writeback: introduce writeback_control.inodes_written (cb9bd115) · Commits · 戴 / test

The flusher works on dirty inodes in batches, and may quit prematurely if the batch of inodes happen to be metadata-only dirtied: in this case wbc->nr_to_write won't be decreased at all, which stands for "no pages written" but also mis-interpreted as "no progress". So introduce writeback_control.inodes_written to count the inodes get cleaned from VFS POV. A non-zero value means there are some progress on writeback, in which case more writeback can be tried. Acked-by:

Jan Kara <jack@suse.cz> Acked-by:

Mel Gorman <mel@csn.ul.ie> Signed-off-by:

Wu Fengguang <fengguang.wu@intel.com>

fs/fs-writeback.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -464,6 +464,7 @@ writeback_single_inode(struct inode inode, struct writeback_control wbc)
		* No need to add it back to the LRU.
		*/
		list_del_init(&inode->i_wb_list);
		wbc->inodes_written++;
		}
		}
		inode_sync_complete(inode);
		@@ -725,6 +726,7 @@ static long wb_writeback(struct bdi_writeback *wb,
		wbc.more_io = 0;
		wbc.nr_to_write = write_chunk;
		wbc.pages_skipped = 0;
		wbc.inodes_written = 0;

		trace_wbc_writeback_start(&wbc, wb->bdi);
		if (work->sb)
		@@ -741,6 +743,8 @@ static long wb_writeback(struct bdi_writeback *wb,
		*/
		if (wbc.nr_to_write <= 0)
		continue;
		if (wbc.inodes_written)
		continue;
		/*
		* Didn't write everything and we don't have more IO, bail
		*/

include/linux/writeback.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -34,6 +34,7 @@ struct writeback_control {
		long nr_to_write; /* Write this many pages, and decrement
		this for each page written */
		long pages_skipped; /* Pages which were not written */
		long inodes_written; /* # of inodes written (at least) */

		/*
		* For a_ops->writepages(): is start or end are non-zero then this is

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