Re: [PATCH 3/4] workqueue: Update workqueue's possible cpumask when a new node, coming up.

Kamezawa Hiroyuki
2014-12-16T08:10:56Z

(2014/12/16 16:49), Lai Jiangshan wrote:
> On 12/15/2014 07:18 PM, Kamezawa Hiroyuki wrote:
>> Workqueue keeps cpu<->node relationship including all possible cpus.
>> The original information was made at boot but it may change when
>> a new node is added.
>>
>> Update information if a new node is ready with using node-hotplug callback.
>>
>> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>> ---
>> include/linux/memory_hotplug.h | 2 ++
>> kernel/workqueue.c | 28 +++++++++++++++++++++++++++-
>> mm/memory_hotplug.c | 4 ++++
>> 3 files changed, 33 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
>> index 8f1a419..cd3cb67 100644
>> --- a/include/linux/memory_hotplug.h
>> +++ b/include/linux/memory_hotplug.h
>> @@ -270,4 +270,6 @@ 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);
>> #endif /* __LINUX_MEMORY_HOTPLUG_H */
>> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
>> index 2fd0bd7..5499b76 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);
>> @@ -4559,6 +4559,32 @@ 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 reflesh_wq_possible_mask(int cpu, int node)
>> +{
>> + int oldnode;
>> + for_each_node_state(oldnode, N_POSSIBLE)
>> + cpumask_clear_cpu(cpu, wq_numa_possible_cpumask[oldnode]);
>
> You need to check and update all the wq->numa_pwq_tbl[oldnode]
>

you mean : if I drop patch 1/4, it will be required. Right ?
I'll add that check.

Thanks,
-Kame

>> + cpumask_set_cpu(cpu, wq_numa_possible_cpumask[node]);
>> +}
>> +/*
>> + * When a cpu is physically added, cpu<->node relationship is established.
>> + * We can catch the whole view when a new NODE_DATA() coming up.
>> + * Update cpumask used for sched affinity of workers.
>> + */
>> +void workqueue_node_register(int node)
>> +{
>> + int cpu;
>> + mutex_lock(&wq_pool_mutex);
>> + for_each_possible_cpu(cpu) {
>> + if (node == cpu_to_node(cpu))
>> + reflesh_wq_possible_mask(cpu, node);
>> + }
>> + 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 1bf4807..d0c1ebb 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -1121,6 +1121,10 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
>> * online_pages() and offline_pages().
>> */
>> reset_node_present_pages(pgdat);
>> + /*
>> + * Update workqueue's cpu/node affinity info.
>> + */
>> + workqueue_node_register(nid);
>>
>> return pgdat;
>> }
>