Module Name: src
Committed By: ad
Date: Wed Jan 22 12:44:54 UTC 2020
Modified Files:
src/sys/kern: kern_rwlock.c
Log Message:
Add a comment.
To generate a diff of this commit:
cvs rdiff -u -r1.63 -r1.64 src/sys/kern/kern_rwlock.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_rwlock.c
diff -u src/sys/kern/kern_rwlock.c:1.63 src/sys/kern/kern_rwlock.c:1.64
--- src/sys/kern/kern_rwlock.c:1.63 Tue Jan 21 20:29:51 2020
+++ src/sys/kern/kern_rwlock.c Wed Jan 22 12:44:54 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_rwlock.c,v 1.63 2020/01/21 20:29:51 ad Exp $ */
+/* $NetBSD: kern_rwlock.c,v 1.64 2020/01/22 12:44:54 ad Exp $ */
/*-
* Copyright (c) 2002, 2006, 2007, 2008, 2009, 2019, 2020
@@ -36,10 +36,16 @@
*
* Solaris Internals: Core Kernel Architecture, Jim Mauro and
* Richard McDougall.
+ *
+ * The NetBSD implementation differs from that described in the book, in
+ * that the locks are partially adaptive. Lock waiters spin wait while a
+ * lock is write held and the holder is still running on a CPU. The method
+ * of choosing which threads to awaken when a lock is released also differs,
+ * mainly to take account of the partially adaptive behaviour.
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_rwlock.c,v 1.63 2020/01/21 20:29:51 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_rwlock.c,v 1.64 2020/01/22 12:44:54 ad Exp $");
#include "opt_lockdebug.h"
