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f2fs: clarify and enhance the f2fs_gc flow 

This patch makes clearer the ambiguous f2fs_gc flow as follows.

1. Remove intermediate checkpoint condition during f2fs_gc
 (i.e., should_do_checkpoint() and GC_BLOCKED)

2. Remove unnecessary return values of f2fs_gc because of #1.
 (i.e., GC_NODE, GC_OK, etc)

3. Simplify write_checkpoint() because of #2.

4. Clarify the main f2fs_gc flow.
 o monitor how many freed sections during one iteration of do_garbage_collect().
 o do GC more without checkpoints if we can't get enough free sections.
 o do checkpoint once we've got enough free sections through forground GCs.

5. Adopt thread-logging (Slack-Space-Recycle) scheme more aggressively on data
  log types. See. get_ssr_segement()

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
This commit is contained in:
Jaegeuk Kim 2013-02-04 15:11:17 +09:00
parent b1f1daf8c7
commit 437275272f
9 changed files with 72 additions and 105 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
fs/f2fs/checkpoint.c
View File

@ -539,7 +539,7 @@ retry:
/*
* Freeze all the FS-operations for checkpoint.
*/
void block_operations(struct f2fs_sb_info *sbi)
static void block_operations(struct f2fs_sb_info *sbi)
{
int t;
struct writeback_control wbc = {
@ -722,15 +722,13 @@ static void do_checkpoint(struct f2fs_sb_info *sbi, bool is_umount)
/*
* We guarantee that this checkpoint procedure should not fail.
*/
void write_checkpoint(struct f2fs_sb_info *sbi, bool blocked, bool is_umount)
void write_checkpoint(struct f2fs_sb_info *sbi, bool is_umount)
{
struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
unsigned long long ckpt_ver;
if (!blocked) {
mutex_lock(&sbi->cp_mutex);
block_operations(sbi);
}
mutex_lock(&sbi->cp_mutex);
block_operations(sbi);
f2fs_submit_bio(sbi, DATA, true);
f2fs_submit_bio(sbi, NODE, true);

3
fs/f2fs/f2fs.h
View File

@ -969,8 +969,7 @@ int get_valid_checkpoint(struct f2fs_sb_info *);
void set_dirty_dir_page(struct inode *, struct page *);
void remove_dirty_dir_inode(struct inode *);
void sync_dirty_dir_inodes(struct f2fs_sb_info *);
void block_operations(struct f2fs_sb_info *);
void write_checkpoint(struct f2fs_sb_info *, bool, bool);
void write_checkpoint(struct f2fs_sb_info *, bool);
void init_orphan_info(struct f2fs_sb_info *);
int __init create_checkpoint_caches(void);
void destroy_checkpoint_caches(void);

107
fs/f2fs/gc.c
View File

@ -78,7 +78,8 @@ static int gc_thread_func(void *data)
sbi->bg_gc++;
if (f2fs_gc(sbi) == GC_NONE)
/* if return value is not zero, no victim was selected */
if (f2fs_gc(sbi))
wait_ms = GC_THREAD_NOGC_SLEEP_TIME;
else if (wait_ms == GC_THREAD_NOGC_SLEEP_TIME)
wait_ms = GC_THREAD_MAX_SLEEP_TIME;
@ -360,7 +361,7 @@ static int check_valid_map(struct f2fs_sb_info *sbi,
sentry = get_seg_entry(sbi, segno);
ret = f2fs_test_bit(offset, sentry->cur_valid_map);
mutex_unlock(&sit_i->sentry_lock);
return ret ? GC_OK : GC_NEXT;
return ret;
}
/*
@ -368,7 +369,7 @@ static int check_valid_map(struct f2fs_sb_info *sbi,
* On validity, copy that node with cold status, otherwise (invalid node)
* ignore that.
*/
static int gc_node_segment(struct f2fs_sb_info *sbi,
static void gc_node_segment(struct f2fs_sb_info *sbi,
struct f2fs_summary *sum, unsigned int segno, int gc_type)
{
bool initial = true;
@ -380,21 +381,12 @@ next_step:
for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
nid_t nid = le32_to_cpu(entry->nid);
struct page *node_page;
int err;
/*
* It makes sure that free segments are able to write
* all the dirty node pages before CP after this CP.
* So let's check the space of dirty node pages.
*/
if (should_do_checkpoint(sbi)) {
mutex_lock(&sbi->cp_mutex);
block_operations(sbi);
return GC_BLOCKED;
}
/* stop BG_GC if there is not enough free sections. */
if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
return;
err = check_valid_map(sbi, segno, off);
if (err == GC_NEXT)
if (check_valid_map(sbi, segno, off) == 0)
continue;
if (initial) {
@ -424,7 +416,6 @@ next_step:
};
sync_node_pages(sbi, 0, &wbc);
}
return GC_DONE;
}
/*
@ -467,13 +458,13 @@ static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
node_page = get_node_page(sbi, nid);
if (IS_ERR(node_page))
return GC_NEXT;
return 0;
get_node_info(sbi, nid, dni);
if (sum->version != dni->version) {
f2fs_put_page(node_page, 1);
return GC_NEXT;
return 0;
}
*nofs = ofs_of_node(node_page);
@ -481,8 +472,8 @@ static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
f2fs_put_page(node_page, 1);
if (source_blkaddr != blkaddr)
return GC_NEXT;
return GC_OK;
return 0;
return 1;
}
static void move_data_page(struct inode *inode, struct page *page, int gc_type)
@ -523,13 +514,13 @@ out:
* If the parent node is not valid or the data block address is different,
* the victim data block is ignored.
*/
static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
struct list_head *ilist, unsigned int segno, int gc_type)
{
struct super_block *sb = sbi->sb;
struct f2fs_summary *entry;
block_t start_addr;
int err, off;
int off;
int phase = 0;
start_addr = START_BLOCK(sbi, segno);
@ -543,20 +534,11 @@ next_step:
unsigned int ofs_in_node, nofs;
block_t start_bidx;
/*
* It makes sure that free segments are able to write
* all the dirty node pages before CP after this CP.
* So let's check the space of dirty node pages.
*/
if (should_do_checkpoint(sbi)) {
mutex_lock(&sbi->cp_mutex);
block_operations(sbi);
err = GC_BLOCKED;
goto stop;
}
/* stop BG_GC if there is not enough free sections. */
if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
return;
err = check_valid_map(sbi, segno, off);
if (err == GC_NEXT)
if (check_valid_map(sbi, segno, off) == 0)
continue;
if (phase == 0) {
@ -565,8 +547,7 @@ next_step:
}
/* Get an inode by ino with checking validity */
err = check_dnode(sbi, entry, &dni, start_addr + off, &nofs);
if (err == GC_NEXT)
if (check_dnode(sbi, entry, &dni, start_addr + off, &nofs) == 0)
continue;
if (phase == 1) {
@ -606,11 +587,9 @@ next_iput:
}
if (++phase < 4)
goto next_step;
err = GC_DONE;
stop:
if (gc_type == FG_GC)
f2fs_submit_bio(sbi, DATA, true);
return err;
}
static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
@ -624,17 +603,16 @@ static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
return ret;
}
static int do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
struct list_head *ilist, int gc_type)
{
struct page *sum_page;
struct f2fs_summary_block *sum;
int ret = GC_DONE;
/* read segment summary of victim */
sum_page = get_sum_page(sbi, segno);
if (IS_ERR(sum_page))
return GC_ERROR;
return;
/*
* CP needs to lock sum_page. In this time, we don't need
@ -646,17 +624,16 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
switch (GET_SUM_TYPE((&sum->footer))) {
case SUM_TYPE_NODE:
ret = gc_node_segment(sbi, sum->entries, segno, gc_type);
gc_node_segment(sbi, sum->entries, segno, gc_type);
break;
case SUM_TYPE_DATA:
ret = gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
break;
}
stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
stat_inc_call_count(sbi->stat_info);
f2fs_put_page(sum_page, 0);
return ret;
}
int f2fs_gc(struct f2fs_sb_info *sbi)
@ -664,40 +641,38 @@ int f2fs_gc(struct f2fs_sb_info *sbi)
struct list_head ilist;
unsigned int segno, i;
int gc_type = BG_GC;
int gc_status = GC_NONE;
int nfree = 0;
int ret = -1;
INIT_LIST_HEAD(&ilist);
gc_more:
if (!(sbi->sb->s_flags & MS_ACTIVE))
goto stop;
if (gc_type == BG_GC && has_not_enough_free_secs(sbi))
if (gc_type == BG_GC && has_not_enough_free_secs(sbi, nfree))
gc_type = FG_GC;
if (!__get_victim(sbi, &segno, gc_type, NO_CHECK_TYPE))
goto stop;
ret = 0;
for (i = 0; i < sbi->segs_per_sec; i++) {
/*
* do_garbage_collect will give us three gc_status:
* GC_ERROR, GC_DONE, and GC_BLOCKED.
* If GC is finished uncleanly, we have to return
* the victim to dirty segment list.
*/
gc_status = do_garbage_collect(sbi, segno + i, &ilist, gc_type);
if (gc_status != GC_DONE)
break;
}
if (has_not_enough_free_secs(sbi)) {
write_checkpoint(sbi, (gc_status == GC_BLOCKED), false);
if (has_not_enough_free_secs(sbi))
goto gc_more;
}
for (i = 0; i < sbi->segs_per_sec; i++)
do_garbage_collect(sbi, segno + i, &ilist, gc_type);
if (gc_type == FG_GC &&
get_valid_blocks(sbi, segno, sbi->segs_per_sec) == 0)
nfree++;
if (has_not_enough_free_secs(sbi, nfree))
goto gc_more;
if (gc_type == FG_GC)
write_checkpoint(sbi, false);
stop:
mutex_unlock(&sbi->gc_mutex);
put_gc_inode(&ilist);
return gc_status;
return ret;
}
void build_gc_manager(struct f2fs_sb_info *sbi)

16
fs/f2fs/gc.h
View File

@ -22,15 +22,6 @@
/* Search max. number of dirty segments to select a victim segment */
#define MAX_VICTIM_SEARCH 20
enum {
GC_NONE = 0,
GC_ERROR,
GC_OK,
GC_NEXT,
GC_BLOCKED,
GC_DONE,
};
struct f2fs_gc_kthread {
struct task_struct *f2fs_gc_task;
wait_queue_head_t gc_wait_queue_head;
@ -103,10 +94,3 @@ static inline int is_idle(struct f2fs_sb_info *sbi)
struct request_list *rl = &q->root_rl;
return !(rl->count[BLK_RW_SYNC]) && !(rl->count[BLK_RW_ASYNC]);
}
static inline bool should_do_checkpoint(struct f2fs_sb_info *sbi)
{
int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES);
int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS);
return free_sections(sbi) <= (node_secs + 2 * dent_secs + 2);
}

2
fs/f2fs/node.c
View File

@ -1135,7 +1135,7 @@ static int f2fs_write_node_pages(struct address_space *mapping,
/* First check balancing cached NAT entries */
if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK)) {
write_checkpoint(sbi, false, false);
write_checkpoint(sbi, false);
return 0;
}

2
fs/f2fs/recovery.c
View File

@ -373,5 +373,5 @@ void recover_fsync_data(struct f2fs_sb_info *sbi)
out:
destroy_fsync_dnodes(sbi, &inode_list);
kmem_cache_destroy(fsync_entry_slab);
write_checkpoint(sbi, false, false);
write_checkpoint(sbi, false);
}

21
fs/f2fs/segment.c
View File

@ -29,7 +29,7 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi)
* We should do GC or end up with checkpoint, if there are so many dirty
* dir/node pages without enough free segments.
*/
if (has_not_enough_free_secs(sbi)) {
if (has_not_enough_free_secs(sbi, 0)) {
mutex_lock(&sbi->gc_mutex);
f2fs_gc(sbi);
}
@ -308,7 +308,7 @@ static unsigned int check_prefree_segments(struct f2fs_sb_info *sbi,
* If there is not enough reserved sections,
* we should not reuse prefree segments.
*/
if (has_not_enough_free_secs(sbi))
if (has_not_enough_free_secs(sbi, 0))
return NULL_SEGNO;
/*
@ -536,6 +536,23 @@ static void change_curseg(struct f2fs_sb_info *sbi, int type, bool reuse)
}
}
static int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
{
struct curseg_info *curseg = CURSEG_I(sbi, type);
const struct victim_selection *v_ops = DIRTY_I(sbi)->v_ops;
if (IS_NODESEG(type) || !has_not_enough_free_secs(sbi, 0))
return v_ops->get_victim(sbi,
&(curseg)->next_segno, BG_GC, type, SSR);
/* For data segments, let's do SSR more intensively */
for (; type >= CURSEG_HOT_DATA; type--)
if (v_ops->get_victim(sbi, &(curseg)->next_segno,
BG_GC, type, SSR))
return 1;
return 0;
}
/*
* flush out current segment and replace it with new segment
* This function should be returned with success, otherwise BUG

12
fs/f2fs/segment.h
View File

@ -450,21 +450,15 @@ static inline bool need_SSR(struct f2fs_sb_info *sbi)
return (free_sections(sbi) < overprovision_sections(sbi));
}
static inline int get_ssr_segment(struct f2fs_sb_info *sbi, int type)
{
struct curseg_info *curseg = CURSEG_I(sbi, type);
return DIRTY_I(sbi)->v_ops->get_victim(sbi,
&(curseg)->next_segno, BG_GC, type, SSR);
}
static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi)
static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi, int freed)
{
int node_secs = get_blocktype_secs(sbi, F2FS_DIRTY_NODES);
int dent_secs = get_blocktype_secs(sbi, F2FS_DIRTY_DENTS);
if (sbi->por_doing)
return false;
return (free_sections(sbi) <= (node_secs + 2 * dent_secs +
return ((free_sections(sbi) + freed) <= (node_secs + 2 * dent_secs +
reserved_sections(sbi)));
}

4
fs/f2fs/super.c
View File

@ -112,7 +112,7 @@ static void f2fs_put_super(struct super_block *sb)
f2fs_destroy_stats(sbi);
stop_gc_thread(sbi);
write_checkpoint(sbi, false, true);
write_checkpoint(sbi, true);
iput(sbi->node_inode);
iput(sbi->meta_inode);
@ -136,7 +136,7 @@ int f2fs_sync_fs(struct super_block *sb, int sync)
return 0;
if (sync)
write_checkpoint(sbi, false, false);
write_checkpoint(sbi, false);
else
f2fs_balance_fs(sbi);