iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

f2fs: add key functions for small discards

Browse Source 
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 <jaegeuk.kim@samsung.com>
This commit is contained in:
Jaegeuk Kim 2013-11-12 14:49:56 +09:00
parent 7fd9e544fb
commit b29555505d
1 changed files with 60 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
fs/f2fs/segment.c
View File

@ -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;