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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 | ||
a6352fd4 | 31 | #include <string.h> |
03d2d293 | 32 | #include <time.h> /* for timer_t */ |
a6352fd4 | 33 | |
14641deb MD |
34 | #include <urcu/list.h> |
35 | #include <urcu/uatomic.h> | |
14641deb | 36 | |
4318ae1b | 37 | #include <lttng/ringbuffer-config.h> |
44c72f10 | 38 | #include <usterr-signal-safe.h> |
4931a13e | 39 | #include "backend_types.h" |
1d498196 | 40 | #include "shm_internal.h" |
03d2d293 | 41 | #include "shm_types.h" |
a3bb4b27 | 42 | #include "vatomic.h" |
852c2936 MD |
43 | |
44 | /* | |
45 | * A switch is done during tracing or as a final flush after tracing (so it | |
46 | * won't write in the new sub-buffer). | |
47 | */ | |
48 | enum switch_mode { SWITCH_ACTIVE, SWITCH_FLUSH }; | |
49 | ||
852c2936 | 50 | /* channel: collection of per-cpu ring buffers. */ |
74d81a6c | 51 | #define RB_CHANNEL_PADDING 32 |
852c2936 | 52 | struct channel { |
14641deb | 53 | int record_disabled; |
852c2936 MD |
54 | unsigned long commit_count_mask; /* |
55 | * Commit count mask, removing | |
56 | * the MSBs corresponding to | |
57 | * bits used to represent the | |
58 | * subbuffer index. | |
59 | */ | |
60 | ||
03d2d293 MD |
61 | unsigned long switch_timer_interval; /* Buffer flush (us) */ |
62 | timer_t switch_timer; | |
63 | int switch_timer_enabled; | |
64 | ||
65 | unsigned long read_timer_interval; /* Reader wakeup (us) */ | |
34a91bdb MD |
66 | timer_t read_timer; |
67 | int read_timer_enabled; | |
68 | ||
852c2936 | 69 | int finalized; /* Has channel been finalized */ |
a3f61e7f | 70 | size_t priv_data_offset; |
74d81a6c | 71 | unsigned int nr_streams; /* Number of streams */ |
03d2d293 | 72 | struct lttng_ust_shm_handle *handle; |
74d81a6c | 73 | char padding[RB_CHANNEL_PADDING]; |
de85e7c3 MD |
74 | /* |
75 | * Associated backend contains a variable-length array. Needs to | |
76 | * be last member. | |
77 | */ | |
78 | struct channel_backend backend; /* Associated backend */ | |
b728d87e | 79 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
852c2936 MD |
80 | |
81 | /* Per-subbuffer commit counters used on the hot path */ | |
3c8964ba | 82 | #define RB_COMMIT_COUNT_HOT_PADDING 16 |
852c2936 MD |
83 | struct commit_counters_hot { |
84 | union v_atomic cc; /* Commit counter */ | |
85 | union v_atomic seq; /* Consecutive commits */ | |
3c8964ba | 86 | char padding[RB_COMMIT_COUNT_HOT_PADDING]; |
b728d87e | 87 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
852c2936 MD |
88 | |
89 | /* Per-subbuffer commit counters used only on cold paths */ | |
3c8964ba | 90 | #define RB_COMMIT_COUNT_COLD_PADDING 24 |
852c2936 MD |
91 | struct commit_counters_cold { |
92 | union v_atomic cc_sb; /* Incremented _once_ at sb switch */ | |
3c8964ba | 93 | char padding[RB_COMMIT_COUNT_COLD_PADDING]; |
b728d87e | 94 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
852c2936 | 95 | |
852c2936 | 96 | /* ring buffer state */ |
3c8964ba | 97 | #define RB_RING_BUFFER_PADDING 64 |
4cfec15c | 98 | struct lttng_ust_lib_ring_buffer { |
852c2936 MD |
99 | /* First 32 bytes cache-hot cacheline */ |
100 | union v_atomic offset; /* Current offset in the buffer */ | |
a6352fd4 | 101 | DECLARE_SHMP(struct commit_counters_hot, commit_hot); |
852c2936 | 102 | /* Commit count per sub-buffer */ |
14641deb | 103 | long consumed; /* |
852c2936 MD |
104 | * Current offset in the buffer |
105 | * standard atomic access (shared) | |
106 | */ | |
14641deb | 107 | int record_disabled; |
852c2936 MD |
108 | /* End of first 32 bytes cacheline */ |
109 | union v_atomic last_tsc; /* | |
110 | * Last timestamp written in the buffer. | |
111 | */ | |
112 | ||
4cfec15c | 113 | struct lttng_ust_lib_ring_buffer_backend backend; /* Associated backend */ |
852c2936 | 114 | |
a6352fd4 | 115 | DECLARE_SHMP(struct commit_counters_cold, commit_cold); |
852c2936 | 116 | /* Commit count per sub-buffer */ |
14641deb | 117 | long active_readers; /* |
852c2936 MD |
118 | * Active readers count |
119 | * standard atomic access (shared) | |
120 | */ | |
121 | /* Dropped records */ | |
122 | union v_atomic records_lost_full; /* Buffer full */ | |
123 | union v_atomic records_lost_wrap; /* Nested wrap-around */ | |
124 | union v_atomic records_lost_big; /* Events too big */ | |
125 | union v_atomic records_count; /* Number of records written */ | |
126 | union v_atomic records_overrun; /* Number of overwritten records */ | |
14641deb | 127 | //wait_queue_head_t read_wait; /* reader buffer-level wait queue */ |
852c2936 | 128 | int finalized; /* buffer has been finalized */ |
852c2936 MD |
129 | unsigned long get_subbuf_consumed; /* Read-side consumed */ |
130 | unsigned long prod_snapshot; /* Producer count snapshot */ | |
131 | unsigned long cons_snapshot; /* Consumer count snapshot */ | |
34a91bdb | 132 | unsigned int get_subbuf:1; /* Sub-buffer being held by reader */ |
5d61a504 | 133 | /* shmp pointer to self */ |
4cfec15c | 134 | DECLARE_SHMP(struct lttng_ust_lib_ring_buffer, self); |
3c8964ba | 135 | char padding[RB_RING_BUFFER_PADDING]; |
b728d87e | 136 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
852c2936 MD |
137 | |
138 | static inline | |
139 | void *channel_get_private(struct channel *chan) | |
140 | { | |
a3f61e7f | 141 | return ((char *) chan) + chan->priv_data_offset; |
852c2936 MD |
142 | } |
143 | ||
0d4aa2df MD |
144 | #ifndef __rb_same_type |
145 | #define __rb_same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) | |
146 | #endif | |
147 | ||
852c2936 MD |
148 | /* |
149 | * Issue warnings and disable channels upon internal error. | |
4cfec15c | 150 | * Can receive struct lttng_ust_lib_ring_buffer or struct lttng_ust_lib_ring_buffer_backend |
852c2936 MD |
151 | * parameters. |
152 | */ | |
153 | #define CHAN_WARN_ON(c, cond) \ | |
154 | ({ \ | |
155 | struct channel *__chan; \ | |
b5a3dfa5 | 156 | int _____ret = caa_unlikely(cond); \ |
852c2936 | 157 | if (_____ret) { \ |
0d4aa2df | 158 | if (__rb_same_type(*(c), struct channel_backend)) \ |
14641deb | 159 | __chan = caa_container_of((void *) (c), \ |
852c2936 MD |
160 | struct channel, \ |
161 | backend); \ | |
0d4aa2df | 162 | else if (__rb_same_type(*(c), struct channel)) \ |
852c2936 MD |
163 | __chan = (void *) (c); \ |
164 | else \ | |
165 | BUG_ON(1); \ | |
14641deb | 166 | uatomic_inc(&__chan->record_disabled); \ |
852c2936 MD |
167 | WARN_ON(1); \ |
168 | } \ | |
169 | _____ret; \ | |
170 | }) | |
171 | ||
e92f3e28 | 172 | #endif /* _LTTNG_RING_BUFFER_FRONTEND_TYPES_H */ |