From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753583AbaCKJgX (ORCPT ); Tue, 11 Mar 2014 05:36:23 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:33791 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752382AbaCKJgV (ORCPT ); Tue, 11 Mar 2014 05:36:21 -0400 X-IronPort-AV: E=Sophos;i="4.97,629,1389715200"; d="scan'208";a="9678097" Message-ID: <531ED89C.4050408@cn.fujitsu.com> Date: Tue, 11 Mar 2014 17:34:20 +0800 From: Dongsheng Yang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130612 Thunderbird/17.0.6 MIME-Version: 1.0 To: Peter Zijlstra CC: linux-kernel@vger.kernel.org, joe@perches.com, mingo@kernel.org, tglx@linutronix.de, heiko.carstens@de.ibm.com, Jens Axboe Subject: Re: [PATCH 07/16] ioprio: Add a macro named NICE_TO_IOPRIO. References: <008cf8bba167646424d0fca68d96463feace2aee.1394529373.git.yangds.fnst@cn.fujitsu.com> <20140311092856.GU9987@twins.programming.kicks-ass.net> In-Reply-To: <20140311092856.GU9987@twins.programming.kicks-ass.net> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2014/03/11 17:33:28, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2014/03/11 17:33:35, Serialize complete at 2014/03/11 17:33:35 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/11/2014 05:28 PM, Peter Zijlstra wrote: > On Tue, Mar 11, 2014 at 05:20:28PM +0800, Dongsheng Yang wrote: >> As the task nice value is in [-20, 19] and the io priority is in [0, 7], >> and the convert method from niceval to ioprio is implemented with an >> opened code in task_nice_ioprio(). >> >> This patch move the implementation to a macro NICE_TO_IOPRIO, making >> it more readable and modular. >> >> Signed-off-by: Dongsheng Yang >> --- >> include/linux/ioprio.h | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/include/linux/ioprio.h b/include/linux/ioprio.h >> index beb9ce1..c0faa0b 100644 >> --- a/include/linux/ioprio.h >> +++ b/include/linux/ioprio.h >> @@ -18,6 +18,11 @@ >> #define ioprio_valid(mask) (IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE) >> >> /* >> + * Convert the nice value [19,-20] to io priority value [0,7]. >> + */ >> +#define NICE_TO_IOPRIO(nice) (nice_to_rlimit(nice) / 5) >> + >> +/* >> * These are the io priority groups as implemented by CFQ. RT is the realtime >> * class, it always gets premium service. BE is the best-effort scheduling >> * class, the default for any process. IDLE is the idle scheduling class, it >> @@ -52,7 +57,7 @@ enum { >> */ >> static inline int task_nice_ioprio(struct task_struct *task) >> { >> - return (task_nice(task) + 20) / 5; >> + return NICE_TO_IOPRIO(task_nice(task)); >> } > How exactly is adding a macro and code complexity making this code > better? About this patch, I think convert a nice value in [-20, 19] to ioprio in [0, 7] is a common requirement. So I add a macro NICE_TO_IOPRIO to achieve it. > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >