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