[tip:perf/core] perf tools: Recognize hugetlb mapping as anon mapping

[tip-bot for Wang Nan]

Commit-ID:  0ac3348e502423cf2fe86beca83b8835a2e6d289
Gitweb:     http://git.kernel.org/tip/0ac3348e502423cf2fe86beca83b8835a2e6d289
Author:     Wang Nan <wangnan0@xxxxxxxxxx>
AuthorDate: Tue, 6 Sep 2016 04:58:27 +0000
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 8 Sep 2016 12:28:06 -0300

perf tools: Recognize hugetlb mapping as anon mapping

Hugetlbfs mapping should be recognized as anon mapping so user has a
chance to create /tmp/perf-<pid>.map file for symbol resolving. This
patch utilizes MAP_HUGETLB to identify hugetlb mapping.

After this patch, if perf is started before a program starts using huge
pages (so perf gets MMAP2 events from kernel), perf is able to recognize
hugetlb mapping as anon mapping.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Nilay Vaish <nilayvaish@xxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1473137909-142064-2-git-send-email-wangnan0@xxxxxxxxxx
Signed-off-by: Hou Pengyang <houpengyang@xxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/map.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 0c54adb..d51a125 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -6,6 +6,7 @@
 #include <string.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <sys/mman.h>
 #include "map.h"
 #include "thread.h"
 #include "strlist.h"
@@ -24,9 +25,15 @@ const char *map_type__name[MAP__NR_TYPES] = {
 	[MAP__VARIABLE] = "Variables",
 };
 
-static inline int is_anon_memory(const char *filename)
+static inline int is_anon_memory(const char *filename, u32 flags)
 {
-	return !strcmp(filename, "//anon") ||
+	u32 anon_flags = 0;
+
+#ifdef MAP_HUGETLB
+	anon_flags |= MAP_HUGETLB;
+#endif
+	return flags & anon_flags ||
+	       !strcmp(filename, "//anon") ||
 	       !strncmp(filename, "/dev/zero", sizeof("/dev/zero") - 1) ||
 	       !strncmp(filename, "/anon_hugepage", sizeof("/anon_hugepage") - 1);
 }
@@ -155,7 +162,7 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
 		int anon, no_dso, vdso, android;
 
 		android = is_android_lib(filename);
-		anon = is_anon_memory(filename);
+		anon = is_anon_memory(filename, flags);
 		vdso = is_vdso_map(filename);
 		no_dso = is_no_dso_memory(filename);