Messages in this thread | | | Date | Fri, 28 May 2010 20:41:44 -0500 | From | "Jayson R. King" <> | Subject | Re: [PATCH 2.6.27.y 1/3] ext4: Use our own write_cache_pages() |
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On 05/28/2010 07:49 PM, tytso@mit.edu wrote: > This doesn't fix a bug; it's to make it easy for Dave Chinner to make > some changes to fix XFS's performance and to undo some ext4-specific > changes to write_cache_pages(). I'm not sure there's a good reason to > backport this to 2.6.27.y....
The difference is that, 2.6.27's write_cache_pages() in page-writeback.c still updates wbc->nr_to_write, since the patch which changed that behavior was dropped from .27-rc2 due to the XFS regression it causes on mainline. ext4 appears to want the behavior of write_cache_pages which does not update wbc->nr_to_write. This write_cache_pages_da() does what ext4 wants, without introducing the XFS regression. So I believe it is needed.
Did I mis-judge?
Rgds,
Jayson
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