Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751172AbaLOCVC (ORCPT ); Sun, 14 Dec 2014 21:21:02 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:38133 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750820AbaLOCUz (ORCPT ); Sun, 14 Dec 2014 21:20:55 -0500 X-SecurityPolicyCheck: OK by SHieldMailChecker v2.2.3 X-SHieldMailCheckerPolicyVersion: FJ-ISEC-20140219-2 Message-ID: <548E4578.3070209@jp.fujitsu.com> Date: Mon, 15 Dec 2014 11:20:40 +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 , Yasuaki Ishimatsu , "Gu, Zheng" , tangchen Subject: Re: [PATCH 4/4] workqueue: handle change in cpu-node relationship. References: <1418379595-6281-1-git-send-email-laijs@cn.fujitsu.com> <548C68DA.20507@jp.fujitsu.com> <548C6B72.5080302@jp.fujitsu.com> <548E4388.5090308@cn.fujitsu.com> In-Reply-To: <548E4388.5090308@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 (2014/12/15 11:12), Lai Jiangshan wrote: > On 12/14/2014 12:38 AM, Kamezawa Hiroyuki wrote: >> Although workqueue detects relationship between cpu<->node at boot, >> it is finally determined in cpu_up(). >> This patch tries to update pool->node using online status of cpus. >> >> 1. When a node goes down, clear per-cpu pool's node attr. >> 2. When a cpu comes up, update per-cpu pool's node attr. >> 3. When a cpu comes up, update possinle node cpumask workqueue is using for sched. >> 4. Detect the best node for unbound pool's cpumask using the latest info. >> >> Signed-off-by: KAMEZAWA Hiroyuki >> --- >> kernel/workqueue.c | 67 ++++++++++++++++++++++++++++++++++++++++++------------ >> 1 file changed, 53 insertions(+), 14 deletions(-) >> >> diff --git a/kernel/workqueue.c b/kernel/workqueue.c >> index 07b4eb5..259b3ba 100644 >> --- a/kernel/workqueue.c >> +++ b/kernel/workqueue.c >> @@ -266,7 +266,8 @@ struct workqueue_struct { >> static struct kmem_cache *pwq_cache; >> >> static cpumask_var_t *wq_numa_possible_cpumask; >> - /* possible CPUs of each node */ >> + /* possible CPUs of each node initialized with possible info at boot. >> + but modified at cpu hotplug to be adjusted to real info. */ >> >> static bool wq_disable_numa; >> module_param_named(disable_numa, wq_disable_numa, bool, 0444); >> @@ -3449,6 +3450,31 @@ static void put_unbound_pool(struct worker_pool *pool) >> call_rcu_sched(&pool->rcu, rcu_free_pool); >> } >> >> +/* >> + * detect best node for given cpumask. >> + */ >> +static int pool_detect_best_node(const struct cpumask *cpumask) >> +{ >> + int node, best, match, selected; >> + static struct cpumask andmask; /* we're under mutex */ >> + >> + /* Is any node okay ? */ >> + if (!wq_numa_enabled || >> + cpumask_subset(cpu_online_mask, cpumask)) >> + return NUMA_NO_NODE; >> + best = 0; >> + selected = NUMA_NO_NODE; >> + /* select a node which contains the most cpu of cpumask */ >> + for_each_node_state(node, N_ONLINE) { >> + cpumask_and(&andmask, cpumask, cpumask_of_node(node)); >> + match = cpumask_weight(&andmask); >> + if (match > best) >> + selected = node; >> + } >> + return selected; >> +} >> + >> + >> /** >> * get_unbound_pool - get a worker_pool with the specified attributes >> * @attrs: the attributes of the worker_pool to get >> @@ -3467,7 +3493,6 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs) >> { >> u32 hash = wqattrs_hash(attrs); >> struct worker_pool *pool; >> - int node; >> >> lockdep_assert_held(&wq_pool_mutex); >> >> @@ -3492,17 +3517,7 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs) >> * 'struct workqueue_attrs' comments for detail. >> */ >> pool->attrs->no_numa = false; >> - >> - /* 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; >> - } >> - } >> - } >> + pool->node = pool_detect_best_node(pool->attrs->cpumask); >> >> if (worker_pool_assign_id(pool) < 0) >> goto fail; >> @@ -4567,7 +4582,7 @@ static int workqueue_cpu_up_callback(struct notifier_block *nfb, >> int cpu = (unsigned long)hcpu; >> struct worker_pool *pool; >> struct workqueue_struct *wq; >> - int pi; >> + int pi, node; >> >> switch (action & ~CPU_TASKS_FROZEN) { >> case CPU_UP_PREPARE: >> @@ -4583,6 +4598,16 @@ static int workqueue_cpu_up_callback(struct notifier_block *nfb, >> case CPU_ONLINE: >> mutex_lock(&wq_pool_mutex); >> >> + /* now cpu <-> node info is established, update the info. */ >> + if (!wq_disable_numa) { > > > >> + for_each_node_state(node, N_POSSIBLE) >> + cpumask_clear_cpu(cpu, >> + wq_numa_possible_cpumask[node]); > > The wq code try to reuse the origin pwqs/pools when the node still have cpu online. > these 3 lines of code will cause the origin pwqs/pools be on the road of dying, and > create a new set of pwqs/pools. because the result of wq_calc_node_cpumask() changes ? Do you mean some comment should be added here ? or explaination for your reply for [3/4] ? Thanks, -Kame > >> + node = cpu_to_node(cpu); >> + cpumask_set_cpu(cpu, wq_numa_possible_cpumask[node]); >> + } >> + for_each_cpu_worker_pool(pool, cpu) >> + pool->node = cpu_to_node(cpu); >> for_each_pool(pool, pi) { >> mutex_lock(&pool->attach_mutex); >> >> @@ -4951,7 +4976,21 @@ void workqueue_register_numanode(int nid) >> void workqueue_unregister_numanode(int nid) >> { >> struct workqueue_struct *wq; >> + const struct cpumask *nodecpumask; >> + struct worker_pool *pool; >> + int cpu; >> >> + /* at this point, cpu-to-node relationship is not lost */ >> + nodecpumask = cpumask_of_node(nid); >> + for_each_cpu(cpu, nodecpumask) { >> + /* >> + * pool is allcated at boot and assumed to be persistent, >> + * we cannot free this. >> + * Update to be NUMA_NO_NODE. This will be fixed at ONLINE >> + */ >> + for_each_cpu_worker_pool(pool, cpu) >> + pool->node = NUMA_NO_NODE; >> + } >> mutex_lock(&wq_pool_mutex); >> list_for_each_entry(wq, &workqueues, list) >> wq_release_unbound_numa(wq, nid); > -- 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/