1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef _TRACE_MMAP_H_
3 #define _TRACE_MMAP_H_
4
5 #include <linux/types.h>
6
7 /**
8 * struct trace_buffer_meta - Ring-buffer Meta-page description
9 * @meta_page_size: Size of this meta-page.
10 * @meta_struct_len: Size of this structure.
11 * @subbuf_size: Size of each sub-buffer.
12 * @nr_subbufs: Number of subbfs in the ring-buffer, including the reader.
13 * @reader.lost_events: Number of events lost at the time of the reader swap.
14 * @reader.id: subbuf ID of the current reader. ID range [0 : @nr_subbufs - 1]
15 * @reader.read: Number of bytes read on the reader subbuf.
16 * @flags: Placeholder for now, 0 until new features are supported.
17 * @entries: Number of entries in the ring-buffer.
18 * @overrun: Number of entries lost in the ring-buffer.
19 * @read: Number of entries that have been read.
20 * @Reserved1: Internal use only.
21 * @Reserved2: Internal use only.
22 */
23 struct trace_buffer_meta {
24 __u32 meta_page_size;
25 __u32 meta_struct_len;
26
27 __u32 subbuf_size;
28 __u32 nr_subbufs;
29
30 struct {
31 __u64 lost_events;
32 __u32 id;
33 __u32 read;
34 } reader;
35
36 __u64 flags;
37
38 __u64 entries;
39 __u64 overrun;
40 __u64 read;
41
42 __u64 Reserved1;
43 __u64 Reserved2;
44 };
45
46 #define TRACE_MMAP_IOCTL_GET_READER _IO('R', 0x20)
47
48 #endif /* _TRACE_MMAP_H_ */
49
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