1 /* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
3 * ringbuffer/backend_types.h
5 * Ring buffer backend (types).
7 * Copyright (C) 2008-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 #ifndef _LIB_RING_BUFFER_BACKEND_TYPES_H
11 #define _LIB_RING_BUFFER_BACKEND_TYPES_H
13 #include <linux/cpumask.h>
14 #include <linux/types.h>
15 #include <lttng/kernel-version.h>
16 #include <lttng/cpuhotplug.h>
18 struct lib_ring_buffer_backend_page
{
19 void *virt
; /* page virtual address (cached) */
20 unsigned long pfn
; /* page frame number */
23 struct lib_ring_buffer_backend_pages
{
24 unsigned long mmap_offset
; /* offset of the subbuffer in mmap */
25 union v_atomic records_commit
; /* current records committed count */
26 union v_atomic records_unread
; /* records to read */
27 unsigned long data_size
; /* Amount of data to read from subbuf */
28 struct lib_ring_buffer_backend_page p
[];
31 struct lib_ring_buffer_backend_subbuffer
{
32 /* Identifier for subbuf backend pages. Exchanged atomically. */
33 unsigned long id
; /* backend subbuffer identifier */
36 struct lib_ring_buffer_backend_counts
{
38 * Counter specific to the sub-buffer location within the ring buffer.
39 * The actual sequence number of the packet within the entire ring
40 * buffer can be derived from the formula nr_subbuffers * seq_cnt +
43 uint64_t seq_cnt
; /* packet sequence number */
47 * Forward declaration of frontend-specific channel and ring_buffer.
50 struct lib_ring_buffer
;
52 struct lib_ring_buffer_backend
{
53 /* Array of ring_buffer_backend_subbuffer for writer */
54 struct lib_ring_buffer_backend_subbuffer
*buf_wsb
;
55 /* ring_buffer_backend_subbuffer for reader */
56 struct lib_ring_buffer_backend_subbuffer buf_rsb
;
57 /* Array of lib_ring_buffer_backend_counts for the packet counter */
58 struct lib_ring_buffer_backend_counts
*buf_cnt
;
60 * Pointer array of backend pages, for whole buffer.
61 * Indexed by ring_buffer_backend_subbuffer identifier (id) index.
63 struct lib_ring_buffer_backend_pages
**array
;
64 unsigned int num_pages_per_subbuf
;
66 struct channel
*chan
; /* Associated channel */
67 int cpu
; /* This buffer's cpu. -1 if global. */
68 union v_atomic records_read
; /* Number of records read */
69 unsigned int allocated
:1; /* is buffer allocated ? */
72 struct channel_backend
{
73 unsigned long buf_size
; /* Size of the buffer */
74 unsigned long subbuf_size
; /* Sub-buffer size */
75 unsigned int subbuf_size_order
; /* Order of sub-buffer size */
76 unsigned int num_subbuf_order
; /*
77 * Order of number of sub-buffers/buffer
80 unsigned int buf_size_order
; /* Order of buffer size */
81 unsigned int extra_reader_sb
:1; /* has extra reader subbuffer ? */
82 struct lib_ring_buffer
*buf
; /* Channel per-cpu buffers */
84 unsigned long num_subbuf
; /* Number of sub-buffers for writer */
85 u64 start_tsc
; /* Channel creation TSC value */
86 void *priv
; /* Client-specific information */
87 void *priv_ops
; /* Client-specific ops pointer */
88 void (*release_priv_ops
)(void *priv_ops
);
89 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
90 struct lttng_cpuhp_node cpuhp_prepare
; /* CPU hotplug prepare */
92 struct notifier_block cpu_hp_notifier
; /* CPU hotplug notifier */
95 * We need to copy config because the module containing the
96 * source config can vanish before the last reference to this
97 * channel's streams is released.
99 struct lib_ring_buffer_config config
; /* Ring buffer configuration */
100 cpumask_var_t cpumask
; /* Allocated per-cpu buffers cpumask */
101 char name
[NAME_MAX
]; /* Channel name */
104 #endif /* _LIB_RING_BUFFER_BACKEND_TYPES_H */