From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f173.google.com ([209.85.212.173]:41997 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932095Ab3KVQxF (ORCPT ); Fri, 22 Nov 2013 11:53:05 -0500 Received: by mail-wi0-f173.google.com with SMTP id hm4so1012466wib.12 for ; Fri, 22 Nov 2013 08:53:03 -0800 (PST) From: Filipe David Borba Manana To: linux-btrfs@vger.kernel.org Cc: Filipe David Borba Manana Subject: [PATCH] Btrfs: avoid unnecessary ordered extent cache resets Date: Fri, 22 Nov 2013 16:52:43 +0000 Message-Id: <1385139163-7539-1-git-send-email-fdmanana@gmail.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: After an ordered extent completes, don't blindly reset the inode's ordered tree last accessed ordered extent pointer. While running the xfstests I noticed that about 29% of the time the ordered extent to which tree->last pointed was not the same as our just completed ordered extent. After that I ran the following sysbench test (after a prepare phase) and noticed that about 68% of the time tree->last pointed to a different ordered extent too. sysbench --test=fileio --file-num=32 --file-total-size=4G \ --file-test-mode=rndwr --num-threads=512 \ --file-block-size=32768 --max-time=60 --max-requests=0 run Therefore reset tree->last on ordered extent removal only if it pointed to the ordered extent we're removing from the tree. Signed-off-by: Filipe David Borba Manana --- fs/btrfs/ordered-data.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c index 69582d5..b8c2ded 100644 --- a/fs/btrfs/ordered-data.c +++ b/fs/btrfs/ordered-data.c @@ -520,7 +520,8 @@ void btrfs_remove_ordered_extent(struct inode *inode, spin_lock_irq(&tree->lock); node = &entry->rb_node; rb_erase(node, &tree->tree); - tree->last = NULL; + if (tree->last == node) + tree->last = NULL; set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags); spin_unlock_irq(&tree->lock); -- 1.7.9.5