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From: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: cl@linux.com, tj@kernel.org, mika.j.penttila@gmail.com,
	mingo@redhat.com, akpm@linux-foundation.org, rjw@rjwysocki.net,
	hpa@zytor.com, yasu.isimatu@gmail.com,
	isimatu.yasuaki@jp.fujitsu.com, kamezawa.hiroyu@jp.fujitsu.com,
	izumi.taku@jp.fujitsu.com, gongzhaogang@inspur.com,
	len.brown@intel.com, lenb@kernel.org, tglx@linutronix.de,
	chen.tang@easystack.cn, rafael@kernel.org, x86@kernel.org,
	linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH v7 0/5] Make cpuid <-> nodeid mapping persistent
Date: Mon, 23 May 2016 15:02:14 +0800	[thread overview]
Message-ID: <5742AAF6.3060901@cn.fujitsu.com> (raw)
In-Reply-To: <20160519144657.GK3206@twins.programming.kicks-ass.net>

Hi,

On 05/19/2016 10:46 PM, Peter Zijlstra wrote:
> On Thu, May 19, 2016 at 06:39:41PM +0800, Zhu Guihua wrote:
>> [Problem]
>>
>> cpuid <-> nodeid mapping is firstly established at boot time. And workqueue caches
>> the mapping in wq_numa_possible_cpumask in wq_numa_init() at boot time.
>>
>> When doing node online/offline, cpuid <-> nodeid mapping is established/destroyed,
>> which means, cpuid <-> nodeid mapping will change if node hotplug happens. But
>> workqueue does not update wq_numa_possible_cpumask.
> So why are you not fixing up wq_numa_possible_cpumask instead? That
> seems the far easier solution.

We tried to do that. You can see our patch at
http://www.gossamer-threads.com/lists/linux/kernel/2116748

But maintainer thought, we should establish persistent cpuid<->nodeid 
relationship,
there is no need to change the map.

Cc TJ,
Could we return to workqueue to fix this?

Thanks,
Zhu

> Do all the other archs that support NUMA and HOTPLUG have the mapping
> stable, or will you now go fix each and every one of them?
>
>
> .
>



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WARNING: multiple messages have this Message-ID (diff)
From: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: <cl@linux.com>, <tj@kernel.org>, <mika.j.penttila@gmail.com>,
	<mingo@redhat.com>, <akpm@linux-foundation.org>,
	<rjw@rjwysocki.net>, <hpa@zytor.com>, <yasu.isimatu@gmail.com>,
	<isimatu.yasuaki@jp.fujitsu.com>,
	<kamezawa.hiroyu@jp.fujitsu.com>, <izumi.taku@jp.fujitsu.com>,
	<gongzhaogang@inspur.com>, <len.brown@intel.com>,
	<lenb@kernel.org>, <tglx@linutronix.de>, <chen.tang@easystack.cn>,
	<rafael@kernel.org>, <x86@kernel.org>,
	<linux-acpi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-mm@kvack.org>
Subject: Re: [PATCH v7 0/5] Make cpuid <-> nodeid mapping persistent
Date: Mon, 23 May 2016 15:02:14 +0800	[thread overview]
Message-ID: <5742AAF6.3060901@cn.fujitsu.com> (raw)
In-Reply-To: <20160519144657.GK3206@twins.programming.kicks-ass.net>

Hi,

On 05/19/2016 10:46 PM, Peter Zijlstra wrote:
> On Thu, May 19, 2016 at 06:39:41PM +0800, Zhu Guihua wrote:
>> [Problem]
>>
>> cpuid <-> nodeid mapping is firstly established at boot time. And workqueue caches
>> the mapping in wq_numa_possible_cpumask in wq_numa_init() at boot time.
>>
>> When doing node online/offline, cpuid <-> nodeid mapping is established/destroyed,
>> which means, cpuid <-> nodeid mapping will change if node hotplug happens. But
>> workqueue does not update wq_numa_possible_cpumask.
> So why are you not fixing up wq_numa_possible_cpumask instead? That
> seems the far easier solution.

We tried to do that. You can see our patch at
http://www.gossamer-threads.com/lists/linux/kernel/2116748

But maintainer thought, we should establish persistent cpuid<->nodeid 
relationship,
there is no need to change the map.

Cc TJ,
Could we return to workqueue to fix this?

Thanks,
Zhu

> Do all the other archs that support NUMA and HOTPLUG have the mapping
> stable, or will you now go fix each and every one of them?
>
>
> .
>

  reply	other threads:[~2016-05-23  7:02 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-19 10:39 [PATCH v7 0/5] Make cpuid <-> nodeid mapping persistent Zhu Guihua
2016-05-19 10:39 ` Zhu Guihua
2016-05-19 10:39 ` [PATCH v7 1/5] x86, memhp, numa: Online memory-less nodes at boot time Zhu Guihua
2016-05-19 10:39   ` Zhu Guihua
2016-05-19 10:40 ` [PATCH v7 2/5] x86, acpi, cpu-hotplug: Enable acpi to register all possible cpus " Zhu Guihua
2016-05-19 10:40   ` Zhu Guihua
2016-05-19 10:40 ` [PATCH v7 3/5] x86, acpi, cpu-hotplug: Introduce cpuid_to_apicid[] array to store persistent cpuid <-> apicid mapping Zhu Guihua
2016-05-19 10:40   ` Zhu Guihua
2016-05-19 10:40 ` [PATCH v7 4/5] x86, acpi, cpu-hotplug: Enable MADT APIs to return disabled apicid Zhu Guihua
2016-05-19 10:40   ` Zhu Guihua
2016-05-19 10:40 ` [PATCH v7 5/5] x86, acpi, cpu-hotplug: Set persistent cpuid <-> nodeid mapping when booting Zhu Guihua
2016-05-19 10:40   ` Zhu Guihua
2016-05-19 10:41 ` [PATCH v7 0/5] Make cpuid <-> nodeid mapping persistent Zhu Guihua
2016-05-19 10:41   ` Zhu Guihua
2016-05-19 12:58   ` Rafael J. Wysocki
2016-05-19 12:58     ` Rafael J. Wysocki
2016-05-19 14:46 ` Peter Zijlstra
2016-05-19 14:46   ` Peter Zijlstra
2016-05-23  7:02   ` Zhu Guihua [this message]
2016-05-23  7:02     ` Zhu Guihua
2016-05-25 20:37     ` Tejun Heo
2016-05-25 20:37       ` Tejun Heo

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