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Date:   Wed, 10 Aug 2022 12:05:42 +0200
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To:     Chao Peng <chao.p.peng@linux.intel.com>
Cc:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
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        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
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        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
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        Shuah Khan <shuah@kernel.org>, Mike Rapoport <rppt@kernel.org>,
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From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
Subject: Re: [PATCH v7 03/14] mm: Introduce memfile_notifier
In-Reply-To: <20220810092232.GC862421@chaop.bj.intel.com>
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On 10.08.22 11:22, Chao Peng wrote:
> On Fri, Aug 05, 2022 at 03:22:58PM +0200, David Hildenbrand wrote:
>> On 06.07.22 10:20, Chao Peng wrote:
>>> This patch introduces memfile_notifier facility so existing memory file
>>> subsystems (e.g. tmpfs/hugetlbfs) can provide memory pages to allow a
>>> third kernel component to make use of memory bookmarked in the memory
>>> file and gets notified when the pages in the memory file become
>>> invalidated.
>>
>> Stupid question, but why is this called "memfile_notifier" and not
>> "memfd_notifier". We're only dealing with memfd's after all ... which
>> are anonymous files essentially. Or what am I missing? Are there any
>> other plans for fs than plain memfd support that I am not aware of?
> 
> There were some discussions on this in v3.
>   https://lkml.org/lkml/2021/12/28/484
> Sean commented it's OK to abstract it from memfd but he also wants the
> kAPI (name) should not bind to memfd to make room for future non-memfd
> usages.

Sorry, but how is "memfile" any better? memfd abstracted to memfile?! :)

I understand Sean's suggestion about abstracting, but if the new name
makes it harder to grasp and there isn't really an alternative to memfd
in sight, I'm not so sure I enjoy the tried abstraction here.

Otherwise we'd have to get creative now and discuss something like
"file_population_notifer" or "mapping_population_notifer" and I am not
sure that our time is well spent doing so right now.

... as this is kernel-internal, we can always adjust the name as we
please later, once we *actually* now what the abstraction should be.
Until then I'd suggest to KIS and soft-glue this to memfd.

Or am I missing something important?

-- 
Thanks,

David / dhildenb