diff options
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index bd71efcc53be..0c21355f04a7 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -27,6 +27,7 @@ #include <linux/list.h> #include <linux/limits.h> #include <linux/perf_event.h> +#include <linux/ring_buffer.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/vfs.h> @@ -2418,13 +2419,12 @@ bpf_perf_event_read_simple(void *mem, unsigned long size, unsigned long page_size, void **buf, size_t *buf_len, bpf_perf_event_print_t fn, void *priv) { - volatile struct perf_event_mmap_page *header = mem; + struct perf_event_mmap_page *header = mem; + __u64 data_head = ring_buffer_read_head(header); __u64 data_tail = header->data_tail; - __u64 data_head = header->data_head; int ret = LIBBPF_PERF_EVENT_ERROR; void *base, *begin, *end; - asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */ if (data_head == data_tail) return LIBBPF_PERF_EVENT_CONT; @@ -2467,8 +2467,6 @@ bpf_perf_event_read_simple(void *mem, unsigned long size, data_tail += ehdr->size; } - __sync_synchronize(); /* smp_mb() */ - header->data_tail = data_tail; - + ring_buffer_write_tail(header, data_tail); return ret; } |