1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 1996-2002 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */ 28 /* All Rights Reserved */ 29 30 31 #pragma ident "%Z%%M% %I% %E% SMI" 32 33 #include <sys/param.h> 34 #include <sys/types.h> 35 #include <sys/sysmacros.h> 36 #include <sys/systm.h> 37 #include <sys/errno.h> 38 #include <sys/thread.h> 39 #include <sys/disp.h> 40 #include <sys/debug.h> 41 #include <sys/cpuvar.h> 42 43 44 /* 45 * The calling LWP is preempted in favor of some other LWP. 46 */ 47 int yield()48yield() 49 { 50 kthread_t *t = curthread; 51 klwp_t *lwp = ttolwp(t); 52 53 thread_lock(t); 54 lwp->lwp_ru.nvcsw++; 55 THREAD_TRANSITION(t); 56 CL_YIELD(t); /* does setbackdq */ 57 thread_unlock_nopreempt(t); 58 swtch(); /* clears cpu_runrun and cpu_kprunrun */ 59 60 return (0); 61 } 62