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886d51a3 MD |
1 | #ifndef _LIB_RING_BUFFER_FRONTEND_H |
2 | #define _LIB_RING_BUFFER_FRONTEND_H | |
f3bc08c5 MD |
3 | |
4 | /* | |
886d51a3 | 5 | * lib/ringbuffer/frontend.h |
f3bc08c5 MD |
6 | * |
7 | * Ring Buffer Library Synchronization Header (API). | |
8 | * | |
886d51a3 MD |
9 | * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
10 | * | |
11 | * This library is free software; you can redistribute it and/or | |
12 | * modify it under the terms of the GNU Lesser General Public | |
13 | * License as published by the Free Software Foundation; only | |
14 | * version 2.1 of the License. | |
15 | * | |
16 | * This library is distributed in the hope that it will be useful, | |
17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
19 | * Lesser General Public License for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU Lesser General Public | |
22 | * License along with this library; if not, write to the Free Software | |
23 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
24 | * | |
f3bc08c5 MD |
25 | * Author: |
26 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
27 | * | |
28 | * See ring_buffer_frontend.c for more information on wait-free algorithms. | |
f3bc08c5 MD |
29 | */ |
30 | ||
31 | #include <linux/pipe_fs_i.h> | |
32 | #include <linux/rcupdate.h> | |
33 | #include <linux/cpumask.h> | |
34 | #include <linux/module.h> | |
35 | #include <linux/bitops.h> | |
36 | #include <linux/splice.h> | |
37 | #include <linux/string.h> | |
38 | #include <linux/timer.h> | |
39 | #include <linux/sched.h> | |
40 | #include <linux/cache.h> | |
41 | #include <linux/time.h> | |
42 | #include <linux/slab.h> | |
43 | #include <linux/init.h> | |
44 | #include <linux/stat.h> | |
45 | #include <linux/cpu.h> | |
46 | #include <linux/fs.h> | |
47 | ||
48 | #include <asm/atomic.h> | |
49 | #include <asm/local.h> | |
50 | ||
51 | /* Internal helpers */ | |
5671a661 | 52 | #include <wrapper/ringbuffer/frontend_internal.h> |
f3bc08c5 MD |
53 | |
54 | /* Buffer creation/removal and setup operations */ | |
55 | ||
56 | /* | |
57 | * switch_timer_interval is the time interval (in us) to fill sub-buffers with | |
58 | * padding to let readers get those sub-buffers. Used for live streaming. | |
59 | * | |
60 | * read_timer_interval is the time interval (in us) to wake up pending readers. | |
61 | * | |
62 | * buf_addr is a pointer the the beginning of the preallocated buffer contiguous | |
63 | * address mapping. It is used only by RING_BUFFER_STATIC configuration. It can | |
64 | * be set to NULL for other backends. | |
65 | */ | |
66 | ||
67 | extern | |
68 | struct channel *channel_create(const struct lib_ring_buffer_config *config, | |
69 | const char *name, void *priv, | |
70 | void *buf_addr, | |
71 | size_t subbuf_size, size_t num_subbuf, | |
72 | unsigned int switch_timer_interval, | |
73 | unsigned int read_timer_interval); | |
74 | ||
75 | /* | |
76 | * channel_destroy returns the private data pointer. It finalizes all channel's | |
77 | * buffers, waits for readers to release all references, and destroys the | |
78 | * channel. | |
79 | */ | |
80 | extern | |
81 | void *channel_destroy(struct channel *chan); | |
82 | ||
83 | ||
84 | /* Buffer read operations */ | |
85 | ||
86 | /* | |
87 | * Iteration on channel cpumask needs to issue a read barrier to match the write | |
88 | * barrier in cpu hotplug. It orders the cpumask read before read of per-cpu | |
89 | * buffer data. The per-cpu buffer is never removed by cpu hotplug; teardown is | |
90 | * only performed at channel destruction. | |
91 | */ | |
92 | #define for_each_channel_cpu(cpu, chan) \ | |
93 | for ((cpu) = -1; \ | |
94 | ({ (cpu) = cpumask_next(cpu, (chan)->backend.cpumask); \ | |
95 | smp_read_barrier_depends(); (cpu) < nr_cpu_ids; });) | |
96 | ||
97 | extern struct lib_ring_buffer *channel_get_ring_buffer( | |
98 | const struct lib_ring_buffer_config *config, | |
99 | struct channel *chan, int cpu); | |
100 | extern int lib_ring_buffer_open_read(struct lib_ring_buffer *buf); | |
101 | extern void lib_ring_buffer_release_read(struct lib_ring_buffer *buf); | |
102 | ||
103 | /* | |
104 | * Read sequence: snapshot, many get_subbuf/put_subbuf, move_consumer. | |
105 | */ | |
106 | extern int lib_ring_buffer_snapshot(struct lib_ring_buffer *buf, | |
107 | unsigned long *consumed, | |
108 | unsigned long *produced); | |
109 | extern void lib_ring_buffer_move_consumer(struct lib_ring_buffer *buf, | |
110 | unsigned long consumed_new); | |
111 | ||
112 | extern int lib_ring_buffer_get_subbuf(struct lib_ring_buffer *buf, | |
113 | unsigned long consumed); | |
114 | extern void lib_ring_buffer_put_subbuf(struct lib_ring_buffer *buf); | |
115 | ||
64af2437 MD |
116 | void lib_ring_buffer_set_quiescent_channel(struct channel *chan); |
117 | void lib_ring_buffer_clear_quiescent_channel(struct channel *chan); | |
118 | ||
f3bc08c5 MD |
119 | /* |
120 | * lib_ring_buffer_get_next_subbuf/lib_ring_buffer_put_next_subbuf are helpers | |
121 | * to read sub-buffers sequentially. | |
122 | */ | |
123 | static inline int lib_ring_buffer_get_next_subbuf(struct lib_ring_buffer *buf) | |
124 | { | |
125 | int ret; | |
126 | ||
127 | ret = lib_ring_buffer_snapshot(buf, &buf->cons_snapshot, | |
128 | &buf->prod_snapshot); | |
129 | if (ret) | |
130 | return ret; | |
131 | ret = lib_ring_buffer_get_subbuf(buf, buf->cons_snapshot); | |
132 | return ret; | |
133 | } | |
134 | ||
135 | static inline void lib_ring_buffer_put_next_subbuf(struct lib_ring_buffer *buf) | |
136 | { | |
137 | lib_ring_buffer_put_subbuf(buf); | |
138 | lib_ring_buffer_move_consumer(buf, subbuf_align(buf->cons_snapshot, | |
139 | buf->backend.chan)); | |
140 | } | |
141 | ||
142 | extern void channel_reset(struct channel *chan); | |
143 | extern void lib_ring_buffer_reset(struct lib_ring_buffer *buf); | |
144 | ||
145 | static inline | |
146 | unsigned long lib_ring_buffer_get_offset(const struct lib_ring_buffer_config *config, | |
147 | struct lib_ring_buffer *buf) | |
148 | { | |
149 | return v_read(config, &buf->offset); | |
150 | } | |
151 | ||
152 | static inline | |
153 | unsigned long lib_ring_buffer_get_consumed(const struct lib_ring_buffer_config *config, | |
154 | struct lib_ring_buffer *buf) | |
155 | { | |
156 | return atomic_long_read(&buf->consumed); | |
157 | } | |
158 | ||
159 | /* | |
160 | * Must call lib_ring_buffer_is_finalized before reading counters (memory | |
161 | * ordering enforced with respect to trace teardown). | |
162 | */ | |
163 | static inline | |
164 | int lib_ring_buffer_is_finalized(const struct lib_ring_buffer_config *config, | |
165 | struct lib_ring_buffer *buf) | |
166 | { | |
167 | int finalized = ACCESS_ONCE(buf->finalized); | |
168 | /* | |
169 | * Read finalized before counters. | |
170 | */ | |
171 | smp_rmb(); | |
172 | return finalized; | |
173 | } | |
174 | ||
24cedcfe MD |
175 | static inline |
176 | int lib_ring_buffer_channel_is_finalized(const struct channel *chan) | |
177 | { | |
178 | return chan->finalized; | |
179 | } | |
180 | ||
254ec7bc MD |
181 | static inline |
182 | int lib_ring_buffer_channel_is_disabled(const struct channel *chan) | |
183 | { | |
184 | return atomic_read(&chan->record_disabled); | |
185 | } | |
186 | ||
f3bc08c5 MD |
187 | static inline |
188 | unsigned long lib_ring_buffer_get_read_data_size( | |
189 | const struct lib_ring_buffer_config *config, | |
190 | struct lib_ring_buffer *buf) | |
191 | { | |
192 | return subbuffer_get_read_data_size(config, &buf->backend); | |
193 | } | |
194 | ||
195 | static inline | |
196 | unsigned long lib_ring_buffer_get_records_count( | |
197 | const struct lib_ring_buffer_config *config, | |
198 | struct lib_ring_buffer *buf) | |
199 | { | |
200 | return v_read(config, &buf->records_count); | |
201 | } | |
202 | ||
203 | static inline | |
204 | unsigned long lib_ring_buffer_get_records_overrun( | |
205 | const struct lib_ring_buffer_config *config, | |
206 | struct lib_ring_buffer *buf) | |
207 | { | |
208 | return v_read(config, &buf->records_overrun); | |
209 | } | |
210 | ||
211 | static inline | |
212 | unsigned long lib_ring_buffer_get_records_lost_full( | |
213 | const struct lib_ring_buffer_config *config, | |
214 | struct lib_ring_buffer *buf) | |
215 | { | |
216 | return v_read(config, &buf->records_lost_full); | |
217 | } | |
218 | ||
219 | static inline | |
220 | unsigned long lib_ring_buffer_get_records_lost_wrap( | |
221 | const struct lib_ring_buffer_config *config, | |
222 | struct lib_ring_buffer *buf) | |
223 | { | |
224 | return v_read(config, &buf->records_lost_wrap); | |
225 | } | |
226 | ||
227 | static inline | |
228 | unsigned long lib_ring_buffer_get_records_lost_big( | |
229 | const struct lib_ring_buffer_config *config, | |
230 | struct lib_ring_buffer *buf) | |
231 | { | |
232 | return v_read(config, &buf->records_lost_big); | |
233 | } | |
234 | ||
235 | static inline | |
236 | unsigned long lib_ring_buffer_get_records_read( | |
237 | const struct lib_ring_buffer_config *config, | |
238 | struct lib_ring_buffer *buf) | |
239 | { | |
240 | return v_read(config, &buf->backend.records_read); | |
241 | } | |
242 | ||
886d51a3 | 243 | #endif /* _LIB_RING_BUFFER_FRONTEND_H */ |