spinlock: try and acquire func

src/arch/x86_64/include/arch/spinlock.h

@@ -1,10 +1,16 @@
 #ifndef _SPINLOCK_H_INCLUDE
 #define _SPINLOCK_H_INCLUDE
 
+#include <stdbool.h>
+
 static inline void spinlock_acquire(int *lock){
 	while(!__sync_bool_compare_and_swap(lock, 0, 1)) asm("pause");
 }
 
+static inline bool spinlock_trytoacquire(int *lock){
+	return __sync_bool_compare_and_swap(lock, 0, 1);
+}
+
 static inline void spinlock_release(int *lock){
 	*lock = 0;
 }