LXR linux/tools/perf/util/mmap.h

   1#ifndef __PERF_MMAP_H
   2#define __PERF_MMAP_H 1
   3
   4#include <linux/compiler.h>
   5#include <linux/refcount.h>
   6#include <linux/types.h>
   7#include <asm/barrier.h>
   8#include <stdbool.h>
   9#include "auxtrace.h"
  10#include "event.h"
  11
  12/**
  13 * struct perf_mmap - perf's ring buffer mmap details
  14 *
  15 * @refcnt - e.g. code using PERF_EVENT_IOC_SET_OUTPUT to share this
  16 */
  17struct perf_mmap {
  18        void             *base;
  19        int              mask;
  20        int              fd;
  21        refcount_t       refcnt;
  22        u64              prev;
  23        struct auxtrace_mmap auxtrace_mmap;
  24        char             event_copy[PERF_SAMPLE_MAX_SIZE] __aligned(8);
  25};
  26
  27/*
  28 * State machine of bkw_mmap_state:
  29 *
  30 *                     .________________(forbid)_____________.
  31 *                     |                                     V
  32 * NOTREADY --(0)--> RUNNING --(1)--> DATA_PENDING --(2)--> EMPTY
  33 *                     ^  ^              |   ^               |
  34 *                     |  |__(forbid)____/   |___(forbid)___/|
  35 *                     |                                     |
  36 *                      \_________________(3)_______________/
  37 *
  38 * NOTREADY     : Backward ring buffers are not ready
  39 * RUNNING      : Backward ring buffers are recording
  40 * DATA_PENDING : We are required to collect data from backward ring buffers
  41 * EMPTY        : We have collected data from backward ring buffers.
  42 *
  43 * (0): Setup backward ring buffer
  44 * (1): Pause ring buffers for reading
  45 * (2): Read from ring buffers
  46 * (3): Resume ring buffers for recording
  47 */
  48enum bkw_mmap_state {
  49        BKW_MMAP_NOTREADY,
  50        BKW_MMAP_RUNNING,
  51        BKW_MMAP_DATA_PENDING,
  52        BKW_MMAP_EMPTY,
  53};
  54
  55struct mmap_params {
  56        int                         prot, mask;
  57        struct auxtrace_mmap_params auxtrace_mp;
  58};
  59
  60int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd);
  61void perf_mmap__munmap(struct perf_mmap *map);
  62
  63void perf_mmap__get(struct perf_mmap *map);
  64void perf_mmap__put(struct perf_mmap *map);
  65
  66void perf_mmap__consume(struct perf_mmap *map, bool overwrite);
  67
  68static inline u64 perf_mmap__read_head(struct perf_mmap *mm)
  69{
  70        struct perf_event_mmap_page *pc = mm->base;
  71        u64 head = READ_ONCE(pc->data_head);
  72        rmb();
  73        return head;
  74}
  75
  76static inline void perf_mmap__write_tail(struct perf_mmap *md, u64 tail)
  77{
  78        struct perf_event_mmap_page *pc = md->base;
  79
  80        /*
  81         * ensure all reads are done before we write the tail out.
  82         */
  83        mb();
  84        pc->data_tail = tail;
  85}
  86
  87union perf_event *perf_mmap__read_forward(struct perf_mmap *map);
  88
  89union perf_event *perf_mmap__read_event(struct perf_mmap *map,
  90                                        bool overwrite,
  91                                        u64 *startp, u64 end);
  92
  93int perf_mmap__push(struct perf_mmap *md, bool backward,
  94                    void *to, int push(void *to, void *buf, size_t size));
  95
  96size_t perf_mmap__mmap_len(struct perf_mmap *map);
  97
  98int perf_mmap__read_init(struct perf_mmap *md, bool overwrite,
  99                         u64 *startp, u64 *endp);
 100void perf_mmap__read_done(struct perf_mmap *map);
 101#endif /*__PERF_MMAP_H */
 102