Module Name: src
Committed By: yamt
Date: Wed Mar 6 11:31:34 UTC 2013
Modified Files:
src/lib/libpthread: pthread_mutex.c
Log Message:
add comments
whitespace
To generate a diff of this commit:
cvs rdiff -u -r1.54 -r1.55 src/lib/libpthread/pthread_mutex.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libpthread/pthread_mutex.c
diff -u src/lib/libpthread/pthread_mutex.c:1.54 src/lib/libpthread/pthread_mutex.c:1.55
--- src/lib/libpthread/pthread_mutex.c:1.54 Thu Aug 16 04:49:47 2012
+++ src/lib/libpthread/pthread_mutex.c Wed Mar 6 11:31:34 2013
@@ -1,4 +1,4 @@
-/* $NetBSD: pthread_mutex.c,v 1.54 2012/08/16 04:49:47 matt Exp $ */
+/* $NetBSD: pthread_mutex.c,v 1.55 2013/03/06 11:31:34 yamt Exp $ */
/*-
* Copyright (c) 2001, 2003, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -47,7 +47,7 @@
*/
#include <sys/cdefs.h>
-__RCSID("$NetBSD: pthread_mutex.c,v 1.54 2012/08/16 04:49:47 matt Exp $");
+__RCSID("$NetBSD: pthread_mutex.c,v 1.55 2013/03/06 11:31:34 yamt Exp $");
#include <sys/types.h>
#include <sys/lwpctl.h>
@@ -130,7 +130,6 @@ pthread_mutex_init(pthread_mutex_t *ptm,
return 0;
}
-
int
pthread_mutex_destroy(pthread_mutex_t *ptm)
{
@@ -465,6 +464,12 @@ pthread__mutex_unlock_slow(pthread_mutex
return error;
}
+/*
+ * pthread__mutex_wakeup: unpark threads waiting for us
+ *
+ * unpark threads on the ptm->ptm_waiters list and self->pt_waiters.
+ */
+
static void
pthread__mutex_wakeup(pthread_t self, pthread_mutex_t *ptm)
{
@@ -530,6 +535,7 @@ pthread__mutex_wakeup(pthread_t self, pt
}
}
}
+
int
pthread_mutexattr_init(pthread_mutexattr_t *attr)
{
@@ -578,6 +584,16 @@ pthread_mutexattr_settype(pthread_mutexa
}
}
+/*
+ * pthread__mutex_deferwake: try to defer unparking threads in self->pt_waiters
+ *
+ * In order to avoid unnecessary contention on the interlocking mutex,
+ * we defer waking up threads until we unlock the mutex. The threads will
+ * be woken up when the calling thread (self) releases the first mutex with
+ * MUTEX_DEFERRED_BIT set. It likely be the mutex 'ptm', but no problem
+ * even if it isn't.
+ */
+
void
pthread__mutex_deferwake(pthread_t self, pthread_mutex_t *ptm)
{
