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>
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index a009f8a..ed38644 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -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;