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>

3 files changed, 8 insertions, 5 deletions

diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index f415b9fc4cc8..2f6d0218dd22 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -169,9 +169,11 @@ Files in /sys/fs/f2fs/<devname>
 
  reclaim_segments             This parameter controls the number of prefree
                               segments to be reclaimed. If the number of prefree
-                              segments is larger than this number, f2fs tries to
-                              conduct checkpoint to reclaim the prefree segments
-                              to free segments. By default, 100 segments, 200MB.
+                              segments is larger than the number of segments
+                              in the proportion to the percentage over total
+                              volume size, f2fs tries to conduct checkpoint to
+                              reclaim the prefree segments to free segments.
+                              By default, 5% over total # of segments.
 
  max_small_discards           This parameter controls the number of discard
                               commands that consist small blocks less than 2MB.
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 6c5a4f0218ca..e7ff23a536a4 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1758,7 +1758,8 @@ int build_segment_manager(struct f2fs_sb_info *sbi)
         sm_info->ovp_segments = le32_to_cpu(ckpt->overprov_segment_count);
         sm_info->main_segments = le32_to_cpu(raw_super->segment_count_main);
         sm_info->ssa_blkaddr = le32_to_cpu(raw_super->ssa_blkaddr);
-        sm_info->rec_prefree_segments = DEF_RECLAIM_PREFREE_SEGMENTS;
+        sm_info->rec_prefree_segments = sm_info->main_segments *
+                                        DEF_RECLAIM_PREFREE_SEGMENTS / 100;
         sm_info->ipu_policy = F2FS_IPU_DISABLE;
         sm_info->min_ipu_util = DEF_MIN_IPU_UTIL;
 
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 9fc46ee27bb8..7091204680f4 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)