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authorJaegeuk Kim <jaegeuk.kim@samsung.com>2013-02-04 15:11:17 +0900
committerJaegeuk Kim <jaegeuk.kim@samsung.com>2013-02-12 07:15:02 +0900
commit437275272f9e635673f065300e5d95226a25cb06 (patch)
treebb0b8945d70971c200d098106b8879c1f84e109a /fs/f2fs/gc.c
parentb1f1daf8c72d615b64163e26488d8effeed29b60 (diff)
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>
Diffstat (limited to 'fs/f2fs/gc.c')
-rw-r--r--fs/f2fs/gc.c107
1 files changed, 41 insertions, 66 deletions
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 16fdec355201..52d3a391b922 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -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)