Merge commit 'b4bf0cf0458759c67920a031021a9d96cd683cfe'
[unleashed.git] / kernel / syscall / nice.c
blob056486575cd8e2f8c3268fa2e3f6d2780c25a28a
1 /*
2 * CDDL HEADER START
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
19 * CDDL HEADER END
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28 /* All Rights Reserved */
30 #pragma ident "%Z%%M% %I% %E% SMI" /* from SVr4.0 1.15 */
32 #include <sys/types.h>
33 #include <sys/param.h>
34 #include <sys/sysmacros.h>
35 #include <sys/systm.h>
36 #include <sys/errno.h>
37 #include <sys/cred.h>
38 #include <sys/proc.h>
39 #include <sys/debug.h>
40 #include <sys/class.h>
41 #include <sys/mutex.h>
42 #include <sys/schedctl.h>
45 * We support the nice system call for compatibility although
46 * the priocntl system call supports a superset of nice's functionality.
47 * We support nice only for time sharing threads. It will fail
48 * if called by a thread from another class.
51 int
52 nice(int niceness)
54 int error = 0;
55 int err, retval;
56 kthread_t *t;
57 proc_t *p = curproc;
59 mutex_enter(&p->p_lock);
60 t = p->p_tlist;
61 do {
62 err = CL_DONICE(t, CRED(), niceness, &retval);
63 schedctl_set_cidpri(t);
64 if (error == 0 && err)
65 error = set_errno(err);
66 } while ((t = t->t_forw) != p->p_tlist);
67 mutex_exit(&p->p_lock);
68 if (error)
69 return (error);
70 return (retval);