From: Mark Fasheh Date: Tue, 6 Apr 2010 01:17:15 +0000 (-0700) Subject: ocfs2: change default reservation window sizes X-Git-Tag: v2.6.35-rc1~469^2~22 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b07f8f24dfe54da0f074b78949044842e8df881f;p=pandora-kernel.git ocfs2: change default reservation window sizes The default reservation size of 4 (32-bit windows) is a bit too ambitious. Scale it back to 16 bits (resv_level=2). I have been testing various sizes on a 4-node cluster which runs a mixed workload that is heavily threaded. With a 256MB local alloc, I get *roughly* the following levels of average file fragmentation: resv_level=0 70% resv_level=1 21% resv_level=2 23% resv_level=3 24% resv_level=4 60% resv_level=5 did not test resv_level=6 60% resv_level=2 seemed like a good compromise between not letting windows be too small, but not so big that heavier workloads will immediately suffer without tuning. This patch also change the behavior of directory reservations - they now track file reservations. The previous compromise of giving directory windows only 8 bits wound up fragmenting more at some window sizes because file allocations had smaller unused windows to poach from. Signed-off-by: Mark Fasheh Signed-off-by: Joel Becker --- Reading git-diff-tree failed