linux-kernel - [PATCH v2 1/3] perf tools: Recognize hugetlb mapping as anon mapping

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Message-ID: <1473137909-142064-2-git-send-email-wangnan0@huawei.com>
Date:   Tue, 6 Sep 2016 04:58:27 +0000
From:   Wang Nan <wangnan0@...wei.com>
To:     <acme@...nel.org>
CC:     <nilayvaish@...il.com>, <linux-kernel@...r.kernel.org>,
        <lizefan@...wei.com>, Wang Nan <wangnan0@...wei.com>,
        Hou Pengyang <houpengyang@...wei.com>,
        He Kuang <hekuang@...wei.com>,
        "Arnaldo Carvalho de Melo" <acme@...hat.com>
Subject: [PATCH v2 1/3] 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 the 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@...wei.com>
Signed-off-by: Hou Pengyang <houpengyang@...wei.com>
Cc: He Kuang <hekuang@...wei.com>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Nilay Vaish <nilayvaish@...il.com>
---
 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 728129a..f52d460 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);
 
-- 
1.8.3.4