[PATCH] Increase xfsbufd_centisecs when in laptop mode

From: Bart Samwel <bart@samwel.tk>

The attached patch is the outcome of a discussion with Nathan.

When laptop mode is active, there is no need for XFS to wake up xfsbufd (the
daemon that flushes buffers that are too old) too often.  The default is once
every second, this patch makes laptop mode do it once every 30 seconds.

Documentation/laptop-mode.txt

@@ -320,6 +320,7 @@ DEF_DIRTY_BACKGROUND_RATIO=10
 DEF_DIRTY_RATIO=40
 DEF_XFS_AGE_BUFFER=15
 DEF_XFS_SYNC_INTERVAL=30
+DEF_XFS_BUFD_INTERVAL=1
 
 # This must be adjusted manually to the value of HZ in the running kernel
 # on 2.4, until the XFS people change their 2.4 external interfaces to work in
@@ -372,6 +373,7 @@ case "$1" in
 			# not USER_HZ, so we have to use $AGE, not $XFS_AGE.
 			echo $AGE > /proc/sys/fs/xfs/age_buffer_centisecs
 			echo $AGE > /proc/sys/fs/xfs/xfssyncd_centisecs
+			echo 3000 > /proc/sys/fs/xfs/xfsbufd_centisecs
 		fi
 
 		case "$KLEVEL" in
@@ -419,6 +421,7 @@ case "$1" in
 			# These need to be restored as well.
 			echo "$((100*$DEF_XFS_AGE_BUFFER))" > /proc/sys/fs/xfs/age_buffer_centisecs
 			echo "$((100*$DEF_XFS_SYNC_INTERVAL))" > /proc/sys/fs/xfs/xfssyncd_centisecs
+			echo "$((100*$DEF_XFS_BUFD_INTERVAL))" > /proc/sys/fs/xfs/xfsbufd_centisecs
 		fi
 		case "$KLEVEL" in
 			"2.4")