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 45 static struct uvm_object *uobj; 46 static struct vm_page *testpg; 47 static kcondvar_t tcv; 48 49 static bool threadrun = false; 50 51 static void thread(void * arg)52 thread(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 63 void rumptest_busypage()64 rumptest_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