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