From ac5d156c78a68b39955ee9b09498ba93831c77d7 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Mon, 29 Apr 2013 16:58:39 +0900 Subject: f2fs: modify the number of issued pages to merge IOs When testing f2fs on an SSD, I found some 128 page IOs followed by 1 page IO were issued by f2fs_write_node_pages. This means that there were some mishandling flows which degrades performance. Previous f2fs_write_node_pages determines the number of pages to be written, nr_to_write, as follows. 1. The bio_get_nr_vecs returns 129 pages. 2. The bio_alloc makes a room for 128 pages. 3. The initial 128 pages go into one bio. 4. The existing bio is submitted, and a new bio is prepared for the last 1 page. 5. Finally, sync_node_pages submits the last 1 page bio. The problem is from the use of bio_get_nr_vecs, so this patch replace it with max_hw_blocks using queue_max_sectors. Signed-off-by: Jaegeuk Kim --- fs/f2fs/node.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'fs/f2fs/node.c') diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index f14eb7b8b2c4..7209d637f942 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -1171,7 +1171,6 @@ static int f2fs_write_node_pages(struct address_space *mapping, struct writeback_control *wbc) { struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb); - struct block_device *bdev = sbi->sb->s_bdev; long nr_to_write = wbc->nr_to_write; /* First check balancing cached NAT entries */ @@ -1185,10 +1184,9 @@ static int f2fs_write_node_pages(struct address_space *mapping, return 0; /* if mounting is failed, skip writing node pages */ - wbc->nr_to_write = bio_get_nr_vecs(bdev); + wbc->nr_to_write = max_hw_blocks(sbi); sync_node_pages(sbi, 0, wbc); - wbc->nr_to_write = nr_to_write - - (bio_get_nr_vecs(bdev) - wbc->nr_to_write); + wbc->nr_to_write = nr_to_write - (max_hw_blocks(sbi) - wbc->nr_to_write); return 0; } -- cgit v1.2.2