1 files changed, 28 insertions, 1 deletions

diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 73579a25a93e..2dd07bd60b4f 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -17,6 +17,13 @@ struct perf_record_opts;
 #define PERF_EVLIST__HLIST_BITS 8
 #define PERF_EVLIST__HLIST_SIZE (1 << PERF_EVLIST__HLIST_BITS)
 
+struct perf_mmap {
+        void             *base;
+        int              mask;
+        unsigned int     prev;
+        union perf_event event_copy;
+};
+
 struct perf_evlist {
         struct list_head entries;
         struct hlist_head heads[PERF_EVLIST__HLIST_SIZE];
@@ -30,7 +37,6 @@ struct perf_evlist {
                 pid_t   pid;
         } workload;
         bool             overwrite;
-        union perf_event event_copy;
         struct perf_mmap *mmap;
         struct pollfd    *pollfd;
         struct thread_map *threads;
@@ -136,4 +142,25 @@ static inline struct perf_evsel *perf_evlist__last(struct perf_evlist *evlist)
 }
 
 size_t perf_evlist__fprintf(struct perf_evlist *evlist, FILE *fp);
+
+static inline unsigned int perf_mmap__read_head(struct perf_mmap *mm)
+{
+        struct perf_event_mmap_page *pc = mm->base;
+        int head = pc->data_head;
+        rmb();
+        return head;
+}
+
+static inline void perf_mmap__write_tail(struct perf_mmap *md,
+                                         unsigned long tail)
+{
+        struct perf_event_mmap_page *pc = md->base;
+
+        /*
+         * ensure all reads are done before we write the tail out.
+         */
+        /* mb(); */
+        pc->data_tail = tail;
+}
+
 #endif /* __PERF_EVLIST_H */