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| author | I Hsin Cheng <richard120310@gmail.com> | 2025-03-19 10:26:40 +0800 |
|---|---|---|
| committer | Joel Fernandes <joelagnelf@nvidia.com> | 2025-05-16 09:00:54 -0400 |
| commit | 9520371e3daa75cd508b262ac16a732d3ffc9a30 (patch) | |
| tree | cabf188350f36fee4c7f28943e59c10fa7c00f4a | |
| parent | da6b85598af30e9fec34d82882d7e1e39f3da769 (diff) | |
| download | ipsec-9520371e3daa75cd508b262ac16a732d3ffc9a30.tar.gz | |
rust: sync: rcu: Mark Guard methods as inline
Currently the implementation of "Guard" methods are basically wrappers
around rcu's function within kernel. Building the kernel with llvm
18.1.8 on x86_64 machine will generate the following symbols:
$ nm vmlinux | grep ' _R'.*Guard | rustfilt
ffffffff817b6c90 T <kernel::sync::rcu::Guard>::new
ffffffff817b6cb0 T <kernel::sync::rcu::Guard>::unlock
ffffffff817b6cd0 T <kernel::sync::rcu::Guard as core::ops::drop::Drop>::drop
ffffffff817b6c90 T <kernel::sync::rcu::Guard as core::default::Default>::default
These Rust symbols are basically wrappers around functions
"rcu_read_lock" and "rcu_read_unlock". Marking them as inline can
reduce the generation of these symbols, and saves the size of code
generation for 132 bytes.
$ ./scripts/bloat-o-meter vmlinux_old vmlinux_new
(Output is demangled for readability)
add/remove: 0/10 grow/shrink: 0/1 up/down: 0/-132 (-132)
Function old new delta
rust_driver_pci::SampleDriver::probe 1041 1034 -7
kernel::sync::rcu::Guard::default 9 - -9
kernel::sync::rcu::Guard::drop 9 - -9
kernel::sync::rcu::read_lock 9 - -9
kernel::sync::rcu::Guard::unlock 9 - -9
kernel::sync::rcu::Guard::new 9 - -9
__pfx__kernel::sync::rcu::Guard::default 16 - -16
__pfx__kernel::sync::rcu::Guard::drop 16 - -16
__pfx__kernel::sync::rcu::read_lock 16 - -16
__pfx__kernel::sync::rcu::Guard::unlock 16 - -16
__pfx__kernel::sync::rcu::Guard::new 16 - -16
Total: Before=23365955, After=23365823, chg -0.00%
Link: https://github.com/Rust-for-Linux/linux/issues/1145
Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Charalampos Mitrodimas <charmitro@posteo.net>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
| -rw-r--r-- | rust/kernel/sync/rcu.rs | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/rust/kernel/sync/rcu.rs b/rust/kernel/sync/rcu.rs index b51d9150ffe285..a32bef6e490b0e 100644 --- a/rust/kernel/sync/rcu.rs +++ b/rust/kernel/sync/rcu.rs @@ -17,6 +17,7 @@ pub struct Guard(NotThreadSafe); impl Guard { /// Acquires the RCU read side lock and returns a guard. + #[inline] pub fn new() -> Self { // SAFETY: An FFI call with no additional requirements. unsafe { bindings::rcu_read_lock() }; @@ -25,16 +26,19 @@ impl Guard { } /// Explicitly releases the RCU read side lock. + #[inline] pub fn unlock(self) {} } impl Default for Guard { + #[inline] fn default() -> Self { Self::new() } } impl Drop for Guard { + #[inline] fn drop(&mut self) { // SAFETY: By the type invariants, the RCU read side is locked, so it is ok to unlock it. unsafe { bindings::rcu_read_unlock() }; @@ -42,6 +46,7 @@ impl Drop for Guard { } /// Acquires the RCU read side lock. +#[inline] pub fn read_lock() -> Guard { Guard::new() } |