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