From 2299432e1950c9ac0aa649d4617374ea24b6f131 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 4 Mar 2014 11:52:16 +0100 Subject: [PATCH] ext3: Speedup WB_SYNC_ALL pass When doing filesystem wide sync, there's no need to force transaction commit separately for each inode because ext3_sync_fs() takes care of forcing commit at the end. Most of the time this slowness doesn't manifest because previous WB_SYNC_NONE writeback doesn't leave much to write but when there are processes aggressively creating new files and several filesystems to sync, the sync slowness can be noticeable. In the following test script sync(1) takes around 6 minutes when there are two ext3 filesystems mounted on a standard SATA drive. After this patch sync is about twice as fast in the default data=ordered mode. For data=writeback mode we have even bigger speedup. function run_writers { for (( i = 0; i < 10; i++ )); do mkdir $1/dir$i for (( j = 0; j < 40000; j++ )); do dd if=/dev/zero of=$1/dir$i/$j bs=4k count=4 &>/dev/null done & done } for dir in "$@"; do run_writers $dir done sleep 40 time sync Signed-off-by: Jan Kara --- fs/ext3/inode.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c index 4ecf88fb69a8..ddf5c21cffbc 100644 --- a/fs/ext3/inode.c +++ b/fs/ext3/inode.c @@ -3210,7 +3210,12 @@ int ext3_write_inode(struct inode *inode, struct writeback_control *wbc) return -EIO; } - if (wbc->sync_mode != WB_SYNC_ALL) + /* + * No need to force transaction in WB_SYNC_NONE mode. Also + * ext3_sync_fs() will force the commit after everything is + * written. + */ + if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync) return 0; return ext3_force_commit(inode->i_sb);