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852c2936 MD |
1 | #ifndef _LINUX_RING_BUFFER_FRONTEND_TYPES_H |
2 | #define _LINUX_RING_BUFFER_FRONTEND_TYPES_H | |
3 | ||
4 | /* | |
5 | * linux/ringbuffer/frontend_types.h | |
6 | * | |
7 | * (C) Copyright 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
8 | * | |
9 | * Ring Buffer Library Synchronization Header (types). | |
10 | * | |
11 | * Author: | |
12 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
13 | * | |
14 | * See ring_buffer_frontend.c for more information on wait-free algorithms. | |
15 | * | |
16 | * Dual LGPL v2.1/GPL v2 license. | |
17 | */ | |
18 | ||
a6352fd4 MD |
19 | #include <string.h> |
20 | ||
14641deb MD |
21 | #include <urcu/list.h> |
22 | #include <urcu/uatomic.h> | |
14641deb | 23 | |
4318ae1b | 24 | #include <lttng/ringbuffer-config.h> |
44c72f10 | 25 | #include <usterr-signal-safe.h> |
4931a13e | 26 | #include "backend_types.h" |
1d498196 | 27 | #include "shm_internal.h" |
a3bb4b27 | 28 | #include "vatomic.h" |
852c2936 MD |
29 | |
30 | /* | |
31 | * A switch is done during tracing or as a final flush after tracing (so it | |
32 | * won't write in the new sub-buffer). | |
33 | */ | |
34 | enum switch_mode { SWITCH_ACTIVE, SWITCH_FLUSH }; | |
35 | ||
852c2936 | 36 | /* channel: collection of per-cpu ring buffers. */ |
3c8964ba | 37 | #define RB_CHANNEL_PADDING 64 |
852c2936 | 38 | struct channel { |
14641deb | 39 | int record_disabled; |
852c2936 MD |
40 | unsigned long commit_count_mask; /* |
41 | * Commit count mask, removing | |
42 | * the MSBs corresponding to | |
43 | * bits used to represent the | |
44 | * subbuffer index. | |
45 | */ | |
46 | ||
852c2936 MD |
47 | unsigned long switch_timer_interval; /* Buffer flush (jiffies) */ |
48 | unsigned long read_timer_interval; /* Reader wakeup (jiffies) */ | |
14641deb | 49 | //wait_queue_head_t read_wait; /* reader wait queue */ |
852c2936 | 50 | int finalized; /* Has channel been finalized */ |
a3f61e7f | 51 | size_t priv_data_offset; |
de85e7c3 MD |
52 | /* |
53 | * Associated backend contains a variable-length array. Needs to | |
54 | * be last member. | |
55 | */ | |
56 | struct channel_backend backend; /* Associated backend */ | |
3c8964ba | 57 | char padding[RB_CHANNEL_PADDING]; |
b728d87e | 58 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
852c2936 MD |
59 | |
60 | /* Per-subbuffer commit counters used on the hot path */ | |
3c8964ba | 61 | #define RB_COMMIT_COUNT_HOT_PADDING 16 |
852c2936 MD |
62 | struct commit_counters_hot { |
63 | union v_atomic cc; /* Commit counter */ | |
64 | union v_atomic seq; /* Consecutive commits */ | |
3c8964ba | 65 | char padding[RB_COMMIT_COUNT_HOT_PADDING]; |
b728d87e | 66 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
852c2936 MD |
67 | |
68 | /* Per-subbuffer commit counters used only on cold paths */ | |
3c8964ba | 69 | #define RB_COMMIT_COUNT_COLD_PADDING 24 |
852c2936 MD |
70 | struct commit_counters_cold { |
71 | union v_atomic cc_sb; /* Incremented _once_ at sb switch */ | |
3c8964ba | 72 | char padding[RB_COMMIT_COUNT_COLD_PADDING]; |
b728d87e | 73 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
852c2936 | 74 | |
852c2936 | 75 | /* ring buffer state */ |
3c8964ba | 76 | #define RB_RING_BUFFER_PADDING 64 |
4cfec15c | 77 | struct lttng_ust_lib_ring_buffer { |
852c2936 MD |
78 | /* First 32 bytes cache-hot cacheline */ |
79 | union v_atomic offset; /* Current offset in the buffer */ | |
a6352fd4 | 80 | DECLARE_SHMP(struct commit_counters_hot, commit_hot); |
852c2936 | 81 | /* Commit count per sub-buffer */ |
14641deb | 82 | long consumed; /* |
852c2936 MD |
83 | * Current offset in the buffer |
84 | * standard atomic access (shared) | |
85 | */ | |
14641deb | 86 | int record_disabled; |
852c2936 MD |
87 | /* End of first 32 bytes cacheline */ |
88 | union v_atomic last_tsc; /* | |
89 | * Last timestamp written in the buffer. | |
90 | */ | |
91 | ||
4cfec15c | 92 | struct lttng_ust_lib_ring_buffer_backend backend; /* Associated backend */ |
852c2936 | 93 | |
a6352fd4 | 94 | DECLARE_SHMP(struct commit_counters_cold, commit_cold); |
852c2936 | 95 | /* Commit count per sub-buffer */ |
14641deb | 96 | long active_readers; /* |
852c2936 MD |
97 | * Active readers count |
98 | * standard atomic access (shared) | |
99 | */ | |
824f40b8 | 100 | long active_shadow_readers; |
852c2936 MD |
101 | /* Dropped records */ |
102 | union v_atomic records_lost_full; /* Buffer full */ | |
103 | union v_atomic records_lost_wrap; /* Nested wrap-around */ | |
104 | union v_atomic records_lost_big; /* Events too big */ | |
105 | union v_atomic records_count; /* Number of records written */ | |
106 | union v_atomic records_overrun; /* Number of overwritten records */ | |
14641deb | 107 | //wait_queue_head_t read_wait; /* reader buffer-level wait queue */ |
852c2936 | 108 | int finalized; /* buffer has been finalized */ |
14641deb MD |
109 | //struct timer_list switch_timer; /* timer for periodical switch */ |
110 | //struct timer_list read_timer; /* timer for read poll */ | |
852c2936 MD |
111 | unsigned long get_subbuf_consumed; /* Read-side consumed */ |
112 | unsigned long prod_snapshot; /* Producer count snapshot */ | |
113 | unsigned long cons_snapshot; /* Consumer count snapshot */ | |
7c2caf2b MD |
114 | unsigned int get_subbuf:1, /* Sub-buffer being held by reader */ |
115 | switch_timer_enabled:1, /* Protected by ring_buffer_nohz_lock */ | |
116 | read_timer_enabled:1; /* Protected by ring_buffer_nohz_lock */ | |
5d61a504 | 117 | /* shmp pointer to self */ |
4cfec15c | 118 | DECLARE_SHMP(struct lttng_ust_lib_ring_buffer, self); |
3c8964ba | 119 | char padding[RB_RING_BUFFER_PADDING]; |
b728d87e | 120 | } __attribute__((aligned(CAA_CACHE_LINE_SIZE))); |
852c2936 MD |
121 | |
122 | static inline | |
123 | void *channel_get_private(struct channel *chan) | |
124 | { | |
a3f61e7f | 125 | return ((char *) chan) + chan->priv_data_offset; |
852c2936 MD |
126 | } |
127 | ||
0d4aa2df MD |
128 | #ifndef __rb_same_type |
129 | #define __rb_same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) | |
130 | #endif | |
131 | ||
852c2936 MD |
132 | /* |
133 | * Issue warnings and disable channels upon internal error. | |
4cfec15c | 134 | * Can receive struct lttng_ust_lib_ring_buffer or struct lttng_ust_lib_ring_buffer_backend |
852c2936 MD |
135 | * parameters. |
136 | */ | |
137 | #define CHAN_WARN_ON(c, cond) \ | |
138 | ({ \ | |
139 | struct channel *__chan; \ | |
b5a3dfa5 | 140 | int _____ret = caa_unlikely(cond); \ |
852c2936 | 141 | if (_____ret) { \ |
0d4aa2df | 142 | if (__rb_same_type(*(c), struct channel_backend)) \ |
14641deb | 143 | __chan = caa_container_of((void *) (c), \ |
852c2936 MD |
144 | struct channel, \ |
145 | backend); \ | |
0d4aa2df | 146 | else if (__rb_same_type(*(c), struct channel)) \ |
852c2936 MD |
147 | __chan = (void *) (c); \ |
148 | else \ | |
149 | BUG_ON(1); \ | |
14641deb | 150 | uatomic_inc(&__chan->record_disabled); \ |
852c2936 MD |
151 | WARN_ON(1); \ |
152 | } \ | |
153 | _____ret; \ | |
154 | }) | |
155 | ||
156 | #endif /* _LINUX_RING_BUFFER_FRONTEND_TYPES_H */ |