[tip:perf/core] perf record: Mark MAP_HUGETLB when synthesizing mmap events

[tip-bot for Wang Nan]

Commit-ID:  d7e404af115bb4996afa4a0236020969ab007554
Gitweb:     http://git.kernel.org/tip/d7e404af115bb4996afa4a0236020969ab007554
Author:     Wang Nan <wangnan0@xxxxxxxxxx>
AuthorDate: Tue, 6 Sep 2016 04:58:29 +0000
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 8 Sep 2016 12:36:01 -0300

perf record: Mark MAP_HUGETLB when synthesizing mmap events

When 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 with 'perf top').

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Reviewed-by: Nilay Vaish <nilayvaish@xxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Hou Pengyang <houpengyang@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1473137909-142064-4-git-send-email-wangnan0@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/event.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 9ad7d32..6c30171 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 +249,10 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
 	bool truncation = false;
 	unsigned long long timeout = proc_map_timeout * 1000000ULL;
 	int rc = 0;
+#ifdef MAP_HUGETLB
+	const char *hugetlbfs_mnt = hugetlbfs__mountpoint();
+	int hugetlbfs_mnt_len = hugetlbfs_mnt ? strlen(hugetlbfs_mnt) : 0;
+#endif
 
 	if (machine__is_default_guest(machine))
 		return 0;
@@ -342,6 +347,12 @@ out:
 
 		if (!strcmp(execname, ""))
 			strcpy(execname, anonstr);
+#ifdef MAP_HUGETLB
+		if (!strncmp(execname, hugetlbfs_mnt, hugetlbfs_mnt_len)) {
+			strcpy(execname, anonstr);
+			event->mmap2.flags |= MAP_HUGETLB;
+		}
+#endif
 
 		size = strlen(execname) + 1;
 		memcpy(event->mmap2.filename, execname, size);