mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Use compare_exchange_weak in futex rwlock implementation.

Browse Source
This commit is contained in:
Mara Bos 2022-04-11 14:29:32 +02:00
parent 1f2c2bb24f
commit c4a4f48c52
1 changed files with 11 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
library/std/src/sys/unix/locks/futex_rwlock.rs
View File

@ -75,7 +75,13 @@ pub unsafe fn try_read(&self) -> bool {
#[inline]
pub unsafe fn read(&self) {
if !self.try_read() {
let state = self.state.load(Relaxed);
if !read_lockable(state)
|| self
.state
.compare_exchange_weak(state, state + READ_LOCKED, Acquire, Relaxed)
.is_err()
{
self.read_contended();
}
}
@ -101,7 +107,8 @@ fn read_contended(&self) {
loop {
// If we can lock it, lock it.
if read_lockable(state) {
match self.state.compare_exchange(state, state + READ_LOCKED, Acquire, Relaxed) {
match self.state.compare_exchange_weak(state, state + READ_LOCKED, Acquire, Relaxed)
{
Ok(_) => return, // Locked!
Err(s) => {
state = s;
@ -140,7 +147,7 @@ pub unsafe fn try_write(&self) -> bool {
#[inline]
pub unsafe fn write(&self) {
if !self.try_write() {
if self.state.compare_exchange_weak(0, WRITE_LOCKED, Acquire, Relaxed).is_err() {
self.write_contended();
}
}
@ -165,7 +172,7 @@ fn write_contended(&self) {
loop {
// If it's unlocked, we try to lock it.
if unlocked(state) {
match self.state.compare_exchange(
match self.state.compare_exchange_weak(
state,
state | WRITE_LOCKED | other_writers_waiting,
Acquire,