From 5039eddc19aee8c894191c24f2dde4e645ca1bbb Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Wed, 15 Jan 2014 13:34:13 -0500 Subject: Btrfs: make fsync latency less sucky Looking into some performance related issues with large amounts of metadata revealed that we can have some pretty huge swings in fsync() performance. If we have a lot of delayed refs backed up (as you will tend to do with lots of metadata) fsync() will wander off and try to run some of those delayed refs which can result in reading from disk and such. Since the actual act of fsync() doesn't create any delayed refs there is no need to make it throttle on delayed ref stuff, that will be handled by other people. With this patch we get much smoother fsync performance with large amounts of metadata. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/transaction.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/transaction.c') diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index da2ac4c6d78b..b16352ce0f73 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -474,6 +474,7 @@ again: h->type = type; h->allocating_chunk = false; h->reloc_reserved = false; + h->sync = false; INIT_LIST_HEAD(&h->qgroup_ref_list); INIT_LIST_HEAD(&h->new_bgs); @@ -713,7 +714,7 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, btrfs_create_pending_block_groups(trans, root); trans->delayed_ref_updates = 0; - if (btrfs_should_throttle_delayed_refs(trans, root)) { + if (!trans->sync && btrfs_should_throttle_delayed_refs(trans, root)) { cur = max_t(unsigned long, cur, 1); trans->delayed_ref_updates = 0; btrfs_run_delayed_refs(trans, root, cur); -- cgit v1.2.3