From nobody Wed Dec 17 23:17:10 2025 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 44272C54FB9 for ; Tue, 21 Nov 2023 09:29:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233986AbjKUJ3o (ORCPT ); Tue, 21 Nov 2023 04:29:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230371AbjKUJ3d (ORCPT ); Tue, 21 Nov 2023 04:29:33 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A197C121 for ; Tue, 21 Nov 2023 01:29:24 -0800 (PST) Received: from canpemm500009.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4SZJrw0K7BzsRPH; Tue, 21 Nov 2023 17:25:52 +0800 (CST) Received: from localhost.localdomain (10.50.165.33) by canpemm500009.china.huawei.com (7.192.105.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Tue, 21 Nov 2023 17:29:19 +0800 From: Yicong Yang To: , , , CC: , , , , , , , Subject: [PATCH v4 1/4] arch_topology: Support basic SMT control for the driver Date: Tue, 21 Nov 2023 17:25:59 +0800 Message-ID: <20231121092602.47792-2-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20231121092602.47792-1-yangyicong@huawei.com> References: <20231121092602.47792-1-yangyicong@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.50.165.33] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500009.china.huawei.com (7.192.105.203) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Yicong Yang The core CPU control framework supports runtime SMT control which is not yet supported by arch_topology driver and thus arch_topology based architectures. This patch implements it in the following aspects: - implement topology_is_primary_thread() to indicate the primary thread, required by the framework - architecture code can get/set the SMT thread number by topology_smt_{get, set}_num_threads() - update the SMT thread number for the framework after the topology enumerated on arm64, which is also required by the framework For disabling SMT we'll offline all the secondary threads and only leave the primary thread. Since we don't have restriction for primary thread selection, the first thread is chosen as the primary thread in this implementation. This patch only implements the basic support for SMT control, which needs to collabrate with ACPI/OF based topology building to fully enable the feature. The SMT control will be enabled unless the correct SMT thread number is set and HOTPLUG_SMT kconfig is selected. Signed-off-by: Yicong Yang --- drivers/base/arch_topology.c | 38 +++++++++++++++++++++++++++++++++++ include/linux/arch_topology.h | 14 +++++++++++++ 2 files changed, 52 insertions(+) diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index b741b5ba82bd..3ed6bdf9460e 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -729,6 +729,36 @@ const struct cpumask *cpu_clustergroup_mask(int cpu) return &cpu_topology[cpu].cluster_sibling; } =20 +#ifdef CONFIG_HOTPLUG_SMT + +/* Maximum threads number per-Core */ +static unsigned int topology_smt_num_threads =3D 1; + +void __init topology_smt_set_num_threads(unsigned int num_threads) +{ + topology_smt_num_threads =3D num_threads; +} + +unsigned int __init topology_smt_get_num_threads(void) +{ + return topology_smt_num_threads; +} + +/* + * On SMT Hotplug the primary thread of the SMT won't be disabled. For x86= they + * seem to have a primary thread for special purpose. For other arthitectu= res + * like arm64 there's no such restriction for a primary thread, so make the + * first thread in the SMT as the primary thread. + */ +bool topology_is_primary_thread(unsigned int cpu) +{ + if (cpu =3D=3D cpumask_first(topology_sibling_cpumask(cpu))) + return true; + + return false; +} +#endif + void update_siblings_masks(unsigned int cpuid) { struct cpu_topology *cpu_topo, *cpuid_topo =3D &cpu_topology[cpuid]; @@ -841,6 +871,14 @@ void __init init_cpu_topology(void) reset_cpu_topology(); } =20 + /* + * By this stage we get to know whether we support SMT or not, update + * the information for the core. We don't support + * CONFIG_SMT_NUM_THREADS_DYNAMIC so make the max_threads =3D=3D num_thre= ads. + */ + cpu_smt_set_num_threads(topology_smt_get_num_threads(), + topology_smt_get_num_threads()); + for_each_possible_cpu(cpu) { ret =3D fetch_cache_info(cpu); if (!ret) diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h index a07b510e7dc5..0367f3a61838 100644 --- a/include/linux/arch_topology.h +++ b/include/linux/arch_topology.h @@ -92,6 +92,20 @@ void update_siblings_masks(unsigned int cpu); void remove_cpu_topology(unsigned int cpuid); void reset_cpu_topology(void); int parse_acpi_topology(void); + +#ifdef CONFIG_HOTPLUG_SMT +bool topology_is_primary_thread(unsigned int cpu); +void topology_smt_set_num_threads(unsigned int num_threads); +unsigned int topology_smt_get_num_threads(void); +#else +static inline bool topology_is_primary_thread(unsigned int cpu) { return f= alse; } +static inline void topology_smt_set_num_threads(unsigned int num_threads) = { } +static inline unsigned int topology_smt_get_num_threads(void) +{ + return 1; +} +#endif + #endif =20 #endif /* _LINUX_ARCH_TOPOLOGY_H_ */ --=20 2.24.0 From nobody Wed Dec 17 23:17:10 2025 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 6E81AC54FB9 for ; Tue, 21 Nov 2023 09:29:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233635AbjKUJ3l (ORCPT ); Tue, 21 Nov 2023 04:29:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232257AbjKUJ3c (ORCPT ); Tue, 21 Nov 2023 04:29:32 -0500 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4929123 for ; Tue, 21 Nov 2023 01:29:24 -0800 (PST) Received: from canpemm500009.china.huawei.com (unknown [172.30.72.57]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4SZJrw6gJ3z1P8k5; Tue, 21 Nov 2023 17:25:52 +0800 (CST) Received: from localhost.localdomain (10.50.165.33) by canpemm500009.china.huawei.com (7.192.105.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Tue, 21 Nov 2023 17:29:20 +0800 From: Yicong Yang To: , , , CC: , , , , , , , Subject: [PATCH v4 2/4] arch_topology: Support SMT control for OF based system Date: Tue, 21 Nov 2023 17:26:00 +0800 Message-ID: <20231121092602.47792-3-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20231121092602.47792-1-yangyicong@huawei.com> References: <20231121092602.47792-1-yangyicong@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.50.165.33] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500009.china.huawei.com (7.192.105.203) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Yicong Yang On building the topology from the devicetree, we've already gotten the SMT thread number of each core. Update the largest SMT thread number to enable the SMT control. Signed-off-by: Yicong Yang --- drivers/base/arch_topology.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 3ed6bdf9460e..252a436e0c1b 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -526,6 +526,13 @@ static int __init parse_core(struct device_node *core,= int package_id, i++; } while (t); =20 + /* + * We've already gotten threads number in this core, update the SMT + * threads number when necessary. + */ + if (i > topology_smt_get_num_threads()) + topology_smt_set_num_threads(i); + cpu =3D get_cpu_for_node(core); if (cpu >=3D 0) { if (!leaf) { --=20 2.24.0 From nobody Wed Dec 17 23:17:10 2025 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 98D7FC54FB9 for ; Tue, 21 Nov 2023 09:29:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230259AbjKUJ3h (ORCPT ); Tue, 21 Nov 2023 04:29:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232033AbjKUJ3c (ORCPT ); Tue, 21 Nov 2023 04:29:32 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3DFF122 for ; Tue, 21 Nov 2023 01:29:24 -0800 (PST) Received: from canpemm500009.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4SZJwT4GGSzvQwK; Tue, 21 Nov 2023 17:28:57 +0800 (CST) Received: from localhost.localdomain (10.50.165.33) by canpemm500009.china.huawei.com (7.192.105.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Tue, 21 Nov 2023 17:29:20 +0800 From: Yicong Yang To: , , , CC: , , , , , , , Subject: [PATCH v4 3/4] arm64: topology: Support SMT control on ACPI based system Date: Tue, 21 Nov 2023 17:26:01 +0800 Message-ID: <20231121092602.47792-4-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20231121092602.47792-1-yangyicong@huawei.com> References: <20231121092602.47792-1-yangyicong@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.50.165.33] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500009.china.huawei.com (7.192.105.203) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Yicong Yang For ACPI we'll build the topology from PPTT and we cannot directly get the SMT number of each core. Instead using a temporary xarray to record the SMT number of each core when building the topology and we can know the largest SMT number in the system. Then we can notify the arch_topology for supporting SMT control. Signed-off-by: Yicong Yang --- arch/arm64/kernel/topology.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 817d788cd866..0dc360c32ec8 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -17,6 +17,7 @@ #include #include #include +#include =20 #include #include @@ -43,11 +44,16 @@ static bool __init acpi_cpu_is_threaded(int cpu) */ int __init parse_acpi_topology(void) { + int thread_num, max_smt_thread_num =3D 1; + struct xarray core_threads; int cpu, topology_id; + void *entry; =20 if (acpi_disabled) return 0; =20 + xa_init(&core_threads); + for_each_possible_cpu(cpu) { topology_id =3D find_acpi_cpu_topology(cpu, 0); if (topology_id < 0) @@ -57,6 +63,20 @@ int __init parse_acpi_topology(void) cpu_topology[cpu].thread_id =3D topology_id; topology_id =3D find_acpi_cpu_topology(cpu, 1); cpu_topology[cpu].core_id =3D topology_id; + + entry =3D xa_load(&core_threads, topology_id); + if (!entry) { + xa_store(&core_threads, topology_id, + xa_mk_value(1), GFP_KERNEL); + } else { + thread_num =3D xa_to_value(entry); + thread_num++; + xa_store(&core_threads, topology_id, + xa_mk_value(thread_num), GFP_KERNEL); + + if (thread_num > max_smt_thread_num) + max_smt_thread_num =3D thread_num; + } } else { cpu_topology[cpu].thread_id =3D -1; cpu_topology[cpu].core_id =3D topology_id; @@ -67,6 +87,9 @@ int __init parse_acpi_topology(void) cpu_topology[cpu].package_id =3D topology_id; } =20 + topology_smt_set_num_threads(max_smt_thread_num); + + xa_destroy(&core_threads); return 0; } #endif --=20 2.24.0 From nobody Wed Dec 17 23:17:10 2025 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 F0C76C5ACB3 for ; Tue, 21 Nov 2023 09:29:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232322AbjKUJ3e (ORCPT ); Tue, 21 Nov 2023 04:29:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232222AbjKUJ3c (ORCPT ); Tue, 21 Nov 2023 04:29:32 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A590E124 for ; Tue, 21 Nov 2023 01:29:24 -0800 (PST) Received: from canpemm500009.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4SZJwJ66JjzWhfF; Tue, 21 Nov 2023 17:28:48 +0800 (CST) Received: from localhost.localdomain (10.50.165.33) by canpemm500009.china.huawei.com (7.192.105.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Tue, 21 Nov 2023 17:29:20 +0800 From: Yicong Yang To: , , , CC: , , , , , , , Subject: [PATCH v4 4/4] arm64: Kconfig: Enable HOTPLUG_SMT Date: Tue, 21 Nov 2023 17:26:02 +0800 Message-ID: <20231121092602.47792-5-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20231121092602.47792-1-yangyicong@huawei.com> References: <20231121092602.47792-1-yangyicong@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.50.165.33] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500009.china.huawei.com (7.192.105.203) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Yicong Yang Enable HOTPLUG_SMT for SMT control. Signed-off-by: Yicong Yang --- arch/arm64/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 7b071a00425d..9f3f4efc0375 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -233,6 +233,7 @@ config ARM64 select HAVE_KRETPROBES select HAVE_GENERIC_VDSO select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU + select HOTPLUG_SMT if (SMP && HOTPLUG_CPU) select IRQ_DOMAIN select IRQ_FORCED_THREADING select KASAN_VMALLOC if KASAN --=20 2.24.0