diff options
| -rw-r--r-- | include/uapi/linux/perf_event.h | 5 | ||||
| -rw-r--r-- | kernel/events/core.c | 2 |
2 files changed, 7 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) diff --git a/kernel/events/core.c b/kernel/events/core.c index 5c13862d3e85..6efa516f1ab8 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4105,6 +4105,8 @@ static void perf_event_init_userpage(struct perf_event *event) /* Allow new userspace to detect that bit 0 is deprecated */ userpg->cap_bit0_is_deprecated = 1; userpg->size = offsetof(struct perf_event_mmap_page, __reserved); + userpg->data_offset = PAGE_SIZE; + userpg->data_size = perf_data_size(rb); unlock: rcu_read_unlock(); |