linux-kernel - Re: [PATCH] mm/khugepaged: sched to numa node when collapse huge page

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Message-ID: <caf087b4-b184-c45e-e212-87f0a573a4d0@redhat.com>
Date:   Fri, 11 Mar 2022 10:55:14 +0100
From:   David Hildenbrand <david@...hat.com>
To:     maobibo <maobibo@...ngson.cn>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm/khugepaged: sched to numa node when collapse huge page

On 11.03.22 10:51, maobibo wrote:
> 
> 
> On 03/11/2022 05:20 PM, David Hildenbrand wrote:
>> On 11.03.22 10:01, Bibo Mao wrote:
>>> collapse huge page is slow, specially when khugepaged daemon runs
>>> on different numa node with that of huge page. It suffers from
>>> huge page copying across nodes, also cache is not used for target
>>> node. With this patch, khugepaged daemon switches to the same numa
>>> node with huge page. It saves copying time and makes use of local
>>> cache better.
>>
>> Hi,
>>
>> just the usual question, do you have any performance numbers to back
>> your claims (e.g., "is slow, specially when") and proof that this patch
>> does the trick?
> With specint 2006 on loongarch 3C5000L 32core numa system, it improves
> about 6%. The page size is 16K and pmd page size is 32M, memory performance
> across numa node is obvious different. However I do not test it on x86 box.
> 

Thanks, can you add these details to the patch description?


-- 
Thanks,

David / dhildenb