X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=Documentation%2FABI%2Ftesting%2Fsysfs-fs-ext4;h=c631253cf85c763de6cfd347a15ce063fd71be07;hb=1db1e31b1ee3ae126ef98f39083b5f213c7b41bf;hp=f22ac0872ae8de41a44406edfab71384d54b830a;hpb=4cb1f43ce8c72ee453c00fcb9f6ee9c4ebd03f98;p=~andy%2Flinux

diff --git a/Documentation/ABI/testing/sysfs-fs-ext4 b/Documentation/ABI/testing/sysfs-fs-ext4
index f22ac0872ae..c631253cf85 100644
--- 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).