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 2E6C9EB64D7 for ; Wed, 28 Jun 2023 10:12:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231896AbjF1KMM (ORCPT ); Wed, 28 Jun 2023 06:12:12 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:13318 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231626AbjF1KGe (ORCPT ); Wed, 28 Jun 2023 06:06:34 -0400 Received: from pps.filterd (m0353726.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 35S9vpFU020511; Wed, 28 Jun 2023 10:06:14 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=cI/uYcWliA0lDscgpvXhyRstakOSqS6a6NVTQTYILCg=; b=BXr907oOhK4D+4xhVXBWlCLH9IFuBCiDIz/Ly59UDUehbWxUDfIwMc7n1XlWQZDo82S+ eXK0FRrfmmgy/jrJa6oyPdFkmOCQ3aBnEtT/Z0bhXNiHcV87ezNU+ctOexia9zj9W9VX 7ESpZD0+HJOji3peAA/PMOpYzY/NL33tdl9VCzM5pCrZdN7xCos8+GLFrm//YSHJpVuT FcXeSeZltTj7wW+kDcSjMMWIrvaDUWXcTDdrFZRz6fcfvYPlYaXtEN2VleYGreN6BLlu ilTs82J3W4A6pDM4hGShFjWSZw3oEE+9g8G47ziwW5DSTQ6MK3/DHdYy0xgpSEwLuON8 Kg== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3rgjpq04y7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 28 Jun 2023 10:06:13 +0000 Received: from m0353726.ppops.net (m0353726.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 35S9x072025432; Wed, 28 Jun 2023 10:06:13 GMT Received: from ppma06fra.de.ibm.com (48.49.7a9f.ip4.static.sl-reverse.com [159.122.73.72]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3rgjpq04wh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 28 Jun 2023 10:06:13 +0000 Received: from pps.filterd (ppma06fra.de.ibm.com [127.0.0.1]) by ppma06fra.de.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 35S3gVgY010615; Wed, 28 Jun 2023 10:06:10 GMT Received: from smtprelay05.fra02v.mail.ibm.com ([9.218.2.225]) by ppma06fra.de.ibm.com (PPS) with ESMTPS id 3rdqre1vv1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 28 Jun 2023 10:06:10 +0000 Received: from smtpav07.fra02v.mail.ibm.com (smtpav07.fra02v.mail.ibm.com [10.20.54.106]) by smtprelay05.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 35SA67VI8651390 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 28 Jun 2023 10:06:07 GMT Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CB9AD2005A; Wed, 28 Jun 2023 10:06:07 +0000 (GMT) Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F183B20043; Wed, 28 Jun 2023 10:06:06 +0000 (GMT) Received: from localhost.localdomain (unknown [9.171.41.43]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 28 Jun 2023 10:06:06 +0000 (GMT) From: Laurent Dufour To: linuxppc-dev@lists.ozlabs.org Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mpe@ellerman.id.au, npiggin@gmail.com, christophe.leroy@csgroup.eu, tglx@linutronix.de, dave.hansen@linux.intel.com, mingo@redhat.com, bp@alien8.de Subject: [PATCH v2 8/9] powerpc: Add HOTPLUG_SMT support Date: Wed, 28 Jun 2023 12:05:57 +0200 Message-ID: <20230628100558.43482-9-ldufour@linux.ibm.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230628100558.43482-1-ldufour@linux.ibm.com> References: <20230628100558.43482-1-ldufour@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 6L5n7ua3NXeNNPuTIch9zHRZ5n9GxjdT X-Proofpoint-ORIG-GUID: VX8Rls4XOBwFrSgy5zXRyqRmt6LpkJUY X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-06-28_06,2023-06-27_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 bulkscore=0 priorityscore=1501 spamscore=0 suspectscore=0 phishscore=0 impostorscore=0 mlxscore=0 lowpriorityscore=0 mlxlogscore=999 adultscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2305260000 definitions=main-2306280088 Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org From: Michael Ellerman Add support for HOTPLUG_SMT, which enables the generic sysfs SMT support files in /sys/devices/system/cpu/smt, as well as the "nosmt" boot parameter. Implement the recently added hooks to allow partial SMT states, allow any number of threads per core. Tie the config symbol to HOTPLUG_CPU, which enables it on the major platforms that support SMT. If there are other platforms that want the SMT support that can be tweaked in future. Signed-off-by: Michael Ellerman [ldufour: pass current SMT level to cpu_smt_set_num_threads] [ldufour: remove topology_smt_supported] [ldufour: remove topology_smt_threads_supported] [ldufour: select CONFIG_SMT_NUM_THREADS_DYNAMIC] [ldufour: update kernel-parameters.txt] Signed-off-by: Laurent Dufour --- Documentation/admin-guide/kernel-parameters.txt | 4 ++-- arch/powerpc/Kconfig | 2 ++ arch/powerpc/include/asm/topology.h | 15 +++++++++++++++ arch/powerpc/kernel/smp.c | 8 +++++++- 4 files changed, 26 insertions(+), 3 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 9e5bab29685f..5efb6c73a928 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3838,10 +3838,10 @@ nosmp [SMP] Tells an SMP kernel to act as a UP kernel, and disable the IO APIC. legacy for "maxcpus=0". - nosmt [KNL,S390] Disable symmetric multithreading (SMT). + nosmt [KNL,S390,PPC] Disable symmetric multithreading (SMT). Equivalent to smt=1. - [KNL,X86] Disable symmetric multithreading (SMT). + [KNL,X86,PPC] Disable symmetric multithreading (SMT). nosmt=force: Force disable SMT, cannot be undone via the sysfs control file. diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 8b955bc7b59f..bacabc3d7f0c 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -273,6 +273,8 @@ config PPC select HAVE_SYSCALL_TRACEPOINTS select HAVE_VIRT_CPU_ACCOUNTING select HAVE_VIRT_CPU_ACCOUNTING_GEN + select HOTPLUG_SMT if HOTPLUG_CPU + select SMT_NUM_THREADS_DYNAMIC select HUGETLB_PAGE_SIZE_VARIABLE if PPC_BOOK3S_64 && HUGETLB_PAGE select IOMMU_HELPER if PPC64 select IRQ_DOMAIN diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h index 8a4d4f4d9749..f4e6f2dd04b7 100644 --- a/arch/powerpc/include/asm/topology.h +++ b/arch/powerpc/include/asm/topology.h @@ -143,5 +143,20 @@ static inline int cpu_to_coregroup_id(int cpu) #endif #endif +#ifdef CONFIG_HOTPLUG_SMT +#include +#include + +static inline bool topology_is_primary_thread(unsigned int cpu) +{ + return cpu == cpu_first_thread_sibling(cpu); +} + +static inline bool topology_smt_thread_allowed(unsigned int cpu) +{ + return cpu_thread_in_core(cpu) < cpu_smt_num_threads; +} +#endif + #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_TOPOLOGY_H */ diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 406e6d0ffae3..eb539325dff8 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -1087,7 +1087,7 @@ static int __init init_big_cores(void) void __init smp_prepare_cpus(unsigned int max_cpus) { - unsigned int cpu; + unsigned int cpu, num_threads; DBG("smp_prepare_cpus\n"); @@ -1154,6 +1154,12 @@ void __init smp_prepare_cpus(unsigned int max_cpus) if (smp_ops && smp_ops->probe) smp_ops->probe(); + + // Initalise the generic SMT topology support + num_threads = 1; + if (smt_enabled_at_boot) + num_threads = smt_enabled_at_boot; + cpu_smt_set_num_threads(num_threads, threads_per_core); } void smp_prepare_boot_cpu(void) -- 2.41.0