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[2620:137:e000::1:20]) by mx.google.com with ESMTP id 127-20020a630185000000b005132381cfb9si9033377pgb.614.2023.04.03.19.01.44; Mon, 03 Apr 2023 19:01:58 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232854AbjDDBmk (ORCPT + 99 others); Mon, 3 Apr 2023 21:42:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232723AbjDDBmh (ORCPT ); Mon, 3 Apr 2023 21:42:37 -0400 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D554B4 for ; Mon, 3 Apr 2023 18:42:36 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.169]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4Pr9Vv6wcxz4f3mVj for ; Tue, 4 Apr 2023 09:42:31 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.127.227]) by APP3 (Coremail) with SMTP id _Ch0CgBH9CGHgCtkmLh6GA--.26422S5; Tue, 04 Apr 2023 09:42:33 +0800 (CST) From: Ye Bin To: dennis@kernel.org, tj@kernel.org, cl@linux.com, linux-mm@kvack.org, yury.norov@gmail.com, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk Cc: linux-kernel@vger.kernel.org, dchinner@redhat.com, yebin10@huawei.com Subject: [PATCH 1/2] cpu/hotplug: introduce 'num_dying_cpus' to get dying CPUs count Date: Tue, 4 Apr 2023 09:42:05 +0800 Message-Id: <20230404014206.3752945-2-yebin@huaweicloud.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20230404014206.3752945-1-yebin@huaweicloud.com> References: <20230404014206.3752945-1-yebin@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: _Ch0CgBH9CGHgCtkmLh6GA--.26422S5 X-Coremail-Antispam: 1UD129KBjvJXoW7WFy8ZFykGrW5KFWDCFy5CFg_yoW5JF4rpr 4UGFW5trWUAFyIga9Yyws8Xr1F9wn5Crn5Gay29F13JFy3Ja4vq3WkuFy5Jr15WrZ3ur1a vrZ0qr409a15Xa7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUB0b4IE77IF4wAFF20E14v26ryj6rWUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUGw A2048vs2IY020Ec7CjxVAFwI0_JFI_Gr1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_ Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82IYc2Ij64 vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8G jcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2I x0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK 8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I 0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUzl1vUUUUU X-CM-SenderInfo: p1hex046kxt4xhlfz01xgou0bp/ X-CFilter-Loop: Reflected X-Spam-Status: No, score=0.0 required=5.0 tests=SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1762209267167688104?= X-GMAIL-MSGID: =?utf-8?q?1762209267167688104?= From: Ye Bin Introduce '__num_dying_cpus' variable to cache the number of dying CPUs in the core and just return the cached variable. Signed-off-by: Ye Bin --- include/linux/cpumask.h | 20 ++++++++++++++++---- kernel/cpu.c | 2 ++ 2 files changed, 18 insertions(+), 4 deletions(-) diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 2a61ddcf8321..8127fd598f51 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -135,6 +135,8 @@ extern struct cpumask __cpu_dying_mask; extern atomic_t __num_online_cpus; +extern atomic_t __num_dying_cpus; + extern cpumask_t cpus_booted_once_mask; static __always_inline void cpu_max_bits_warn(unsigned int cpu, unsigned int bits) @@ -1018,10 +1020,14 @@ set_cpu_active(unsigned int cpu, bool active) static __always_inline void set_cpu_dying(unsigned int cpu, bool dying) { - if (dying) - cpumask_set_cpu(cpu, &__cpu_dying_mask); - else - cpumask_clear_cpu(cpu, &__cpu_dying_mask); + if (dying) { + if (!cpumask_test_and_set_cpu(cpu, &__cpu_dying_mask)) + atomic_inc(&__num_dying_cpus); + } + else { + if (cpumask_test_and_clear_cpu(cpu, &__cpu_dying_mask)) + atomic_dec(&__num_dying_cpus); + } } /** @@ -1073,6 +1079,11 @@ static __always_inline unsigned int num_online_cpus(void) { return arch_atomic_read(&__num_online_cpus); } + +static __always_inline unsigned int num_dying_cpus(void) +{ + return arch_atomic_read(&__num_dying_cpus); +} #define num_possible_cpus() cpumask_weight(cpu_possible_mask) #define num_present_cpus() cpumask_weight(cpu_present_mask) #define num_active_cpus() cpumask_weight(cpu_active_mask) @@ -1108,6 +1119,7 @@ static __always_inline bool cpu_dying(unsigned int cpu) #define num_possible_cpus() 1U #define num_present_cpus() 1U #define num_active_cpus() 1U +#define num_dying_cpus() 0U static __always_inline bool cpu_online(unsigned int cpu) { diff --git a/kernel/cpu.c b/kernel/cpu.c index f4a2c5845bcb..1c96c04cb259 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -2662,6 +2662,8 @@ EXPORT_SYMBOL(__cpu_dying_mask); atomic_t __num_online_cpus __read_mostly; EXPORT_SYMBOL(__num_online_cpus); +atomic_t __num_dying_cpus __read_mostly; + void init_cpu_present(const struct cpumask *src) { cpumask_copy(&__cpu_present_mask, src);