From 107bfe5badb795dece336d251f0406580b9b1ac1 Mon Sep 17 00:00:00 2001
From: cynecx <me@cynecx.net>
Date: Thu, 20 Aug 2020 22:32:21 +0200
Subject: [PATCH] Add spin_loop_hint in `register` spinlock

---
 src/lib.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index 17f87f4..b92e23f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,7 +2,7 @@
 
 use std::cell::UnsafeCell;
 use std::fmt;
-use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::{self, AtomicUsize};
 use std::sync::atomic::Ordering::{Acquire, Release, AcqRel};
 use std::task::Waker;
 
@@ -330,6 +330,9 @@ impl AtomicWaker {
                 // could also spin here trying to acquire the lock
                 // to register).
                 waker.wake_by_ref();
+
+                // This is equivalent to a spin lock, so use a spin hint.
+                atomic::spin_loop_hint();
             }
             state => {
                 // In this case, a concurrent thread is holding the