linux-kernel - Re: [RFC 2/2] rust: sync: Add atomic support

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Message-ID: <c243bef3-e152-462f-be68-91dbf876092b@nvidia.com>
Date: Fri, 14 Jun 2024 18:28:00 -0700
From: John Hubbard <jhubbard@...dia.com>
To: Boqun Feng <boqun.feng@...il.com>
CC: Miguel Ojeda <miguel.ojeda.sandonis@...il.com>, Gary Guo
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	<linux-kernel@...r.kernel.org>, <linux-arch@...r.kernel.org>,
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	Björn Roy Baron <bjorn3_gh@...tonmail.com>, Benno Lossin
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Subject: Re: [RFC 2/2] rust: sync: Add atomic support

On 6/14/24 6:24 PM, Boqun Feng wrote:
> On Fri, Jun 14, 2024 at 06:03:37PM -0700, John Hubbard wrote:
>> On 6/14/24 2:59 AM, Miguel Ojeda wrote:
>>> On Thu, Jun 13, 2024 at 9:05 PM Boqun Feng <boqun.feng@...il.com> wrote:
>>>>
>>>> Does this make sense?
>>>
>>> Implementation-wise, if you think it is simpler or more clear/elegant
>>> to have the extra lower level layer, then that sounds fine.
>>>
>>> However, I was mainly talking about what we would eventually expose to
>>> users, i.e. do we want to provide `Atomic<T>` to begin with? If yes,
>>> then we could make the lower layer private already.
>>>
>>> We can defer that extra layer/work if needed even if we go for
>>> `Atomic<T>`, but it would be nice to understand if we have consensus
>>> for an eventual user-facing API, or if someone has any other opinion
>>> or concerns on one vs. the other.
>>
>> Well, here's one:
>>
>> The reason that we have things like atomic64_read() in the C code is
>> because C doesn't have generics.
>>
>> In Rust, we should simply move directly to Atomic<T>, as there are,
>> after all, associated benefits. And it's very easy to see the connection
> 
> What are the associated benefits you are referring to? Rust std doesn't
> use Atomic<T>, that somewhat proves that we don't need it.
  
Just the stock things that a generic provides: less duplicated code,
automatic support for future types (although here it's really just
integer types we care about of course).


thanks,
-- 
John Hubbard
NVIDIA