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         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  */
  48 enum bkw_mmap_state {
  49         BKW_MMAP_NOTREADY,
  50         BKW_MMAP_RUNNING,
  51         BKW_MMAP_DATA_PENDING,
  52         BKW_MMAP_EMPTY,
  53 };
  54
  55 struct mmap_params {
  56         int                         prot, mask;
  57         struct auxtrace_mmap_params auxtrace_mp;
  58 };
  59
  60 int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd);
  61 void perf_mmap__munmap(struct perf_mmap *map);
  62
  63 void perf_mmap__get(struct perf_mmap *map);
  64 void perf_mmap__put(struct perf_mmap *map);
  65
  66 void perf_mmap__consume(struct perf_mmap *map, bool overwrite);
  67
  68 static 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
  76 static 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
  87 union perf_event *perf_mmap__read_forward(struct perf_mmap *map);
  88
  89 union perf_event *perf_mmap__read_event(struct perf_mmap *map,
  90                                         bool overwrite,
  91                                         u64 *startp, u64 end);
  92
  93 int perf_mmap__push(struct perf_mmap *md, bool backward,
  94                     void *to, int push(void *to, void *buf, size_t size));
  95
  96 size_t perf_mmap__mmap_len(struct perf_mmap *map);
  97
  98 int perf_mmap__read_init(struct perf_mmap *md, bool overwrite,
  99                          u64 *startp, u64 *endp);
 100 void perf_mmap__read_done(struct perf_mmap *map);
 101 #endif /*__PERF_MMAP_H */