fsdevel/20201026151849.24232-1-willy@infradead.org/
We can also reduce the size of the rwsem by one word by replacing the list_head with a single pointer.
https://git.infradead.org/users/willy/pagecache.git/shortlog/refs/heads/wlist
(haven't touched it in almost four years, seemed to have a bug last time
i looked at it).
next prev parent reply other threads:[~2021-01-20 17:58 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 16:06 [PATCH 0/3 RFC] fs: Hole punch vs page cache filling races Jan Kara
2021-01-20 16:06 ` [PATCH 1/3] mm: Do not pass iter into generic_file_buffered_read_get_pages() Jan Kara
2021-01-20 16:18 ` Christoph Hellwig
2021-01-20 16:06 ` [PATCH 2/3] mm: Provide address_space operation for filling pages for read Jan Kara
2021-01-20 16:20 ` Christoph Hellwig
2021-01-20 17:27 ` Jan Kara
2021-01-20 17:28 ` Christoph Hellwig
2021-01-20 17:56 ` Matthew Wilcox [this message]
2021-04-02 21:17 ` Kent Overstreet
2021-04-06 12:21 ` Jan Kara
2021-01-20 16:06 ` [PATCH 3/3] ext4: Fix stale data exposure when read races with hole punch Jan Kara
2021-01-21 19:27 ` [PATCH 0/3 RFC] fs: Hole punch vs page cache filling races Matthew Wilcox
2021-01-22 14:32 ` Jan Kara
2021-04-02 19:34 ` Theodore Ts'o
2021-04-06 12:17 ` Jan Kara
2021-04-06 16:45 ` Theodore Ts'o
2021-04-06 16:50 ` Theodore Ts'o
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