--- Gnu-Mach/ipc/ipc_thread.h	2020/09/02 04:36:56	1.1.1.1
+++ Gnu-Mach/ipc/ipc_thread.h	2020/09/02 04:45:04	1.1.1.2
@@ -46,6 +46,11 @@ typedef thread_t ipc_thread_t;
 #define	ith_lock(thread)	simple_lock(&(thread)->ith_lock_data)
 #define	ith_unlock(thread)	simple_unlock(&(thread)->ith_lock_data)
 
+/*
+ *	Note that this isn't a queue, but rather a stack. This causes
+ *	threads that were recently running to be reused earlier, which
+ *	helps improve locality of reference.
+ */
 typedef struct ipc_thread_queue {
 	ipc_thread_t ithq_base;
 } *ipc_thread_queue_t;
@@ -103,6 +108,7 @@ MACRO_BEGIN								\
 		(thread)->ith_prev = _last;				\
 		_first->ith_prev = (thread);				\
 		_last->ith_next = (thread);				\
+		(queue)->ithq_base = (thread);				\
 	}								\
 MACRO_END