From: Christoph Hellwig <hch@lst.de>
To: Neil Brown <neilb@suse.de>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>,
Jens Axboe <axboe@kernel.dk>, "Theodore Ts'o" <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Alasdair G Kergon <agk@redhat.com>, Jan Kara <jack@suse.cz>,
Mike Snitzer <snitzer@redhat.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-raid@vger.kernel.org, Keith Mannthey <kmannth@us.ibm.com>,
dm-devel@redhat.com, Mingming Cao <cmm@us.ibm.com>,
Tejun Heo <tj@kernel.org>,
linux-ext4@vger.kernel.org, Ric Wheeler <rwheeler@redhat.com>,
Christoph Hellwig <hch@lst.de>, Josef Bacik <josef@redhat.com>
Subject: Re: [PATCH v6 0/4] ext4: Coordinate data-only flush requests sent by fsync
Date: Tue, 30 Nov 2010 17:43:01 +0100 [thread overview]
Message-ID: <20101130164301.GB30858@lst.de> (raw)
In-Reply-To: <20101130113906.176ffcad@notabene.brown>
On Tue, Nov 30, 2010 at 11:39:06AM +1100, Neil Brown wrote:
> Would it not be sufficient to simply gather flushes while a flush is pending.
> i.e
> - if no flush is pending, set the 'flush pending' flag, submit a flush,
> then clear the flag.
> - if a flush is pending, then wait for it to complete, and then submit a
> single flush on behalf of all pending flushes.
>
> That way when flush is fast, you do a flush every time, and when it is slow
> you gather multiple flushes together.
We can even optimize the second flush away if no other I/O has
completed since the first flush has started. That will always be the
case for SATA devices as the cache flush command is not queued.
next prev parent reply other threads:[~2010-11-30 16:43 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-29 22:05 [PATCH v6 0/4] ext4: Coordinate data-only flush requests sent by fsync Darrick J. Wong
2010-11-29 22:05 ` [PATCH 1/4] block: Measure flush round-trip times and report average value Darrick J. Wong
2010-12-02 9:49 ` Lukas Czerner
2010-11-29 22:05 ` [PATCH 2/4] md: Compute average flush time from component devices Darrick J. Wong
2010-11-29 22:05 ` [PATCH 3/4] dm: " Darrick J. Wong
2010-11-30 5:21 ` Mike Snitzer
2010-11-29 22:06 ` [PATCH 4/4] ext4: Coordinate data-only flush requests sent by fsync Darrick J. Wong
2010-11-29 23:48 ` [PATCH v6 0/4] " Ric Wheeler
2010-11-30 0:19 ` Darrick J. Wong
2010-12-01 0:14 ` Mingming Cao
2010-11-30 0:39 ` Neil Brown
2010-11-30 0:48 ` Ric Wheeler
2010-11-30 1:26 ` Neil Brown
2010-11-30 23:32 ` Darrick J. Wong
2010-11-30 13:45 ` Tejun Heo
2010-11-30 13:58 ` Ric Wheeler
2010-11-30 16:43 ` Christoph Hellwig [this message]
2010-11-30 23:31 ` Darrick J. Wong
2010-11-30 16:41 ` Christoph Hellwig
2011-01-07 23:54 ` Patch to issue pure flushes directly (Was: Re: [PATCH v6 0/4] ext4: Coordinate data-only flush requests sent) " Ted Ts'o
2011-01-08 7:45 ` Christoph Hellwig
[not found] ` <20110108074524.GA13024@lst.de>
2011-01-08 14:08 ` Tejun Heo
2011-01-04 16:27 ` [RFC PATCH v7] ext4: Coordinate data-only flush requests sent " Darrick J. Wong
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