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Commit 0a87f664 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: detect congestion of flush command issues 



If flush commands do not incur any congestion, we don't need to throw that to
dispatching queue which causes unnecessary latency.

Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 6d94c74a

fs/f2fs/f2fs.h

+1 −0
Original line number Diff line number Diff line
@@ -603,6 +603,7 @@ struct flush_cmd { 
struct flush_cmd_control {

	struct task_struct *f2fs_issue_flush;	/* flush thread */

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

	atomic_t submit_flush;			/* # of issued flushes */

	struct llist_head issue_list;		/* list for command issue */

	struct llist_node *dispatch_list;	/* list for command dispatch */

};

fs/f2fs/segment.c

+6 −1
Original line number Diff line number Diff line
@@ -433,24 +433,28 @@ int f2fs_issue_flush(struct f2fs_sb_info *sbi) 
	if (test_opt(sbi, NOBARRIER))

		return 0;



	if (!test_opt(sbi, FLUSH_MERGE)) {

	if (!test_opt(sbi, FLUSH_MERGE) || !atomic_read(&fcc->submit_flush)) {

		struct bio *bio = f2fs_bio_alloc(0);

		int ret;



		atomic_inc(&fcc->submit_flush);

		bio->bi_bdev = sbi->sb->s_bdev;

		ret = submit_bio_wait(WRITE_FLUSH, bio);

		atomic_dec(&fcc->submit_flush);

		bio_put(bio);

		return ret;

	}



	init_completion(&cmd.wait);



	atomic_inc(&fcc->submit_flush);

	llist_add(&cmd.llnode, &fcc->issue_list);



	if (!fcc->dispatch_list)

		wake_up(&fcc->flush_wait_queue);



	wait_for_completion(&cmd.wait);

	atomic_dec(&fcc->submit_flush);



	return cmd.ret;

}
@@ -464,6 +468,7 @@ int create_flush_cmd_control(struct f2fs_sb_info *sbi) 
	fcc = kzalloc(sizeof(struct flush_cmd_control), GFP_KERNEL);

	if (!fcc)

		return -ENOMEM;

	atomic_set(&fcc->submit_flush, 0);

	init_waitqueue_head(&fcc->flush_wait_queue);

	init_llist_head(&fcc->issue_list);

	SM_I(sbi)->cmd_control_info = fcc;