writeback: set max_pause to lowest value on zero bdi_dirty
authorWu Fengguang <fengguang.wu@intel.com>
Sat, 3 Dec 2011 00:21:51 +0000 (18:21 -0600)
committerWu Fengguang <fengguang.wu@intel.com>
Thu, 8 Dec 2011 02:49:29 +0000 (10:49 +0800)
commit82e230a07de3812a5e87a27979f033dad59172e3
tree672ecaa3a1cf3585aa941491b2cf77ae38f1d8ff
parentc5c6343c4d75f9d3226e05a72e7861e967fc8099
writeback: set max_pause to lowest value on zero bdi_dirty

Some trace shows lots of bdi_dirty=0 lines where it's actually some
small value if w/o the accounting errors in the per-cpu bdi stats.

In this case the max pause time should really be set to the smallest
(non-zero) value to avoid IO queue underrun and improve throughput.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
mm/page-writeback.c