From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B479C43381 for ; Wed, 27 Feb 2019 17:02:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 53A0320823 for ; Wed, 27 Feb 2019 17:02:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726389AbfB0RC3 (ORCPT ); Wed, 27 Feb 2019 12:02:29 -0500 Received: from mx2.suse.de ([195.135.220.15]:34276 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726223AbfB0RC2 (ORCPT ); Wed, 27 Feb 2019 12:02:28 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id D607EAF8F for ; Wed, 27 Feb 2019 17:02:27 +0000 (UTC) Date: Wed, 27 Feb 2019 11:02:25 -0600 From: Goldwyn Rodrigues To: dsterba@suse.cz, linux-btrfs@vger.kernel.org Subject: Re: [PATCH 1/3] btrfs: Initialize btrfs_io_ctl instead of memsetting it Message-ID: <20190227170225.ew57rgkm4linbafj@merlin> References: <20190225190744.21664-1-rgoldwyn@suse.de> <20190227154705.GR24609@twin.jikos.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190227154705.GR24609@twin.jikos.cz> User-Agent: NeoMutt/20180323 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 16:47 27/02, David Sterba wrote: > On Mon, Feb 25, 2019 at 01:07:42PM -0600, Goldwyn Rodrigues wrote: > > From: Goldwyn Rodrigues > > > > io_ctl_init() memsets it to zero anyways. However, I presume the > > memset was added to avoid the WARN_ON in io_ctl_init(). > > I don't see any WARN_ON in io_ctl_init, you probably mean > __btrfs_write_out_cache. Yes, __btrfs_write_out_cache. > > > > Signed-off-by: Goldwyn Rodrigues > > --- > > fs/btrfs/free-space-cache.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c > > index 74aa552f4793..c813378ebf08 100644 > > --- a/fs/btrfs/free-space-cache.c > > +++ b/fs/btrfs/free-space-cache.c > > @@ -3544,13 +3544,12 @@ int btrfs_write_out_ino_cache(struct btrfs_root *root, > > struct btrfs_fs_info *fs_info = root->fs_info; > > struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; > > int ret; > > - struct btrfs_io_ctl io_ctl; > > + struct btrfs_io_ctl io_ctl = {0}; > > Doesn't this zero the bytes unconditionally? The memset below happens > only when the inode cache is on. Yes, but does it matter. I assumed assignment is faster than memset, but a google search says gcc optimization is smart enough now. So, this patch seems irrelevant. -- Goldwyn