include/uapi/linux/trace_mmap.h

   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_ */