From: Joe Thornber Date: Wed, 22 Oct 2014 13:30:58 +0000 (+0100) Subject: dm cache policy mq: tweak algorithm that decides when to promote a block X-Git-Tag: omap-for-v3.19/fixes-for-merge-window~22^2~27 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b155aa0e5a81ea1f05ff7aced0ec8e34c980c19e;p=pandora-kernel.git dm cache policy mq: tweak algorithm that decides when to promote a block Rather than maintaining a separate promote_threshold variable that we periodically update we now use the hit count of the oldest clean block. Also add a fudge factor to discourage demoting dirty blocks. With some tests this has a sizeable difference, because the old code was too eager to demote blocks. For example, device-mapper-test-suite's git_extract_cache_quick test goes from taking 190 seconds, to 142 (linear on spindle takes 250). Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer --- Reading git-diff-tree failed