Commit 687de7f1 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: avoid IO split due to mixed WB_SYNC_ALL and WB_SYNC_NONE 



If two threads try to flush dirty pages in different inodes respectively,
f2fs_write_data_pages() will produce WRITE and WRITE_SYNC one at a time,
resulting in a lot of 4KB seperated IOs.

So, this patch gives higher priority to WB_SYNC_ALL IOs and gathers write
IOs with a big WRITE_SYNC'ed bio.

Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent ef095d19

fs/f2fs/data.c

+13 −2
Original line number Diff line number Diff line
@@ -1605,7 +1605,9 @@ continue_unlock: 
				last_idx = page->index;

			}



			if (--wbc->nr_to_write <= 0 &&

			/* give a priority to WB_SYNC threads */

			if ((atomic_read(&F2FS_M_SB(mapping)->wb_sync_req) ||

					--wbc->nr_to_write <= 0) &&

					wbc->sync_mode == WB_SYNC_NONE) {

				done = 1;

				break;
@@ -1662,9 +1664,18 @@ static int f2fs_write_data_pages(struct address_space *mapping, 


	trace_f2fs_writepages(mapping->host, wbc, DATA);



	/* to avoid spliting IOs due to mixed WB_SYNC_ALL and WB_SYNC_NONE */

	if (wbc->sync_mode == WB_SYNC_ALL)

		atomic_inc(&sbi->wb_sync_req);

	else if (atomic_read(&sbi->wb_sync_req))

		goto skip_write;



	blk_start_plug(&plug);

	ret = f2fs_write_cache_pages(mapping, wbc);

	blk_finish_plug(&plug);



	if (wbc->sync_mode == WB_SYNC_ALL)

		atomic_dec(&sbi->wb_sync_req);

	/*

	 * if some pages were truncated, we cannot guarantee its mapping->host

	 * to detect pending bios.

fs/f2fs/f2fs.h

+3 −0
Original line number Diff line number Diff line
@@ -887,6 +887,9 @@ struct f2fs_sb_info { 
	/* # of allocated blocks */

	struct percpu_counter alloc_valid_block_count;



	/* writeback control */

	atomic_t wb_sync_req;			/* count # of WB_SYNC threads */



	/* valid inode count */

	struct percpu_counter total_valid_inode_count;

fs/f2fs/super.c

+2 −0
Original line number Diff line number Diff line
@@ -1566,6 +1566,8 @@ static void init_sb_info(struct f2fs_sb_info *sbi) 
	for (i = 0; i < NR_COUNT_TYPE; i++)

		atomic_set(&sbi->nr_pages[i], 0);



	atomic_set(&sbi->wb_sync_req, 0);



	INIT_LIST_HEAD(&sbi->s_list);

	mutex_init(&sbi->umount_mutex);

	mutex_init(&sbi->wio_mutex[NODE]);

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