From 687de7f1010cb819d04b768556960d3689abe02b Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Tue, 28 Mar 2017 18:07:38 -0700 Subject: 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: Jaegeuk Kim --- fs/f2fs/data.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'fs/f2fs/data.c') diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 8f36080b47c4..b1cac6d85bcb 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -1605,8 +1605,10 @@ continue_unlock: last_idx = page->index; } - if (--wbc->nr_to_write <= 0 && - wbc->sync_mode == WB_SYNC_NONE) { + /* 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. -- cgit v1.2.3