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Message-ID: <20250317081351.2503049-1-kunwu.chan@linux.dev>
Date: Mon, 17 Mar 2025 16:13:50 +0800
From: Kunwu Chan <kunwu.chan@...ux.dev>
To: ojeda@...nel.org,
alex.gaynor@...il.com,
boqun.feng@...il.com,
gary@...yguo.net,
bjorn3_gh@...tonmail.com,
benno.lossin@...ton.me,
a.hindborg@...nel.org,
aliceryhl@...gle.com,
tmgross@...ch.edu,
dakr@...nel.org,
nathan@...nel.org,
nick.desaulniers+lkml@...il.com,
morbo@...gle.com,
justinstitt@...gle.com
Cc: rust-for-linux@...r.kernel.org,
linux-kernel@...r.kernel.org,
llvm@...ts.linux.dev,
Kunwu Chan <kunwu.chan@...mail.com>,
Grace Deng <Grace.Deng006@...il.com>
Subject: [PATCH] rust: sync: optimize rust symbol generation for CondVar
From: Kunwu Chan <kunwu.chan@...mail.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'.*CondVar | rustfilt
... T <kernel::sync::condvar::CondVar>::notify_all
... T <kernel::sync::condvar::CondVar>::notify_one
... T <kernel::sync::condvar::CondVar>::notify_sync
... T <kernel::sync::condvar::CondVar>::new::{closure#0}::{closure#0}::panic_cold_explicit
... T <kernel::sync::condvar::CondVar>::new::{closure#0}::{closure#0}::panic_cold_explicit
... T <kernel::sync::poll::PollCondVar>::new::{closure#0}::{closure#0}::panic_cold_explicit
... T <kernel::sync::poll::PollCondVar as core::ops::drop::Drop>::drop
These notify* symbols are trivial wrappers around the C functions
__wake_up and __wake_up_sync.
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@...gle.com>
Co-developed-by: Grace Deng <Grace.Deng006@...il.com>
Signed-off-by: Grace Deng <Grace.Deng006@...il.com>
Signed-off-by: Kunwu Chan <kunwu.chan@...mail.com>
---
rust/kernel/sync/condvar.rs | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/rust/kernel/sync/condvar.rs b/rust/kernel/sync/condvar.rs
index 7df565038d7d..a826896ba3f0 100644
--- a/rust/kernel/sync/condvar.rs
+++ b/rust/kernel/sync/condvar.rs
@@ -181,6 +181,7 @@ pub fn wait_interruptible_timeout<T: ?Sized, B: Backend>(
}
/// Calls the kernel function to notify the appropriate number of threads.
+ #[inline]
fn notify(&self, count: c_int) {
// SAFETY: `wait_queue_head` points to valid memory.
unsafe {
@@ -198,6 +199,7 @@ fn notify(&self, count: c_int) {
/// This method behaves like `notify_one`, except that it hints to the scheduler that the
/// current thread is about to go to sleep, so it should schedule the target thread on the same
/// CPU.
+ #[inline]
pub fn notify_sync(&self) {
// SAFETY: `wait_queue_head` points to valid memory.
unsafe { bindings::__wake_up_sync(self.wait_queue_head.get(), TASK_NORMAL) };
@@ -207,6 +209,7 @@ pub fn notify_sync(&self) {
///
/// This is not 'sticky' in the sense that if no thread is waiting, the notification is lost
/// completely (as opposed to automatically waking up the next waiter).
+ #[inline]
pub fn notify_one(&self) {
self.notify(1);
}
@@ -215,6 +218,7 @@ pub fn notify_one(&self) {
///
/// This is not 'sticky' in the sense that if no thread is waiting, the notification is lost
/// completely (as opposed to automatically waking up the next waiter).
+ #[inline]
pub fn notify_all(&self) {
self.notify(0);
}
--
2.43.0
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