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1 | #ifndef _LIB_RING_BUFFER_FRONTEND_TYPES_H |
2 | #define _LIB_RING_BUFFER_FRONTEND_TYPES_H | |
f3bc08c5 MD |
3 | |
4 | /* | |
886d51a3 | 5 | * lib/ringbuffer/frontend_types.h |
f3bc08c5 MD |
6 | * |
7 | * Ring Buffer Library Synchronization Header (types). | |
8 | * | |
886d51a3 MD |
9 | * Copyright (C) 2010-2012 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 | ||
f40270ad | 31 | #include <linux/kref.h> |
f3bc08c5 MD |
32 | #include "../../wrapper/ringbuffer/config.h" |
33 | #include "../../wrapper/ringbuffer/backend_types.h" | |
a181050f | 34 | #include "../../wrapper/spinlock.h" |
a88db018 | 35 | #include "../../lib/prio_heap/lttng_prio_heap.h" /* For per-CPU read-side iterator */ |
f3bc08c5 MD |
36 | |
37 | /* | |
38 | * A switch is done during tracing or as a final flush after tracing (so it | |
39 | * won't write in the new sub-buffer). | |
40 | */ | |
41 | enum switch_mode { SWITCH_ACTIVE, SWITCH_FLUSH }; | |
42 | ||
43 | /* channel-level read-side iterator */ | |
44 | struct channel_iter { | |
45 | /* Prio heap of buffers. Lowest timestamps at the top. */ | |
a88db018 | 46 | struct lttng_ptr_heap heap; /* Heap of struct lib_ring_buffer ptrs */ |
f3bc08c5 MD |
47 | struct list_head empty_head; /* Empty buffers linked-list head */ |
48 | int read_open; /* Opened for reading ? */ | |
49 | u64 last_qs; /* Last quiescent state timestamp */ | |
50 | u64 last_timestamp; /* Last timestamp (for WARN_ON) */ | |
51 | int last_cpu; /* Last timestamp cpu */ | |
52 | /* | |
53 | * read() file operation state. | |
54 | */ | |
55 | unsigned long len_left; | |
56 | }; | |
57 | ||
58 | /* channel: collection of per-cpu ring buffers. */ | |
59 | struct channel { | |
60 | atomic_t record_disabled; | |
61 | unsigned long commit_count_mask; /* | |
62 | * Commit count mask, removing | |
63 | * the MSBs corresponding to | |
64 | * bits used to represent the | |
65 | * subbuffer index. | |
66 | */ | |
67 | ||
68 | struct channel_backend backend; /* Associated backend */ | |
69 | ||
70 | unsigned long switch_timer_interval; /* Buffer flush (jiffies) */ | |
71 | unsigned long read_timer_interval; /* Reader wakeup (jiffies) */ | |
72 | struct notifier_block cpu_hp_notifier; /* CPU hotplug notifier */ | |
73 | struct notifier_block tick_nohz_notifier; /* CPU nohz notifier */ | |
74 | struct notifier_block hp_iter_notifier; /* hotplug iterator notifier */ | |
9cccf98a MD |
75 | unsigned int cpu_hp_enable:1; /* Enable CPU hotplug notif. */ |
76 | unsigned int hp_iter_enable:1; /* Enable hp iter notif. */ | |
f3bc08c5 | 77 | wait_queue_head_t read_wait; /* reader wait queue */ |
24cedcfe MD |
78 | wait_queue_head_t hp_wait; /* CPU hotplug wait queue */ |
79 | int finalized; /* Has channel been finalized */ | |
f3bc08c5 | 80 | struct channel_iter iter; /* Channel read-side iterator */ |
f40270ad | 81 | struct kref ref; /* Reference count */ |
f3bc08c5 MD |
82 | }; |
83 | ||
84 | /* Per-subbuffer commit counters used on the hot path */ | |
85 | struct commit_counters_hot { | |
86 | union v_atomic cc; /* Commit counter */ | |
87 | union v_atomic seq; /* Consecutive commits */ | |
88 | }; | |
89 | ||
90 | /* Per-subbuffer commit counters used only on cold paths */ | |
91 | struct commit_counters_cold { | |
92 | union v_atomic cc_sb; /* Incremented _once_ at sb switch */ | |
93 | }; | |
94 | ||
95 | /* Per-buffer read iterator */ | |
96 | struct lib_ring_buffer_iter { | |
97 | u64 timestamp; /* Current record timestamp */ | |
98 | size_t header_len; /* Current record header length */ | |
99 | size_t payload_len; /* Current record payload length */ | |
100 | ||
101 | struct list_head empty_node; /* Linked list of empty buffers */ | |
102 | unsigned long consumed, read_offset, data_size; | |
103 | enum { | |
104 | ITER_GET_SUBBUF = 0, | |
105 | ITER_TEST_RECORD, | |
106 | ITER_NEXT_RECORD, | |
107 | ITER_PUT_SUBBUF, | |
108 | } state; | |
9cccf98a MD |
109 | unsigned int allocated:1; |
110 | unsigned int read_open:1; /* Opened for reading ? */ | |
f3bc08c5 MD |
111 | }; |
112 | ||
113 | /* ring buffer state */ | |
114 | struct lib_ring_buffer { | |
115 | /* First 32 bytes cache-hot cacheline */ | |
116 | union v_atomic offset; /* Current offset in the buffer */ | |
117 | struct commit_counters_hot *commit_hot; | |
118 | /* Commit count per sub-buffer */ | |
119 | atomic_long_t consumed; /* | |
120 | * Current offset in the buffer | |
121 | * standard atomic access (shared) | |
122 | */ | |
123 | atomic_t record_disabled; | |
124 | /* End of first 32 bytes cacheline */ | |
125 | union v_atomic last_tsc; /* | |
126 | * Last timestamp written in the buffer. | |
127 | */ | |
128 | ||
129 | struct lib_ring_buffer_backend backend; /* Associated backend */ | |
130 | ||
131 | struct commit_counters_cold *commit_cold; | |
132 | /* Commit count per sub-buffer */ | |
133 | atomic_long_t active_readers; /* | |
134 | * Active readers count | |
135 | * standard atomic access (shared) | |
136 | */ | |
137 | /* Dropped records */ | |
138 | union v_atomic records_lost_full; /* Buffer full */ | |
139 | union v_atomic records_lost_wrap; /* Nested wrap-around */ | |
140 | union v_atomic records_lost_big; /* Events too big */ | |
141 | union v_atomic records_count; /* Number of records written */ | |
142 | union v_atomic records_overrun; /* Number of overwritten records */ | |
143 | wait_queue_head_t read_wait; /* reader buffer-level wait queue */ | |
71c1d843 | 144 | wait_queue_head_t write_wait; /* writer buffer-level wait queue (for metadata only) */ |
f3bc08c5 MD |
145 | int finalized; /* buffer has been finalized */ |
146 | struct timer_list switch_timer; /* timer for periodical switch */ | |
147 | struct timer_list read_timer; /* timer for read poll */ | |
148 | raw_spinlock_t raw_tick_nohz_spinlock; /* nohz entry lock/trylock */ | |
149 | struct lib_ring_buffer_iter iter; /* read-side iterator */ | |
150 | unsigned long get_subbuf_consumed; /* Read-side consumed */ | |
151 | unsigned long prod_snapshot; /* Producer count snapshot */ | |
152 | unsigned long cons_snapshot; /* Consumer count snapshot */ | |
9cccf98a MD |
153 | unsigned int get_subbuf:1, /* Sub-buffer being held by reader */ |
154 | switch_timer_enabled:1, /* Protected by ring_buffer_nohz_lock */ | |
155 | read_timer_enabled:1; /* Protected by ring_buffer_nohz_lock */ | |
f3bc08c5 MD |
156 | }; |
157 | ||
9115fbdc MD |
158 | static inline |
159 | void *channel_get_private(struct channel *chan) | |
160 | { | |
161 | return chan->backend.priv; | |
162 | } | |
163 | ||
f3bc08c5 MD |
164 | /* |
165 | * Issue warnings and disable channels upon internal error. | |
166 | * Can receive struct lib_ring_buffer or struct lib_ring_buffer_backend | |
167 | * parameters. | |
168 | */ | |
169 | #define CHAN_WARN_ON(c, cond) \ | |
170 | ({ \ | |
171 | struct channel *__chan; \ | |
172 | int _____ret = unlikely(cond); \ | |
173 | if (_____ret) { \ | |
174 | if (__same_type(*(c), struct channel_backend)) \ | |
175 | __chan = container_of((void *) (c), \ | |
176 | struct channel, \ | |
177 | backend); \ | |
178 | else if (__same_type(*(c), struct channel)) \ | |
179 | __chan = (void *) (c); \ | |
180 | else \ | |
181 | BUG_ON(1); \ | |
182 | atomic_inc(&__chan->record_disabled); \ | |
183 | WARN_ON(1); \ | |
184 | } \ | |
185 | _____ret; \ | |
186 | }) | |
187 | ||
886d51a3 | 188 | #endif /* _LIB_RING_BUFFER_FRONTEND_TYPES_H */ |