From 81eb8d6e2869b119d4a7b8c02091c3779733a3ac Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Thu, 24 Oct 2013 13:31:34 +0900 Subject: [PATCH] f2fs: reclaim prefree segments periodically Previously, f2fs postpones reclaiming prefree segments into free segments as much as possible. However, if user writes and deletes a bunch of data without any sync or fsync calls, some flash storages can suffer from garbage collections. So, this patch adds the reclaiming codes to f2fs_write_node_pages and background GC thread. If there are a lot of prefree segments, let's do checkpoint so that f2fs submits discard commands for the prefree regions to the flash storage. Signed-off-by: Changman Lee Signed-off-by: Jaegeuk Kim --- fs/f2fs/f2fs.h | 3 +++ fs/f2fs/gc.c | 5 +++++ fs/f2fs/node.c | 3 ++- fs/f2fs/segment.c | 1 + fs/f2fs/segment.h | 7 +++++++ 5 files changed, 18 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index e8f3fd345ca3..6dff777cd94a 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -299,6 +299,9 @@ struct f2fs_sm_info { unsigned int main_segments; /* # of segments in main area */ unsigned int reserved_segments; /* # of reserved segments */ unsigned int ovp_segments; /* # of overprovision segments */ + + /* a threshold to reclaim prefree segments */ + unsigned int rec_prefree_segments; }; /* diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index cb286d7b02b2..783c6cc6253c 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -82,6 +82,11 @@ static int gc_thread_func(void *data) /* if return value is not zero, no victim was selected */ if (f2fs_gc(sbi)) wait_ms = gc_th->no_gc_sleep_time; + + /* balancing prefree segments */ + if (excess_prefree_segs(sbi)) + f2fs_sync_fs(sbi->sb, true); + } while (!kthread_should_stop()); return 0; } diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index cc119b65a0d3..89dd8a5a3ca3 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -1206,7 +1206,8 @@ static int f2fs_write_node_pages(struct address_space *mapping, long nr_to_write = wbc->nr_to_write; /* First check balancing cached NAT entries */ - if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK)) { + if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK) || + excess_prefree_segs(sbi)) { f2fs_sync_fs(sbi->sb, true); return 0; } diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 177a33b16b2c..62b52f2f293a 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -1645,6 +1645,7 @@ 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; err = build_sit_info(sbi); if (err) diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index 7f94d78cda3d..abe7094c4f7a 100644 --- a/fs/f2fs/segment.h +++ b/fs/f2fs/segment.h @@ -14,6 +14,8 @@ #define NULL_SEGNO ((unsigned int)(~0)) #define NULL_SECNO ((unsigned int)(~0)) +#define DEF_RECLAIM_PREFREE_SEGMENTS 100 /* 200MB of prefree segments */ + /* 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) @@ -472,6 +474,11 @@ static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, int freed) reserved_sections(sbi))); } +static inline bool excess_prefree_segs(struct f2fs_sb_info *sbi) +{ + return (prefree_segments(sbi) > SM_I(sbi)->rec_prefree_segments); +} + static inline int utilization(struct f2fs_sb_info *sbi) { return div_u64((u64)valid_user_blocks(sbi) * 100, sbi->user_block_count);