Skip to content

Commit

Permalink
f2fs: issue discard commands proactively in high fs utilization
Browse files Browse the repository at this point in the history 
In the high utilization like over 80%, we don't expect huge # of large discard
commands, but do many small pending discards which affects FTL GCs a lot.
Let's issue them in that case.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
  • Loading branch information
Jaegeuk Kim committed May 30, 2018
1 parent d629081 commit 8bb4f25
Show file tree
Hide file tree
Showing 2 changed files with 40 additions and 34 deletions.
3 changes: 1 addition & 2 deletions fs/f2fs/f2fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -186,6 +186,7 @@ enum {
#define DEF_MAX_DISCARD_LEN 512 /* Max. 2MB per discard */
#define DEF_MIN_DISCARD_ISSUE_TIME 50 /* 50 ms, if exists */
#define DEF_MAX_DISCARD_ISSUE_TIME 60000 /* 60 s, if no candidates */
#define DEF_DISCARD_URGENT_UTIL 80 /* do more discard over 80% */
#define DEF_CP_INTERVAL 60 /* 60 secs */
#define DEF_IDLE_INTERVAL 5 /* 5 secs */

Expand Down Expand Up @@ -2777,8 +2778,6 @@ int f2fs_flush_device_cache(struct f2fs_sb_info *sbi);
void destroy_flush_cmd_control(struct f2fs_sb_info *sbi, bool free);
void invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr);
bool is_checkpointed_data(struct f2fs_sb_info *sbi, block_t blkaddr);
void init_discard_policy(struct discard_policy *dpolicy, int discard_type,
unsigned int granularity);
void drop_discard_cmd(struct f2fs_sb_info *sbi);
void stop_discard_thread(struct f2fs_sb_info *sbi);
bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi);
Expand Down
71 changes: 39 additions & 32 deletions fs/f2fs/segment.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -915,6 +915,38 @@ static void __check_sit_bitmap(struct f2fs_sb_info *sbi,
#endif
}

static void __init_discard_policy(struct f2fs_sb_info *sbi,
struct discard_policy *dpolicy,
int discard_type, unsigned int granularity)
{
/* common policy */
dpolicy->type = discard_type;
dpolicy->sync = true;
dpolicy->granularity = granularity;

dpolicy->max_requests = DEF_MAX_DISCARD_REQUEST;
dpolicy->io_aware_gran = MAX_PLIST_NUM;

if (discard_type == DPOLICY_BG) {
dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
dpolicy->io_aware = true;
if (utilization(sbi) > DEF_DISCARD_URGENT_UTIL) {
dpolicy->granularity = 1;
dpolicy->max_interval = DEF_MIN_DISCARD_ISSUE_TIME;
}
} else if (discard_type == DPOLICY_FORCE) {
dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
dpolicy->io_aware = false;
} else if (discard_type == DPOLICY_FSTRIM) {
dpolicy->io_aware = false;
} else if (discard_type == DPOLICY_UMOUNT) {
dpolicy->io_aware = false;
}
}


/* this function is copied from blkdev_issue_discard from block/blk-lib.c */
static void __submit_discard_cmd(struct f2fs_sb_info *sbi,
struct discard_policy *dpolicy,
Expand Down Expand Up @@ -1278,9 +1310,9 @@ static void __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
}

/* wait all */
init_discard_policy(&dp, DPOLICY_FSTRIM, 1);
__init_discard_policy(sbi, &dp, DPOLICY_FSTRIM, 1);
__wait_discard_cmd_range(sbi, &dp, 0, UINT_MAX);
init_discard_policy(&dp, DPOLICY_UMOUNT, 1);
__init_discard_policy(sbi, &dp, DPOLICY_UMOUNT, 1);
__wait_discard_cmd_range(sbi, &dp, 0, UINT_MAX);
}

Expand Down Expand Up @@ -1326,7 +1358,8 @@ bool f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
struct discard_policy dpolicy;
bool dropped;

init_discard_policy(&dpolicy, DPOLICY_UMOUNT, dcc->discard_granularity);
__init_discard_policy(sbi, &dpolicy, DPOLICY_UMOUNT,
dcc->discard_granularity);
__issue_discard_cmd(sbi, &dpolicy);
dropped = __drop_discard_cmd(sbi);

Expand All @@ -1347,7 +1380,7 @@ static int issue_discard_thread(void *data)
set_freezable();

do {
init_discard_policy(&dpolicy, DPOLICY_BG,
__init_discard_policy(sbi, &dpolicy, DPOLICY_BG,
dcc->discard_granularity);

wait_event_interruptible_timeout(*q,
Expand All @@ -1365,7 +1398,7 @@ static int issue_discard_thread(void *data)
dcc->discard_wake = 0;

if (sbi->gc_thread && sbi->gc_thread->gc_urgent)
init_discard_policy(&dpolicy, DPOLICY_FORCE, 1);
__init_discard_policy(sbi, &dpolicy, DPOLICY_FORCE, 1);

sb_start_intwrite(sbi->sb);

Expand Down Expand Up @@ -1658,32 +1691,6 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
wake_up_discard_thread(sbi, false);
}

void init_discard_policy(struct discard_policy *dpolicy,
int discard_type, unsigned int granularity)
{
/* common policy */
dpolicy->type = discard_type;
dpolicy->sync = true;
dpolicy->granularity = granularity;

dpolicy->max_requests = DEF_MAX_DISCARD_REQUEST;
dpolicy->io_aware_gran = MAX_PLIST_NUM;

if (discard_type == DPOLICY_BG) {
dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
dpolicy->io_aware = true;
} else if (discard_type == DPOLICY_FORCE) {
dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
dpolicy->io_aware = false;
} else if (discard_type == DPOLICY_FSTRIM) {
dpolicy->io_aware = false;
} else if (discard_type == DPOLICY_UMOUNT) {
dpolicy->io_aware = false;
}
}

static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
{
dev_t dev = sbi->sb->s_bdev->bd_dev;
Expand Down Expand Up @@ -2442,7 +2449,7 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
start_block = START_BLOCK(sbi, start_segno);
end_block = START_BLOCK(sbi, min(cur_segno, end_segno) + 1);

init_discard_policy(&dpolicy, DPOLICY_FSTRIM, cpc.trim_minlen);
__init_discard_policy(sbi, &dpolicy, DPOLICY_FSTRIM, cpc.trim_minlen);
__issue_discard_cmd_range(sbi, &dpolicy, start_block, end_block);
trimmed = __wait_discard_cmd_range(sbi, &dpolicy,
start_block, end_block);
Expand Down

0 comments on commit 8bb4f25

Please sign in to comment.