From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756601Ab3EFUkG (ORCPT ); Mon, 6 May 2013 16:40:06 -0400 Received: from mail-yh0-f43.google.com ([209.85.213.43]:35074 "EHLO mail-yh0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756251Ab3EFUkD (ORCPT ); Mon, 6 May 2013 16:40:03 -0400 Date: Mon, 6 May 2013 13:39:59 -0700 From: Tejun Heo To: Vivek Goyal Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org, lizefan@huawei.com, containers@lists.linux-foundation.org, cgroups@vger.kernel.org Subject: Re: [PATCH 21/31] blk-throttle: implement sq_to_tg(), sq_to_td() and throtl_log() Message-ID: <20130506203959.GF800@mtj.dyndns.org> References: <1367455189-6957-1-git-send-email-tj@kernel.org> <1367455189-6957-22-git-send-email-tj@kernel.org> <20130506173644.GD11731@redhat.com> <20130506203827.GE800@mtj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130506203827.GE800@mtj.dyndns.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 06, 2013 at 01:38:27PM -0700, Tejun Heo wrote: > On Mon, May 06, 2013 at 01:36:44PM -0400, Vivek Goyal wrote: > > On Wed, May 01, 2013 at 05:39:39PM -0700, Tejun Heo wrote: > > > > [..] > > > +#define throtl_log(sq, fmt, args...) do { \ > > > + struct throtl_grp *__tg = sq_to_tg((sq)); \ > > > + struct throtl_data *__td = sq_to_td((sq)); \ > > > char __pbuf[128]; \ > > > \ > > > - blkg_path(tg_to_blkg(tg), __pbuf, sizeof(__pbuf)); \ > > > - blk_add_trace_msg((tg)->td->queue, "throtl %s " fmt, __pbuf, ##args); \ > > > + __pbuf[0] = ' '; \ > > > + __pbuf[1] = '\0'; \ > > > + if ((__tg)) \ > > > + blkg_path(tg_to_blkg(__tg), __pbuf + 1, sizeof(__pbuf) - 1); \ > > > + blk_add_trace_msg(__td->queue, "throtl%s" fmt, __pbuf, ##args); \ > > > > We need one extra space ("throtl%s "), otherwise all the messages > > start right after cgroup path. We need a space between cgroup path > > and actual message. > > Okay, we don't - __pbuf[0] = ' '. The reason it's doing the above > instead of "throtl %s " is because when the path is nil, we don't > wanna print out two consecutive spaces, so AFAICS the code is correct. Oops, I was wrong again, you mean after '%s'. Yeah, right. I need to change it so that it does __pbuf[0] = '\0' if no path and add space after '%s'. Updating... Sorry about the confusion. -- tejun