f2fs: readahead contiguous SSA blocks for f2fs_gc

If there are multi segments in one section, we will read those SSA blocks which
have contiguous address one by one in f2fs_gc. It may lost performance, let's
read ahead SSA blocks by merge multi read request.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

3 files changed, 12 insertions, 4 deletions

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 757b77b7118e..c8516ee24126 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -82,6 +82,7 @@ inline int get_max_meta_blks(struct f2fs_sb_info *sbi, int type)
                 return NM_I(sbi)->max_nid / NAT_ENTRY_PER_BLOCK;
         case META_SIT:
                 return SIT_BLK_CNT(sbi);
+        case META_SSA:
         case META_CP:
                 return 0;
         default:
@@ -90,7 +91,7 @@ inline int get_max_meta_blks(struct f2fs_sb_info *sbi, int type)
 }
 
 /*
- * Readahead CP/NAT/SIT pages
+ * Readahead CP/NAT/SIT/SSA pages
  */
 int ra_meta_pages(struct f2fs_sb_info *sbi, int start, int nrpages, int type)
 {
@@ -125,8 +126,9 @@ int ra_meta_pages(struct f2fs_sb_info *sbi, int start, int nrpages, int type)
                                 goto out;
                         prev_blk_addr = blk_addr;
                         break;
+                case META_SSA:
                 case META_CP:
-                        /* get cp block addr */
+                        /* get ssa/cp block addr */
                         blk_addr = blkno;
                         break;
                 default:
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 6f88191f2a34..bd6666e1bf2f 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -89,12 +89,13 @@ enum {
 };
 
 /*
- * For CP/NAT/SIT readahead
+ * For CP/NAT/SIT/SSA readahead
  */
 enum {
         META_CP,
         META_NAT,
-        META_SIT
+        META_SIT,
+        META_SSA
 };
 
 /* for the list of orphan inodes */
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index b161db4a96a4..d94acbc3d928 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -708,6 +708,11 @@ gc_more:
                 goto stop;
         ret = 0;
 
+        /* readahead multi ssa blocks those have contiguous address */
+        if (sbi->segs_per_sec > 1)
+                ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno), sbi->segs_per_sec,
+                                                                META_SSA);
+
         for (i = 0; i < sbi->segs_per_sec; i++)
                 do_garbage_collect(sbi, segno + i, &ilist, gc_type);