diff options
author | Wu Fengguang <fengguang.wu@intel.com> | 2011-12-02 19:21:51 -0500 |
---|---|---|
committer | Wu Fengguang <fengguang.wu@intel.com> | 2011-12-07 21:49:29 -0500 |
commit | 82e230a07de3812a5e87a27979f033dad59172e3 (patch) | |
tree | 672ecaa3a1cf3585aa941491b2cf77ae38f1d8ff /mm/page-writeback.c | |
parent | c5c6343c4d75f9d3226e05a72e7861e967fc8099 (diff) |
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>
Diffstat (limited to 'mm/page-writeback.c')
-rw-r--r-- | mm/page-writeback.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 17403e3a7c89..50f08241f981 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c | |||
@@ -989,8 +989,7 @@ static unsigned long bdi_max_pause(struct backing_dev_info *bdi, | |||
989 | * | 989 | * |
990 | * 8 serves as the safety ratio. | 990 | * 8 serves as the safety ratio. |
991 | */ | 991 | */ |
992 | if (bdi_dirty) | 992 | t = min(t, bdi_dirty * HZ / (8 * bw + 1)); |
993 | t = min(t, bdi_dirty * HZ / (8 * bw + 1)); | ||
994 | 993 | ||
995 | /* | 994 | /* |
996 | * The pause time will be settled within range (max_pause/4, max_pause). | 995 | * The pause time will be settled within range (max_pause/4, max_pause). |