linux-kernel - Re: [PATCH v8 mm-new 04/12] mm: thp: add support for BPF based THP order selection

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Message-ID: <a5015724-a799-4151-bcc4-000c2c5c7178@infradead.org>
Date: Fri, 26 Sep 2025 12:17:45 -0700
From: Randy Dunlap <rdunlap@...radead.org>
To: Usama Arif <usamaarif642@...il.com>, Yafang Shao <laoar.shao@...il.com>,
 akpm@...ux-foundation.org, david@...hat.com, ziy@...dia.com,
 baolin.wang@...ux.alibaba.com, lorenzo.stoakes@...cle.com,
 Liam.Howlett@...cle.com, npache@...hat.com, ryan.roberts@....com,
 dev.jain@....com, hannes@...xchg.org, gutierrez.asier@...wei-partners.com,
 willy@...radead.org, ast@...nel.org, daniel@...earbox.net,
 andrii@...nel.org, ameryhung@...il.com, rientjes@...gle.com, corbet@....net,
 21cnbao@...il.com, shakeel.butt@...ux.dev, tj@...nel.org,
 lance.yang@...ux.dev
Cc: bpf@...r.kernel.org, linux-mm@...ck.org, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v8 mm-new 04/12] mm: thp: add support for BPF based THP
 order selection



On 9/26/25 8:13 AM, Usama Arif wrote:
>> +config BPF_THP_GET_ORDER_EXPERIMENTAL
>> +	bool "BPF-based THP order selection (EXPERIMENTAL)"
>> +	depends on TRANSPARENT_HUGEPAGE && BPF_SYSCALL
>> +
>> +	help
>> +	  Enable dynamic THP order selection using BPF programs. This
>> +	  experimental feature allows custom BPF logic to determine optimal
>> +	  transparent hugepage allocation sizes at runtime.
>> +
>> +	  WARNING: This feature is unstable and may change in future kernel
>> +	  versions.
>> +
> I am assuming this series opens up the possibility of additional hooks being added in
> the future. Instead of naming this BPF_THP_GET_ORDER_EXPERIMENTAL, should we
> name it BPF_THP? Otherwise we will end up with 1 Kconfig option per hook, which
> is quite bad.
> 
> Also It would be really nice if we dont put "EXPERIMENTAL" in the name of the defconfig.
> If its decided that its not experimental anymore without any change to the code needed,
> renaming the defconfig will break it for everyone.

s/defconfig/Kconfig symbol/

Otherwise agreed.
Thanks.
-- 
~Randy