1 files changed, 5 insertions, 0 deletions

diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 91803e54ee73..86c44ae66d43 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -522,9 +522,14 @@ struct perf_event_mmap_page {
          * In this case the kernel will not over-write unread data.
          *
          * See perf_output_put_handle() for the data ordering.
+         *
+         * data_{offset,size} indicate the location and size of the perf record
+         * buffer within the mmapped area.
          */
         __u64   data_head;              /* head in the data section */
         __u64   data_tail;              /* user-space written tail */
+        __u64   data_offset;            /* where the buffer starts */
+        __u64   data_size;              /* data buffer size */
 };
 
 #define PERF_RECORD_MISC_CPUMODE_MASK           (7 << 0)