From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from fgwmail3.fujitsu.co.jp ([164.71.1.134]:58711 "EHLO fgwmail4.fujitsu.co.jp" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754881AbaFQFLY (ORCPT ); Tue, 17 Jun 2014 01:11:24 -0400 Received: from fgwmail.fujitsu.co.jp (fgwmail.fujitsu.co.jp [164.71.1.133]) by fgwmail4.fujitsu.co.jp (Postfix) with ESMTP id ADE15178C261 for ; Tue, 17 Jun 2014 14:03:10 +0900 (JST) Received: from kw-mxoi2.gw.nic.fujitsu.com (unknown [10.0.237.143]) by fgwmail.fujitsu.co.jp (Postfix) with ESMTP id A39443EE0C2 for ; Tue, 17 Jun 2014 14:02:59 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.nic.fujitsu.com [10.0.50.91]) by kw-mxoi2.gw.nic.fujitsu.com (Postfix) with ESMTP id 61BE3AC0272 for ; Tue, 17 Jun 2014 14:02:58 +0900 (JST) Received: from g01jpfmpwyt03.exch.g01.fujitsu.local (g01jpfmpwyt03.exch.g01.fujitsu.local [10.128.193.57]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 0F5021DB8050 for ; Tue, 17 Jun 2014 14:02:58 +0900 (JST) Message-ID: <539FCBED.6010600@jp.fujitsu.com> Date: Tue, 17 Jun 2014 14:02:37 +0900 From: Satoru Takeuchi MIME-Version: 1.0 To: Filipe David Borba Manana , CC: Chris Mason Subject: Re: [PATCH] Btrfs: remove unused wait queue in struct extent_buffer References: <1402920865-3120-1-git-send-email-fdmanana@gmail.com> In-Reply-To: <1402920865-3120-1-git-send-email-fdmanana@gmail.com> Content-Type: text/plain; charset="ISO-2022-JP" Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hi Filipe, (2014/06/16 21:14), Filipe David Borba Manana wrote: > The lock_wq wait queue is not used anywhere, therefore just remove it. > On a x86_64 system, this reduced sizeof(struct extent_buffer) from 320 > bytes down to 296 bytes, which means a 4Kb page can now be used for > 13 extent buffers instead of 12. > > Signed-off-by: Filipe David Borba Manana It looks good to me. This field was once removed by bd681513. However, re-introduced in error by 727011e07c (both are Chris's patch). I consider it's better to fix the following comment too. === $ cat -n fs/btrfs/extent_io.h | grep -B 3 write_lock_wq 152 /* readers use lock_wq while they wait for the write 153 * lock holders to unlock 154 */ 155 wait_queue_head_t write_lock_wq; === We should "s/ lock_wq / write_lock_wq /" here. Thanks, Satoru > --- > fs/btrfs/extent_io.h | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h > index 8b63f2d..dbbea4f 100644 > --- a/fs/btrfs/extent_io.h > +++ b/fs/btrfs/extent_io.h > @@ -158,7 +158,6 @@ struct extent_buffer { > * to unlock > */ > wait_queue_head_t read_lock_wq; > - wait_queue_head_t lock_wq; > struct page *pages[INLINE_EXTENT_BUFFER_PAGES]; > #ifdef CONFIG_BTRFS_DEBUG > struct list_head leak_list; >