[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <926bd5f9-bf05-2e01-26da-da3f66439d3b@redhat.com>
Date: Wed, 14 Apr 2021 10:12:29 +0200
From: David Hildenbrand <david@...hat.com>
To: Oscar Salvador <osalvador@...e.de>, Wei Xu <weixugc@...gle.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>,
Linux MM <linux-mm@...ck.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Yang Shi <shy828301@...il.com>,
David Rientjes <rientjes@...gle.com>,
Huang Ying <ying.huang@...el.com>,
Dan Williams <dan.j.williams@...el.com>
Subject: Re: [PATCH 02/10] mm/numa: automatically generate node migration
order
On 14.04.21 10:08, Oscar Salvador wrote:
> On Fri, Apr 09, 2021 at 08:07:08PM -0700, Wei Xu wrote:
>> On Thu, Apr 1, 2021 at 11:35 AM Dave Hansen <dave.hansen@...ux.intel.com> wrote:
>>> + * When Node 0 fills up, its memory should be migrated to
>>> + * Node 1. When Node 1 fills up, it should be migrated to
>>> + * Node 2. The migration path start on the nodes with the
>>> + * processors (since allocations default to this node) and
>>> + * fast memory, progress through medium and end with the
>>> + * slow memory:
>>> + *
>>> + * 0 -> 1 -> 2 -> stop
>>> + * 3 -> 4 -> 5 -> stop
>>> + *
>>> + * This is represented in the node_demotion[] like this:
>>> + *
>>> + * { 1, // Node 0 migrates to 1
>>> + * 2, // Node 1 migrates to 2
>>> + * -1, // Node 2 does not migrate
>>> + * 4, // Node 3 migrates to 4
>>> + * 5, // Node 4 migrates to 5
>>> + * -1} // Node 5 does not migrate
>>> + */
>>
>> In this example, if we want to support multiple nodes as the demotion
>> target of a source node, we can group these nodes into three tiers
>> (classes):
>>
>> fast class:
>> 0 -> {1, 4} // 1 is the preferred
>> 3 -> {4, 1} // 4 is the preferred
>>
>> medium class:
>> 1 -> {2, 5} // 2 is the preferred
>> 4 -> {5, 2} // 5 is the preferred
>>
>> slow class:
>> 2 -> stop
>> 5 -> stop
>
> Hi Wei Xu,
>
> I have some questions about it
>
> Fast class/memory are pictured as those nodes with CPUs, while Slow class/memory
> are PMEM, right?
> Then, what stands for medium class/memory?
My guest best is that fast class is something like HBM (High Bandwidth
Memory), medium class is ordinary RAM, slow class is PMEM.
--
Thanks,
David / dhildenb
Powered by blists - more mailing lists