f2fs: change reclaim rate in percentage

It is more reasonable to determine the reclaiming rate of prefree segments
according to the volume size, which is set to 5% by default.
For example, if the volume is 128GB, the prefree segments are reclaimed
when the number reaches to 6.4GB.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 9fc46ee..7091204 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -14,7 +14,7 @@
 #define NULL_SEGNO			((unsigned int)(~0))
 #define NULL_SECNO			((unsigned int)(~0))
 
-#define DEF_RECLAIM_PREFREE_SEGMENTS	100	/* 200MB of prefree segments */
+#define DEF_RECLAIM_PREFREE_SEGMENTS	5	/* 5% over total segments */
 
 /* L: Logical segment # in volume, R: Relative segment # in main area */
 #define GET_L2R_SEGNO(free_i, segno)	(segno - free_i->start_segno)