From: Wu Fengguang Date: Fri, 5 Aug 2011 04:16:46 +0000 (-0600) Subject: writeback: dirty position control - bdi reserve area X-Git-Tag: v3.2-rc1~23^2~6 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8927f66c4ede9a18b4b58f7e6f9debca67065f6b;p=pandora-kernel.git writeback: dirty position control - bdi reserve area Keep a minimal pool of dirty pages for each bdi, so that the disk IO queues won't underrun. Also gently increase a small bdi_thresh to avoid it stuck in 0 for some light dirtied bdi. It's particularly useful for JBOD and small memory system. It may result in (pos_ratio > 1) at the setpoint and push the dirty pages high. This is more or less intended because the bdi is in the danger of IO queue underflow. Signed-off-by: Wu Fengguang --- Reading git-diff-tree failed