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 7145FC54EE9 for ; Wed, 28 Sep 2022 01:24:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229771AbiI1BYP (ORCPT ); Tue, 27 Sep 2022 21:24:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229907AbiI1BYP (ORCPT ); Tue, 27 Sep 2022 21:24:15 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A5EB188BEA for ; Tue, 27 Sep 2022 18:24:13 -0700 (PDT) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Mcdvb4flXzlVjC; Wed, 28 Sep 2022 09:19:55 +0800 (CST) Received: from dggpemm500016.china.huawei.com (7.185.36.25) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 28 Sep 2022 09:24:11 +0800 Received: from [10.67.111.115] (10.67.111.115) by dggpemm500016.china.huawei.com (7.185.36.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 28 Sep 2022 09:24:11 +0800 Message-ID: <9b142399-7968-2300-24c4-5a60cee76ec3@huawei.com> Date: Wed, 28 Sep 2022 09:24:10 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.0.3 Subject: Re: [PATCH] rcu: remove rcu_is_idle_cpu To: , Frederic Weisbecker CC: , , , , , , , , References: <20220926015827.227050-1-zouyipeng@huawei.com> <20220926203629.GA183228@lothringen> <20220927185121.GU4196@paulmck-ThinkPad-P17-Gen-1> Content-Language: en-US From: Yipeng Zou In-Reply-To: <20220927185121.GU4196@paulmck-ThinkPad-P17-Gen-1> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.67.111.115] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500016.china.huawei.com (7.185.36.25) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org 在 2022/9/28 2:51, Paul E. McKenney 写道: > On Mon, Sep 26, 2022 at 10:36:29PM +0200, Frederic Weisbecker wrote: >> On Mon, Sep 26, 2022 at 09:58:27AM +0800, Yipeng Zou wrote: >>> The commit "x86/cpu: Avoid cpuinfo-induced IPIing of idle CPUs" introduce >>> this function to identify the current CPU idle state. >>> But after commit "x86/aperfmperf: Replace arch_freq_get_on_cpu()" we >>> just use MAX_SAMPLE_AGE to do that, So there is no use of this function. >>> >>> Fixes: f3eca381bd49 ("x86/aperfmperf: Replace arch_freq_get_on_cpu()") >>> Signed-off-by: Yipeng Zou >> Reviewed-by: Frederic Weisbecker > Good eyes, Yipeng! Queued and pushed, thank you both! > > As usual, I could not resist the urge to wordsmith, so please check the > patch below and let me know if I messed something up. Its all good, and thanks for review. > And please include both commit IDs in future patches with the > formatting shows below. Makes it easier for me to accept your > patches, after all. ;-) ok，got it. > > Thanx, Paul > > ------------------------------------------------------------------------ > > commit f8b389c24cf9a523472e3e505815b26f0174856c > Author: Yipeng Zou > Date: Mon Sep 26 09:58:27 2022 +0800 > > rcu: Remove rcu_is_idle_cpu() > > The commit 3fcd6a230fa7 ("x86/cpu: Avoid cpuinfo-induced IPIing of > idle CPUs") introduced rcu_is_idle_cpu() in order to identify the > current CPU idle state. But commit f3eca381bd49 ("x86/aperfmperf: > Replace arch_freq_get_on_cpu()") switched to using MAX_SAMPLE_AGE, > so rcu_is_idle_cpu() is no longer used. This commit therefore removes it. > > Fixes: f3eca381bd49 ("x86/aperfmperf: Replace arch_freq_get_on_cpu()") > Signed-off-by: Yipeng Zou > Reviewed-by: Frederic Weisbecker > Signed-off-by: Paul E. McKenney > > diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h > index 84e930c11065..93485b812712 100644 > --- a/include/linux/rcutiny.h > +++ b/include/linux/rcutiny.h > @@ -146,8 +146,6 @@ static inline void rcu_virt_note_context_switch(void) { } > static inline void rcu_cpu_stall_reset(void) { } > static inline int rcu_jiffies_till_stall_check(void) { return 21 * HZ; } > static inline void rcu_irq_exit_check_preempt(void) { } > -#define rcu_is_idle_cpu(cpu) \ > - (is_idle_task(current) && !in_nmi() && !in_hardirq() && !in_serving_softirq()) > static inline void exit_rcu(void) { } > static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t) > { > diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h > index 3066e0975022..f41c4ab2a884 100644 > --- a/include/linux/rcutree.h > +++ b/include/linux/rcutree.h > @@ -87,8 +87,6 @@ bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp); > void cond_synchronize_rcu(unsigned long oldstate); > void cond_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp); > > -bool rcu_is_idle_cpu(int cpu); > - > #ifdef CONFIG_PROVE_RCU > void rcu_irq_exit_check_preempt(void); > #else > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index 1930cee1ccdb..96d678c9cfb6 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -301,12 +301,6 @@ static bool rcu_dynticks_in_eqs(int snap) > return !(snap & RCU_DYNTICKS_IDX); > } > > -/* Return true if the specified CPU is currently idle from an RCU viewpoint. */ > -bool rcu_is_idle_cpu(int cpu) > -{ > - return rcu_dynticks_in_eqs(rcu_dynticks_snap(cpu)); > -} > - > /* > * Return true if the CPU corresponding to the specified rcu_data > * structure has spent some time in an extended quiescent state since -- Regards, Yipeng Zou