Re: [PATCH updated] ext4: Fix file fragmentation during large file write.

On Fri, 2008-10-10 at 23:32 +0530, Aneesh Kumar K.V wrote:

The range_cyclic writeback mode use the address_space
writeback_index as the start index for writeback. With
delayed allocation we were updating writeback_index
wrongly resulting in highly fragmented file. Number of
extents reduced from 4000 to 27 for a 3GB file with
the below patch.

I tested the ext4 patch queue from today on top of 2.6.27, and this
includes Aneesh's latest patches.

Things are going at disk speed for streaming writes, with the number of
extents generated for a 32GB file down to 27.  So, this is definitely an
improvement for ext4.

-chris


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