From 19f4e688f89a9ce07b86d06d3df23c1cd877ab4e Mon Sep 17 00:00:00 2001 From: Hou Pengyang Date: Sat, 25 Feb 2017 03:57:38 +0000 Subject: [PATCH] f2fs: avoid bggc->fggc when enough free segments are avaliable after cp We use has_not_enough_free_secs to check if there are enough free segments, (free_sections(sbi) + freed) <= (node_secs + 2 * dent_secs + imeta_secs + reserved_sections(sbi) + needed); Under scenario with large number of dirty nodes, these nodes would be flushed during cp, as a result, right side of the inequality would be decreased, while left side stays unchanged if these nodes are flushed in SSR way, which means there are enough free segments after this cp. For this case, we just do a bggc instead of fggc. Signed-off-by: Hou Pengyang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/gc.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index 8be5144da8e6..023f043edefd 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -953,21 +953,22 @@ gc_more: goto stop; } - if (gc_type == BG_GC && has_not_enough_free_secs(sbi, sec_freed, 0)) { - gc_type = FG_GC; + if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) { /* - * If there is no victim and no prefree segment but still not - * enough free sections, we should flush dent/node blocks and do - * garbage collections. + * For example, if there are many prefree_segments below given + * threshold, we can make them free by checkpoint. Then, we + * secure free segments which doesn't need fggc any more. */ ret = write_checkpoint(sbi, &cpc); if (ret) goto stop; - } else if (gc_type == BG_GC && !background) { - /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */ - goto stop; + if (has_not_enough_free_secs(sbi, 0, 0)) + gc_type = FG_GC; } + /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */ + if (gc_type == BG_GC && !background) + goto stop; if (!__get_victim(sbi, &segno, gc_type)) goto stop; ret = 0; -- 2.30.2