From: Arnd Bergmann <arnd@arndb.de>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: axboe@kernel.dk, hch@infradead.org, akpm@linux-foundation.org,
torvalds@linux-foundation.org, martin.petersen@oracle.com,
linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
shane.seymour@hpe.com, bfields@fieldses.org,
linux-fsdevel@vger.kernel.org, jlayton@poochiereds.net
Subject: Re: [PATCH v5.1 0/2] create BLKZEROOUT ioctl that invalidates page cache
Date: Wed, 02 Mar 2016 10:15:02 +0100 [thread overview]
Message-ID: <1889689.0axyUkdxkf@wuerfel> (raw)
In-Reply-To: <20160302040932.16685.62789.stgit@birch.djwong.org>
On Tuesday 01 March 2016 20:09:32 Darrick J. Wong wrote:
> This is (yet another) repost of the patch series that fixes the
> existing BLKZEROOUT ioctl to invalidate the page cache if the zeroing
> command to the underlying device succeeds. This patch is against
> 4.5-rc6 and hasn't changed much in months.
>
> The new BLKZEROOUT ioctl has the same semantics as the old one, but it
> invalidates the page cache to prevent surprising results, just like
> how dio writes invalidate page cache.
>
> I've incorporated all the feedback I've received into these patches,
> but haven't heard yea or nay or anything at all from the maintainer.
> Will someone please pick this up for 4.6?
>
> Comments and questions are, as always, welcome.
I'm missing the background on this, just saw the patch fly by,
so sorry if this has been asked before:
Why do you want to invalidate the cache? Is this to save RAM
or is something else going to write here and you have to invalidate
it for correctness?
If you just want to save RAM, would it be possible to instead
point the page cache to the empty zero page to speed up subsequent
reads? Maybe that just causes more complexity than it helps.
Arnd
next prev parent reply other threads:[~2016-03-02 9:17 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-02 4:09 [PATCH v5.1 0/2] create BLKZEROOUT ioctl that invalidates page cache Darrick J. Wong
2016-03-02 4:09 ` [PATCH 1/2] block: invalidate the page cache when issuing BLKZEROOUT Darrick J. Wong
2016-03-02 9:19 ` Christoph Hellwig
2016-03-02 4:09 ` [PATCH 2/2] block: create ioctl to discard-or-zeroout a range of blocks Darrick J. Wong
2016-03-02 9:20 ` Christoph Hellwig
2016-03-02 18:52 ` Linus Torvalds
2016-03-02 22:56 ` Darrick J. Wong
2016-03-02 23:49 ` Linus Torvalds
2016-03-03 17:02 ` Theodore Ts'o
2016-03-03 17:55 ` Linus Torvalds
2016-03-03 18:00 ` Christoph Hellwig
2016-03-03 18:14 ` Martin K. Petersen
2016-03-03 18:21 ` Theodore Ts'o
2016-03-03 18:01 ` Martin K. Petersen
2016-03-03 18:09 ` Christoph Hellwig
2016-03-03 18:12 ` Darrick J. Wong
2016-03-03 18:54 ` Martin K. Petersen
2016-03-03 22:39 ` Theodore Ts'o
2016-03-03 23:10 ` Dave Chinner
2016-03-04 0:20 ` Theodore Ts'o
2016-03-09 22:20 ` Gregory Farnum
2016-03-09 23:08 ` Theodore Ts'o
2016-03-10 14:58 ` Ric Wheeler
2016-03-10 18:33 ` Linus Torvalds
2016-03-10 21:47 ` Theodore Ts'o
2016-03-11 4:42 ` Ric Wheeler
2016-03-11 13:59 ` One Thousand Gnomes
2016-03-11 15:27 ` Theodore Ts'o
2016-03-11 17:23 ` Linus Torvalds
2016-03-11 17:30 ` Andy Lutomirski
2016-03-11 18:25 ` Linus Torvalds
2016-03-11 22:30 ` Dave Chinner
2016-03-12 0:33 ` Linus Torvalds
2016-03-12 0:35 ` Theodore Ts'o
2016-03-12 0:44 ` Linus Torvalds
2016-03-12 7:19 ` Theodore Ts'o
2016-03-12 10:11 ` Thomas Schoebel-Theuer
2016-03-13 23:30 ` Dave Chinner
2016-03-14 10:34 ` Ric Wheeler
2016-03-14 14:46 ` Theodore Ts'o
2016-03-15 20:14 ` Dave Chinner
2016-03-15 20:43 ` Linus Torvalds
2016-03-15 21:29 ` Theodore Ts'o
2016-03-15 22:33 ` Dave Chinner
2016-03-15 22:52 ` Theodore Ts'o
2016-03-16 1:51 ` Darrick J. Wong
2016-03-16 21:45 ` Andreas Dilger
2016-03-17 0:15 ` Theodore Ts'o
2016-03-17 0:33 ` Eric Sandeen
2016-03-17 0:59 ` Theodore Ts'o
2016-03-17 5:18 ` Gregory Farnum
2016-03-17 12:36 ` Theodore Ts'o
2016-03-17 17:47 ` Linus Torvalds
2016-03-17 17:50 ` Ric Wheeler
2016-03-17 17:59 ` Linus Torvalds
2016-03-17 18:35 ` Chris Mason
2016-03-17 20:49 ` Andreas Dilger
2016-03-17 21:00 ` Chris Mason
2016-03-18 3:20 ` Theodore Ts'o
2016-03-18 15:15 ` Jeff Moyer
2016-03-18 20:05 ` Martin K. Petersen
2016-03-18 6:52 ` Gregory Farnum
2016-03-18 7:19 ` Linus Torvalds
2016-03-17 1:01 ` Dave Chinner
2016-03-17 2:38 ` Darrick J. Wong
2016-03-18 22:55 ` NeilBrown
2016-03-15 23:06 ` Linus Torvalds
2016-03-15 23:14 ` Linus Torvalds
2016-03-16 0:08 ` Dave Chinner
2016-03-15 23:52 ` Dave Chinner
2016-03-16 0:06 ` Linus Torvalds
2016-03-16 0:30 ` Eric Sandeen
2016-03-16 0:51 ` Chris Mason
2016-03-16 22:23 ` Chris Mason
2016-03-17 13:49 ` Ric Wheeler
2016-03-15 22:38 ` Eric Sandeen
2016-03-03 22:56 ` Dave Chinner
2016-03-04 2:30 ` Thomas Schoebel-Theuer
2016-03-03 18:14 ` Linus Torvalds
2016-03-02 9:15 ` Arnd Bergmann [this message]
2016-03-02 9:44 ` [PATCH v5.1 0/2] create BLKZEROOUT ioctl that invalidates page cache Christoph Hellwig
2016-03-02 10:55 ` Arnd Bergmann
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