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f2fs: add a kernel thread to issue discard commands asynchronously 

This patch adds a kernel thread to issue discard commands.
It proposes three states, D_PREP, D_SUBMIT, and D_DONE to identify current
bio status.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Jaegeuk Kim 2017-01-09 20:32:07 -08:00
parent 0b54fb8458
commit 1546996348
2 changed files with 111 additions and 33 deletions
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12
fs/f2fs/f2fs.h
View File

@ -133,6 +133,8 @@ enum {
(SM_I(sbi)->trim_sections * (sbi)->segs_per_sec)
#define BATCHED_TRIM_BLOCKS(sbi) \
(BATCHED_TRIM_SEGMENTS(sbi) << (sbi)->log_blocks_per_seg)
#define DISCARD_ISSUE_RATE 8
#define DEF_CP_INTERVAL 60 /* 60 secs */
#define DEF_IDLE_INTERVAL 5 /* 5 secs */
@ -181,18 +183,28 @@ struct discard_entry {
int len; /* # of consecutive blocks of the discard */
};
enum {
D_PREP,
D_SUBMIT,
D_DONE,
};
struct discard_cmd {
struct list_head list; /* command list */
struct completion wait; /* compleation */
block_t lstart; /* logical start address */
block_t len; /* length */
struct bio *bio; /* bio */
int state; /* state */
};
struct discard_cmd_control {
struct task_struct *f2fs_issue_discard; /* discard thread */
struct list_head discard_entry_list; /* 4KB discard entry list */
int nr_discards; /* # of discards in the list */
struct list_head discard_cmd_list; /* discard cmd list */
wait_queue_head_t discard_wait_queue; /* waiting queue for wake-up */
struct mutex cmd_lock;
int max_discards; /* max. discards to be issued */
};

132
fs/f2fs/segment.c
View File

@ -628,7 +628,7 @@ static void locate_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno)
mutex_unlock(&dirty_i->seglist_lock);
}
static struct discard_cmd *__add_discard_cmd(struct f2fs_sb_info *sbi,
static void __add_discard_cmd(struct f2fs_sb_info *sbi,
struct bio *bio, block_t lstart, block_t len)
{
struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
@ -638,12 +638,30 @@ static struct discard_cmd *__add_discard_cmd(struct f2fs_sb_info *sbi,
dc = f2fs_kmem_cache_alloc(discard_cmd_slab, GFP_NOFS);
INIT_LIST_HEAD(&dc->list);
dc->bio = bio;
bio->bi_private = dc;
dc->lstart = lstart;
dc->len = len;
dc->state = D_PREP;
init_completion(&dc->wait);
list_add_tail(&dc->list, cmd_list);
return dc;
mutex_lock(&dcc->cmd_lock);
list_add_tail(&dc->list, cmd_list);
mutex_unlock(&dcc->cmd_lock);
}
static void __remove_discard_cmd(struct f2fs_sb_info *sbi, struct discard_cmd *dc)
{
int err = dc->bio->bi_error;
if (err == -EOPNOTSUPP)
err = 0;
if (err)
f2fs_msg(sbi->sb, KERN_INFO,
"Issue discard failed, ret: %d", err);
bio_put(dc->bio);
list_del(&dc->list);
kmem_cache_free(discard_cmd_slab, dc);
}
/* This should be covered by global mutex, &sit_i->sentry_lock */
@ -653,31 +671,28 @@ void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
struct list_head *wait_list = &(dcc->discard_cmd_list);
struct discard_cmd *dc, *tmp;
mutex_lock(&dcc->cmd_lock);
list_for_each_entry_safe(dc, tmp, wait_list, list) {
struct bio *bio = dc->bio;
int err;
if (!completion_done(&dc->wait)) {
if ((dc->lstart <= blkaddr &&
blkaddr < dc->lstart + dc->len) ||
blkaddr == NULL_ADDR)
wait_for_completion_io(&dc->wait);
else
continue;
if (blkaddr == NULL_ADDR) {
if (dc->state == D_PREP) {
dc->state = D_SUBMIT;
submit_bio(dc->bio);
}
wait_for_completion_io(&dc->wait);
__remove_discard_cmd(sbi, dc);
continue;
}
err = bio->bi_error;
if (err == -EOPNOTSUPP)
err = 0;
if (err)
f2fs_msg(sbi->sb, KERN_INFO,
"Issue discard failed, ret: %d", err);
bio_put(bio);
list_del(&dc->list);
kmem_cache_free(discard_cmd_slab, dc);
if (dc->lstart <= blkaddr && blkaddr < dc->lstart + dc->len) {
if (dc->state == D_SUBMIT)
wait_for_completion_io(&dc->wait);
else
__remove_discard_cmd(sbi, dc);
}
}
mutex_unlock(&dcc->cmd_lock);
}
static void f2fs_submit_discard_endio(struct bio *bio)
@ -685,8 +700,48 @@ static void f2fs_submit_discard_endio(struct bio *bio)
struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
complete(&dc->wait);
dc->state = D_DONE;
}
static int issue_discard_thread(void *data)
{
struct f2fs_sb_info *sbi = data;
struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
wait_queue_head_t *q = &dcc->discard_wait_queue;
struct list_head *cmd_list = &dcc->discard_cmd_list;
struct discard_cmd *dc, *tmp;
struct blk_plug plug;
int iter = 0;
repeat:
if (kthread_should_stop())
return 0;
blk_start_plug(&plug);
mutex_lock(&dcc->cmd_lock);
list_for_each_entry_safe(dc, tmp, cmd_list, list) {
if (dc->state == D_PREP) {
dc->state = D_SUBMIT;
submit_bio(dc->bio);
if (iter++ > DISCARD_ISSUE_RATE)
break;
} else if (dc->state == D_DONE) {
__remove_discard_cmd(sbi, dc);
}
}
mutex_unlock(&dcc->cmd_lock);
blk_finish_plug(&plug);
iter = 0;
congestion_wait(BLK_RW_SYNC, HZ/50);
wait_event_interruptible(*q,
kthread_should_stop() || !list_empty(&dcc->discard_cmd_list));
goto repeat;
}
/* this function is copied from blkdev_issue_discard from block/blk-lib.c */
static int __f2fs_issue_discard_async(struct f2fs_sb_info *sbi,
struct block_device *bdev, block_t blkstart, block_t blklen)
@ -707,13 +762,11 @@ static int __f2fs_issue_discard_async(struct f2fs_sb_info *sbi,
SECTOR_FROM_BLOCK(blklen),
GFP_NOFS, 0, &bio);
if (!err && bio) {
struct discard_cmd *dc = __add_discard_cmd(sbi, bio,
lblkstart, blklen);
bio->bi_private = dc;
bio->bi_end_io = f2fs_submit_discard_endio;
bio->bi_opf |= REQ_SYNC;
submit_bio(bio);
__add_discard_cmd(sbi, bio, lblkstart, blklen);
wake_up(&SM_I(sbi)->dcc_info->discard_wait_queue);
}
return err;
}
@ -919,14 +972,11 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
struct list_head *head = &(SM_I(sbi)->dcc_info->discard_entry_list);
struct discard_entry *entry, *this;
struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
struct blk_plug plug;
unsigned long *prefree_map = dirty_i->dirty_segmap[PRE];
unsigned int start = 0, end = -1;
unsigned int secno, start_segno;
bool force = (cpc->reason == CP_DISCARD);
blk_start_plug(&plug);
mutex_lock(&dirty_i->seglist_lock);
while (1) {
@ -979,12 +1029,11 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
SM_I(sbi)->dcc_info->nr_discards -= entry->len;
kmem_cache_free(discard_entry_slab, entry);
}
blk_finish_plug(&plug);
}
int create_discard_cmd_control(struct f2fs_sb_info *sbi)
{
dev_t dev = sbi->sb->s_bdev->bd_dev;
struct discard_cmd_control *dcc;
int err = 0;
@ -999,11 +1048,22 @@ int create_discard_cmd_control(struct f2fs_sb_info *sbi)
INIT_LIST_HEAD(&dcc->discard_entry_list);
INIT_LIST_HEAD(&dcc->discard_cmd_list);
mutex_init(&dcc->cmd_lock);
dcc->nr_discards = 0;
dcc->max_discards = 0;
init_waitqueue_head(&dcc->discard_wait_queue);
SM_I(sbi)->dcc_info = dcc;
init_thread:
dcc->f2fs_issue_discard = kthread_run(issue_discard_thread, sbi,
"f2fs_discard-%u:%u", MAJOR(dev), MINOR(dev));
if (IS_ERR(dcc->f2fs_issue_discard)) {
err = PTR_ERR(dcc->f2fs_issue_discard);
kfree(dcc);
SM_I(sbi)->dcc_info = NULL;
return err;
}
return err;
}
@ -1011,6 +1071,12 @@ void destroy_discard_cmd_control(struct f2fs_sb_info *sbi, bool free)
{
struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
if (dcc && dcc->f2fs_issue_discard) {
struct task_struct *discard_thread = dcc->f2fs_issue_discard;
dcc->f2fs_issue_discard = NULL;
kthread_stop(discard_thread);
}
if (free) {
kfree(dcc);
SM_I(sbi)->dcc_info = NULL;