xnu-792.18.15.tar.gz

[apple/xnu.git] / osfmk / kern / wait_queue.h

diff --git a/osfmk/kern/wait_queue.h b/osfmk/kern/wait_queue.h
index 5650b85e82fb673fd8b9aed59352d499ddfd602a..74c8fa6d7175a6c1494e8968a4d86764e7a3fb36 100644 (file)
--- a/osfmk/kern/wait_queue.h
+++ b/osfmk/kern/wait_queue.h
@@ -1,31 +1,29 @@
 /*
  * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
  *
- * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
- * This file contains Original Code and/or Modifications of Original Code 
- * as defined in and that are subject to the Apple Public Source License 
- * Version 2.0 (the 'License'). You may not use this file except in 
- * compliance with the License.  The rights granted to you under the 
- * License may not be used to create, or enable the creation or 
- * redistribution of, unlawful or unlicensed copies of an Apple operating 
- * system, or to circumvent, violate, or enable the circumvention or 
- * violation of, any terms of an Apple operating system software license 
- * agreement.
- *
- * Please obtain a copy of the License at 
- * http://www.opensource.apple.com/apsl/ and read it before using this 
- * file.
- *
- * The Original Code and all software distributed under the License are 
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
- * Please see the License for the specific language governing rights and 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ * 
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
  * limitations under the License.
- *
- * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
+ * 
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 
 #ifdef KERNEL_PRIVATE
@@ -157,13 +155,24 @@ typedef struct wait_queue_link {
  * a problem with a thread lock, it normally times out at the wait
  * queue level first, hiding the real problem.
  */
-#define wait_queue_lock(wq)    \
-       ((void) (!hw_lock_to(&(wq)->wq_interlock, LockTimeOut * 2) ? \
-                panic("wait queue deadlock - wq=0x%x, cpu=%d\n", \
-                      wq, cpu_number()) : 0))
 
-#define wait_queue_unlock(wq) \
-       (assert(wait_queue_held(wq)), hw_lock_unlock(&(wq)->wq_interlock))
+static inline void wait_queue_lock(wait_queue_t wq) {
+       if (!hw_lock_to(&(wq)->wq_interlock, LockTimeOut * 2))
+               panic("wait queue deadlock - wq=0x%x, cpu=%d\n", wq, cpu_number());
+}
+
+static inline void wait_queue_unlock(wait_queue_t wq) {
+       assert(wait_queue_held(wq));
+#if defined(__i386__)
+       /* On certain x86 systems, this spinlock is susceptible to
+        * lock starvation. Hence use an unlock variant which performs
+        * a cacheline flush to minimize cache affinity on acquisition.
+        */
+       i386_lock_unlock_with_flush(&(wq)->wq_interlock);
+#else
+        hw_lock_unlock(&(wq)->wq_interlock);
+#endif
+}
 
 #define wqs_lock(wqs)          wait_queue_lock(&(wqs)->wqs_wait_queue)
 #define wqs_unlock(wqs)                wait_queue_unlock(&(wqs)->wqs_wait_queue)