From 714e73112dfc3b2b6160c37f554012a307547861 Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Wed, 26 Apr 2023 15:55:40 +0200
Subject: [PATCH] Simplify Mutex implementation, for now.
---
src/sync/pthread_mutex.rs | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
diff --git a/src/sync/pthread_mutex.rs b/src/sync/pthread_mutex.rs
index 4b648bc6..93eea912 100644
--- a/src/sync/pthread_mutex.rs
+++ b/src/sync/pthread_mutex.rs
@@ -90,10 +90,13 @@ impl RlctMutex {
return Err(Errno(EAGAIN));
}
// CAS spuriously failed, simply retry the CAS. TODO: Use core::hint::spin_loop()?
- Err(thread) if thread & INDEX_MASK == 0 => continue,
+ Err(thread) if thread & INDEX_MASK == 0 => {
+ continue;
+ }
// CAS failed because some other thread owned the lock. We must now wait.
Err(thread) => {
- if spins_left > 0 {
+ /*if spins_left > 0 {
+ // TODO: Faster to spin trying to load the flag, compared to CAS?
spins_left -= 1;
core::hint::spin_loop();
continue;
@@ -105,10 +108,11 @@ impl RlctMutex {
if inner == STATE_UNLOCKED {
continue;
- }
+ }*/
// If the mutex is not robust, simply futex_wait until unblocked.
- crate::sync::futex_wait(&self.inner, inner | WAITING_BIT, None);
+ //crate::sync::futex_wait(&self.inner, inner | WAITING_BIT, None);
+ crate::sync::futex_wait(&self.inner, thread, None);
}
}
}
@@ -161,7 +165,7 @@ impl RlctMutex {
}
// Safe because we are not protecting any data.
pub fn unlock(&self) -> Result<(), Errno> {
- if self.robust || matches!(self.ty, Ty::Recursive | Ty::Errck){
+ if self.robust || matches!(self.ty, Ty::Recursive | Ty::Errck) {
if self.inner.load(Ordering::Relaxed) & INDEX_MASK != os_tid_invalid_after_fork() {
return Err(Errno(EPERM));
}
@@ -177,11 +181,13 @@ impl RlctMutex {
if next > 0 { return Ok(()) }
}
- let was_waiting = self.inner.swap(STATE_UNLOCKED, Ordering::Release) & WAITING_BIT != 0;
+ self.inner.store(STATE_UNLOCKED, Ordering::Release);
+ crate::sync::futex_wake(&self.inner, i32::MAX);
+ /*let was_waiting = self.inner.swap(STATE_UNLOCKED, Ordering::Release) & WAITING_BIT != 0;
if was_waiting {
let _ = crate::sync::futex_wake(&self.inner, 1);
- }
+ }*/
Ok(())
}
--
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