Messages in this thread | | | Date | Tue, 16 Dec 2014 13:32:26 +0800 | From | Lai Jiangshan <> | Subject | Re: [PATCH 2/4] workqueue: update per-cpu workqueue's node affinity at,online-offline |
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On 12/15/2014 07:16 PM, Kamezawa Hiroyuki wrote: > The percpu workqueue pool are persistend and never be freed. > But cpu<->node relationship can be changed by cpu hotplug and pool->node > can point to an offlined node. > > If pool->node points to an offlined node, > following allocation failure can happen. > == > 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 clears per-cpu workqueue pool's node affinity at > cpu offlining and restore it at cpu onlining. > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > --- > kernel/workqueue.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index 7809154..2fd0bd7 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -4586,6 +4586,11 @@ static int workqueue_cpu_up_callback(struct notifier_block *nfb, > case CPU_DOWN_FAILED: > case CPU_ONLINE: > mutex_lock(&wq_pool_mutex); > + /* > + * now cpu <-> node info is established. update numa node > + */ > + for_each_cpu_worker_pool(pool, cpu) > + pool->node = cpu_to_node(cpu); > > for_each_pool(pool, pi) { > mutex_lock(&pool->attach_mutex); > @@ -4619,6 +4624,7 @@ static int workqueue_cpu_down_callback(struct notifier_block *nfb, > int cpu = (unsigned long)hcpu; > struct work_struct unbind_work; > struct workqueue_struct *wq; > + struct worker_pool *pool; > > switch (action & ~CPU_TASKS_FROZEN) { > case CPU_DOWN_PREPARE: > @@ -4626,10 +4632,13 @@ static int workqueue_cpu_down_callback(struct notifier_block *nfb, > INIT_WORK_ONSTACK(&unbind_work, wq_unbind_fn); > queue_work_on(cpu, system_highpri_wq, &unbind_work); > > - /* update NUMA affinity of unbound workqueues */ > mutex_lock(&wq_pool_mutex); > + /* update NUMA affinity of unbound workqueues */ > list_for_each_entry(wq, &workqueues, list) > wq_update_unbound_numa(wq, cpu, false); > + /* clear per-cpu workqueues's numa affinity. */ > + for_each_cpu_worker_pool(pool, cpu) > + pool->node = NUMA_NO_NODE; /* restored at online */
If the node is still online, it is better to keep the original pool->node.
> mutex_unlock(&wq_pool_mutex); > > /* wait for per-cpu unbinding to finish */
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