2 * SPDX-License-Identifier: LGPL-2.1-only
4 * Copyright (C) 2008-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
6 * Ring buffer backend (types).
9 #ifndef _LTTNG_RING_BUFFER_BACKEND_TYPES_H
10 #define _LTTNG_RING_BUFFER_BACKEND_TYPES_H
14 #include "shm_internal.h"
17 #define RB_BACKEND_PAGES_PADDING 16
18 struct lttng_ust_lib_ring_buffer_backend_pages
{
19 unsigned long mmap_offset
; /* offset of the subbuffer in mmap */
20 union v_atomic records_commit
; /* current records committed count */
21 union v_atomic records_unread
; /* records to read */
22 unsigned long data_size
; /* Amount of data to read from subbuf */
23 DECLARE_SHMP(char, p
); /* Backing memory map */
24 char padding
[RB_BACKEND_PAGES_PADDING
];
27 struct lttng_ust_lib_ring_buffer_backend_subbuffer
{
28 /* Identifier for subbuf backend pages. Exchanged atomically. */
29 unsigned long id
; /* backend subbuffer identifier */
32 struct lttng_ust_lib_ring_buffer_backend_counts
{
34 * Counter specific to the sub-buffer location within the ring buffer.
35 * The actual sequence number of the packet within the entire ring
36 * buffer can be derived from the formula nr_subbuffers * seq_cnt +
39 uint64_t seq_cnt
; /* packet sequence number */
43 * Forward declaration of frontend-specific channel and ring_buffer.
45 struct lttng_ust_lib_ring_buffer_channel
;
46 struct lttng_ust_lib_ring_buffer
;
48 struct lttng_ust_lib_ring_buffer_backend_pages_shmp
{
49 DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_pages
, shmp
);
52 #define RB_BACKEND_RING_BUFFER_PADDING 64
53 struct lttng_ust_lib_ring_buffer_backend
{
54 /* Array of ring_buffer_backend_subbuffer for writer */
55 DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_subbuffer
, buf_wsb
);
56 /* ring_buffer_backend_subbuffer for reader */
57 struct lttng_ust_lib_ring_buffer_backend_subbuffer buf_rsb
;
58 /* Array of lib_ring_buffer_backend_counts for the packet counter */
59 DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_counts
, buf_cnt
);
61 * Pointer array of backend pages, for whole buffer.
62 * Indexed by ring_buffer_backend_subbuffer identifier (id) index.
64 DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_pages_shmp
, array
);
65 DECLARE_SHMP(char, memory_map
); /* memory mapping */
67 DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_channel
, chan
); /* Associated channel */
68 int cpu
; /* This buffer's cpu. -1 if global. */
69 union v_atomic records_read
; /* Number of records read */
70 unsigned int allocated
:1; /* is buffer allocated ? */
71 char padding
[RB_BACKEND_RING_BUFFER_PADDING
];
74 struct lttng_ust_lib_ring_buffer_shmp
{
75 DECLARE_SHMP(struct lttng_ust_lib_ring_buffer
, shmp
); /* Channel per-cpu buffers */
78 #define RB_BACKEND_CHANNEL_PADDING 64
79 struct channel_backend
{
80 unsigned long buf_size
; /* Size of the buffer */
81 unsigned long subbuf_size
; /* Sub-buffer size */
82 unsigned int subbuf_size_order
; /* Order of sub-buffer size */
83 unsigned int num_subbuf_order
; /*
84 * Order of number of sub-buffers/buffer
87 unsigned int buf_size_order
; /* Order of buffer size */
88 unsigned int extra_reader_sb
:1; /* has extra reader subbuffer ? */
89 unsigned long num_subbuf
; /* Number of sub-buffers for writer */
90 uint64_t start_tsc
; /* Channel creation TSC value */
91 DECLARE_SHMP(void *, priv_data
);/* Client-specific information */
92 struct lttng_ust_lib_ring_buffer_config config
; /* Ring buffer configuration */
93 char name
[NAME_MAX
]; /* Channel name */
94 char padding
[RB_BACKEND_CHANNEL_PADDING
];
95 struct lttng_ust_lib_ring_buffer_shmp buf
[];
98 #endif /* _LTTNG_RING_BUFFER_BACKEND_TYPES_H */