linux-ext4 - Re: delalloc fragmenting files?

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Date:	Sun, 04 Nov 2007 21:36:04 +0300
From:	Alex Tomas <bzzz.tomas@...il.com>
To:	Eric Sandeen <sandeen@...hat.com>
Cc:	Andreas Dilger <adilger@....COM>,
	ext4 development <linux-ext4@...r.kernel.org>
Subject: Re: delalloc fragmenting files?

thanks for the data. the attached patch should fix couple issues:
broken history output and policy in that smaller usable chunk to
be used. can you give it a spin, please?

thanks, Alex

Eric Sandeen wrote:
> Alex Tomas wrote:
>> Eric,
>>
>> would you mind to repeat the run and then grab /proc/fs/ext4/<dev>/mb_history?
>>
>> thanks in advance, Alex
> 
> Sure thing, attached; this is from a 1024x1M run, wound up with 32
> fragments, out of order:
> 
> First block: 122880
> Last block: 491519
> Discontinuity: Block 7424 is at 114688 (was 130303)
> Discontinuity: Block 15616 is at 106496 (was 122879)
> Discontinuity: Block 23552 is at 102400 (was 114431)
> Discontinuity: Block 26624 is at 155648 (was 105471)
> Discontinuity: Block 33792 is at 147456 (was 162815)
> Discontinuity: Block 41472 is at 162816 (was 155135)
> Discontinuity: Block 42496 is at 188416 (was 163839)
> Discontinuity: Block 50176 is at 180224 (was 196095)
> Discontinuity: Block 58368 is at 172032 (was 188415)
> Discontinuity: Block 66560 is at 167936 (was 180223)
> ....
> 
> pid 3695 is pdflush, I assume 7634 was the dd itself.
> 
> -Eric


View attachment "mballoc-use-smaller-good-chunk.patch" of type "text/x-patch" (973 bytes)