From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dou Liyang Subject: [PATCH v8 0/7] Make cpuid <-> nodeid mapping persistent Date: Tue, 19 Jul 2016 15:28:01 +0800 Message-ID: <1468913288-16605-1-git-send-email-douly.fnst@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Return-path: Sender: owner-linux-mm@kvack.org To: cl@linux.com, tj@kernel.org, mika.j.penttila@gmail.com, mingo@redhat.com, akpm@linux-foundation.org, rjw@rjwysocki.net, hpa@zytor.com, yasu.isimatu@gmail.com, isimatu.yasuaki@jp.fujitsu.com, kamezawa.hiroyu@jp.fujitsu.com, izumi.taku@jp.fujitsu.com, gongzhaogang@inspur.com, len.brown@intel.com, lenb@kernel.org, tglx@linutronix.de, chen.tang@easystack.cn, rafael@kernel.org Cc: x86@kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dou Liyang List-Id: linux-acpi@vger.kernel.org [Problem] cpuid <-> nodeid mapping is firstly established at boot time. And workque= ue 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/d= estroyed, 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, i= ts 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 =3D node; break; } } } Since wq_numa_possible_cpumask is not updated, it could be mapped to an o= ffline node, which will lead to memory allocation failure: SLUB: Unable to allocate memory on node 2 (gfp=3D0x80d0) 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 =3D alloc_worker(pool->node); static struct worker *alloc_worker(int node) { struct worker *worker; worker =3D kzalloc_node(sizeof(*worker), GFP_KERNEL, node); --> H= ere, 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 nodei= d <-> pxm mapping is setup at boot time. This mapping is persistent, won't chang= e. 2. apicid <-> nodeid mapping is setup using info in 1. The mapping is set= up at boot time and CPU hotadd time, and cleared at CPU hotremove time. This mapp= ing is also persistent. 3. cpuid <-> apicid mapping is setup at boot time and CPU hotadd time. cp= uid 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 tim= e, and cleared at CPU hotremove time. As a result of 3, this mapping is not p= ersistent. To fix this problem, we establish cpuid <-> nodeid mapping for all the po= ssible cpus at boot time, and make it persistent. And according to init_cpu_to_n= ode(), 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 foun= d in MADT (Multiple APIC Description Table). So we finish the job in the follo= wing steps: 1. Enable apic registeration flow to handle both enabled and disabled cpu= s. This is done by introducing an extra parameter to generic_processor_in= fo to let the caller control if disabled cpus are ignored. 2. Introduce a new array storing all possible cpuid <-> apicid mapping. A= nd also modify the way cpuid is calculated. Establish all possible cpuid <-> apicid m= apping when registering local apic. Store the mapping in this array. 3. Enable _MAT and MADT relative apis to return non-presnet or disabled c= pus' apicid. This is also done by introducing an extra parameter to these apis to l= et 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 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= .=20 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 fa= ll=20 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): Provide the mechanism to validate processors in the ACPI tables Provide the interface to validate the proc_id which they give 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 | 10 ++-- arch/x86/kernel/apic/apic.c | 85 +++++++++++++++++++++++++--- arch/x86/mm/numa.c | 27 +++++---- drivers/acpi/acpi_processor.c | 105 ++++++++++++++++++++++++++++++++++- drivers/acpi/bus.c | 3 + drivers/acpi/processor_core.c | 126 +++++++++++++++++++++++++++++++++++-= ------ include/linux/acpi.h | 5 ++ 9 files changed, 314 insertions(+), 51 deletions(-) --=20 2.5.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org