/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ #ifndef _TRACE_MMAP_H_ #define _TRACE_MMAP_H_ #include <linux/types.h> /** * struct trace_buffer_meta - Ring-buffer Meta-page description * @meta_page_size: Size of this meta-page. * @meta_struct_len: Size of this structure. * @subbuf_size: Size of each sub-buffer. * @nr_subbufs: Number of subbfs in the ring-buffer, including the reader. * @reader: The reader composite info structure * @reader.lost_events: Number of events lost at the time of the reader swap. * @reader.id: subbuf ID of the current reader. ID range [0 : @nr_subbufs - 1] * @reader.read: Number of bytes read on the reader subbuf. * @flags: Placeholder for now, 0 until new features are supported. * @entries: Number of entries in the ring-buffer. * @overrun: Number of entries lost in the ring-buffer. * @read: Number of entries that have been read. * @pages_lost: Number of pages overwritten by the writer. * @pages_touched: Number of pages written by the writer. */ struct trace_buffer_meta { __u32 meta_page_size; __u32 meta_struct_len; __u32 subbuf_size; __u32 nr_subbufs; struct { __u64 lost_events; __u32 id; __u32 read; } reader; __u64 flags; __u64 entries; __u64 overrun; __u64 read; __u64 pages_lost; __u64 pages_touched; }; #define TRACE_MMAP_IOCTL_GET_READER _IO('R', 0x20) #endif /* _TRACE_MMAP_H_ */