From patchwork Fri Apr 6 08:11:04 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 10325769 X-Patchwork-Delegate: rjw@sisk.pl Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5BBD26053F for ; Fri, 6 Apr 2018 08:10:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4A140294AD for ; Fri, 6 Apr 2018 08:10:59 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3B841294B1; Fri, 6 Apr 2018 08:10:59 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6C6CC294AD for ; Fri, 6 Apr 2018 08:10:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751312AbeDFIK5 (ORCPT ); Fri, 6 Apr 2018 04:10:57 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:53072 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751298AbeDFIKy (ORCPT ); Fri, 6 Apr 2018 04:10:54 -0400 Received: from 79.184.255.92.ipv4.supernova.orange.pl (79.184.255.92) (HELO aspire.rjw.lan) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83) id 7e8d7ea7b48e261f; Fri, 6 Apr 2018 10:10:52 +0200 From: "Rafael J. Wysocki" To: Frederic Weisbecker Cc: Linux PM , Peter Zijlstra , Frederic Weisbecker , Thomas Gleixner , Paul McKenney , Thomas Ilsche , Doug Smythies , Rik van Riel , Aubrey Li , Mike Galbraith , LKML , Len Brown Subject: Re: [PATCH v9 05/10] cpuidle: Return nohz hint from cpuidle_select() Date: Fri, 06 Apr 2018 10:11:04 +0200 Message-ID: <6471749.luEdDuCiOl@aspire.rjw.lan> In-Reply-To: <20180406024413.GB4400@lerouge> References: <1736751.LdhZHb50jq@aspire.rjw.lan> <5818594.T4StF86Hkt@aspire.rjw.lan> <20180406024413.GB4400@lerouge> MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On Friday, April 6, 2018 4:44:14 AM CEST Frederic Weisbecker wrote: > On Wed, Apr 04, 2018 at 10:39:50AM +0200, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki > > Index: linux-pm/kernel/time/tick-sched.c > > =================================================================== > > --- linux-pm.orig/kernel/time/tick-sched.c > > +++ linux-pm/kernel/time/tick-sched.c > > @@ -991,6 +991,20 @@ void tick_nohz_irq_exit(void) > > } > > > > /** > > + * tick_nohz_idle_got_tick - Check whether or not the tick handler has run > > + */ > > +bool tick_nohz_idle_got_tick(void) > > +{ > > + struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched); > > + > > + if (ts->inidle > 1) { > > + ts->inidle = 1; > > + return true; > > + } > > + return false; > > +} > > + > > +/** > > * tick_nohz_get_sleep_length - return the length of the current sleep > > * > > * Called from power state control code with interrupts disabled > > @@ -1101,6 +1115,9 @@ static void tick_nohz_handler(struct clo > > struct pt_regs *regs = get_irq_regs(); > > ktime_t now = ktime_get(); > > > > + if (ts->inidle) > > + ts->inidle = 2; > > + > > You can move that to tick_sched_do_timer() to avoid code duplication. > > Also these constants are very opaque. And even with proper symbols it wouldn't look > right to extend ts->inidle that way. > > Perhaps you should add a field such as ts->got_idle_tick under the boolean fields > after the below patch: > > -- > From c7b2ca5a4c512517ddfeb9f922d5999f82542ced Mon Sep 17 00:00:00 2001 > From: Frederic Weisbecker > Date: Fri, 6 Apr 2018 04:32:37 +0200 > Subject: [PATCH] nohz: Gather tick_sched booleans under a common flag field > > This optimize the space and leave plenty of room for further flags. > > Signed-off-by: Frederic Weisbecker > --- > kernel/time/tick-sched.h | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/kernel/time/tick-sched.h b/kernel/time/tick-sched.h > index 954b43d..38f24dc 100644 > --- a/kernel/time/tick-sched.h > +++ b/kernel/time/tick-sched.h > @@ -45,14 +45,17 @@ struct tick_sched { > struct hrtimer sched_timer; > unsigned long check_clocks; > enum tick_nohz_mode nohz_mode; > + > + unsigned int inidle : 1; > + unsigned int tick_stopped : 1; This particular change breaks build, because tick_stopped is accessed via __this_cpu_read() in tick_nohz_tick_stopped(). > + unsigned int idle_active : 1; > + unsigned int do_timer_last : 1; > + > ktime_t last_tick; > ktime_t next_tick; > - int inidle; > - int tick_stopped; > unsigned long idle_jiffies; > unsigned long idle_calls; > unsigned long idle_sleeps; > - int idle_active; > ktime_t idle_entrytime; > ktime_t idle_waketime; > ktime_t idle_exittime; > @@ -62,7 +65,6 @@ struct tick_sched { > unsigned long last_jiffies; > u64 next_timer; > ktime_t idle_expires; > - int do_timer_last; > atomic_t tick_dep_mask; > }; > > So what about this? And moving the duplicated piece of got_idle_tick manipulation on top of it? --- From: Frederic Weisbecker Subject: [PATCH] nohz: Gather tick_sched booleans under a common flag field Optimize the space and leave plenty of room for further flags. Signed-off-by: Frederic Weisbecker [ rjw: Do not use __this_cpu_read() to access tick_stopped and add got_idle_tick to avoid overloading inidle ] Signed-off-by: Rafael J. Wysocki --- kernel/time/tick-sched.c | 12 +++++++----- kernel/time/tick-sched.h | 12 ++++++++---- 2 files changed, 15 insertions(+), 9 deletions(-) Index: linux-pm/kernel/time/tick-sched.h =================================================================== --- linux-pm.orig/kernel/time/tick-sched.h +++ linux-pm/kernel/time/tick-sched.h @@ -41,19 +41,24 @@ enum tick_nohz_mode { * @timer_expires: Anticipated timer expiration time (in case sched tick is stopped) * @timer_expires_base: Base time clock monotonic for @timer_expires * @do_timer_lst: CPU was the last one doing do_timer before going idle + * @got_idle_tick: Tick timer function has run with @inidle set */ struct tick_sched { struct hrtimer sched_timer; unsigned long check_clocks; enum tick_nohz_mode nohz_mode; + + unsigned int inidle : 1; + unsigned int tick_stopped : 1; + unsigned int idle_active : 1; + unsigned int do_timer_last : 1; + unsigned int got_idle_tick : 1; + ktime_t last_tick; ktime_t next_tick; - int inidle; - int tick_stopped; unsigned long idle_jiffies; unsigned long idle_calls; unsigned long idle_sleeps; - int idle_active; ktime_t idle_entrytime; ktime_t idle_waketime; ktime_t idle_exittime; @@ -64,7 +69,6 @@ struct tick_sched { u64 timer_expires_base; u64 next_timer; ktime_t idle_expires; - int do_timer_last; atomic_t tick_dep_mask; }; Index: linux-pm/kernel/time/tick-sched.c =================================================================== --- linux-pm.orig/kernel/time/tick-sched.c +++ linux-pm/kernel/time/tick-sched.c @@ -465,7 +465,9 @@ __setup("nohz=", setup_tick_nohz); bool tick_nohz_tick_stopped(void) { - return __this_cpu_read(tick_cpu_sched.tick_stopped); + struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched); + + return ts->tick_stopped; } bool tick_nohz_tick_stopped_cpu(int cpu) @@ -1014,8 +1016,8 @@ bool tick_nohz_idle_got_tick(void) { struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched); - if (ts->inidle > 1) { - ts->inidle = 1; + if (ts->got_idle_tick) { + ts->got_idle_tick = 0; return true; } return false; @@ -1161,7 +1163,7 @@ static void tick_nohz_handler(struct clo ktime_t now = ktime_get(); if (ts->inidle) - ts->inidle = 2; + ts->got_idle_tick = 1; dev->next_event = KTIME_MAX; @@ -1261,7 +1263,7 @@ static enum hrtimer_restart tick_sched_t ktime_t now = ktime_get(); if (ts->inidle) - ts->inidle = 2; + ts->got_idle_tick = 1; tick_sched_do_timer(now);