[RFC PATCH 4/4] bpf tools: Enable/disable the perf events stored in 'struct bpf_object'

[Kaixu Xia]

This patch enable/disable the perf events stored in 'struct
bpf_object' at the appropriate time. These events we're
interested in come from 'maps' sections.

Signed-off-by: Kaixu Xia <xiakaixu@xxxxxxxxxx>
---
 tools/lib/bpf/libbpf.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 2b3940e..7fab959 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -20,6 +20,7 @@
 #include <linux/list.h>
 #include <libelf.h>
 #include <gelf.h>
+#include <sys/ioctl.h>
 
 #include "libbpf.h"
 #include "bpf.h"
@@ -972,6 +973,32 @@ bpf_object__load_progs(struct bpf_object *obj)
 	return 0;
 }
 
+static int
+bpf_object__maps_event_enable(struct bpf_object *obj)
+{
+	int i;
+	int nr_bpf_event = obj->nr_bpf_event_fds;
+
+	for (i = 0; i < nr_bpf_event; i++)
+		ioctl((int)obj->bpf_event_fds[i],
+		      PERF_EVENT_IOC_ENABLE, 0);
+
+	return 0;
+}
+
+static void bpf_object__maps_event_close(struct bpf_object *obj)
+{
+	int i;
+	int nr_bpf_event = obj->nr_bpf_event_fds;
+
+	for (i = 0; i < nr_bpf_event; i++) {
+		int maps_event_fd = (int)obj->bpf_event_fds[i];
+
+		ioctl(maps_event_fd, PERF_EVENT_IOC_DISABLE, 0);
+		close(maps_event_fd);
+	}
+}
+
 static int bpf_object__validate(struct bpf_object *obj)
 {
 	if (obj->kern_version == 0) {
@@ -1072,6 +1099,8 @@ int bpf_object__load(struct bpf_object *obj)
 		goto out;
 	if (bpf_object__load_progs(obj))
 		goto out;
+	if (bpf_object__maps_event_enable(obj))
+		goto out;
 
 	return 0;
 out:
@@ -1087,6 +1116,7 @@ void bpf_object__close(struct bpf_object *obj)
 	if (!obj)
 		return;
 
+	bpf_object__maps_event_close(obj);
 	bpf_object__elf_finish(obj);
 	bpf_object__unload(obj);
 
-- 
1.8.3.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/