xref: /freebsd/sys/sys/epoch.h (revision 95ee2897e98f5d444f26ed2334cc7c439f9c16c6)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2018, Matthew Macy <mmacy@freebsd.org>
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #ifndef _SYS_EPOCH_H_
29 #define _SYS_EPOCH_H_
30 
31 #include <sys/cdefs.h>
32 
33 struct epoch_context {
34 	void   *data[2];
35 } __aligned(sizeof(void *));
36 
37 typedef struct epoch_context *epoch_context_t;
38 typedef	void epoch_callback_t(epoch_context_t);
39 
40 #ifdef _KERNEL
41 #include <sys/lock.h>
42 #include <sys/pcpu.h>
43 #include <ck_epoch.h>
44 
45 struct epoch;
46 typedef struct epoch *epoch_t;
47 
48 #define EPOCH_PREEMPT 0x1
49 #define EPOCH_LOCKED 0x2
50 
51 extern epoch_t global_epoch;
52 extern epoch_t global_epoch_preempt;
53 
54 struct epoch_tracker {
55 	TAILQ_ENTRY(epoch_tracker) et_link;
56 	struct thread *et_td;
57 	ck_epoch_section_t et_section;
58 	uint8_t et_old_priority;
59 #ifdef EPOCH_TRACE
60 	struct epoch *et_epoch;
61 	SLIST_ENTRY(epoch_tracker) et_tlink;
62 	const char *et_file;
63 	int et_line;
64 	int et_flags;
65 #define	ET_REPORT_EXIT	0x1
66 #endif
67 }  __aligned(sizeof(void *));
68 typedef struct epoch_tracker *epoch_tracker_t;
69 
70 epoch_t	epoch_alloc(const char *name, int flags);
71 void	epoch_free(epoch_t epoch);
72 void	epoch_wait(epoch_t epoch);
73 void	epoch_wait_preempt(epoch_t epoch);
74 void	epoch_drain_callbacks(epoch_t epoch);
75 void	epoch_call(epoch_t epoch, epoch_callback_t cb, epoch_context_t ctx);
76 int	in_epoch(epoch_t epoch);
77 int in_epoch_verbose(epoch_t epoch, int dump_onfail);
78 DPCPU_DECLARE(int, epoch_cb_count);
79 DPCPU_DECLARE(struct grouptask, epoch_cb_task);
80 
81 #ifdef EPOCH_TRACE
82 #define	EPOCH_FILE_LINE	, const char *file, int line
83 #else
84 #define	EPOCH_FILE_LINE
85 #endif
86 
87 void _epoch_enter_preempt(epoch_t epoch, epoch_tracker_t et EPOCH_FILE_LINE);
88 void _epoch_exit_preempt(epoch_t epoch, epoch_tracker_t et EPOCH_FILE_LINE);
89 #ifdef EPOCH_TRACE
90 void epoch_trace_list(struct thread *);
91 void epoch_where_report(epoch_t);
92 #define	epoch_enter_preempt(epoch, et)	_epoch_enter_preempt(epoch, et, __FILE__, __LINE__)
93 #define	epoch_exit_preempt(epoch, et)	_epoch_exit_preempt(epoch, et, __FILE__, __LINE__)
94 #else
95 #define epoch_enter_preempt(epoch, et)	_epoch_enter_preempt(epoch, et)
96 #define	epoch_exit_preempt(epoch, et)	_epoch_exit_preempt(epoch, et)
97 #endif
98 void epoch_enter(epoch_t epoch);
99 void epoch_exit(epoch_t epoch);
100 
101 /*
102  * Globally recognized epochs in the FreeBSD kernel.
103  */
104 /* Network preemptible epoch, declared in sys/net/if.c. */
105 extern epoch_t net_epoch_preempt;
106 #define	NET_EPOCH_ENTER(et)	epoch_enter_preempt(net_epoch_preempt, &(et))
107 #define	NET_EPOCH_EXIT(et)	epoch_exit_preempt(net_epoch_preempt, &(et))
108 #define	NET_EPOCH_WAIT()	epoch_wait_preempt(net_epoch_preempt)
109 #define	NET_EPOCH_CALL(f, c)	epoch_call(net_epoch_preempt, (f), (c))
110 #define	NET_EPOCH_DRAIN_CALLBACKS() epoch_drain_callbacks(net_epoch_preempt)
111 #define	NET_EPOCH_ASSERT()	MPASS(in_epoch(net_epoch_preempt))
112 #define	NET_TASK_INIT(t, p, f, c) TASK_INIT_FLAGS(t, p, f, c, TASK_NETWORK)
113 #define	NET_GROUPTASK_INIT(gtask, prio, func, ctx)			\
114 	    GTASK_INIT(&(gtask)->gt_task, TASK_NETWORK, (prio), (func), (ctx))
115 
116 #endif	/* _KERNEL */
117 #endif	/* _SYS_EPOCH_H_ */
118