From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752778AbcIMLe0 (ORCPT ); Tue, 13 Sep 2016 07:34:26 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:23104 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750747AbcIMLeV (ORCPT ); Tue, 13 Sep 2016 07:34:21 -0400 X-IronPort-AV: E=Sophos;i="5.22,518,1449504000"; d="scan'208";a="10932193" Subject: Re: [PATCH v12 0/7] Make cpuid <-> nodeid mapping persistent To: , , , , , , , , , , , , , , , , References: <1472114120-3281-1-git-send-email-douly.fnst@cn.fujitsu.com> <5cdaa83f-142b-b9a0-6b7b-57c9162fc537@cn.fujitsu.com> CC: , , , From: Dou Liyang Message-ID: <1c2fb3fb-be7b-8980-e70d-e57080888c94@cn.fujitsu.com> Date: Tue, 13 Sep 2016 19:33:54 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <5cdaa83f-142b-b9a0-6b7b-57c9162fc537@cn.fujitsu.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.167.226.106] X-yoursite-MailScanner-ID: E84114042436.ABCFE X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: douly.fnst@cn.fujitsu.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ping... At 09/02/2016 02:57 PM, Dou Liyang wrote: > Ping... > > At 08/25/2016 04:35 PM, Dou Liyang wrote: >> [Summary] >> >> Use ACPI tables: MADT, DSDT. >> 1. Create cpuid in order based on Local Apic ID in MADT(apicid). >> 2. Obtain the nodeid by the proc_id in DSDT. >> 3. Make the cpuid <-> nodeid mapping persistent. >> >> The mapping relations: >> >> proc_id in DSDT <--> Processor ID in MADT(acpiid) <--> Local Apic ID >> in MADT(apicid) >> ^ ^ >> | | >> v  v  >> pxm in DSDT cpuid >> ^ >> | >> v >> nodeid >> >> [Problem] >> >> cpuid <-> nodeid mapping is firstly established at boot time. And >> workqueue caches >> the mapping in wq_numa_possible_cpumask in wq_numa_init() at boot time. >> >> When doing node online/offline, cpuid <-> nodeid mapping is >> established/destroyed, >> which means, cpuid <-> nodeid mapping will change if node hotplug >> happens. But >> workqueue does not update wq_numa_possible_cpumask. >> >> So here is the problem: >> >> Assume we have the following cpuid <-> nodeid in the beginning: >> >> Node | CPU >> ------------------------ >> node 0 | 0-14, 60-74 >> node 1 | 15-29, 75-89 >> node 2 | 30-44, 90-104 >> node 3 | 45-59, 105-119 >> >> and we hot-remove node2 and node3, it becomes: >> >> Node | CPU >> ------------------------ >> node 0 | 0-14, 60-74 >> node 1 | 15-29, 75-89 >> >> and we hot-add node4 and node5, it becomes: >> >> Node | CPU >> ------------------------ >> node 0 | 0-14, 60-74 >> node 1 | 15-29, 75-89 >> node 4 | 30-59 >> node 5 | 90-119 >> >> But in wq_numa_possible_cpumask, cpu30 is still mapped to node2, and >> the like. >> >> When a pool workqueue is initialized, if its cpumask belongs to a >> node, its >> pool->node will be mapped to that node. And memory used by this >> workqueue will >> also be allocated on that node. >> >> static struct worker_pool *get_unbound_pool(const struct >> workqueue_attrs *attrs){ >> ... >> /* if cpumask is contained inside a NUMA node, we belong to >> that node */ >> if (wq_numa_enabled) { >> for_each_node(node) { >> if (cpumask_subset(pool->attrs->cpumask, >> >> wq_numa_possible_cpumask[node])) { >> pool->node = node; >> break; >> } >> } >> } >> >> Since wq_numa_possible_cpumask is not updated, it could be mapped to >> an offline node, >> which will lead to memory allocation failure: >> >> SLUB: Unable to allocate memory on node 2 (gfp=0x80d0) >> cache: kmalloc-192, object size: 192, buffer size: 192, default >> order: 1, min order: 0 >> node 0: slabs: 6172, objs: 259224, free: 245741 >> node 1: slabs: 3261, objs: 136962, free: 127656 >> >> It happens here: >> >> create_worker(struct worker_pool *pool) >> |--> worker = alloc_worker(pool->node); >> >> static struct worker *alloc_worker(int node) >> { >> struct worker *worker; >> >> worker = kzalloc_node(sizeof(*worker), GFP_KERNEL, node); --> >> Here, useing the wrong node. >> >> ...... >> >> return worker; >> } >> >> >> [Solution] >> >> There are four mappings in the kernel: >> 1. nodeid (logical node id) <-> pxm >> 2. apicid (physical cpu id) <-> nodeid >> 3. cpuid (logical cpu id) <-> apicid >> 4. cpuid (logical cpu id) <-> nodeid >> >> 1. pxm (proximity domain) is provided by ACPI firmware in SRAT, and >> nodeid <-> pxm >> mapping is setup at boot time. This mapping is persistent, won't >> change. >> >> 2. apicid <-> nodeid mapping is setup using info in 1. The mapping is >> setup at boot >> time and CPU hotadd time, and cleared at CPU hotremove time. This >> mapping is also >> persistent. >> >> 3. cpuid <-> apicid mapping is setup at boot time and CPU hotadd time. >> cpuid is >> allocated, lower ids first, and released at CPU hotremove time, >> reused for other >> hotadded CPUs. So this mapping is not persistent. >> >> 4. cpuid <-> nodeid mapping is also setup at boot time and CPU hotadd >> time, and >> cleared at CPU hotremove time. As a result of 3, this mapping is >> not persistent. >> >> To fix this problem, we establish cpuid <-> nodeid mapping for all the >> possible >> cpus at boot time, and make it persistent. And according to >> init_cpu_to_node(), >> cpuid <-> nodeid mapping is based on apicid <-> nodeid mapping and >> cpuid <-> apicid >> mapping. So the key point is obtaining all cpus' apicid. >> >> apicid can be obtained by _MAT (Multiple APIC Table Entry) method or >> found in >> MADT (Multiple APIC Description Table). So we finish the job in the >> following steps: >> >> 1. Enable apic registeration flow to handle both enabled and disabled >> cpus. >> This is done by introducing an extra parameter to >> generic_processor_info to let the >> caller control if disabled cpus are ignored. >> >> 2. Introduce a new array storing all possible cpuid <-> apicid >> mapping. And also modify >> the way cpuid is calculated. Establish all possible cpuid <-> >> apicid mapping when >> registering local apic. Store the mapping in this array. >> >> 3. Enable _MAT and MADT relative apis to return non-presnet or >> disabled cpus' apicid. >> This is also done by introducing an extra parameter to these apis >> to let the caller >> control if disabled cpus are ignored. >> >> 4. Establish all possible cpuid <-> nodeid mapping. >> This is done via an additional acpi namespace walk for processors. >> >> >> For previous discussion, please refer to: >> https://lkml.org/lkml/2015/2/27/145 >> https://lkml.org/lkml/2015/3/25/989 >> https://lkml.org/lkml/2015/5/14/244 >> https://lkml.org/lkml/2015/7/7/200 >> https://lkml.org/lkml/2015/9/27/209 >> https://lkml.org/lkml/2016/5/19/212 >> https://lkml.org/lkml/2016/7/19/181 >> https://lkml.org/lkml/2016/7/25/99 >> https://lkml.org/lkml/2016/7/26/52 >> https://lkml.org/lkml/2016/8/8/96 >> >> Change log v11 -> v12: >> 1. Rebase >> 2. Add a short summary >> >> Change log v10 -> v11: >> 1. Reduce the number of repeat judgment of online/offline >> 2. Seperate out the functionality in the enable or disable situation >> >> Change log v9 -> v10: >> 1. Providing an empty definition of acpi_set_processor_mapping() for >> CONFIG_ACPI_HOTPLUG_CPU unset. In patch 5. >> 2. Fix auto build test ERROR on ia64/next. In patch 5. >> 3. Fix some comment. >> >> Change log v8 -> v9: >> 1. Providing an empty definition of acpi_set_processor_mapping() for >> CONFIG_ACPI_HOTPLUG_CPU unset. >> >> Change log v7 -> v8: >> 1. Provide the mechanism to validate processors in the ACPI tables. >> 2. Provide the interface to validate the proc_id when setting the >> mapping. >> >> Change log v6 -> v7: >> 1. Fix arm64 build failure. >> >> Change log v5 -> v6: >> 1. Define func acpi_map_cpu2node() for x86 and ia64 respectively. >> >> Change log v4 -> v5: >> 1. Remove useless code in patch 1. >> 2. Small improvement of commit message. >> >> Change log v3 -> v4: >> 1. Fix the kernel panic at boot time. The cause is that I tried to >> build zonelists >> before per cpu areas were initialized. >> >> Change log v2 -> v3: >> 1. Online memory-less nodes at boot time to map cpus of memory-less >> nodes. >> 2. Build zonelists for memory-less nodes so that memory allocator will >> fall >> back to proper nodes automatically. >> >> Change log v1 -> v2: >> 1. Split code movement and actual changes. Add patch 1. >> 2. Synchronize best near online node record when node hotplug happens. >> In patch 2. >> 3. Fix some comment. >> >> Dou Liyang (2): >> acpi: Provide the mechanism to validate processors in the ACPI tables >> acpi: Provide the interface to validate the proc_id >> >> Gu Zheng (4): >> x86, acpi, cpu-hotplug: Enable acpi to register all possible cpus at >> boot time. >> x86, acpi, cpu-hotplug: Introduce cpuid_to_apicid[] array to store >> persistent cpuid <-> apicid mapping. >> x86, acpi, cpu-hotplug: Enable MADT APIs to return disabled apicid. >> x86, acpi, cpu-hotplug: Set persistent cpuid <-> nodeid mapping when >> booting. >> >> Tang Chen (1): >> x86, memhp, numa: Online memory-less nodes at boot time. >> >> arch/ia64/kernel/acpi.c | 3 +- >> arch/x86/include/asm/mpspec.h | 1 + >> arch/x86/kernel/acpi/boot.c | 11 ++-- >> arch/x86/kernel/apic/apic.c | 77 +++++++++++++++++++++++-- >> arch/x86/mm/numa.c | 27 +++++---- >> drivers/acpi/acpi_processor.c | 105 ++++++++++++++++++++++++++++++++- >> drivers/acpi/bus.c | 1 + >> drivers/acpi/processor_core.c | 131 >> +++++++++++++++++++++++++++++++++++------- >> include/linux/acpi.h | 6 ++ >> 9 files changed, 311 insertions(+), 51 deletions(-) >> > >