Re: [PATCH 10/11] readahead: dont do start-of-file readahead afterlseek()

[Linus Torvalds]

On Tue, 2 Feb 2010, Wu Fengguang wrote:
>
> Some applications (eg. blkid, id3tool etc.) seek around the file
> to get information. For example, blkid does
> 	     seek to	0
> 	     read	1024
> 	     seek to	1536
> 	     read	16384
> 
> The start-of-file readahead heuristic is wrong for them, whose 
> access pattern can be identified by lseek() calls.
> 
> So test-and-set a READAHEAD_LSEEK flag on lseek() and don't
> do start-of-file readahead on seeing it. Proposed by Linus.
> 
> CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> 
> Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>

Acked-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

		Linus
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