From: Alice Ryhl <aliceryhl@google.com>
To: Kunwu Chan <kunwu.chan@linux.dev>
Cc: ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com,
gary@garyguo.net, bjorn3_gh@protonmail.com,
benno.lossin@proton.me, a.hindborg@kernel.org,
tmgross@umich.edu, dakr@kernel.org, nathan@kernel.org,
nick.desaulniers+lkml@gmail.com, morbo@google.com,
justinstitt@google.com, rust-for-linux@vger.kernel.org,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
Kunwu Chan <kunwu.chan@hotmail.com>,
Grace Deng <Grace.Deng006@gmail.com>
Subject: Re: [PATCH] rust: page:: optimize rust symbol generation for Page
Date: Mon, 17 Mar 2025 10:33:10 +0000 [thread overview]
Message-ID: <Z9f6Zi2_eZFFY0Q7@google.com> (raw)
In-Reply-To: <20250317094004.2622640-1-kunwu.chan@linux.dev>
On Mon, Mar 17, 2025 at 05:40:04PM +0800, Kunwu Chan wrote:
> From: Kunwu Chan <kunwu.chan@hotmail.com>
>
> When build the kernel using the llvm-18.1.3-rust-1.85.0-x86_64
> with ARCH=arm64, the following symbols are generated:
>
> $nm vmlinux | grep ' _R'.*Page | rustfilt
> ffff8000805b6f98 T <kernel::page::Page>::alloc_page
> ffff8000805b715c T <kernel::page::Page>::fill_zero_raw
> ffff8000805b720c T <kernel::page::Page>::copy_from_user_slice_raw
> ffff8000805b6fb4 T <kernel::page::Page>::read_raw
> ffff8000805b7088 T <kernel::page::Page>::write_raw
> ffff8000805b72fc T <kernel::page::Page as core::ops::drop::Drop>::drop
>
> These Rust symbols are trivial wrappers around the C functions
> alloc_pages, kunmap_local and __free_pages.
> It doesn't make sense to go through a trivial wrapper for these
> functions, so mark them inline.
>
> Link: https://github.com/Rust-for-Linux/linux/issues/1145
> Suggested-by: Alice Ryhl <aliceryhl@google.com>
> Co-developed-by: Grace Deng <Grace.Deng006@Gmail.com>
> Signed-off-by: Grace Deng <Grace.Deng006@Gmail.com>
> Signed-off-by: Kunwu Chan <kunwu.chan@hotmail.com>
For sure `alloc_page` and `drop` should be inline, but the other methods
are not as simple. It is less clear that they should be inline.
At the very least, the claim that they are a trivial wrapper around
"kunmap_local" is false. They don't just call that method.
Alice
next prev parent reply other threads:[~2025-03-17 10:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-17 9:40 [PATCH] rust: page:: optimize rust symbol generation for Page Kunwu Chan
2025-03-17 10:33 ` Alice Ryhl [this message]
2025-03-18 2:30 ` Kunwu Chan
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