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From: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Tejun Heo <tj@kernel.org>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>,
	<linux-kernel@vger.kernel.org>, <laijs@cn.fujitsu.com>,
	<isimatu.yasuaki@jp.fujitsu.com>, <tangchen@cn.fujitsu.com>,
	<izumi.taku@jp.fujitsu.com>
Subject: Re: [PATCH 0/2] workqueue: fix a bug when numa mapping is changed
Date: Wed, 1 Apr 2015 11:55:11 +0900	[thread overview]
Message-ID: <551B5E0F.1020302@jp.fujitsu.com> (raw)
In-Reply-To: <20150331152822.GE9974@htj.duckdns.org>

On 2015/04/01 0:28, Tejun Heo wrote:
> Hello, Kamezawa.
>
> On Tue, Mar 31, 2015 at 03:09:05PM +0900, Kamezawa Hiroyuki wrote:
>> But this may be considered as API change for most hot-add users.
>
> Hmm... Why would it be?  What can that possibly break?
>

Now, hot-added cpus will have the lowest free cpu id.

Because of this, in most of systems which has only cpu-hot-add, cpu-ids are always
contiguous even after cpu hot add.
In enterprise, this would be considered as imcompatibility.

determining cpuid <-> lapicid at boot will make cpuids sparse. That may corrupt
exisiting script or configuration/resource management software.

>> So, for now, I vote for detemining ids at online but record it is a good way.
>
> If we know the information during boot, let's please do it at boot
> time by all means.

I basically agree. Just thinking influence of this small imcompatibility of forcing
ideal way because of my standing point.

Thanks,
-Kame


  reply	other threads:[~2015-04-01  2:55 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-26  2:17 Gu Zheng
2015-03-26  2:17 ` [PATCH 1/2] x86/cpu hotplug: make apicid <--> cpuid mapping persistent Gu Zheng
2015-03-26  3:19   ` Kamezawa Hiroyuki
2015-03-26  4:55     ` Gu Zheng
2015-03-26 15:13       ` Tejun Heo
2015-03-26 16:31       ` Kamezawa Hiroyuki
2015-03-30  9:58         ` Gu Zheng
2015-04-01  2:59           ` Kamezawa Hiroyuki
2015-03-26  2:17 ` [PATCH 2/2] workqueue: update per cpu workqueue's numa affinity when cpu preparing online Gu Zheng
2015-03-26  3:12 ` [PATCH 0/2] workqueue: fix a bug when numa mapping is changed Kamezawa Hiroyuki
2015-03-26  5:04   ` Gu Zheng
2015-03-26 15:18     ` Tejun Heo
2015-03-26 16:42       ` Kamezawa Hiroyuki
2015-03-30  9:49         ` Gu Zheng
2015-03-30  9:49         ` Gu Zheng
2015-03-31  6:09           ` Kamezawa Hiroyuki
2015-03-31 15:28             ` Tejun Heo
2015-04-01  2:55               ` Kamezawa Hiroyuki [this message]
2015-04-01  3:02                 ` Tejun Heo
2015-04-01  3:05                   ` Tejun Heo
2015-04-01  8:30                   ` Kamezawa Hiroyuki
2015-04-02  1:36                     ` Gu Zheng
2015-04-02  2:54                       ` Kamezawa Hiroyuki

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