f2fs: introduce f2fs_get_section_mtime

When segs_per_sec is larger than 1, section may contain invalid segments,
mtime should be the average value of each valid blocks,
so introduce f2fs_get_section_mtime to
record the average mtime of all valid blocks in a section.

Signed-off-by: liuderong <liuderong@oppo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 33f5449..60cf1e9 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3783,6 +3783,8 @@ enum rw_hint f2fs_io_type_to_rw_hint(struct f2fs_sb_info *sbi,
 unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi);
 unsigned int f2fs_usable_blks_in_seg(struct f2fs_sb_info *sbi,
                        unsigned int segno);
+unsigned long long f2fs_get_section_mtime(struct f2fs_sb_info *sbi,
+                       unsigned int segno);
 
 #define DEF_FRAGMENT_SIZE      4
 #define MIN_FRAGMENT_SIZE      1

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 9322a72..e40bdd1 100644 (file)
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -361,20 +361,15 @@ static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 {
        struct sit_info *sit_i = SIT_I(sbi);
-       unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
-       unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
        unsigned long long mtime = 0;
        unsigned int vblocks;
        unsigned char age = 0;
        unsigned char u;
-       unsigned int i;
        unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi);
 
-       for (i = 0; i < usable_segs_per_sec; i++)
-               mtime += get_seg_entry(sbi, start + i)->mtime;
+       mtime = f2fs_get_section_mtime(sbi, segno);
+       f2fs_bug_on(sbi, mtime == INVALID_MTIME);
        vblocks = get_valid_blocks(sbi, segno, true);
-
-       mtime = div_u64(mtime, usable_segs_per_sec);
        vblocks = div_u64(vblocks, usable_segs_per_sec);
 
        u = BLKS_TO_SEGS(sbi, vblocks * 100);
@@ -519,10 +514,7 @@ static void add_victim_entry(struct f2fs_sb_info *sbi,
                                struct victim_sel_policy *p, unsigned int segno)
 {
        struct sit_info *sit_i = SIT_I(sbi);
-       unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
-       unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
        unsigned long long mtime = 0;
-       unsigned int i;
 
        if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
                if (p->gc_mode == GC_AT &&
@@ -530,9 +522,8 @@ static void add_victim_entry(struct f2fs_sb_info *sbi,
                        return;
        }
 
-       for (i = 0; i < SEGS_PER_SEC(sbi); i++)
-               mtime += get_seg_entry(sbi, start + i)->mtime;
-       mtime = div_u64(mtime, SEGS_PER_SEC(sbi));
+       mtime = f2fs_get_section_mtime(sbi, segno);
+       f2fs_bug_on(sbi, mtime == INVALID_MTIME);
 
        /* Handle if the system time has changed by the user */
        if (mtime < sit_i->min_mtime)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 1766254..d91fbd1 100644 (file)
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -5430,6 +5430,35 @@ unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi)
        return SEGS_PER_SEC(sbi);
 }
 
+unsigned long long f2fs_get_section_mtime(struct f2fs_sb_info *sbi,
+       unsigned int segno)
+{
+       unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi);
+       unsigned int secno = 0, start = 0;
+       unsigned int total_valid_blocks = 0;
+       unsigned long long mtime = 0;
+       unsigned int i = 0;
+
+       secno = GET_SEC_FROM_SEG(sbi, segno);
+       start = GET_SEG_FROM_SEC(sbi, secno);
+
+       if (!__is_large_section(sbi))
+               return get_seg_entry(sbi, start + i)->mtime;
+
+       for (i = 0; i < usable_segs_per_sec; i++) {
+               /* for large section, only check the mtime of valid segments */
+               struct seg_entry *se = get_seg_entry(sbi, start+i);
+
+               mtime += se->mtime * se->valid_blocks;
+               total_valid_blocks += se->valid_blocks;
+       }
+
+       if (total_valid_blocks == 0)
+               return INVALID_MTIME;
+
+       return div_u64(mtime, total_valid_blocks);
+}
+
 /*
  * Update min, max modified time for cost-benefit GC algorithm
  */
@@ -5443,13 +5472,9 @@ static void init_min_max_mtime(struct f2fs_sb_info *sbi)
        sit_i->min_mtime = ULLONG_MAX;
 
        for (segno = 0; segno < MAIN_SEGS(sbi); segno += SEGS_PER_SEC(sbi)) {
-               unsigned int i;
                unsigned long long mtime = 0;
 
-               for (i = 0; i < SEGS_PER_SEC(sbi); i++)
-                       mtime += get_seg_entry(sbi, segno + i)->mtime;
-
-               mtime = div_u64(mtime, SEGS_PER_SEC(sbi));
+               mtime = f2fs_get_section_mtime(sbi, segno);
 
                if (sit_i->min_mtime > mtime)
                        sit_i->min_mtime = mtime;

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 71adb4a..e9cc730 100644 (file)
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -18,6 +18,8 @@
 #define F2FS_MIN_SEGMENTS      9 /* SB + 2 (CP + SIT + NAT) + SSA + MAIN */
 #define F2FS_MIN_META_SEGMENTS 8 /* SB + 2 (CP + SIT + NAT) + SSA */
 
+#define INVALID_MTIME ULLONG_MAX /* no valid blocks in a segment/section */
+
 /* L: Logical segment # in volume, R: Relative segment # in main area */
 #define GET_L2R_SEGNO(free_i, segno)   ((segno) - (free_i)->start_segno)
 #define GET_R2L_SEGNO(free_i, segno)   ((segno) + (free_i)->start_segno)