linux-kernel - Re: [RFC PATCH v2 0/5] Reduce NUMA balance caused TLB-shootdowns in a VM

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Message-ID: <37325c27-223d-400d-bd86-34bdbfb92a5f@nvidia.com>
Date:   Wed, 16 Aug 2023 11:00:36 -0700
From:   John Hubbard <jhubbard@...dia.com>
To:     David Hildenbrand <david@...hat.com>,
        Yan Zhao <yan.y.zhao@...el.com>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, pbonzini@...hat.com, seanjc@...gle.com,
        mike.kravetz@...cle.com, apopple@...dia.com, jgg@...dia.com,
        rppt@...nel.org, akpm@...ux-foundation.org, kevin.tian@...el.com,
        Mel Gorman <mgorman@...hsingularity.net>
Subject: Re: [RFC PATCH v2 0/5] Reduce NUMA balance caused TLB-shootdowns in a
 VM

On 8/16/23 02:49, David Hildenbrand wrote:
> But do 32bit architectures even care about NUMA hinting? If not, just 
> ignore them ...

Probably not!

...
>> So, do you mean that let kernel provide a per-VMA allow/disallow 
>> mechanism, and
>> it's up to the user space to choose between per-VMA and complex way or
>> global and simpler way?
> 
> QEMU could do either way. The question would be if a per-vma settings 
> makes sense for NUMA hinting.

 From our experience with compute on GPUs, a per-mm setting would suffice.
No need to go all the way to VMA granularity.


thanks,
-- 
John Hubbard
NVIDIA