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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
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.
12 *
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]
18 *
19 * CDDL HEADER END
20 */
21/*
22 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
27/*	  All Rights Reserved  	*/
28
29
30#ifndef _SYS_DISP_H
31#define	_SYS_DISP_H
32
33#pragma ident	"%Z%%M%	%I%	%E% SMI"	/* SVr4.0 1.11	*/
34
35#include <sys/priocntl.h>
36#include <sys/thread.h>
37#include <sys/class.h>
38
39#ifdef	__cplusplus
40extern "C" {
41#endif
42
43/*
44 * The following is the format of a dispatcher queue entry.
45 */
46typedef struct dispq {
47	kthread_t	*dq_first;	/* first thread on queue or NULL */
48	kthread_t	*dq_last;	/* last thread on queue or NULL */
49	int		dq_sruncnt;	/* number of loaded, runnable */
50					/*    threads on queue */
51} dispq_t;
52
53/*
54 * Dispatch queue structure.
55 */
56typedef struct _disp {
57	disp_lock_t	disp_lock;	/* protects dispatching fields */
58	pri_t		disp_npri;	/* # of priority levels in queue */
59	dispq_t		*disp_q;		/* the dispatch queue */
60	dispq_t		*disp_q_limit;	/* ptr past end of dispatch queue */
61	ulong_t		*disp_qactmap;	/* bitmap of active dispatch queues */
62
63	/*
64	 * Priorities:
65	 *	disp_maxrunpri is the maximum run priority of runnable threads
66	 * 	on this queue.  It is -1 if nothing is runnable.
67	 *
68	 *	disp_max_unbound_pri is the maximum run priority of threads on
69	 *	this dispatch queue but runnable by any CPU.  This may be left
70	 * 	artificially high, then corrected when some CPU tries to take
71	 *	an unbound thread.  It is -1 if nothing is runnable.
72	 */
73	pri_t		disp_maxrunpri;	/* maximum run priority */
74	pri_t		disp_max_unbound_pri;	/* max pri of unbound threads */
75
76	volatile int	disp_nrunnable;	/* runnable threads in cpu dispq */
77
78	struct cpu	*disp_cpu;	/* cpu owning this queue or NULL */
79	hrtime_t	disp_steal;	/* time when threads become stealable */
80} disp_t;
81
82#if defined(_KERNEL)
83
84#define	MAXCLSYSPRI	99
85#define	MINCLSYSPRI	60
86
87
88/*
89 * Global scheduling variables.
90 *	- See sys/cpuvar.h for CPU-local variables.
91 */
92extern int	nswapped;	/* number of swapped threads */
93				/* nswapped protected by swap_lock */
94
95extern	pri_t	minclsyspri;	/* minimum level of any system class */
96extern	pri_t	maxclsyspri;	/* maximum level of any system class */
97extern	pri_t	intr_pri;	/* interrupt thread priority base level */
98
99/*
100 * Minimum amount of time that a thread can remain runnable before it can
101 * be stolen by another CPU (in nanoseconds).
102 */
103extern hrtime_t nosteal_nsec;
104
105/*
106 * Kernel preemption occurs if a higher-priority thread is runnable with
107 * a priority at or above kpreemptpri.
108 *
109 * So that other processors can watch for such threads, a separate
110 * dispatch queue with unbound work above kpreemptpri is maintained.
111 * This is part of the CPU partition structure (cpupart_t).
112 */
113extern	pri_t	kpreemptpri;	/* level above which preemption takes place */
114
115extern void		disp_kp_alloc(disp_t *, pri_t);	/* allocate kp queue */
116extern void		disp_kp_free(disp_t *);		/* free kp queue */
117
118/*
119 * Macro for use by scheduling classes to decide whether the thread is about
120 * to be scheduled or not.  This returns the maximum run priority.
121 */
122#define	DISP_MAXRUNPRI(t)	((t)->t_disp_queue->disp_maxrunpri)
123
124/*
125 * Platform callbacks for various dispatcher operations
126 *
127 * idle_cpu() is invoked when a cpu goes idle, and has nothing to do.
128 * disp_enq_thread() is invoked when a thread is placed on a run queue.
129 */
130extern void	(*idle_cpu)();
131extern void	(*disp_enq_thread)(struct cpu *, int);
132
133
134extern int		dispdeq(kthread_t *);
135extern void		dispinit(void);
136extern void		disp_add(sclass_t *);
137extern int		intr_active(struct cpu *, int);
138extern int		servicing_interrupt(void);
139extern void		preempt(void);
140extern void		setbackdq(kthread_t *);
141extern void		setfrontdq(kthread_t *);
142extern void		swtch(void);
143extern void		swtch_to(kthread_t *);
144extern void		swtch_from_zombie(void)
145				__NORETURN;
146extern void		dq_sruninc(kthread_t *);
147extern void		dq_srundec(kthread_t *);
148extern void		cpu_rechoose(kthread_t *);
149extern void		cpu_surrender(kthread_t *);
150extern void		kpreempt(int);
151extern struct cpu	*disp_lowpri_cpu(struct cpu *, struct lgrp_ld *, pri_t,
152			    struct cpu *);
153extern int		disp_bound_threads(struct cpu *, int);
154extern int		disp_bound_anythreads(struct cpu *, int);
155extern int		disp_bound_partition(struct cpu *, int);
156extern void		disp_cpu_init(struct cpu *);
157extern void		disp_cpu_fini(struct cpu *);
158extern void		disp_cpu_inactive(struct cpu *);
159extern void		disp_adjust_unbound_pri(kthread_t *);
160extern void		resume(kthread_t *);
161extern void		resume_from_intr(kthread_t *);
162extern void		resume_from_zombie(kthread_t *)
163				__NORETURN;
164extern void		disp_swapped_enq(kthread_t *);
165extern int		disp_anywork(void);
166
167#define	KPREEMPT_SYNC		(-1)
168#define	kpreempt_disable()				\
169	{						\
170		curthread->t_preempt++;			\
171		ASSERT(curthread->t_preempt >= 1);	\
172	}
173#define	kpreempt_enable()				\
174	{						\
175		ASSERT(curthread->t_preempt >= 1);	\
176		if (--curthread->t_preempt == 0 &&	\
177		    CPU->cpu_kprunrun)			\
178			kpreempt(KPREEMPT_SYNC);	\
179	}
180
181#endif	/* _KERNEL */
182
183#ifdef	__cplusplus
184}
185#endif
186
187#endif	/* _SYS_DISP_H */
188