Commit 76e780d8 authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
Browse files

f2fs: introduce f2fs_schedule_timeout() 



In f2fs retry logic, we will call f2fs_io_schedule_timeout() to sleep as
uninterruptible state (waiting for IO) for a while, however, in several
paths below, we are not blocked by IO:
- f2fs_write_single_data_page() return -EAGAIN due to racing on cp_rwsem.
- f2fs_flush_device_cache() failed to submit preflush command.
- __issue_discard_cmd_range() sleeps periodically in between two in batch
discard submissions.

So, in order to reveal state of task more accurate, let's introduce
f2fs_schedule_timeout() and call it in above paths in where we are waiting
for non-IO reasons.

Then we can get real reason of uninterruptible sleep for a thread in
tracepoint, perfetto, etc.

Signed-off-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 30a84966

fs/f2fs/checkpoint.c

+2 −2
Original line number Diff line number Diff line
@@ -1318,7 +1318,7 @@ void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type) 
			f2fs_submit_merged_write(sbi, DATA);



		prepare_to_wait(&sbi->cp_wait, &wait, TASK_UNINTERRUPTIBLE);

		io_schedule_timeout(DEFAULT_IO_TIMEOUT);

		io_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);

	}

	finish_wait(&sbi->cp_wait, &wait);

}
@@ -1974,7 +1974,7 @@ void f2fs_flush_ckpt_thread(struct f2fs_sb_info *sbi) 


	/* Let's wait for the previous dispatched checkpoint. */

	while (atomic_read(&cprc->queued_ckpt))

		io_schedule_timeout(DEFAULT_IO_TIMEOUT);

		io_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);

}



void f2fs_init_ckpt_req_control(struct f2fs_sb_info *sbi)

fs/f2fs/compress.c

+2 −2
Original line number Diff line number Diff line
@@ -1057,7 +1057,7 @@ static void cancel_cluster_writeback(struct compress_ctx *cc, 
		f2fs_submit_merged_write(F2FS_I_SB(cc->inode), DATA);

		while (atomic_read(&cic->pending_pages) !=

					(cc->valid_nr_cpages - submitted + 1))

			f2fs_io_schedule_timeout(DEFAULT_IO_TIMEOUT);

			f2fs_io_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);

	}



	/* Cancel writeback and stay locked. */
@@ -1574,7 +1574,7 @@ static int f2fs_write_raw_pages(struct compress_ctx *cc, 
				 */

				if (IS_NOQUOTA(cc->inode))

					goto out;

				f2fs_io_schedule_timeout(DEFAULT_IO_TIMEOUT);

				f2fs_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);

				goto retry_write;

			}

			goto out;

fs/f2fs/data.c

+2 −2
Original line number Diff line number Diff line
@@ -3141,8 +3141,8 @@ static int f2fs_write_cache_pages(struct address_space *mapping, 
				} else if (ret == -EAGAIN) {

					ret = 0;

					if (wbc->sync_mode == WB_SYNC_ALL) {

						f2fs_io_schedule_timeout(

							DEFAULT_IO_TIMEOUT);

						f2fs_schedule_timeout(

							DEFAULT_SCHEDULE_TIMEOUT);

						goto retry_write;

					}

					goto next;

fs/f2fs/f2fs.h

+15 −7
Original line number Diff line number Diff line
@@ -656,8 +656,8 @@ enum { 


#define DEFAULT_RETRY_IO_COUNT	8	/* maximum retry read IO or flush count */



/* congestion wait timeout value, default: 20ms */

#define	DEFAULT_IO_TIMEOUT	(msecs_to_jiffies(20))

/* IO/non-IO congestion wait timeout value, default: 20ms */

#define	DEFAULT_SCHEDULE_TIMEOUT	(msecs_to_jiffies(20))



/* timeout value injected, default: 1000ms */

#define DEFAULT_FAULT_TIMEOUT	(msecs_to_jiffies(1000))
@@ -4908,22 +4908,30 @@ static inline bool f2fs_block_unit_discard(struct f2fs_sb_info *sbi) 
	return F2FS_OPTION(sbi).discard_unit == DISCARD_UNIT_BLOCK;

}



static inline void f2fs_io_schedule_timeout(long timeout)

static inline void __f2fs_schedule_timeout(long timeout, bool io)

{

	set_current_state(TASK_UNINTERRUPTIBLE);

	if (io)

		io_schedule_timeout(timeout);

	else

		schedule_timeout(timeout);

}



#define f2fs_io_schedule_timeout(timeout)		\

			__f2fs_schedule_timeout(timeout, true)

#define f2fs_schedule_timeout(timeout)			\

			__f2fs_schedule_timeout(timeout, false)



static inline void f2fs_io_schedule_timeout_killable(long timeout)

{

	while (timeout) {

		if (fatal_signal_pending(current))

			return;

		set_current_state(TASK_UNINTERRUPTIBLE);

		io_schedule_timeout(DEFAULT_IO_TIMEOUT);

		if (timeout <= DEFAULT_IO_TIMEOUT)

		io_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);

		if (timeout <= DEFAULT_SCHEDULE_TIMEOUT)

			return;

		timeout -= DEFAULT_IO_TIMEOUT;

		timeout -= DEFAULT_SCHEDULE_TIMEOUT;

	}

}

fs/f2fs/segment.c

+2 −2
Original line number Diff line number Diff line
@@ -750,7 +750,7 @@ int f2fs_flush_device_cache(struct f2fs_sb_info *sbi) 
		do {

			ret = __submit_flush_wait(sbi, FDEV(i).bdev);

			if (ret)

				f2fs_io_schedule_timeout(DEFAULT_IO_TIMEOUT);

				f2fs_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);

		} while (ret && --count);



		if (ret) {
@@ -3471,7 +3471,7 @@ static unsigned int __issue_discard_cmd_range(struct f2fs_sb_info *sbi, 
			blk_finish_plug(&plug);

			mutex_unlock(&dcc->cmd_lock);

			trimmed += __wait_all_discard_cmd(sbi, NULL);

			f2fs_io_schedule_timeout(DEFAULT_IO_TIMEOUT);

			f2fs_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);

			goto next;

		}

skip: