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Commit 4dde6ded authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux 

* 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
  writeback: set max_pause to lowest value on zero bdi_dirty
  writeback: permit through good bdi even when global dirty exceeded
  writeback: comment on the bdi dirty threshold
  fs: Make write(2) interruptible by a fatal signal
  writeback: Fix issue on make htmldocs
parents 442ee5a9 82e230a0

fs/fs-writeback.c

+5 −0
Original line number Original line Diff line number Diff line
@@ -156,6 +156,7 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, 
 * bdi_start_writeback - start writeback

 * bdi_start_writeback - start writeback

 * @bdi: the backing device to write from

 * @bdi: the backing device to write from

 * @nr_pages: the number of pages to write

 * @nr_pages: the number of pages to write

 * @reason: reason why some writeback work was initiated

 *

 *

 * Description:

 * Description:

 *   This does WB_SYNC_NONE opportunistic writeback. The IO is only

 *   This does WB_SYNC_NONE opportunistic writeback. The IO is only
@@ -1223,6 +1224,7 @@ static void wait_sb_inodes(struct super_block *sb) 
 * writeback_inodes_sb_nr -	writeback dirty inodes from given super_block

 * writeback_inodes_sb_nr -	writeback dirty inodes from given super_block

 * @sb: the superblock

 * @sb: the superblock

 * @nr: the number of pages to write

 * @nr: the number of pages to write

 * @reason: reason why some writeback work initiated

 *

 *

 * Start writeback on some inodes on this super_block. No guarantees are made

 * Start writeback on some inodes on this super_block. No guarantees are made

 * on how many (if any) will be written, and this function does not wait

 * on how many (if any) will be written, and this function does not wait
@@ -1251,6 +1253,7 @@ EXPORT_SYMBOL(writeback_inodes_sb_nr); 
/**

/**

 * writeback_inodes_sb	-	writeback dirty inodes from given super_block

 * writeback_inodes_sb	-	writeback dirty inodes from given super_block

 * @sb: the superblock

 * @sb: the superblock

 * @reason: reason why some writeback work was initiated

 *

 *

 * Start writeback on some inodes on this super_block. No guarantees are made

 * Start writeback on some inodes on this super_block. No guarantees are made

 * on how many (if any) will be written, and this function does not wait

 * on how many (if any) will be written, and this function does not wait
@@ -1265,6 +1268,7 @@ EXPORT_SYMBOL(writeback_inodes_sb); 
/**

/**

 * writeback_inodes_sb_if_idle	-	start writeback if none underway

 * writeback_inodes_sb_if_idle	-	start writeback if none underway

 * @sb: the superblock

 * @sb: the superblock

 * @reason: reason why some writeback work was initiated

 *

 *

 * Invoke writeback_inodes_sb if no writeback is currently underway.

 * Invoke writeback_inodes_sb if no writeback is currently underway.

 * Returns 1 if writeback was started, 0 if not.

 * Returns 1 if writeback was started, 0 if not.
@@ -1285,6 +1289,7 @@ EXPORT_SYMBOL(writeback_inodes_sb_if_idle); 
 * writeback_inodes_sb_if_idle	-	start writeback if none underway

 * writeback_inodes_sb_if_idle	-	start writeback if none underway

 * @sb: the superblock

 * @sb: the superblock

 * @nr: the number of pages to write

 * @nr: the number of pages to write

 * @reason: reason why some writeback work was initiated

 *

 *

 * Invoke writeback_inodes_sb if no writeback is currently underway.

 * Invoke writeback_inodes_sb if no writeback is currently underway.

 * Returns 1 if writeback was started, 0 if not.

 * Returns 1 if writeback was started, 0 if not.

mm/filemap.c

+4 −2
Original line number Original line Diff line number Diff line
@@ -2407,7 +2407,6 @@ static ssize_t generic_perform_write(struct file *file, 
						iov_iter_count(i));

						iov_iter_count(i));





again:

again:



		/*

		/*

		 * Bring in the user page that we will copy from _first_.

		 * Bring in the user page that we will copy from _first_.

		 * Otherwise there's a nasty deadlock on copying from the

		 * Otherwise there's a nasty deadlock on copying from the
@@ -2463,7 +2462,10 @@ static ssize_t generic_perform_write(struct file *file, 
		written += copied;

		written += copied;





		balance_dirty_pages_ratelimited(mapping);

		balance_dirty_pages_ratelimited(mapping);



		if (fatal_signal_pending(current)) {

			status = -EINTR;

			break;

		}

	} while (iov_iter_count(i));

	} while (iov_iter_count(i));





	return written ? written : status;

	return written ? written : status;

mm/page-writeback.c

+28 −4
Original line number Original line Diff line number Diff line
@@ -411,8 +411,13 @@ void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) 
 *

 *

 * Returns @bdi's dirty limit in pages. The term "dirty" in the context of

 * Returns @bdi's dirty limit in pages. The term "dirty" in the context of

 * dirty balancing includes all PG_dirty, PG_writeback and NFS unstable pages.

 * dirty balancing includes all PG_dirty, PG_writeback and NFS unstable pages.

 * And the "limit" in the name is not seriously taken as hard limit in

 *

 * balance_dirty_pages().

 * Note that balance_dirty_pages() will only seriously take it as a hard limit

 * when sleeping max_pause per page is not enough to keep the dirty pages under

 * control. For example, when the device is completely stalled due to some error

 * conditions, or when there are 1000 dd tasks writing to a slow 10MB/s USB key.

 * In the other normal situations, it acts more gently by throttling the tasks

 * more (rather than completely block them) when the bdi dirty pages go high.

 *

 *

 * It allocates high/low dirty limits to fast/slow devices, in order to prevent

 * It allocates high/low dirty limits to fast/slow devices, in order to prevent

 * - starving fast devices

 * - starving fast devices
@@ -594,6 +599,13 @@ static unsigned long bdi_position_ratio(struct backing_dev_info *bdi, 
	 */

	 */

	if (unlikely(bdi_thresh > thresh))

	if (unlikely(bdi_thresh > thresh))

		bdi_thresh = thresh;

		bdi_thresh = thresh;

	/*

	 * It's very possible that bdi_thresh is close to 0 not because the

	 * device is slow, but that it has remained inactive for long time.

	 * Honour such devices a reasonable good (hopefully IO efficient)

	 * threshold, so that the occasional writes won't be blocked and active

	 * writes can rampup the threshold quickly.

	 */

	bdi_thresh = max(bdi_thresh, (limit - dirty) / 8);

	bdi_thresh = max(bdi_thresh, (limit - dirty) / 8);

	/*

	/*

	 * scale global setpoint to bdi's:

	 * scale global setpoint to bdi's:
@@ -977,7 +989,6 @@ static unsigned long bdi_max_pause(struct backing_dev_info *bdi, 
	 *

	 *

	 * 8 serves as the safety ratio.

	 * 8 serves as the safety ratio.

	 */

	 */

	if (bdi_dirty)

	t = min(t, bdi_dirty * HZ / (8 * bw + 1));

	t = min(t, bdi_dirty * HZ / (8 * bw + 1));





	/*

	/*
@@ -1136,6 +1147,19 @@ static void balance_dirty_pages(struct address_space *mapping, 
		if (task_ratelimit)

		if (task_ratelimit)

			break;

			break;





		/*

		 * In the case of an unresponding NFS server and the NFS dirty

		 * pages exceeds dirty_thresh, give the other good bdi's a pipe

		 * to go through, so that tasks on them still remain responsive.

		 *

		 * In theory 1 page is enough to keep the comsumer-producer

		 * pipe going: the flusher cleans 1 page => the task dirties 1

		 * more page. However bdi_dirty has accounting errors.  So use

		 * the larger and more IO friendly bdi_stat_error.

		 */

		if (bdi_dirty <= bdi_stat_error(bdi))

			break;



		if (fatal_signal_pending(current))

		if (fatal_signal_pending(current))

			break;

			break;

	}

	}