f2fs: add sysfs support for controlling the gc_thread

Add sysfs entries to control the timing parameters for
f2fs gc thread.

Various Sysfs options introduced are:
gc_min_sleep_time: Min Sleep time for GC in ms
gc_max_sleep_time: Max Sleep time for GC in ms
gc_no_gc_sleep_time: Default Sleep time for GC in ms

Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Pankaj Kumar <pankaj.km@samsung.com>
Reviewed-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
[Jaegeuk Kim: fix an umount bug and some minor changes]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index 0500c198cd08..5daf3bb2eef9 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -133,6 +133,32 @@ f2fs. Each file shows the whole f2fs information.
  - current memory footprint consumed by f2fs.
 
 ================================================================================
+SYSFS ENTRIES
+================================================================================
+
+Information about mounted f2f2 file systems can be found in
+/sys/fs/f2fs.  Each mounted filesystem will have a directory in
+/sys/fs/f2fs based on its device name (i.e., /sys/fs/f2fs/sda).
+The files in each per-device directory are shown in table below.
+
+Files in /sys/fs/f2fs/<devname>
+(see also Documentation/ABI/testing/sysfs-fs-f2fs)
+..............................................................................
+ File                         Content
+
+ gc_max_sleep_time            This tuning parameter controls the maximum sleep
+                              time for the garbage collection thread. Time is
+                              in milliseconds.
+
+ gc_min_sleep_time            This tuning parameter controls the minimum sleep
+                              time for the garbage collection thread. Time is
+                              in milliseconds.
+
+ gc_no_gc_sleep_time          This tuning parameter controls the default sleep
+                              time for the garbage collection thread. Time is
+                              in milliseconds.
+
+================================================================================
 USAGE
 ================================================================================