Message-ID: <a7f8be91-32c1-bfbe-7e81-5b1e818ba01d@redhat.com>
Date:   Tue, 14 Feb 2023 12:48:19 +0100
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Subject: Re: [PATCH] mm: page_alloc: don't allocate page from memoryless nodes
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To:     Mike Rapoport <rppt@kernel.org>
Cc:     Qi Zheng <zhengqi.arch@bytedance.com>,
        Qi Zheng <arch0.zheng@gmail.com>,
        Vlastimil Babka <vbabka@suse.cz>, akpm@linux-foundation.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Teng Hu <huteng.ht@bytedance.com>,
        Matthew Wilcox <willy@infradead.org>,
        Mel Gorman <mgorman@techsingularity.net>,
        Oscar Salvador <osalvador@suse.de>,
        Muchun Song <muchun.song@linux.dev>
References: <20230212110305.93670-1-zhengqi.arch@bytedance.com>
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 <c6908bd0-5f76-47eb-2b77-ce8f7bf9fbff@suse.cz>
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 <67240e55-af49-f20a-2b4b-b7d574cd910d@gmail.com>
 <22f0e262-982e-ea80-e52a-a3c924b31d58@redhat.com>
 <dbfbd982-27f3-0d72-49e0-d3dd5fe636a8@bytedance.com>
 <4386151c-0328-d207-9a71-933ef61817f9@redhat.com>
 <Y+t0Bhu7BCzH2Dp4@kernel.org>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <Y+t0Bhu7BCzH2Dp4@kernel.org>
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On 14.02.23 12:44, Mike Rapoport wrote:
> (added x86 folks)
> 
> On Tue, Feb 14, 2023 at 12:29:42PM +0100, David Hildenbrand wrote:
>> On 14.02.23 12:26, Qi Zheng wrote:
>>> On 2023/2/14 19:22, David Hildenbrand wrote:
>>>>
>>>> TBH, this is the first time I hear of NODE_MIN_SIZE and it seems to be a
>>>> pretty x86 specific thing.
>>>>
>>>> Are we sure we want to get NODE_MIN_SIZE involved?
>>>
>>> Maybe add an arch_xxx() to handle it?
>>
>> I still haven't figured out what we want to achieve with NODE_MIN_SIZE at
>> all. It smells like an arch-specific hack looking at
>>
>> "Don't confuse VM with a node that doesn't have the minimum amount of
>> memory"
>>
>> Why shouldn't mm-core deal with that?
> 
> Well, a node with <4M RAM is not very useful and bears all the overhead of
> an extra live node.

And totally not with 4.1M, haha.

I really like the "Might fix boot" in the commit description.

> 
> But, hey, why won't we just drop that '< NODE_MIN_SIZE' and let people with
> weird HW configurations just live with this?


;)

-- 
Thanks,

David / dhildenb