linux-kernel - [PATCH v2 3/3] perf record: Mark MAP_HUGETLB during synthesizing mmap events

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Date:   Tue, 6 Sep 2016 04:58:29 +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 3/3] perf record: Mark MAP_HUGETLB during synthesizing mmap events

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@...wei.com>
Reviewed-by: Nilay Vaish <nilayvaish@...il.com>
Cc: Hou Pengyang <houpengyang@...wei.com>
Cc: He Kuang <hekuang@...wei.com>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 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 e20438b..23c3ebd 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);
-- 
1.8.3.4