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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87F99C4332F for ; Wed, 8 Nov 2023 11:02:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344242AbjKHLC1 (ORCPT ); Wed, 8 Nov 2023 06:02:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235571AbjKHLC0 (ORCPT ); Wed, 8 Nov 2023 06:02:26 -0500 Received: from out-189.mta1.migadu.com (out-189.mta1.migadu.com [95.215.58.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A9B42101 for ; Wed, 8 Nov 2023 03:02:24 -0800 (PST) Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1699441342; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lrsGIeSPv8adeJPVKHQwa6CAoZZ5O1YM+LcVCeqgST0=; b=uhRHZ41eWkbVGNq6qeIC+gwENJ3O0sOoFBlonVzAzmGoIAsfS0crQYHoCxeSl82r8pi8Ls rHLCv+WGo4gtzEsM/Y21o5PVMKQ+M6wh7bE1LT8LHV0T9GSJHJ62UX4iVJ12DYvGSww65i jYmCJ+twtPKib4xK4sfnuuq0F9JLR5U= Date: Wed, 8 Nov 2023 19:02:14 +0800 MIME-Version: 1.0 Subject: Re: [PATCH] sched/rt: Redefine RR_TIMESLICE to 100 msecs To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com Cc: linux-kernel@vger.kernel.org References: <20231018081709.2289264-1-yajun.deng@linux.dev> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yajun Deng In-Reply-To: <20231018081709.2289264-1-yajun.deng@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Kindly ping... Thanks On 2023/10/18 16:17, Yajun Deng wrote: > The RR_TIMESLICE is currently defined as the jiffies corresponding to > 100 msecs. And then sysctl_sched_rr_timeslice will convert RR_TIMESLICE > to 100 msecs. These are opposite calculations. > > There are msecs_to_jiffies and jiffies_to_msecs in sched_rr_handler. > These are also opposite calculations. > > Redefine RR_TIMESLICE to 100 msecs, only sched_rr_timeslice needs to > convert RR_TIMESLICE to jiffies. > > Signed-off-by: Yajun Deng > --- > include/linux/sched/rt.h | 2 +- > init/init_task.c | 2 +- > kernel/sched/rt.c | 12 +++++------- > 3 files changed, 7 insertions(+), 9 deletions(-) > > diff --git a/include/linux/sched/rt.h b/include/linux/sched/rt.h > index b2b9e6eb9683..74f8f456a804 100644 > --- a/include/linux/sched/rt.h > +++ b/include/linux/sched/rt.h > @@ -58,6 +58,6 @@ extern void normalize_rt_tasks(void); > * default timeslice is 100 msecs (used only for SCHED_RR tasks). > * Timeslices get refilled after they expire. > */ > -#define RR_TIMESLICE (100 * HZ / 1000) > +#define RR_TIMESLICE (100) > > #endif /* _LINUX_SCHED_RT_H */ > diff --git a/init/init_task.c b/init/init_task.c > index 5727d42149c3..86619a425342 100644 > --- a/init/init_task.c > +++ b/init/init_task.c > @@ -94,7 +94,7 @@ struct task_struct init_task > }, > .rt = { > .run_list = LIST_HEAD_INIT(init_task.rt.run_list), > - .time_slice = RR_TIMESLICE, > + .time_slice = (RR_TIMESLICE * HZ) / MSEC_PER_SEC, > }, > .tasks = LIST_HEAD_INIT(init_task.tasks), > #ifdef CONFIG_SMP > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index 6aaf0a3d6081..7c0e912094a9 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -4,7 +4,7 @@ > * policies) > */ > > -int sched_rr_timeslice = RR_TIMESLICE; > +int sched_rr_timeslice = (RR_TIMESLICE * HZ) / MSEC_PER_SEC; > /* More than 4 hours if BW_SHIFT equals 20. */ > static const u64 max_rt_runtime = MAX_BW; > > @@ -25,7 +25,7 @@ int sysctl_sched_rt_period = 1000000; > int sysctl_sched_rt_runtime = 950000; > > #ifdef CONFIG_SYSCTL > -static int sysctl_sched_rr_timeslice = (MSEC_PER_SEC * RR_TIMESLICE) / HZ; > +static int sysctl_sched_rr_timeslice = RR_TIMESLICE; > static int sched_rt_handler(struct ctl_table *table, int write, void *buffer, > size_t *lenp, loff_t *ppos); > static int sched_rr_handler(struct ctl_table *table, int write, void *buffer, > @@ -3014,12 +3014,10 @@ static int sched_rr_handler(struct ctl_table *table, int write, void *buffer, > * Also, writing zero resets the timeslice to default: > */ > if (!ret && write) { > - sched_rr_timeslice = > - sysctl_sched_rr_timeslice <= 0 ? RR_TIMESLICE : > - msecs_to_jiffies(sysctl_sched_rr_timeslice); > - > if (sysctl_sched_rr_timeslice <= 0) > - sysctl_sched_rr_timeslice = jiffies_to_msecs(RR_TIMESLICE); > + sysctl_sched_rr_timeslice = RR_TIMESLICE; > + > + sched_rr_timeslice = msecs_to_jiffies(sysctl_sched_rr_timeslice); > } > mutex_unlock(&mutex); >