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e92f3e28 MD |
1 | #ifndef _LTTNG_RING_BUFFER_FRONTEND_TYPES_H |
2 | #define _LTTNG_RING_BUFFER_FRONTEND_TYPES_H | |
852c2936 MD |
3 | |
4 | /* | |
e92f3e28 | 5 | * libringbuffer/frontend_types.h |
852c2936 MD |
6 | * |
7 | * Ring Buffer Library Synchronization Header (types). | |
8 | * | |
e92f3e28 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 | * | |
852c2936 MD |
25 | * Author: |
26 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
27 | * | |
28 | * See ring_buffer_frontend.c for more information on wait-free algorithms. | |
852c2936 MD |
29 | */ |
30 | ||
fb31eb73 | 31 | #include <stdint.h> |
a6352fd4 | 32 | #include <string.h> |
03d2d293 | 33 | #include <time.h> /* for timer_t */ |
a6352fd4 | 34 | |
14641deb MD |
35 | #include <urcu/list.h> |
36 | #include <urcu/uatomic.h> | |
14641deb | 37 | |
4318ae1b | 38 | #include <lttng/ringbuffer-config.h> |
44c72f10 | 39 | #include <usterr-signal-safe.h> |
4931a13e | 40 | #include "backend_types.h" |
1d498196 | 41 | #include "shm_internal.h" |
03d2d293 | 42 | #include "shm_types.h" |
a3bb4b27 | 43 | #include "vatomic.h" |
852c2936 MD |
44 | |
45 | /* | |
46 | * A switch is done during tracing or as a final flush after tracing (so it | |
47 | * won't write in the new sub-buffer). | |
48 | */ | |
49 | enum switch_mode { SWITCH_ACTIVE, SWITCH_FLUSH }; | |
50 | ||
852c2936 | 51 | /* channel: collection of per-cpu ring buffers. */ |
74d81a6c | 52 | #define RB_CHANNEL_PADDING 32 |
852c2936 | 53 | struct channel { |
14641deb | 54 | int record_disabled; |
852c2936 MD |
55 | unsigned long commit_count_mask; /* |
56 | * Commit count mask, removing | |
57 | * the MSBs corresponding to | |
58 | * bits used to represent the | |
59 | * subbuffer index. | |
60 | */ | |
61 | ||
03d2d293 MD |
62 | unsigned long switch_timer_interval; /* Buffer flush (us) */ |
63 | timer_t switch_timer; | |
64 | int switch_timer_enabled; | |
65 | ||
66 | unsigned long read_timer_interval; /* Reader wakeup (us) */ | |
34a91bdb MD |
67 | timer_t read_timer; |
68 | int read_timer_enabled; | |
69 | ||
852c2936 | 70 | int finalized; /* Has channel been finalized */ |
a3f61e7f | 71 | size_t priv_data_offset; |
74d81a6c | 72 | unsigned int nr_streams; /* Number of streams */ |
03d2d293 | 73 | struct lttng_ust_shm_handle *handle; |
b2c5f61a MD |
74 | /* Extended options. */ |
75 | union { | |
76 | struct { | |
77 | int32_t blocking_timeout_ms; | |
78 | } s; | |
79 | char padding[RB_CHANNEL_PADDING]; | |
80 | } u; | |
de85e7c3 MD |
81 | /* |
82 | * Associated backend contains a variable-length array. Needs to | |
83 | * be last member. | |
84 | */ | |
85 | struct channel_backend backend; /* Associated backend */ | |
b728d87e | 86 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
852c2936 MD |
87 | |
88 | /* Per-subbuffer commit counters used on the hot path */ | |
3c8964ba | 89 | #define RB_COMMIT_COUNT_HOT_PADDING 16 |
852c2936 MD |
90 | struct commit_counters_hot { |
91 | union v_atomic cc; /* Commit counter */ | |
92 | union v_atomic seq; /* Consecutive commits */ | |
3c8964ba | 93 | char padding[RB_COMMIT_COUNT_HOT_PADDING]; |
b728d87e | 94 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
852c2936 MD |
95 | |
96 | /* Per-subbuffer commit counters used only on cold paths */ | |
3c8964ba | 97 | #define RB_COMMIT_COUNT_COLD_PADDING 24 |
852c2936 MD |
98 | struct commit_counters_cold { |
99 | union v_atomic cc_sb; /* Incremented _once_ at sb switch */ | |
3c8964ba | 100 | char padding[RB_COMMIT_COUNT_COLD_PADDING]; |
b728d87e | 101 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
852c2936 | 102 | |
852c2936 | 103 | /* ring buffer state */ |
a9ff648c MD |
104 | #define RB_CRASH_DUMP_ABI_LEN 256 |
105 | #define RB_RING_BUFFER_PADDING 60 | |
106 | ||
107 | #define RB_CRASH_DUMP_ABI_MAGIC_LEN 16 | |
108 | ||
109 | /* | |
110 | * The 128-bit magic number is xor'd in the process data so it does not | |
111 | * cause a false positive when searching for buffers by scanning memory. | |
112 | * The actual magic number is: | |
113 | * 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17, 0x7B, 0xF1, | |
114 | * 0x77, 0xBF, 0x17, 0x7B, 0xF1, 0x77, 0xBF, 0x17, | |
115 | */ | |
116 | #define RB_CRASH_DUMP_ABI_MAGIC_XOR \ | |
117 | { \ | |
118 | 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, 0x77 ^ 0xFF, \ | |
119 | 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, 0xF1 ^ 0xFF, \ | |
120 | 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, 0x7B ^ 0xFF, \ | |
121 | 0xF1 ^ 0xFF, 0x77 ^ 0xFF, 0xBF ^ 0xFF, 0x17 ^ 0xFF, \ | |
122 | } | |
123 | ||
124 | #define RB_CRASH_ENDIAN 0x1234 | |
125 | ||
126 | #define RB_CRASH_DUMP_ABI_MAJOR 0 | |
127 | #define RB_CRASH_DUMP_ABI_MINOR 0 | |
128 | ||
129 | enum lttng_crash_type { | |
130 | LTTNG_CRASH_TYPE_UST = 0, | |
131 | LTTNG_CRASH_TYPE_KERNEL = 1, | |
132 | }; | |
133 | ||
134 | struct lttng_crash_abi { | |
135 | uint8_t magic[RB_CRASH_DUMP_ABI_MAGIC_LEN]; | |
136 | uint64_t mmap_length; /* Overall lenght of crash record */ | |
137 | uint16_t endian; /* | |
138 | * { 0x12, 0x34 }: big endian | |
139 | * { 0x34, 0x12 }: little endian | |
140 | */ | |
141 | uint16_t major; /* Major number. */ | |
142 | uint16_t minor; /* Minor number. */ | |
143 | uint8_t word_size; /* Word size (bytes). */ | |
144 | uint8_t layout_type; /* enum lttng_crash_type */ | |
145 | ||
146 | struct { | |
147 | uint32_t prod_offset; | |
148 | uint32_t consumed_offset; | |
149 | uint32_t commit_hot_array; | |
150 | uint32_t commit_hot_seq; | |
151 | uint32_t buf_wsb_array; | |
152 | uint32_t buf_wsb_id; | |
153 | uint32_t sb_array; | |
154 | uint32_t sb_array_shmp_offset; | |
155 | uint32_t sb_backend_p_offset; | |
156 | uint32_t content_size; | |
157 | uint32_t packet_size; | |
158 | } __attribute__((packed)) offset; | |
159 | struct { | |
160 | uint8_t prod_offset; | |
161 | uint8_t consumed_offset; | |
162 | uint8_t commit_hot_seq; | |
163 | uint8_t buf_wsb_id; | |
164 | uint8_t sb_array_shmp_offset; | |
165 | uint8_t sb_backend_p_offset; | |
166 | uint8_t content_size; | |
167 | uint8_t packet_size; | |
168 | } __attribute__((packed)) length; | |
169 | struct { | |
170 | uint32_t commit_hot_array; | |
171 | uint32_t buf_wsb_array; | |
172 | uint32_t sb_array; | |
173 | } __attribute__((packed)) stride; | |
174 | ||
175 | uint64_t buf_size; /* Size of the buffer */ | |
176 | uint64_t subbuf_size; /* Sub-buffer size */ | |
177 | uint64_t num_subbuf; /* Number of sub-buffers for writer */ | |
178 | uint32_t mode; /* Buffer mode: 0: overwrite, 1: discard */ | |
179 | } __attribute__((packed)); | |
180 | ||
4cfec15c | 181 | struct lttng_ust_lib_ring_buffer { |
a9ff648c MD |
182 | /* First 32 bytes are for the buffer crash dump ABI */ |
183 | struct lttng_crash_abi crash_abi; | |
184 | ||
185 | /* 32 bytes cache-hot cacheline */ | |
186 | union v_atomic __attribute__((aligned(32))) offset; | |
187 | /* Current offset in the buffer */ | |
a6352fd4 | 188 | DECLARE_SHMP(struct commit_counters_hot, commit_hot); |
852c2936 | 189 | /* Commit count per sub-buffer */ |
14641deb | 190 | long consumed; /* |
852c2936 MD |
191 | * Current offset in the buffer |
192 | * standard atomic access (shared) | |
193 | */ | |
14641deb | 194 | int record_disabled; |
a9ff648c MD |
195 | /* End of cache-hot 32 bytes cacheline */ |
196 | ||
852c2936 MD |
197 | union v_atomic last_tsc; /* |
198 | * Last timestamp written in the buffer. | |
199 | */ | |
200 | ||
a9ff648c MD |
201 | struct lttng_ust_lib_ring_buffer_backend backend; |
202 | /* Associated backend */ | |
852c2936 | 203 | |
a6352fd4 | 204 | DECLARE_SHMP(struct commit_counters_cold, commit_cold); |
852c2936 | 205 | /* Commit count per sub-buffer */ |
6c737d05 MD |
206 | DECLARE_SHMP(uint64_t, ts_end); /* |
207 | * timestamp_end per sub-buffer. | |
208 | * Time is sampled by the | |
209 | * switch_*_end() callbacks | |
210 | * which are the last space | |
211 | * reservation performed in the | |
212 | * sub-buffer before it can be | |
213 | * fully committed and | |
214 | * delivered. This time value is | |
215 | * then read by the deliver | |
216 | * callback, performed by the | |
217 | * last commit before the buffer | |
218 | * becomes readable. | |
219 | */ | |
14641deb | 220 | long active_readers; /* |
852c2936 MD |
221 | * Active readers count |
222 | * standard atomic access (shared) | |
223 | */ | |
224 | /* Dropped records */ | |
225 | union v_atomic records_lost_full; /* Buffer full */ | |
226 | union v_atomic records_lost_wrap; /* Nested wrap-around */ | |
227 | union v_atomic records_lost_big; /* Events too big */ | |
228 | union v_atomic records_count; /* Number of records written */ | |
229 | union v_atomic records_overrun; /* Number of overwritten records */ | |
14641deb | 230 | //wait_queue_head_t read_wait; /* reader buffer-level wait queue */ |
852c2936 | 231 | int finalized; /* buffer has been finalized */ |
852c2936 MD |
232 | unsigned long get_subbuf_consumed; /* Read-side consumed */ |
233 | unsigned long prod_snapshot; /* Producer count snapshot */ | |
234 | unsigned long cons_snapshot; /* Consumer count snapshot */ | |
34a91bdb | 235 | unsigned int get_subbuf:1; /* Sub-buffer being held by reader */ |
5d61a504 | 236 | /* shmp pointer to self */ |
4cfec15c | 237 | DECLARE_SHMP(struct lttng_ust_lib_ring_buffer, self); |
3c8964ba | 238 | char padding[RB_RING_BUFFER_PADDING]; |
b728d87e | 239 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
852c2936 MD |
240 | |
241 | static inline | |
242 | void *channel_get_private(struct channel *chan) | |
243 | { | |
a3f61e7f | 244 | return ((char *) chan) + chan->priv_data_offset; |
852c2936 MD |
245 | } |
246 | ||
0d4aa2df MD |
247 | #ifndef __rb_same_type |
248 | #define __rb_same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) | |
249 | #endif | |
250 | ||
852c2936 MD |
251 | /* |
252 | * Issue warnings and disable channels upon internal error. | |
4cfec15c | 253 | * Can receive struct lttng_ust_lib_ring_buffer or struct lttng_ust_lib_ring_buffer_backend |
852c2936 MD |
254 | * parameters. |
255 | */ | |
256 | #define CHAN_WARN_ON(c, cond) \ | |
257 | ({ \ | |
258 | struct channel *__chan; \ | |
b5a3dfa5 | 259 | int _____ret = caa_unlikely(cond); \ |
852c2936 | 260 | if (_____ret) { \ |
0d4aa2df | 261 | if (__rb_same_type(*(c), struct channel_backend)) \ |
14641deb | 262 | __chan = caa_container_of((void *) (c), \ |
852c2936 MD |
263 | struct channel, \ |
264 | backend); \ | |
0d4aa2df | 265 | else if (__rb_same_type(*(c), struct channel)) \ |
852c2936 MD |
266 | __chan = (void *) (c); \ |
267 | else \ | |
268 | BUG_ON(1); \ | |
14641deb | 269 | uatomic_inc(&__chan->record_disabled); \ |
852c2936 MD |
270 | WARN_ON(1); \ |
271 | } \ | |
257ecc17 | 272 | _____ret = _____ret; /* For clang "unused result". */ \ |
852c2936 MD |
273 | }) |
274 | ||
e92f3e28 | 275 | #endif /* _LTTNG_RING_BUFFER_FRONTEND_TYPES_H */ |