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From: Dave Chinner <david@fromorbit.com>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Theodore Ts'o <tytso@mit.edu>,
	linux-ext4 <linux-ext4@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: semi-stable page writes
Date: Tue, 30 Oct 2012 09:01:22 +1100	[thread overview]
Message-ID: <20121029220122.GT29378@dastard> (raw)
In-Reply-To: <20121026101909.GB19617@blackbox.djwong.org>

On Fri, Oct 26, 2012 at 03:19:09AM -0700, Darrick J. Wong wrote:
> Hi everyone,
> 
> Are people still annoyed about writes taking unexpectedly long amounts of tme
> due to the stable page write patchset?  I'm guessing yes...

I haven't heard anyone except th elunatic fringe complain
recently...

> I'm close to posting a patchset that (a) gates the wait_on_page_writeback calls
> on a flag that you can set in the bdi to indicate that you need stable writes
> (which blk_integrity_register will set);

I'd prefer stable pages by default (e.g. btrfs needs it for sane
data crc calculations), with an option to turn it off.

> (b) (ab)uses a page flag bit (PG_slab)
> to indicate that a page is actually being sent out to disk hardware; and (c)

I don't think you can do that. You can send slab allocated memory to
disk (e.g. kmalloc()d memory) and XFS definitely does that for
sub-page sized metadata. I'm pretty sure that means the PG_slab
flag is not available for (ab)use in the IO path....

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

  parent reply	other threads:[~2012-10-29 22:01 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-26 10:19 semi-stable page writes Darrick J. Wong
2012-10-27  1:35 ` [RFC PATCH 1/2] bdi: Create a flag to indicate that a backing device needs stable " Darrick J. Wong
2012-10-29 18:13   ` Jan Kara
2012-10-29 18:30     ` Jan Kara
2012-10-29 23:48       ` NeilBrown
2012-10-30  0:10         ` Jan Kara
2012-10-30  0:34           ` NeilBrown
2012-10-30 13:38             ` Jan Kara
2012-10-30 21:49               ` NeilBrown
2012-10-30  4:10   ` Martin K. Petersen
2012-10-30  4:48     ` NeilBrown
2012-10-30 12:19       ` Martin K. Petersen
2012-10-30 20:14         ` Darrick J. Wong
2012-10-30 22:14           ` NeilBrown
2012-10-30 23:58             ` Boaz Harrosh
2012-10-31  8:56             ` Darrick J. Wong
2012-10-31 11:56               ` Jan Kara
2012-10-31 19:36                 ` Darrick J. Wong
2012-10-31 23:12                   ` Boaz Harrosh
2012-11-01  5:51                     ` Darrick J. Wong
2012-11-01  6:25                       ` Boaz Harrosh
2012-11-01  8:59                   ` Jan Kara
2012-11-01 17:24                     ` Boaz Harrosh
2012-11-01 22:42                       ` Jan Kara
2012-10-30 22:40   ` Boaz Harrosh
2012-10-27  1:36 ` [RFC PATCH 2/2] mm: Gate stable page writes on the bdi flag Darrick J. Wong
2012-10-29 18:28   ` Jan Kara
2012-10-31  8:58     ` Darrick J. Wong
2012-10-29 22:01 ` Dave Chinner [this message]
2012-10-30  1:00   ` semi-stable page writes Theodore Ts'o
2012-10-30 23:30     ` Dave Chinner
2012-10-31 11:45       ` Jan Kara
2012-10-30 20:40   ` Darrick J. Wong
2012-10-30 23:43     ` Dave Chinner
2012-10-31  9:05       ` Darrick J. Wong

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