Merge branch 'cgroup-rmdir-updates' into cgroup/for-3.8

[~andy/linux] / Documentation / ABI / testing / sysfs-fs-ext4

diff --git a/Documentation/ABI/testing/sysfs-fs-ext4 b/Documentation/ABI/testing/sysfs-fs-ext4
index f22ac0872ae8de41a44406edfab71384d54b830a..c631253cf85c763de6cfd347a15ce063fd71be07 100644 (file)
--- a/Documentation/ABI/testing/sysfs-fs-ext4
+++ b/Documentation/ABI/testing/sysfs-fs-ext4
@@ -96,3 +96,16 @@ Contact:     "Theodore Ts'o" <tytso@mit.edu>
 Description:
                The maximum number of megabytes the writeback code will
                try to write out before move on to another inode.
+
+What:          /sys/fs/ext4/<disk>/extent_max_zeroout_kb
+Date:          August 2012
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               The maximum number of kilobytes which will be zeroed
+               out in preference to creating a new uninitialized
+               extent when manipulating an inode's extent tree.  Note
+               that using a larger value will increase the
+               variability of time necessary to complete a random
+               write operation (since a 4k random write might turn
+               into a much larger write due to the zeroout
+               operation).