1/*	$NetBSD: busypage.c,v 1.5 2011/08/07 14:03:15 rmind Exp $	*/
2
3/*-
4 * Copyright (c) 2010 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND
17 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
18 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
23 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
25 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
26 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
27 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31#if !defined(lint)
32__RCSID("$NetBSD: busypage.c,v 1.5 2011/08/07 14:03:15 rmind Exp $");
33#endif /* !lint */
34
35#include <sys/param.h>
36#include <sys/condvar.h>
37#include <sys/kthread.h>
38#include <sys/mutex.h>
39#include <sys/proc.h>
40
41#include <uvm/uvm.h>
42
43#include "kernspace.h"
44
45static struct uvm_object *uobj;
46static struct vm_page *testpg;
47static kcondvar_t tcv;
48
49static bool threadrun = false;
50
51static void
52thread(void *arg)
53{
54
55	mutex_enter(uobj->vmobjlock);
56	threadrun = true;
57	cv_signal(&tcv);
58	testpg->flags |= PG_WANTED;
59	UVM_UNLOCK_AND_WAIT(testpg, uobj->vmobjlock, false, "tw", 0);
60	kthread_exit(0);
61}
62
63void
64rumptest_busypage()
65{
66	struct lwp *newl;
67	int rv;
68
69	cv_init(&tcv, "napina");
70
71	uobj = uao_create(1, 0);
72	mutex_enter(uobj->vmobjlock);
73	testpg = uvm_pagealloc(uobj, 0, NULL, 0);
74	mutex_exit(uobj->vmobjlock);
75	if (testpg == NULL)
76		panic("couldn't create vm page");
77
78	rv = kthread_create(PRI_NONE, KTHREAD_MUSTJOIN | KTHREAD_MPSAFE, NULL,
79	    thread, NULL, &newl, "jointest");
80	if (rv)
81		panic("thread creation failed: %d", rv);
82
83	mutex_enter(uobj->vmobjlock);
84	while (!threadrun)
85		cv_wait(&tcv, uobj->vmobjlock);
86
87	uvm_page_unbusy(&testpg, 1);
88	mutex_exit(uobj->vmobjlock);
89
90	rv = kthread_join(newl);
91	if (rv)
92		panic("thread join failed: %d", rv);
93
94}
95