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Message-ID: <35bd1d51-35ac-3ee6-e068-f50dff7774bf@bytedance.com>
Date:   Wed, 18 Oct 2023 21:20:37 +0800
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Subject: Re: [PATCH v2] x86/mm: Drop 4MB restriction on minimal NUMA node
 memory size
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To:     Ingo Molnar <mingo@kernel.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Mike Rapoport <rppt@kernel.org>,
        David Hildenbrand <david@redhat.com>,
        Michal Hocko <mhocko@suse.com>, x86@kernel.org,
        Andy Lutomirski <luto@kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
References: <20231017062215.171670-1-rppt@kernel.org>
 <ZS+2qqjEO5/867br@gmail.com>
 <605cc166-e731-e7d1-25d7-b6797a802e6f@bytedance.com>
 <ZS/TRNf02Un8IOTK@gmail.com>
From:   Qi Zheng <zhengqi.arch@bytedance.com>
In-Reply-To: <ZS/TRNf02Un8IOTK@gmail.com>
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Hi Ingo,

On 2023/10/18 20:44, Ingo Molnar wrote:
> 
> * Qi Zheng <zhengqi.arch@bytedance.com> wrote:
> 
>>> While I agree with dropping the limitation, and I agree that
>>> 9391a3f9c7f1 should have provided more of a justification, I believe a
>>> core MM fix is in order as well, for it to not crash. [ If it's fixed
>>> upstream already, please reference the relevant commit ID. ]
>>
>> Agree. I posted a fixed patchset[1] before, maybe we can reconsider it.
>> :)
>>
>> [1]. https://lore.kernel.org/lkml/20230215152412.13368-1-zhengqi.arch@bytedance.com/
>>
>> For memoryless node, this patchset skip it and fallback to other nodes
>> when build its zonelists.
> 
> Mind resubmitting that to the MM folks, with the NULL dereference crash
> mentioned prominently? Feel free to Cc: me.

OK, I will resend it if no one else objects. :)

Thanks,
Qi

> 
> Fixing hypothetical robustness problems is good, fixing specific crashes is
> better. :-)
> 
> Thanks,
> 
> 	Ingo