From 5c154d34dc52edcff32355c819bdcc8b999cb3da Mon Sep 17 00:00:00 2001
From: colin <124654806@qq.com>
Date: Wed, 30 Jun 2021 12:42:58 +0800
Subject: [PATCH] improve spinlock (#1431)

* improve spinlock

* improve spinlock

* typo

Co-authored-by: colin <linzhengqun@163.com>
---
 skynet-src/spinlock.h | 60 +++++++++++++++++++++++++++++++++++--------
 1 file changed, 50 insertions(+), 10 deletions(-)

diff --git a/skynet-src/spinlock.h b/skynet-src/spinlock.h
index 673a207c..04668082 100644
--- a/skynet-src/spinlock.h
+++ b/skynet-src/spinlock.h
@@ -15,16 +15,6 @@
 #define atomic_flag_test_and_set_(ptr) __sync_lock_test_and_set(ptr, 1)
 #define atomic_flag_clear_(ptr) __sync_lock_release(ptr)
 
-#else
-
-#include <stdatomic.h>
-#define atomic_flag_ atomic_flag
-#define ATOMIC_FLAG_INIT_ ATOMIC_FLAG_INIT
-#define atomic_flag_test_and_set_ atomic_flag_test_and_set
-#define atomic_flag_clear_ atomic_flag_clear
-
-#endif
-
 struct spinlock {
 	atomic_flag_ lock;
 };
@@ -55,6 +45,56 @@ spinlock_destroy(struct spinlock *lock) {
 	(void) lock;
 }
 
+#else  // __STDC_NO_ATOMICS__
+
+#include <stdatomic.h>
+#define atomic_test_and_set_(ptr) atomic_exchange_explicit(ptr, 1, memory_order_acquire)
+#define atomic_clear_(ptr) atomic_store_explicit(ptr, 0, memory_order_release);
+#define atomic_load_relaxed_(ptr) atomic_load_explicit(ptr, memory_order_relaxed)
+
+#if defined(__x86_64__)
+#define atomic_pause_() __builtin_ia32_pause()
+#else
+#define atomic_pause_() ((void)0)
+#endif
+
+struct spinlock {
+	atomic_int lock;
+};
+
+static inline void
+spinlock_init(struct spinlock *lock) {
+	atomic_init(&lock->lock, 0);
+}
+
+static inline void
+spinlock_lock(struct spinlock *lock) {
+	for (;;) {
+	  if (!atomic_test_and_set_(&lock->lock))
+		return;
+	  while (atomic_load_relaxed_(&lock->lock))
+		atomic_pause_();
+	}
+}
+
+static inline int
+spinlock_trylock(struct spinlock *lock) {
+	return !atomic_load_relaxed_(&lock->lock) &&
+		!atomic_test_and_set_(&lock->lock);
+}
+
+static inline void
+spinlock_unlock(struct spinlock *lock) {
+	atomic_clear_(&lock->lock);
+}
+
+static inline void
+spinlock_destroy(struct spinlock *lock) {
+	(void) lock;
+}
+
+#endif  // __STDC_NO_ATOMICS__
+
 #else
 
 #include <pthread.h>