From nobody Tue Dec 30 16:40:54 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 D6F44C4167D for ; Tue, 14 Nov 2023 04:04:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231983AbjKNEEi (ORCPT ); Mon, 13 Nov 2023 23:04:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231514AbjKNEEb (ORCPT ); Mon, 13 Nov 2023 23:04:31 -0500 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5896B1A7 for ; Mon, 13 Nov 2023 20:04:25 -0800 (PST) Received: from canpemm500009.china.huawei.com (unknown [172.30.72.53]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4STsxx1hqkzMml7; Tue, 14 Nov 2023 11:59:49 +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 15.1.2507.31; Tue, 14 Nov 2023 12:04:23 +0800 From: Yicong Yang To: , , , CC: , , , , , , , Subject: [PATCH v3 1/4] arch_topology: Support basic SMT control for the driver Date: Tue, 14 Nov 2023 12:01:07 +0800 Message-ID: <20231114040110.54590-2-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20231114040110.54590-1-yangyicong@huawei.com> References: <20231114040110.54590-1-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 - record the allowed setting of SMT thread number by topology_smt_set_num_threads() - update the SMT thread number for the framework after the topology enumerated on arm64 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 | 32 ++++++++++++++++++++++++++++++++ include/linux/arch_topology.h | 9 +++++++++ 2 files changed, 41 insertions(+) diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index b741b5ba82bd..7fb91f41d66d 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -28,6 +28,9 @@ static struct cpumask scale_freq_counters_mask; static bool scale_freq_invariant; static DEFINE_PER_CPU(u32, freq_factor) =3D 1; =20 +/* Maximum threads number per-Core */ +static int topology_smt_num_threads =3D 1; + static bool supports_scale_freq_counters(const struct cpumask *cpus) { return cpumask_subset(cpus, &scale_freq_counters_mask); @@ -729,6 +732,28 @@ const struct cpumask *cpu_clustergroup_mask(int cpu) return &cpu_topology[cpu].cluster_sibling; } =20 +#ifdef CONFIG_HOTPLUG_SMT + +void __init topology_smt_set_num_threads(unsigned int num_threads) +{ + topology_smt_num_threads =3D 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 +866,13 @@ 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_num_threads, topology_smt_num_thread= s); + 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..574942a12ae1 100644 --- a/include/linux/arch_topology.h +++ b/include/linux/arch_topology.h @@ -92,6 +92,15 @@ 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); +#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) = { } +#endif + #endif =20 #endif /* _LINUX_ARCH_TOPOLOGY_H_ */ --=20 2.24.0 From nobody Tue Dec 30 16:40:54 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 09EFAC4332F for ; Tue, 14 Nov 2023 04:04:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231948AbjKNEEc (ORCPT ); Mon, 13 Nov 2023 23:04:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41108 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229645AbjKNEEa (ORCPT ); Mon, 13 Nov 2023 23:04:30 -0500 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BECCD43 for ; Mon, 13 Nov 2023 20:04:26 -0800 (PST) Received: from canpemm500009.china.huawei.com (unknown [172.30.72.54]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4STszQ0Bd9z1P8JP; Tue, 14 Nov 2023 12:01:06 +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 15.1.2507.31; Tue, 14 Nov 2023 12:04:23 +0800 From: Yicong Yang To: , , , CC: , , , , , , , Subject: [PATCH v3 2/4] arch_topology: Support SMT control for OF based system Date: Tue, 14 Nov 2023 12:01:08 +0800 Message-ID: <20231114040110.54590-3-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20231114040110.54590-1-yangyicong@huawei.com> References: <20231114040110.54590-1-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 7fb91f41d66d..02dc0266cbac 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -529,6 +529,13 @@ 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_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 Tue Dec 30 16:40:54 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 B62F9C4332F for ; Tue, 14 Nov 2023 04:04:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231971AbjKNEEp (ORCPT ); Mon, 13 Nov 2023 23:04:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229708AbjKNEEb (ORCPT ); Mon, 13 Nov 2023 23:04:31 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6C590D45 for ; Mon, 13 Nov 2023 20:04:26 -0800 (PST) Received: from canpemm500009.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4STt2x0HVNzvQh4; Tue, 14 Nov 2023 12:04:09 +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 15.1.2507.31; Tue, 14 Nov 2023 12:04:24 +0800 From: Yicong Yang To: , , , CC: , , , , , , , Subject: [PATCH v3 3/4] arm64: topology: Support SMT control on ACPI based system Date: Tue, 14 Nov 2023 12:01:09 +0800 Message-ID: <20231114040110.54590-4-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20231114040110.54590-1-yangyicong@huawei.com> References: <20231114040110.54590-1-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 Tue Dec 30 16:40:54 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 C5F19C4167B for ; Tue, 14 Nov 2023 04:04:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232018AbjKNEEm (ORCPT ); Mon, 13 Nov 2023 23:04:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229742AbjKNEEb (ORCPT ); Mon, 13 Nov 2023 23:04:31 -0500 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6C11DD44 for ; Mon, 13 Nov 2023 20:04:26 -0800 (PST) Received: from canpemm500009.china.huawei.com (unknown [172.30.72.55]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4STsxx6GSyzMmPP; Tue, 14 Nov 2023 11:59:49 +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 15.1.2507.31; Tue, 14 Nov 2023 12:04:24 +0800 From: Yicong Yang To: , , , CC: , , , , , , , Subject: [PATCH v3 4/4] arm64: Kconfig: Enable HOTPLUG_SMT Date: Tue, 14 Nov 2023 12:01:10 +0800 Message-ID: <20231114040110.54590-5-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20231114040110.54590-1-yangyicong@huawei.com> References: <20231114040110.54590-1-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..002bcde32575 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 select IRQ_DOMAIN select IRQ_FORCED_THREADING select KASAN_VMALLOC if KASAN --=20 2.24.0