From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: Tejun Heo <tj@kernel.org>
Cc: <linux-kernel@vger.kernel.org>,
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
"Gu, Zheng" <guz.fnst@cn.fujitsu.com>,
tangchen <tangchen@cn.fujitsu.com>,
Hiroyuki KAMEZAWA <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH 2/5] workqueue: update wq_numa_possible_cpumask
Date: Mon, 15 Dec 2014 10:02:04 +0800 [thread overview]
Message-ID: <548E411C.3030102@cn.fujitsu.com> (raw)
In-Reply-To: <20141212171821.GB20020@htj.dyndns.org>
On 12/13/2014 01:18 AM, Tejun Heo wrote:
> On Fri, Dec 12, 2014 at 06:19:52PM +0800, Lai Jiangshan wrote:
> ...
>> +static void wq_update_numa_mapping(int cpu)
>> +{
>> + int node, orig_node = NUMA_NO_NODE, new_node = cpu_to_node(cpu);
>> +
>> + lockdep_assert_held(&wq_pool_mutex);
>> +
>> + if (!wq_numa_enabled)
>> + return;
>> +
>> + /* the node of onlining CPU is not NUMA_NO_NODE */
>> + if (WARN_ON(new_node == NUMA_NO_NODE))
>> + return;
>> +
>> + /* test whether the NUMA node mapping is changed. */
>> + if (cpumask_test_cpu(cpu, wq_numa_possible_cpumask[new_node]))
>> + return;
>> +
>> + /* find the origin node */
>> + for_each_node(node) {
>> + if (cpumask_test_cpu(cpu, wq_numa_possible_cpumask[node])) {
>> + orig_node = node;
>> + break;
>> + }
>> + }
>> +
>> + /* there may be multi mappings changed, re-initial. */
>> + cpumask_clear(wq_numa_possible_cpumask[new_node]);
>> + if (orig_node != NUMA_NO_NODE)
>> + cpumask_clear(wq_numa_possible_cpumask[orig_node]);
>> + for_each_possible_cpu(cpu) {
>> + node = cpu_to_node(node);
>> + if (node == new_node)
>> + cpumask_set_cpu(cpu, wq_numa_possible_cpumask[new_node]);
>> + else if (orig_node != NUMA_NO_NODE && node == orig_node)
>> + cpumask_set_cpu(cpu, wq_numa_possible_cpumask[orig_node]);
>> + }
>> +}
>
> Let's please move this to NUMA code and properly update it on actual
> mapping changes.
>
Hi, TJ
I didn't get your means. What did you mean "NUMA code"? Which one did you mean?
1) "NUMA code" = system's NUMA memory hotplug code, AKA, keep the numa mapping stable
I think this is the better idea. This idea came to my mind immediately at the time
I received the bug report. And after some discussions, I was told that it is too HARD
to keep the numa mapping stable across multiple physical system-board/node online/offline.
This idea makes the assumption "the numa mapping is stable after system booted" as
a restriction of the NUMA. And it will favor all the code outside of the numa code,
otherwise (we deny the assumption like this patchset) all the code which use
"cpu_to_node()" and cache the return value will have to be fixed up like this patchset.
Hi, hotplug-team, any idea to keep the numa mapping stable?
2) "NUMA code" = workqueue's NUMA code
I think I already did it, the code I added was right below the code of
wq_update_unbound_numa(). Or I missed something?
Thanks,
Lai
next prev parent reply other threads:[~2014-12-15 1:58 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-12 10:19 [PATCH 0/5] workqueue: fix bug when numa mapping is changed Lai Jiangshan
2014-12-12 10:19 ` [PATCH 1/5] workqueue: fix memory leak in wq_numa_init() Lai Jiangshan
2014-12-12 17:12 ` Tejun Heo
2014-12-15 5:25 ` Lai Jiangshan
2014-12-12 10:19 ` [PATCH 2/5] workqueue: update wq_numa_possible_cpumask Lai Jiangshan
2014-12-12 17:18 ` Tejun Heo
2014-12-15 2:02 ` Lai Jiangshan [this message]
2014-12-25 20:16 ` Tejun Heo
2014-12-18 2:22 ` Lai Jiangshan
2014-12-12 10:19 ` [PATCH 3/5] workqueue: fixup existing pool->node Lai Jiangshan
2014-12-12 17:25 ` Tejun Heo
2014-12-15 1:23 ` Lai Jiangshan
2014-12-25 20:14 ` Tejun Heo
2015-01-13 7:08 ` Lai Jiangshan
2015-01-13 15:24 ` Tejun Heo
2014-12-12 10:19 ` [PATCH 4/5] workqueue: update NUMA affinity for the node lost CPU Lai Jiangshan
2014-12-12 17:27 ` Tejun Heo
2014-12-15 1:28 ` Lai Jiangshan
2014-12-25 20:17 ` Tejun Heo
2014-12-12 10:19 ` [PATCH 5/5] workqueue: retry on NUMA_NO_NODE when create_worker() fails Lai Jiangshan
2014-12-12 16:05 ` KOSAKI Motohiro
2014-12-12 17:29 ` KOSAKI Motohiro
2014-12-12 17:29 ` Tejun Heo
2014-12-12 17:13 ` [PATCH 0/5] workqueue: fix bug when numa mapping is changed Yasuaki Ishimatsu
2014-12-15 1:34 ` Lai Jiangshan
2014-12-18 1:50 ` Yasuaki Ishimatsu
2014-12-13 16:27 ` [PATCH 0/4] workqueue: fix bug when numa mapping is changed v2 Kamezawa Hiroyuki
2014-12-13 16:30 ` [PATCH 1/4] workqueue: add a hook for node hotplug Kamezawa Hiroyuki
2014-12-13 16:33 ` [PATCH 2/4] workqueue: add warning if pool->node is offline Kamezawa Hiroyuki
2014-12-13 16:35 ` [PATCH 3/4] workqueue: remove per-node unbound pool when node goes offline Kamezawa Hiroyuki
2014-12-15 2:06 ` Lai Jiangshan
2014-12-15 2:06 ` Kamezawa Hiroyuki
2014-12-13 16:38 ` [PATCH 4/4] workqueue: handle change in cpu-node relationship Kamezawa Hiroyuki
2014-12-15 2:12 ` Lai Jiangshan
2014-12-15 2:20 ` Kamezawa Hiroyuki
2014-12-15 2:48 ` Lai Jiangshan
2014-12-15 2:55 ` Kamezawa Hiroyuki
2014-12-15 3:30 ` Lai Jiangshan
2014-12-15 3:34 ` Lai Jiangshan
2014-12-15 4:04 ` Kamezawa Hiroyuki
2014-12-15 5:19 ` Lai Jiangshan
2014-12-15 5:33 ` Kamezawa Hiroyuki
2014-12-15 11:11 ` [PATCH 0/4] workqueue: fix memory allocation after numa mapping is changed v3 Kamezawa Hiroyuki
2014-12-15 11:14 ` [PATCH 1/4] workqueue:Fix unbound workqueue's node affinity detection Kamezawa Hiroyuki
2014-12-16 5:30 ` Lai Jiangshan
2014-12-16 7:32 ` Kamezawa Hiroyuki
2014-12-16 7:54 ` Lai Jiangshan
2014-12-15 11:16 ` [PATCH 2/4] workqueue: update per-cpu workqueue's node affinity at,online-offline Kamezawa Hiroyuki
2014-12-16 5:32 ` Lai Jiangshan
2014-12-16 7:25 ` Kamezawa Hiroyuki
2014-12-15 11:18 ` [PATCH 3/4] workqueue: Update workqueue's possible cpumask when a new node, coming up Kamezawa Hiroyuki
2014-12-16 7:49 ` Lai Jiangshan
2014-12-16 8:10 ` Kamezawa Hiroyuki
2014-12-16 8:18 ` Kamezawa Hiroyuki
2014-12-15 11:22 ` [PATCH 4/4] workqueue: Handle cpu-node affinity change at CPU_ONLINE Kamezawa Hiroyuki
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