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From: Adrian Hunter <adrian.hunter@nokia.com>
To: Stephen Tweedie <sct@redhat.com>,
	Andreas Dilger <adilger@sun.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: Artem Bityutskiy <artem.bityutskiy@nokia.com>,
	linux-ext4@vger.kernel.org,
	Adrian Hunter <adrian.hunter@nokia.com>
Subject: [PATCH 0/2] ext3 HACKs
Date: Tue, 14 Jul 2009 17:05:48 +0300	[thread overview]
Message-ID: <20090714140548.26116.2919.sendpatchset@ahunter-tower> (raw)

Hi

We are using linux 2.6.28 and we have a situation where ext3
can take 30-60 seconds to mount.

The cause is the underlying device has extremely poor random
write speed (several orders of magnitude slower than sequential
write speed), and journal recovery can involve many small random
writes.

To alleviate this situation somewhat, I have two moderately ugly
hacks:
	HACK 1: ext3: mount fast even when recovering
	HACK 2: do I/O read requests while ext3 journal recovers

HACK 1 uses a I/O barrier in place of waiting for recovery I/O to be
flushed.

HACK 2 crudely throws I/O read requests to the front of the dispatch
queue until the I/O barrier from HACK 1 is reached.

If you can spare a moment to glance at these hacks and notice
any obvious flaws, or suggest a better alternative, it would be
greatly appreciated.

Regards
Adrian Hunter


             reply	other threads:[~2009-07-14 14:05 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-07-14 14:05 Adrian Hunter [this message]
2009-07-14 14:05 ` [PATCH 1/2] HACK: ext3: mount fast even when recovering Adrian Hunter
2009-07-14 21:34   ` Andrew Morton
2009-07-14 21:46     ` Eric Sandeen
2009-07-14 22:36       ` Theodore Tso
2009-07-15 15:35         ` Adrian Hunter
2009-07-15  5:53     ` Artem Bityutskiy
2009-07-15 15:35     ` Adrian Hunter
2009-07-14 14:06 ` [PATCH 2/2] HACK: do I/O read requests while ext3 journal recovers Adrian Hunter
  -- strict thread matches above, loose matches on Subject: below --
2009-07-14 14:02 [PATCH 0/2] ext3 HACKs Adrian Hunter
2009-07-14 15:51 ` Theodore Tso

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