From 34ff636f322c6d5e4f0a52338fa63a7dff09a495 Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Sat, 18 Jul 2026 13:15:36 -0400 Subject: scftorture: Count single_rpc offline failures in statistics output scf_torture_stats_print() aggregates each invoker thread's counters into a local scf_statistics structure before printing, but the n_single_rpc_ofl field is missing from the aggregation loop. As a result, the "single_rpc_ofl" value printed in the statistics line is always zero, even when smp_call_function_single() invocations for the RPC test have failed due to offline CPUs and been counted by the invoker threads. Add the missing accumulation so that the printed value reflects the actual counts. Signed-off-by: Joel Fernandes Signed-off-by: Paul E. McKenney --- rust/pin-init/examples/mutex.rs | 224 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 224 insertions(+) create mode 100644 rust/pin-init/examples/mutex.rs (limited to 'rust/pin-init/examples/mutex.rs') diff --git a/rust/pin-init/examples/mutex.rs b/rust/pin-init/examples/mutex.rs new file mode 100644 index 000000000..35ecb5f68 --- /dev/null +++ b/rust/pin-init/examples/mutex.rs @@ -0,0 +1,224 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +#![allow(clippy::undocumented_unsafe_blocks)] +#![cfg_attr(feature = "alloc", feature(allocator_api))] +#![allow(clippy::missing_safety_doc)] + +use core::{ + cell::{Cell, UnsafeCell}, + marker::PhantomPinned, + ops::{Deref, DerefMut}, + pin::Pin, + sync::atomic::{AtomicBool, Ordering}, +}; +#[cfg(feature = "std")] +use std::{ + sync::Arc, + thread::{self, sleep, Builder, Thread}, + time::Duration, +}; + +use pin_init::*; +#[allow(unused_attributes)] +#[path = "./linked_list.rs"] +pub mod linked_list; +use linked_list::*; + +pub struct SpinLock { + inner: AtomicBool, +} + +impl SpinLock { + #[inline] + pub fn acquire(&self) -> SpinLockGuard<'_> { + while self + .inner + .compare_exchange(false, true, Ordering::Acquire, Ordering::Relaxed) + .is_err() + { + #[cfg(feature = "std")] + while self.inner.load(Ordering::Relaxed) { + thread::yield_now(); + } + } + SpinLockGuard(self) + } + + #[inline] + #[allow(clippy::new_without_default)] + pub const fn new() -> Self { + Self { + inner: AtomicBool::new(false), + } + } +} + +pub struct SpinLockGuard<'a>(&'a SpinLock); + +impl Drop for SpinLockGuard<'_> { + #[inline] + fn drop(&mut self) { + self.0.inner.store(false, Ordering::Release); + } +} + +#[pin_data] +pub struct CMutex { + #[pin] + wait_list: ListHead, + spin_lock: SpinLock, + locked: Cell, + #[pin] + data: UnsafeCell, +} + +impl CMutex { + #[inline] + pub fn new(val: impl PinInit) -> impl PinInit { + pin_init!(CMutex { + wait_list <- ListHead::new(), + spin_lock: SpinLock::new(), + locked: Cell::new(false), + data <- unsafe { + pin_init_from_closure(|slot: *mut UnsafeCell| { + val.__pinned_init(slot.cast::()) + }) + }, + }) + } + + #[inline] + pub fn lock(&self) -> Pin> { + let mut sguard = self.spin_lock.acquire(); + if self.locked.get() { + stack_pin_init!(let wait_entry = WaitEntry::insert_new(&self.wait_list)); + // println!("wait list length: {}", self.wait_list.size()); + while self.locked.get() { + drop(sguard); + #[cfg(feature = "std")] + thread::park(); + sguard = self.spin_lock.acquire(); + } + // This does have an effect, as the ListHead inside wait_entry implements Drop! + #[expect(clippy::drop_non_drop)] + drop(wait_entry); + } + self.locked.set(true); + unsafe { + Pin::new_unchecked(CMutexGuard { + mtx: self, + _pin: PhantomPinned, + }) + } + } + + #[allow(dead_code)] + pub fn get_data_mut(self: Pin<&mut Self>) -> &mut T { + // SAFETY: we have an exclusive reference and thus nobody has access to data. + unsafe { &mut *self.data.get() } + } +} + +unsafe impl Send for CMutex {} +unsafe impl Sync for CMutex {} + +pub struct CMutexGuard<'a, T> { + mtx: &'a CMutex, + _pin: PhantomPinned, +} + +impl Drop for CMutexGuard<'_, T> { + #[inline] + fn drop(&mut self) { + let sguard = self.mtx.spin_lock.acquire(); + self.mtx.locked.set(false); + if let Some(list_field) = self.mtx.wait_list.next() { + let _wait_entry = list_field.as_ptr().cast::(); + #[cfg(feature = "std")] + unsafe { + (*_wait_entry).thread.unpark() + }; + } + drop(sguard); + } +} + +impl Deref for CMutexGuard<'_, T> { + type Target = T; + + #[inline] + fn deref(&self) -> &Self::Target { + unsafe { &*self.mtx.data.get() } + } +} + +impl DerefMut for CMutexGuard<'_, T> { + #[inline] + fn deref_mut(&mut self) -> &mut Self::Target { + unsafe { &mut *self.mtx.data.get() } + } +} + +#[pin_data] +#[repr(C)] +struct WaitEntry { + #[pin] + wait_list: ListHead, + #[cfg(feature = "std")] + thread: Thread, +} + +impl WaitEntry { + #[inline] + fn insert_new(list: &ListHead) -> impl PinInit + '_ { + #[cfg(feature = "std")] + { + pin_init!(Self { + thread: thread::current(), + wait_list <- ListHead::insert_prev(list), + }) + } + #[cfg(not(feature = "std"))] + { + pin_init!(Self { + wait_list <- ListHead::insert_prev(list), + }) + } + } +} + +#[cfg_attr(test, test)] +#[allow(dead_code)] +fn main() { + #[cfg(feature = "std")] + { + let mtx: Pin>> = Arc::pin_init(CMutex::new(0)).unwrap(); + let mut handles = vec![]; + let thread_count = 20; + let workload = if cfg!(miri) { 100 } else { 1_000 }; + for i in 0..thread_count { + let mtx = mtx.clone(); + handles.push( + Builder::new() + .name(format!("worker #{i}")) + .spawn(move || { + for _ in 0..workload { + *mtx.lock() += 1; + } + println!("{i} halfway"); + sleep(Duration::from_millis((i as u64) * 10)); + for _ in 0..workload { + *mtx.lock() += 1; + } + println!("{i} finished"); + }) + .expect("should not fail"), + ); + } + for h in handles { + h.join().expect("thread panicked"); + } + println!("{:?}", *mtx.lock()); + assert_eq!(*mtx.lock(), workload * thread_count * 2); + } +} -- cgit v1.3.1