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Commit ba48a33e authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
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f2fs: in prior to issue big discard 



Keep issuing big size discard in prior instead of the one with random
size, so that we expect that it will help to:
- be quick to recycle unused large space in flash storage device.
- give a chance for
  a) wait to merge small piece discards into bigger one, or
  b) avoid issuing discards while they have being reallocated by SSR.

Signed-off-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 46f84c2c

fs/f2fs/f2fs.h

+6 −1
Original line number Diff line number Diff line
@@ -188,6 +188,11 @@ struct discard_entry { 
	unsigned char discard_map[SIT_VBLOCK_MAP_SIZE];	/* segment discard bitmap */

};



/* max discard pend list number */

#define MAX_PLIST_NUM		512

#define plist_idx(blk_num)	((blk_num) >= MAX_PLIST_NUM ?		\

					(MAX_PLIST_NUM - 1) : (blk_num - 1))



enum {

	D_PREP,

	D_SUBMIT,
@@ -221,7 +226,7 @@ struct discard_cmd { 
struct discard_cmd_control {

	struct task_struct *f2fs_issue_discard;	/* discard thread */

	struct list_head entry_list;		/* 4KB discard entry list */

	struct list_head pend_list;		/* store pending entries */

	struct list_head pend_list[MAX_PLIST_NUM];/* store pending entries */

	struct list_head wait_list;		/* store on-flushing entries */

	wait_queue_head_t discard_wait_queue;	/* waiting queue for wake-up */

	struct mutex cmd_lock;

fs/f2fs/segment.c

+39 −15
Original line number Diff line number Diff line
@@ -677,9 +677,13 @@ static struct discard_cmd *__create_discard_cmd(struct f2fs_sb_info *sbi, 
		block_t start, block_t len)

{

	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;

	struct list_head *pend_list = &(dcc->pend_list);

	struct list_head *pend_list;

	struct discard_cmd *dc;



	f2fs_bug_on(sbi, !len);



	pend_list = &dcc->pend_list[plist_idx(len)];



	dc = f2fs_kmem_cache_alloc(discard_cmd_slab, GFP_NOFS);

	INIT_LIST_HEAD(&dc->list);

	dc->bdev = bdev;
@@ -806,9 +810,16 @@ static struct discard_cmd *__insert_discard_tree(struct f2fs_sb_info *sbi, 
	return dc;

}



static void __relocate_discard_cmd(struct discard_cmd_control *dcc,

						struct discard_cmd *dc)

{

	list_move_tail(&dc->list, &dcc->pend_list[plist_idx(dc->len)]);

}



static void __punch_discard_cmd(struct f2fs_sb_info *sbi,

				struct discard_cmd *dc, block_t blkaddr)

{

	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;

	struct discard_info di = dc->di;

	bool modified = false;
@@ -819,6 +830,7 @@ static void __punch_discard_cmd(struct f2fs_sb_info *sbi, 


	if (blkaddr > di.lstart) {

		dc->len = blkaddr - dc->lstart;

		__relocate_discard_cmd(dcc, dc);

		modified = true;

	}
@@ -832,6 +844,7 @@ static void __punch_discard_cmd(struct f2fs_sb_info *sbi, 
			dc->lstart++;

			dc->len--;

			dc->start++;

			__relocate_discard_cmd(dcc, dc);

		}

	}

}
@@ -890,6 +903,7 @@ static void __update_discard_tree_range(struct f2fs_sb_info *sbi, 
			prev_dc->bdev == bdev &&

			__is_discard_back_mergeable(&di, &prev_dc->di)) {

			prev_dc->di.len += di.len;

			__relocate_discard_cmd(dcc, prev_dc);

			di = prev_dc->di;

			tdc = prev_dc;

			merged = true;
@@ -901,6 +915,7 @@ static void __update_discard_tree_range(struct f2fs_sb_info *sbi, 
			next_dc->di.lstart = di.lstart;

			next_dc->di.len += di.len;

			next_dc->di.start = di.start;

			__relocate_discard_cmd(dcc, next_dc);

			if (tdc)

				__remove_discard_cmd(sbi, tdc);
@@ -961,16 +976,20 @@ void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr) 
void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)

{

	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;

	struct list_head *pend_list = &(dcc->pend_list);

	struct list_head *pend_list;

	struct list_head *wait_list = &(dcc->wait_list);

	struct discard_cmd *dc, *tmp;

	struct blk_plug plug;

	int i;



	mutex_lock(&dcc->cmd_lock);



	blk_start_plug(&plug);

	for (i = 0; i < MAX_PLIST_NUM; i++) {

		pend_list = &dcc->pend_list[i];

		list_for_each_entry_safe(dc, tmp, pend_list, list)

			__submit_discard_cmd(sbi, dc);

	}

	blk_finish_plug(&plug);



	list_for_each_entry_safe(dc, tmp, wait_list, list) {
@@ -986,17 +1005,19 @@ 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 *pend_list = &dcc->pend_list;

	struct list_head *pend_list;

	struct list_head *wait_list = &dcc->wait_list;

	struct discard_cmd *dc, *tmp;

	struct blk_plug plug;

	int iter = 0;

	int iter = 0, i;

repeat:

	if (kthread_should_stop())

		return 0;



	mutex_lock(&dcc->cmd_lock);

	blk_start_plug(&plug);

	for (i = MAX_PLIST_NUM - 1; i >= 0; i--) {

		pend_list = &dcc->pend_list[i];

		list_for_each_entry_safe(dc, tmp, pend_list, list) {

			f2fs_bug_on(sbi, dc->state != D_PREP);
@@ -1004,8 +1025,10 @@ static int issue_discard_thread(void *data) 
				__submit_discard_cmd(sbi, dc);



			if (iter++ > DISCARD_ISSUE_RATE)

			break;

				goto next_step;

		}

	}

next_step:

	blk_finish_plug(&plug);



	list_for_each_entry_safe(dc, tmp, wait_list, list) {
@@ -1020,7 +1043,7 @@ static int issue_discard_thread(void *data) 
	congestion_wait(BLK_RW_SYNC, HZ/50);



	wait_event_interruptible(*q, kthread_should_stop() ||

			!list_empty(pend_list) || !list_empty(wait_list));

				atomic_read(&dcc->discard_cmd_cnt));

	goto repeat;

}
@@ -1300,7 +1323,7 @@ static 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;

	int err = 0, i;



	if (SM_I(sbi)->dcc_info) {

		dcc = SM_I(sbi)->dcc_info;
@@ -1312,7 +1335,8 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi) 
		return -ENOMEM;



	INIT_LIST_HEAD(&dcc->entry_list);

	INIT_LIST_HEAD(&dcc->pend_list);

	for (i = 0; i < MAX_PLIST_NUM; i++)

		INIT_LIST_HEAD(&dcc->pend_list[i]);

	INIT_LIST_HEAD(&dcc->wait_list);

	mutex_init(&dcc->cmd_lock);

	atomic_set(&dcc->issued_discard, 0);