Module Name: src
Committed By: ad
Date: Thu Jan 30 12:36:38 UTC 2020
Modified Files:
src/sys/kern: sys_lwp.c
Log Message:
Update comments
To generate a diff of this commit:
cvs rdiff -u -r1.74 -r1.75 src/sys/kern/sys_lwp.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/sys_lwp.c
diff -u src/sys/kern/sys_lwp.c:1.74 src/sys/kern/sys_lwp.c:1.75
--- src/sys/kern/sys_lwp.c:1.74 Wed Jan 29 15:47:52 2020
+++ src/sys/kern/sys_lwp.c Thu Jan 30 12:36:38 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: sys_lwp.c,v 1.74 2020/01/29 15:47:52 ad Exp $ */
+/* $NetBSD: sys_lwp.c,v 1.75 2020/01/30 12:36:38 ad Exp $ */
/*-
* Copyright (c) 2001, 2006, 2007, 2008, 2019, 2020 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.74 2020/01/29 15:47:52 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.75 2020/01/30 12:36:38 ad Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -480,15 +480,21 @@ lwp_unpark(const lwpid_t *tp, const u_in
continue;
}
- /* It may not have parked yet or we may have raced. */
lwp_lock(t);
if (t->l_syncobj == &lwp_park_syncobj) {
- /* Releases the LWP lock. */
+ /*
+ * As expected it's parked, so wake it up.
+ * lwp_unsleep() will release the LWP lock.
+ */
lwp_unsleep(t, true);
} else {
/*
- * Set the operation pending. The next call to
- * _lwp_park() will return early.
+ * It hasn't parked yet because the wakeup side won
+ * the race, or something else has happened to make
+ * the thread not park. Why doesn't really matter.
+ * Set the operation pending, so that the next call
+ * to _lwp_park() in the LWP returns early. If it
+ * turns out to be a spurious wakeup, no harm done.
*/
t->l_flag |= LW_UNPARKED;
lwp_unlock(t);
