On Sat, Aug 16, 2008 at 02:10:10PM -0400, Chris Mason wrote:

I tried just the writeback_index patch and got only 4 fragmented files
on ext4 after a compilebench run.  Then I tried again and got 1200.
Seems there is something timing dependent in here ;)

Yeah, the patch Aneesh sent to change where we added the inode to the
dirty list was false lead.  The right fix is in the ext4 patch queue
now.  I think we have the problem licked and a quick test showed it
increased the compilebench MB/s by a very tiny amount (enough so that
I wasnt sure whether or not it was measurement error), but it does
avoid the needly fragmentation.

						- Ted