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Use less restricted memory ordering in xous::thread_local_key.

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SeqCst isn't necessary in any of these cases.
This commit is contained in:
Mara Bos 2024-03-19 15:10:35 +01:00
parent 5a594f7bcd
commit 8b519f98e2
1 changed files with 5 additions and 5 deletions
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10
library/std/src/sys/pal/xous/thread_local_key.rs
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@ -2,7 +2,7 @@
use crate::ptr; use crate::ptr;
use crate::sync::atomic::AtomicPtr; use crate::sync::atomic::AtomicPtr;
use crate::sync::atomic::AtomicUsize; use crate::sync::atomic::AtomicUsize;
use crate::sync::atomic::Ordering::SeqCst; use crate::sync::atomic::Ordering::{Acquire, Relaxed, Release};
use core::arch::asm; use core::arch::asm;
use crate::os::xous::ffi::{map_memory, unmap_memory, MemoryFlags}; use crate::os::xous::ffi::{map_memory, unmap_memory, MemoryFlags};
@ -92,7 +92,7 @@ fn tls_table() -> &'static mut [*mut u8] {
pub unsafe fn create(dtor: Option<Dtor>) -> Key { pub unsafe fn create(dtor: Option<Dtor>) -> Key {
// Allocate a new TLS key. These keys are shared among all threads. // Allocate a new TLS key. These keys are shared among all threads.
#[allow(unused_unsafe)] #[allow(unused_unsafe)]
let key = unsafe { TLS_KEY_INDEX.fetch_add(1, SeqCst) }; let key = unsafe { TLS_KEY_INDEX.fetch_add(1, Relaxed) };
if let Some(f) = dtor { if let Some(f) = dtor {
unsafe { register_dtor(key, f) }; unsafe { register_dtor(key, f) };
} }
@ -154,11 +154,11 @@ unsafe fn register_dtor(key: Key, dtor: Dtor) {
let mut node = ManuallyDrop::new(Box::new(Node { key, dtor, next: ptr::null_mut() })); let mut node = ManuallyDrop::new(Box::new(Node { key, dtor, next: ptr::null_mut() }));
#[allow(unused_unsafe)] #[allow(unused_unsafe)]
let mut head = unsafe { DTORS.load(SeqCst) }; let mut head = unsafe { DTORS.load(Acquire) };
loop { loop {
node.next = head; node.next = head;
#[allow(unused_unsafe)] #[allow(unused_unsafe)]
match unsafe { DTORS.compare_exchange(head, &mut **node, SeqCst, SeqCst) } { match unsafe { DTORS.compare_exchange(head, &mut **node, Release, Acquire) } {
Ok(_) => return, // nothing to drop, we successfully added the node to the list Ok(_) => return, // nothing to drop, we successfully added the node to the list
Err(cur) => head = cur, Err(cur) => head = cur,
} }
@ -199,7 +199,7 @@ unsafe fn run_dtors() {
} }
any_run = false; any_run = false;
#[allow(unused_unsafe)] #[allow(unused_unsafe)]
let mut cur = unsafe { DTORS.load(SeqCst) }; let mut cur = unsafe { DTORS.load(Acquire) };
while !cur.is_null() { while !cur.is_null() {
let ptr = unsafe { get((*cur).key) }; let ptr = unsafe { get((*cur).key) };