From: Danilo Krummrich <dakr@redhat.com>
To: Gary Guo <gary@garyguo.net>
Cc: Benno Lossin <benno.lossin@proton.me>,
ojeda@kernel.org, alex.gaynor@gmail.com, wedsonaf@gmail.com,
boqun.feng@gmail.com, bjorn3_gh@protonmail.com,
a.hindborg@samsung.com, aliceryhl@google.com,
ajanulgu@redhat.com, zhiw@nvidia.com, acurrid@nvidia.com,
cjia@nvidia.com, jhubbard@nvidia.com,
rust-for-linux@vger.kernel.org
Subject: Re: [PATCH WIP 3/8] rust: alloc: implement AllocatorWithFlags trait
Date: Mon, 6 May 2024 15:17:07 +0200 [thread overview]
Message-ID: <ab50e6b7-b6a0-488c-a225-d71bc626ccc2@redhat.com> (raw)
In-Reply-To: <20240503162714.67188a22@eugeo>
On 5/3/24 17:27, Gary Guo wrote:
> On Wed, 1 May 2024 14:50:27 +0200
> Danilo Krummrich <dakr@redhat.com> wrote:
>
>>>
>>>> +
>>>> + fn default_allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
>>>> + unsafe { self.realloc_flags(ptr::null_mut(), 0, layout, GFP_KERNEL) }
>>>> + }
>>>
>>> Why do we want to have these functions? I think that it would make sense
>>> to forbid all other ways of allocating memory. So only allow allocation
>>> where the flags are explicitly passed.
>>
>> I agree that we should forbid allocating memory with implicit default page
>> flags.
>>
>> I added them, since I think we'll always need some implementation of the
>> Allocator trait. And this just was the obvious generic implementation.
>
> Ignoring Benno's point about enforcing explicit allocation, these
> functions still shouldn't exist. Given `Allocator` is a super trait,
> all implementors should just implement their default allocation
> behaviour in their `Allocator` implementation rather than calling into
> the `default_allocate` function.
Well, most Allocator's default allocation behavior is likely to be the same,
which is calling *their* realloc_flags() implementation with a NULL pointer
and GFP_KERNEL for allocate() and with an additional __GFP_ZERO for
allocate_zeroed(), hence the corresponding default helpers.
However, it doesn't really save a lot of boilerplate, hence I agree we could
just omit those.
>
> - Gary
>
next prev parent reply other threads:[~2024-05-06 13:17 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-29 20:11 [PATCH WIP 0/8] Draft: Alternative allocator support Danilo Krummrich
2024-04-29 20:11 ` [PATCH WIP 1/8] rust: alloc: re-enable allocator_api Danilo Krummrich
2024-04-29 20:11 ` [PATCH WIP 2/8] rust: alloc: use AllocError from core::alloc Danilo Krummrich
2024-04-29 20:11 ` [PATCH WIP 3/8] rust: alloc: implement AllocatorWithFlags trait Danilo Krummrich
2024-05-01 8:32 ` Benno Lossin
2024-05-01 12:50 ` Danilo Krummrich
2024-05-01 15:39 ` Benno Lossin
2024-05-01 15:48 ` Danilo Krummrich
2024-05-01 21:38 ` Miguel Ojeda
2024-05-03 15:27 ` Gary Guo
2024-05-06 13:17 ` Danilo Krummrich [this message]
2024-04-29 20:11 ` [PATCH WIP 4/8] rust: alloc: separate krealloc_aligned() Danilo Krummrich
2024-04-29 20:11 ` [PATCH WIP 5/8] rust: alloc: implement AllocatorWithFlags for KernelAllocator Danilo Krummrich
2024-05-01 8:44 ` Benno Lossin
2024-05-01 12:52 ` Danilo Krummrich
2024-04-29 20:11 ` [PATCH WIP 6/8] rust: alloc: implement BoxExtAlloc Danilo Krummrich
2024-05-01 8:53 ` Benno Lossin
2024-05-01 13:06 ` Danilo Krummrich
2024-05-01 15:46 ` Benno Lossin
2024-05-01 17:30 ` Danilo Krummrich
2024-04-29 20:11 ` [PATCH WIP 7/8] rust: alloc: implement VecExtAlloc Danilo Krummrich
2024-04-29 20:11 ` [PATCH WIP 8/8] rust: alloc: implement vmalloc allocator Danilo Krummrich
2024-05-01 21:32 ` [PATCH WIP 0/8] Draft: Alternative allocator support Miguel Ojeda
2024-05-01 22:31 ` Danilo Krummrich
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