From patchwork Tue Oct 15 02:18:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yicong Yang X-Patchwork-Id: 13835673 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3C711CFC505 for ; Tue, 15 Oct 2024 02:25:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=yxMQkFNJOuqgt5TZoJ5crdWj69vXOCSCWIGzmUSCNws=; b=B1Vo0r9CAYLcljFcbV4OAk95rh LOt1tH3TncQ3fpfqjeU37dMFU9HHLLlVf627BFv2q2XUqeWQu5Q4ulvvqVtD070lZy5pcrCQb0CQN rSrK3UxtRTJxmWt1MnfNny0yR8Dnz6LOOYw8Qw01E3WEAPCPVSzlyqkLcitWZQX3B7MEDqrYYsFW/ tmtmixWcvFjr8E/w7z+LVG0GYu65zbnb1zDJkTTviayuy9fFOPd8XR8CvYgdRPnnsJHFJ5ZNwt+V4 llQsEH5UA49AEOiTpjtVN00oftsZRdWiM1uf2khDVs26ciYVvycX28rOHNDhQw6vG9tOv+YrWEScW FxJ4Q6mA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t0XEx-00000006sYi-1mYP; Tue, 15 Oct 2024 02:24:51 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t0X9T-00000006rc8-3r0s for linux-arm-kernel@lists.infradead.org; Tue, 15 Oct 2024 02:19:14 +0000 Received: from mail.maildlp.com (unknown [172.19.88.214]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4XSHjg49Wgz1HL2y; Tue, 15 Oct 2024 10:14:47 +0800 (CST) Received: from kwepemd200014.china.huawei.com (unknown [7.221.188.8]) by mail.maildlp.com (Postfix) with ESMTPS id 6D5901A016C; Tue, 15 Oct 2024 10:18:59 +0800 (CST) Received: from localhost.localdomain (10.50.165.33) by kwepemd200014.china.huawei.com (7.221.188.8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.34; Tue, 15 Oct 2024 10:18:58 +0800 From: Yicong Yang To: , , , , , , , , , , , CC: , , , , , , , , , , , , Subject: [PATCH v6 1/4] cpu/SMT: Provide a default topology_is_primary_thread() Date: Tue, 15 Oct 2024 10:18:38 +0800 Message-ID: <20241015021841.35713-2-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20241015021841.35713-1-yangyicong@huawei.com> References: <20241015021841.35713-1-yangyicong@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.50.165.33] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemd200014.china.huawei.com (7.221.188.8) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241014_191912_638484_9811127A X-CRM114-Status: GOOD ( 15.77 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Yicong Yang Currently if architectures want to support HOTPLUG_SMT they need to provide a topology_is_primary_thread() telling the framework which thread in the SMT cannot offline. However arm64 doesn't have a restriction on which thread in the SMT cannot offline, a simplest choice is that just make 1st thread as the "primary" thread. So just make this as the default implementation in the framework and let architectures like x86 that have special primary thread to override this function (which they've already done). There's no need to provide a stub function if !CONFIG_SMP or !CONFIG_HOTPLUG_SMP. In such case the testing CPU is already the 1st CPU in the SMT so it's always the primary thread. Signed-off-by: Yicong Yang --- arch/powerpc/include/asm/topology.h | 1 + arch/x86/include/asm/topology.h | 2 +- include/linux/topology.h | 14 ++++++++++++++ 3 files changed, 16 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h index 16bacfe8c7a2..da15b5efe807 100644 --- a/arch/powerpc/include/asm/topology.h +++ b/arch/powerpc/include/asm/topology.h @@ -152,6 +152,7 @@ static inline bool topology_is_primary_thread(unsigned int cpu) { return cpu == cpu_first_thread_sibling(cpu); } +#define topology_is_primary_thread topology_is_primary_thread static inline bool topology_smt_thread_allowed(unsigned int cpu) { diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h index aef70336d624..3a7c18851016 100644 --- a/arch/x86/include/asm/topology.h +++ b/arch/x86/include/asm/topology.h @@ -219,11 +219,11 @@ static inline bool topology_is_primary_thread(unsigned int cpu) { return cpumask_test_cpu(cpu, cpu_primary_thread_mask); } +#define topology_is_primary_thread topology_is_primary_thread #else /* CONFIG_SMP */ static inline int topology_phys_to_logical_pkg(unsigned int pkg) { return 0; } static inline int topology_max_smt_threads(void) { return 1; } -static inline bool topology_is_primary_thread(unsigned int cpu) { return true; } static inline unsigned int topology_amd_nodes_per_pkg(void) { return 1; } #endif /* !CONFIG_SMP */ diff --git a/include/linux/topology.h b/include/linux/topology.h index 52f5850730b3..9c9f6b9f3462 100644 --- a/include/linux/topology.h +++ b/include/linux/topology.h @@ -240,6 +240,20 @@ static inline const struct cpumask *cpu_smt_mask(int cpu) } #endif +#ifndef topology_is_primary_thread +#define topology_is_primary_thread topology_is_primary_thread +static inline bool topology_is_primary_thread(unsigned int cpu) +{ + /* + * On SMT hotplug the primary thread of the SMT won't be disabled. + * Architectures do have a special primary thread (e.g. x86) need + * to override this function. Otherwise just make the first thread + * in the SMT as the primary thread. + */ + return cpu == cpumask_first(topology_sibling_cpumask(cpu)); +} +#endif + static inline const struct cpumask *cpu_cpu_mask(int cpu) { return cpumask_of_node(cpu_to_node(cpu));