From b29555505d81e496fdbd125190c8043f3c09a83c Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Tue, 12 Nov 2013 14:49:56 +0900 Subject: [PATCH] f2fs: add key functions for small discards This patch adds key functions to activate the small discard feature. Note that this procedure is conducted during the checkpoint only. In flush_sit_entries(), when a new dirty sit entry is flushed, f2fs calls add_discard_addrs() which searches candidates to be discarded. The candidates should be marked *invalidated* and also previous checkpoint recognizes it as *valid*. At the end of a checkpoint procedure, f2fs throws discards based on the discard entry list. Signed-off-by: Jaegeuk Kim --- fs/f2fs/segment.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 823526e..505a889 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -266,6 +266,47 @@ static void locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno) mutex_unlock(&dirty_i->seglist_lock); } +static void add_discard_addrs(struct f2fs_sb_info *sbi, + unsigned int segno, struct seg_entry *se) +{ + struct list_head *head = &SM_I(sbi)->discard_list; + struct discard_entry *new; + int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long); + int max_blocks = sbi->blocks_per_seg; + unsigned long *cur_map = (unsigned long *)se->cur_valid_map; + unsigned long *ckpt_map = (unsigned long *)se->ckpt_valid_map; + unsigned long dmap[entries]; + unsigned int start = 0, end = -1; + int i; + + if (!test_opt(sbi, DISCARD)) + return; + + /* zero block will be discarded through the prefree list */ + if (!se->valid_blocks || se->valid_blocks == max_blocks) + return; + + /* SIT_VBLOCK_MAP_SIZE should be multiple of sizeof(unsigned long) */ + for (i = 0; i < entries; i++) + dmap[i] = (cur_map[i] ^ ckpt_map[i]) & ckpt_map[i]; + + while (SM_I(sbi)->nr_discards <= SM_I(sbi)->max_discards) { + start = __find_rev_next_bit(dmap, max_blocks, end + 1); + if (start >= max_blocks) + break; + + end = __find_rev_next_zero_bit(dmap, max_blocks, start + 1); + + new = f2fs_kmem_cache_alloc(discard_entry_slab, GFP_NOFS); + INIT_LIST_HEAD(&new->list); + new->blkaddr = START_BLOCK(sbi, segno) + start; + new->len = end - start; + + list_add_tail(&new->list, head); + SM_I(sbi)->nr_discards += end - start; + } +} + /* * Should call clear_prefree_segments after checkpoint is done. */ @@ -288,6 +329,9 @@ static void set_prefree_as_free_segments(struct f2fs_sb_info *sbi) void clear_prefree_segments(struct f2fs_sb_info *sbi) { + struct list_head *head = &(SM_I(sbi)->discard_list); + struct list_head *this, *next; + struct discard_entry *entry; struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); unsigned long *prefree_map = dirty_i->dirty_segmap[PRE]; unsigned int total_segs = TOTAL_SEGS(sbi); @@ -318,6 +362,18 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi) GFP_NOFS, 0); } mutex_unlock(&dirty_i->seglist_lock); + + /* send small discards */ + list_for_each_safe(this, next, head) { + entry = list_entry(this, struct discard_entry, list); + blkdev_issue_discard(sbi->sb->s_bdev, + entry->blkaddr << sbi->log_sectors_per_block, + (1 << sbi->log_sectors_per_block) * entry->len, + GFP_NOFS, 0); + list_del(&entry->list); + SM_I(sbi)->nr_discards -= entry->len; + kmem_cache_free(discard_entry_slab, entry); + } } static void __mark_sit_entry_dirty(struct f2fs_sb_info *sbi, unsigned int segno) @@ -1469,6 +1525,10 @@ void flush_sit_entries(struct f2fs_sb_info *sbi) sit_offset = SIT_ENTRY_OFFSET(sit_i, segno); + /* add discard candidates */ + if (SM_I(sbi)->nr_discards < SM_I(sbi)->max_discards) + add_discard_addrs(sbi, segno, se); + if (flushed) goto to_sit_page; -- 2.7.4