1 /*
2  *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
3  *  Copyright (C) 2007 The Regents of the University of California.
4  *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
5  *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
6  *  UCRL-CODE-235197
7  *
8  *  This file is part of the SPL, Solaris Porting Layer.
9  *
10  *  The SPL is free software; you can redistribute it and/or modify it
11  *  under the terms of the GNU General Public License as published by the
12  *  Free Software Foundation; either version 2 of the License, or (at your
13  *  option) any later version.
14  *
15  *  The SPL is distributed in the hope that it will be useful, but WITHOUT
16  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
17  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
18  *  for more details.
19  *
20  *  You should have received a copy of the GNU General Public License along
21  *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
22  */
23 
24 #ifndef _SPL_TASKQ_H
25 #define	_SPL_TASKQ_H
26 
27 #include <linux/module.h>
28 #include <linux/gfp.h>
29 #include <linux/slab.h>
30 #include <linux/interrupt.h>
31 #include <linux/kthread.h>
32 #include <sys/types.h>
33 #include <sys/thread.h>
34 #include <sys/rwlock.h>
35 #include <sys/wait.h>
36 
37 #define	TASKQ_NAMELEN		31
38 
39 #define	TASKQ_PREPOPULATE	0x00000001
40 #define	TASKQ_CPR_SAFE		0x00000002
41 #define	TASKQ_DYNAMIC		0x00000004
42 #define	TASKQ_THREADS_CPU_PCT	0x00000008
43 #define	TASKQ_DC_BATCH		0x00000010
44 #define	TASKQ_ACTIVE		0x80000000
45 
46 /*
47  * Flags for taskq_dispatch. TQ_SLEEP/TQ_NOSLEEP should be same as
48  * KM_SLEEP/KM_NOSLEEP.  TQ_NOQUEUE/TQ_NOALLOC are set particularly
49  * large so as not to conflict with already used GFP_* defines.
50  */
51 #define	TQ_SLEEP		0x00000000
52 #define	TQ_NOSLEEP		0x00000001
53 #define	TQ_PUSHPAGE		0x00000002
54 #define	TQ_NOQUEUE		0x01000000
55 #define	TQ_NOALLOC		0x02000000
56 #define	TQ_NEW			0x04000000
57 #define	TQ_FRONT		0x08000000
58 
59 /*
60  * Reserved taskqid values.
61  */
62 #define	TASKQID_INVALID		((taskqid_t)0)
63 #define	TASKQID_INITIAL		((taskqid_t)1)
64 
65 /*
66  * spin_lock(lock) and spin_lock_nested(lock,0) are equivalent,
67  * so TQ_LOCK_DYNAMIC must not evaluate to 0
68  */
69 typedef enum tq_lock_role {
70 	TQ_LOCK_GENERAL =	0,
71 	TQ_LOCK_DYNAMIC =	1,
72 } tq_lock_role_t;
73 
74 typedef unsigned long taskqid_t;
75 typedef void (task_func_t)(void *);
76 
77 typedef struct taskq {
78 	spinlock_t		tq_lock;	/* protects taskq_t */
79 	char			*tq_name;	/* taskq name */
80 	int			tq_instance;	/* instance of tq_name */
81 	struct list_head	tq_thread_list;	/* list of all threads */
82 	struct list_head	tq_active_list;	/* list of active threads */
83 	int			tq_nactive;	/* # of active threads */
84 	int			tq_nthreads;	/* # of existing threads */
85 	int			tq_nspawn;	/* # of threads being spawned */
86 	int			tq_maxthreads;	/* # of threads maximum */
87 	/* If PERCPU flag is set, percent of NCPUs to have as threads */
88 	int			tq_cpu_pct;
89 	int			tq_pri;		/* priority */
90 	int			tq_minalloc;	/* min taskq_ent_t pool size */
91 	int			tq_maxalloc;	/* max taskq_ent_t pool size */
92 	int			tq_nalloc;	/* cur taskq_ent_t pool size */
93 	uint_t			tq_flags;	/* flags */
94 	taskqid_t		tq_next_id;	/* next pend/work id */
95 	taskqid_t		tq_lowest_id;	/* lowest pend/work id */
96 	struct list_head	tq_free_list;	/* free taskq_ent_t's */
97 	struct list_head	tq_pend_list;	/* pending taskq_ent_t's */
98 	struct list_head	tq_prio_list;	/* priority taskq_ent_t's */
99 	struct list_head	tq_delay_list;	/* delayed taskq_ent_t's */
100 	struct list_head	tq_taskqs;	/* all taskq_t's */
101 	spl_wait_queue_head_t	tq_work_waitq;	/* new work waitq */
102 	spl_wait_queue_head_t	tq_wait_waitq;	/* wait waitq */
103 	tq_lock_role_t		tq_lock_class;	/* class when taking tq_lock */
104 	/* list node for the cpu hotplug callback */
105 	struct hlist_node	tq_hp_cb_node;
106 	boolean_t		tq_hp_support;
107 	unsigned long		lastspawnstop;	/* when to purge dynamic */
108 } taskq_t;
109 
110 typedef struct taskq_ent {
111 	spinlock_t		tqent_lock;
112 	spl_wait_queue_head_t	tqent_waitq;
113 	struct timer_list	tqent_timer;
114 	struct list_head	tqent_list;
115 	taskqid_t		tqent_id;
116 	task_func_t		*tqent_func;
117 	void			*tqent_arg;
118 	taskq_t			*tqent_taskq;
119 	uintptr_t		tqent_flags;
120 	unsigned long		tqent_birth;
121 } taskq_ent_t;
122 
123 #define	TQENT_FLAG_PREALLOC	0x1
124 #define	TQENT_FLAG_CANCEL	0x2
125 
126 typedef struct taskq_thread {
127 	struct list_head	tqt_thread_list;
128 	struct list_head	tqt_active_list;
129 	struct task_struct	*tqt_thread;
130 	taskq_t			*tqt_tq;
131 	taskqid_t		tqt_id;
132 	taskq_ent_t		*tqt_task;
133 	uintptr_t		tqt_flags;
134 } taskq_thread_t;
135 
136 /* Global system-wide dynamic task queue available for all consumers */
137 extern taskq_t *system_taskq;
138 /* Global dynamic task queue for long delay */
139 extern taskq_t *system_delay_taskq;
140 
141 /* List of all taskqs */
142 extern struct list_head tq_list;
143 extern struct rw_semaphore tq_list_sem;
144 
145 extern taskqid_t taskq_dispatch(taskq_t *, task_func_t, void *, uint_t);
146 extern taskqid_t taskq_dispatch_delay(taskq_t *, task_func_t, void *,
147     uint_t, clock_t);
148 extern void taskq_dispatch_ent(taskq_t *, task_func_t, void *, uint_t,
149     taskq_ent_t *);
150 extern int taskq_empty_ent(taskq_ent_t *);
151 extern void taskq_init_ent(taskq_ent_t *);
152 extern taskq_t *taskq_create(const char *, int, pri_t, int, int, uint_t);
153 extern taskq_t *taskq_create_synced(const char *, int, pri_t, int, int, uint_t,
154     kthread_t ***);
155 extern void taskq_destroy(taskq_t *);
156 extern void taskq_wait_id(taskq_t *, taskqid_t);
157 extern void taskq_wait_outstanding(taskq_t *, taskqid_t);
158 extern void taskq_wait(taskq_t *);
159 extern int taskq_cancel_id(taskq_t *, taskqid_t);
160 extern int taskq_member(taskq_t *, kthread_t *);
161 extern taskq_t *taskq_of_curthread(void);
162 
163 #define	taskq_create_proc(name, nthreads, pri, min, max, proc, flags) \
164     taskq_create(name, nthreads, pri, min, max, flags)
165 #define	taskq_create_sysdc(name, nthreads, min, max, proc, dc, flags) \
166 	((void) sizeof (dc), \
167 	    taskq_create(name, nthreads, maxclsyspri, min, max, flags))
168 
169 int spl_taskq_init(void);
170 void spl_taskq_fini(void);
171 
172 #endif  /* _SPL_TASKQ_H */
173