From 8927f66c4ede9a18b4b58f7e6f9debca67065f6b Mon Sep 17 00:00:00 2001 From: Wu Fengguang Date: Thu, 4 Aug 2011 22:16:46 -0600 Subject: [PATCH] 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-format-patch failed