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AJvYcCWLVoma4Q8JlRZ6pn/pjuOjgn6DzFH5asEd8mePxlE9ylPm9JDbYAYfZuqgPrjwNNv3IAlIe+XYbR+gA2jzCg==@vger.kernel.org X-Gm-Message-State: AOJu0YySKu7c27pik0hhtHJNfZZII0N7zTVQV46FLutN1VRftoGmy3IU tWs1Vc5K/Bb8wL+JI0SBwXSKAXrI5uOcuK6hoxNDbDTMVPEf1TPwKPM/eqzrIeu3CjtXz4CTfK4 3Qvv5StHVd44KeA== X-Google-Smtp-Source: AGHT+IHGHyX+6ByhebHTO9V3LY5GS887qbOd27cikxIO2WguSKFpckY3Ttr8Dc4mg9GMsrlGAQAL0Lzpoi+1cFY= X-Received: from wmbgz10.prod.google.com ([2002:a05:600c:888a:b0:43b:d6ca:6dd3]) (user=aliceryhl job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:35c9:b0:43c:fd72:f039 with SMTP id 5b1f17b1804b1-43d1ec835e8mr138658855e9.11.1742207592764; Mon, 17 Mar 2025 03:33:12 -0700 (PDT) Date: Mon, 17 Mar 2025 10:33:10 +0000 In-Reply-To: <20250317094004.2622640-1-kunwu.chan@linux.dev> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250317094004.2622640-1-kunwu.chan@linux.dev> Message-ID: Subject: Re: [PATCH] rust: page:: optimize rust symbol generation for Page From: Alice Ryhl To: Kunwu Chan 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 , Grace Deng Content-Type: text/plain; charset="utf-8" On Mon, Mar 17, 2025 at 05:40:04PM +0800, Kunwu Chan wrote: > From: Kunwu Chan > > 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 ::alloc_page > ffff8000805b715c T ::fill_zero_raw > ffff8000805b720c T ::copy_from_user_slice_raw > ffff8000805b6fb4 T ::read_raw > ffff8000805b7088 T ::write_raw > ffff8000805b72fc T ::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 > Co-developed-by: Grace Deng > Signed-off-by: Grace Deng > Signed-off-by: Kunwu Chan 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