From 6f3a01ae9b72d5b7c57632632b8c8088db11e7ab Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Tue, 4 Aug 2020 21:14:46 +0800 Subject: [PATCH] f2fs: record average update time of segment Previously, once we update one block in segment, we will update mtime of segment to last time, making aged segment becoming freshest, result in that GC with cost benefit algorithm missing such segment, So this patch changes to record mtime as average block updating time instead of last updating time. It's not needed to reset mtime for prefree segment, as se->valid_blocks is zero, then old se->mtime won't take any weight with below calculation: se->mtime = div_u64(se->mtime * se->valid_blocks + mtime, se->valid_blocks + 1); Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/segment.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 907fdaad59be..9f366b4f1dc7 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -2154,6 +2154,22 @@ static void __set_sit_entry_type(struct f2fs_sb_info *sbi, int type, __mark_sit_entry_dirty(sbi, segno); } +static void update_segment_mtime(struct f2fs_sb_info *sbi, block_t blkaddr) +{ + unsigned int segno = GET_SEGNO(sbi, blkaddr); + struct seg_entry *se = get_seg_entry(sbi, segno); + unsigned long long mtime = get_mtime(sbi, false); + + if (!se->mtime) + se->mtime = mtime; + else + se->mtime = div_u64(se->mtime * se->valid_blocks + mtime, + se->valid_blocks + 1); + + if (mtime > SIT_I(sbi)->max_mtime) + SIT_I(sbi)->max_mtime = mtime; +} + static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del) { struct seg_entry *se; @@ -2173,10 +2189,9 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del) f2fs_bug_on(sbi, (new_vblocks < 0 || (new_vblocks > f2fs_usable_blks_in_seg(sbi, segno)))); + update_segment_mtime(sbi, blkaddr); + se->valid_blocks = new_vblocks; - se->mtime = get_mtime(sbi, false); - if (se->mtime > SIT_I(sbi)->max_mtime) - SIT_I(sbi)->max_mtime = se->mtime; /* Update valid block bitmap */ if (del > 0) {