Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751427AbaLQDXK (ORCPT ); Tue, 16 Dec 2014 22:23:10 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:35348 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751209AbaLQDXJ (ORCPT ); Tue, 16 Dec 2014 22:23:09 -0500 X-SecurityPolicyCheck: OK by SHieldMailChecker v2.2.3 X-SHieldMailCheckerPolicyVersion: FJ-ISEC-20140219-2 Message-ID: <5490F70E.4010703@jp.fujitsu.com> Date: Wed, 17 Dec 2014 12:22:54 +0900 From: Kamezawa Hiroyuki User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Lai Jiangshan CC: Tejun Heo , "linux-kernel@vger.kernel.org" , =?UTF-8?B?IklzaGltYXRzdSwgWWFzdWFraS/nn7Pmnb4g6Z2W56ugIg==?= , Tang Chen , "guz.fnst@cn.fujitsu.com" Subject: Re: [PATCH 1/2] workqueue: update numa affinity info at node hotplug References: <54905F87.2030302@jp.fujitsu.com> <549061BD.3040802@jp.fujitsu.com> <5490DE23.9000602@cn.fujitsu.com> In-Reply-To: <5490DE23.9000602@cn.fujitsu.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-SecurityPolicyCheck-GC: OK by FENCE-Mail Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2014/12/17 10:36), Lai Jiangshan wrote: > On 12/17/2014 12:45 AM, Kamezawa Hiroyuki wrote: >> With node online/offline, cpu<->node relationship is established. >> Workqueue uses a info which was established at boot time but >> it may be changed by node hotpluging. >> >> Once pool->node points to a stale node, following allocation failure >> happens. >> == >> 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 >> == >> This patch updates per cpu workqueue pool's node affinity and >> updates wq_numa_possible_cpumask at node online/offline event. >> This update of mask is very important because it affects cpumasks >> and preferred node detection. >> >> Unbound workqueue's per node pool are updated by >> by wq_update_unbound_numa() at CPU_DOWN_PREPARE of the last cpu, by existing code. >> What important here is to avoid wrong node detection when a cpu get onlined. >> And it's handled by wq_numa_possible_cpumask update introduced by this patch. >> >> Changelog v3->v4: >> - added workqueue_node_unregister >> - clear wq_numa_possible_cpumask at node offline. >> - merged a patch which handles per cpu pools. >> - clear per-cpu-pool's pool->node at node offlining. >> - set per-cpu-pool's pool->node at node onlining. >> - dropped modification to get_unbound_pool() >> - dropped per-cpu-pool handling at cpu online/offline. >> >> Reported-by: Yasuaki Ishimatsu >> Signed-off-by: KAMEZAWA Hiroyuki >> --- >> include/linux/memory_hotplug.h | 3 +++ >> kernel/workqueue.c | 58 +++++++++++++++++++++++++++++++++++++++++- >> mm/memory_hotplug.c | 6 ++++- >> 3 files changed, 65 insertions(+), 2 deletions(-) >> >> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h >> index 8f1a419..7b4a292 100644 >> --- a/include/linux/memory_hotplug.h >> +++ b/include/linux/memory_hotplug.h >> @@ -270,4 +270,7 @@ extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms) >> extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map, >> unsigned long pnum); >> >> +/* update for workqueues */ >> +void workqueue_node_register(int node); >> +void workqueue_node_unregister(int node); >> #endif /* __LINUX_MEMORY_HOTPLUG_H */ >> diff --git a/kernel/workqueue.c b/kernel/workqueue.c >> index 6202b08..f6ad05a 100644 >> --- a/kernel/workqueue.c >> +++ b/kernel/workqueue.c >> @@ -266,7 +266,7 @@ struct workqueue_struct { >> static struct kmem_cache *pwq_cache; >> >> static cpumask_var_t *wq_numa_possible_cpumask; >> - /* possible CPUs of each node */ >> + /* PL: possible CPUs of each node */ >> >> static bool wq_disable_numa; >> module_param_named(disable_numa, wq_disable_numa, bool, 0444); >> @@ -4563,6 +4563,62 @@ static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu) >> WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, >> pool->attrs->cpumask) < 0); >> } >> +#ifdef CONFIG_MEMORY_HOTPLUG >> + >> +static void workqueue_update_cpu_numa_affinity(int cpu, int node) >> +{ >> + struct worker_pool *pool; >> + >> + if (node != cpu_to_node(cpu)) >> + return; >> + cpumask_set_cpu(cpu, wq_numa_possible_cpumask[node]); >> + for_each_cpu_worker_pool(pool, cpu) >> + pool->node = node; > > Again, You need to check and update all the wq->numa_pwq_tbl[oldnode], > but in this patchset, the required information is lost and we can't find out oldnode. > > > cpus of oldnode, 16-31(online),48,56,64,72(offline,randomly assigned to the oldnode by numa_init_array()) > > and then cpu#48 is allocated for newnode and online > > Now, the wq->numa_pwq_tbl[oldnode]'s cpumask still have cpu#48, and it may be scheduled to cpu#48. > See the information of my patch 4/5 > That will not cause page allocation failure, right ? If so, it's out of scope of this patch 1/2. I think it's handled in patch 2/2, isn't it ? Thanks, -Kame > >> +} >> + >> +/* >> + * When a cpu is physically added, cpu<->node relationship is established >> + * based on firmware info. We can catch the whole view when a new NODE_DATA() >> + * coming up (a node is added). >> + * If we don't update the info, pool->node will points to a not-online node >> + * and the kernel will have allocation failure. >> + * >> + * Update wp_numa_possible_mask at online and clear it at offline. >> + */ >> +void workqueue_node_register(int node) >> +{ >> + int cpu; >> + >> + mutex_lock(&wq_pool_mutex); >> + for_each_possible_cpu(cpu) >> + workqueue_update_cpu_numa_affinity(cpu, node); >> + /* unbound workqueue will be updated when the 1st cpu comes up.*/ >> + mutex_unlock(&wq_pool_mutex); >> +} >> + >> +void workqueue_node_unregister(int node) >> +{ >> + struct worker_pool *pool; >> + int cpu; >> + >> + mutex_lock(&wq_pool_mutex); >> + cpumask_clear(wq_numa_possible_cpumask[node]); >> + for_each_possible_cpu(cpu) { >> + if (node == cpu_to_node(cpu)) >> + for_each_cpu_worker_pool(pool, cpu) >> + pool->node = NUMA_NO_NODE; >> + } >> + /* >> + * unbound workqueue's per-node pwqs are already refleshed >> + * by wq_update_unbound_numa() at CPU_DOWN_PREPARE of the last cpu >> + * on this node, because all cpus of this node went down. >> + * (see wq_calc_node_cpumask()). per-node unbound pwqs has been replaced >> + * with wq->dfl_pwq, already. >> + */ >> + mutex_unlock(&wq_pool_mutex); >> +} >> + >> +#endif >> >> /* >> * Workqueues should be brought up before normal priority CPU notifiers. >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> index 9fab107..a0cb5c1 100644 >> --- a/mm/memory_hotplug.c >> +++ b/mm/memory_hotplug.c >> @@ -1122,6 +1122,9 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) >> */ >> reset_node_present_pages(pgdat); >> >> + /* Update workqueue's numa affinity info. */ >> + workqueue_node_register(nid); >> + >> return pgdat; >> } >> >> @@ -1958,7 +1961,8 @@ void try_offline_node(int nid) >> >> if (check_and_unmap_cpu_on_node(pgdat)) >> return; >> - >> + /* update workqueue's numa affinity info. */ >> + workqueue_node_unregister(nid); >> /* >> * all memory/cpu of this node are removed, we can offline this >> * node now. > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/