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| author | Wu Fengguang <fengguang.wu@intel.com> | 2011-12-02 18:21:51 -0600 |
|---|---|---|
| committer | Wu Fengguang <fengguang.wu@intel.com> | 2011-12-08 10:49:29 +0800 |
| commit | 82e230a07de3812a5e87a27979f033dad59172e3 (patch) | |
| tree | 672ecaa3a1cf3585aa941491b2cf77ae38f1d8ff | |
| parent | c5c6343c4d75f9d3226e05a72e7861e967fc8099 (diff) | |
| download | linux-82e230a07de3812a5e87a27979f033dad59172e3.tar.gz linux-82e230a07de3812a5e87a27979f033dad59172e3.tar.bz2 linux-82e230a07de3812a5e87a27979f033dad59172e3.zip | |
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>
| -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, * * 8 serves as the safety ratio. */ - if (bdi_dirty) - t = min(t, bdi_dirty * HZ / (8 * bw + 1)); + t = min(t, bdi_dirty * HZ / (8 * bw + 1)); /* * The pause time will be settled within range (max_pause/4, max_pause). |