[PATCH 3/3] perf record: Mark MAP_HUGETLB during synthesizing mmap events

[Wang Nan]

During synthesizing mmap events, add MAP_HUGETLB map flag if the
source of mapping is file in hugetlbfs.

After this patch, perf can identify hugetlb mapping even if perf
is started after the mapping of huge pages (like perf top).

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Hou Pengyang <houpengyang@xxxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/event.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index e20438b..4c2abdf 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -1,5 +1,6 @@
 #include <linux/types.h>
 #include <sys/mman.h>
+#include <api/fs/fs.h>
 #include "event.h"
 #include "debug.h"
 #include "hist.h"
@@ -248,6 +249,8 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
 	bool truncation = false;
 	unsigned long long timeout = proc_map_timeout * 1000000ULL;
 	int rc = 0;
+	const char *hugetlbfs_mnt = hugetlbfs__mountpoint();
+	int hugetlbfs_mnt_len = hugetlbfs_mnt ? strlen(hugetlbfs_mnt) : 0;
 
 	if (machine__is_default_guest(machine))
 		return 0;
@@ -342,6 +345,10 @@ out:
 
 		if (!strcmp(execname, ""))
 			strcpy(execname, anonstr);
+		if (!strncmp(execname, hugetlbfs_mnt, hugetlbfs_mnt_len)) {
+			strcpy(execname, anonstr);
+			event->mmap2.flags |= MAP_HUGETLB;
+		}
 
 		size = strlen(execname) + 1;
 		memcpy(event->mmap2.filename, execname, size);
-- 
1.8.3.4