2015-11-26 11:43:04

by Yannick Brosseau

[permalink] [raw]
Subject: [PATCH] perf: Correctly identify anon_hugepage when generating map (v2)

When parsing /proc/xxx/maps, the sscanf in perf_event__synthesize_mmap_events
truncate the map name at the space in "/anon_hugepage (deleted)".
is_anon_memory then only receive the string "/anon_hugepage" and do not detect it.
We change is_anon_memory to only compare the first part of the string
effectively ignoring if the (deleted) part is there or not.

Signed-off-by: Yannick Brosseau <[email protected]>
---
tools/perf/util/map.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index afc6b56..97e11a7 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -26,8 +26,8 @@ const char *map_type__name[MAP__NR_TYPES] = {
static inline int is_anon_memory(const char *filename)
{
return !strcmp(filename, "//anon") ||
- !strcmp(filename, "/dev/zero (deleted)") ||
- !strcmp(filename, "/anon_hugepage (deleted)");
+ !strncmp(filename, "/dev/zero", sizeof("/dev/zero")-1) ||
+ !strncmp(filename, "/anon_hugepage", sizeof("/anon_hugepage")-1);
}

static inline int is_no_dso_memory(const char *filename)
--
2.6.2


2015-11-26 17:12:37

by Arnaldo Carvalho de Melo

[permalink] [raw]
Subject: Re: [PATCH] perf: Correctly identify anon_hugepage when generating map (v2)

Em Thu, Nov 26, 2015 at 03:42:32AM -0800, Yannick Brosseau escreveu:
> When parsing /proc/xxx/maps, the sscanf in perf_event__synthesize_mmap_events
> truncate the map name at the space in "/anon_hugepage (deleted)".
> is_anon_memory then only receive the string "/anon_hugepage" and do not detect it.
> We change is_anon_memory to only compare the first part of the string
> effectively ignoring if the (deleted) part is there or not.

Thanks, applied, tested with:

[acme@zoo c]$ cat scanf_proc_smaps.c
#include <inttypes.h>
#include <limits.h>
#include <stdio.h>

typedef unsigned int u32;
typedef unsigned long long u64;

struct mmap2_event {
u32 pid, tid;
u64 start;
u64 len;
u64 pgoff;
u32 maj;
u32 min;
u64 ino;
u64 ino_generation;
u32 prot;
u32 flags;
char filename[PATH_MAX];
};

union perf_event {
struct mmap2_event mmap2;
};

static inline int is_anon_memory(const char *filename)
{
return !strcmp(filename, "//anon") ||
!strncmp(filename, "/dev/zero", sizeof("/dev/zero") - 1) ||
!strncmp(filename, "/anon_hugepage", sizeof("/anon_hugepage") - 1);
}

int main(void)
{
union perf_event event;
unsigned int ino;
char prot[5];
char bf[] = "7f939395e000-7f939395f000 rw-s 00000000 00:05 98715 /dev/zero (deleted)";
int n = sscanf(bf, "%"PRIx64"-%"PRIx64" %s %"PRIx64" %x:%x %u %s\n",
&event.mmap2.start, &event.mmap2.len, prot,
&event.mmap2.pgoff, &event.mmap2.maj,
&event.mmap2.min,
&ino, event.mmap2.filename);

printf("event.filename=\"%s\"\n", event.mmap2.filename);
if (is_anon_memory(event.mmap2.filename))
printf("This is anonymous memory\n");
return 0;
}
[acme@zoo c]$ ./scanf_proc_smaps
event.filename="/dev/zero"
This is anonymous memory
[acme@zoo c]$

> Signed-off-by: Yannick Brosseau <[email protected]>
> ---
> tools/perf/util/map.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> index afc6b56..97e11a7 100644
> --- a/tools/perf/util/map.c
> +++ b/tools/perf/util/map.c
> @@ -26,8 +26,8 @@ const char *map_type__name[MAP__NR_TYPES] = {
> static inline int is_anon_memory(const char *filename)
> {
> return !strcmp(filename, "//anon") ||
> - !strcmp(filename, "/dev/zero (deleted)") ||
> - !strcmp(filename, "/anon_hugepage (deleted)");
> + !strncmp(filename, "/dev/zero", sizeof("/dev/zero")-1) ||
> + !strncmp(filename, "/anon_hugepage", sizeof("/anon_hugepage")-1);
> }
>
> static inline int is_no_dso_memory(const char *filename)
> --
> 2.6.2

Subject: [tip:perf/core] perf tools: Correctly identify anon_hugepage when generating map (v2)

Commit-ID: b2be5451f660e0ee230969cc24121d9e210a91de
Gitweb: http://git.kernel.org/tip/b2be5451f660e0ee230969cc24121d9e210a91de
Author: Yannick Brosseau <[email protected]>
AuthorDate: Thu, 26 Nov 2015 03:42:32 -0800
Committer: Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Thu, 26 Nov 2015 14:08:17 -0300

perf tools: Correctly identify anon_hugepage when generating map (v2)

When parsing /proc/xxx/maps, the sscanf in perf_event__synthesize_mmap_events
truncate the map name at the space in "/anon_hugepage (deleted)".

is_anon_memory() then only receives the string "/anon_hugepage" and does
not detect it. We change is_anon_memory() to only compare the first
part of the string, effectively ignoring if " (deleted)" is there.

Signed-off-by: Yannick Brosseau <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Joshua Zhu <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/util/map.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index afc6b56..93d9f1c 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -26,8 +26,8 @@ const char *map_type__name[MAP__NR_TYPES] = {
static inline int is_anon_memory(const char *filename)
{
return !strcmp(filename, "//anon") ||
- !strcmp(filename, "/dev/zero (deleted)") ||
- !strcmp(filename, "/anon_hugepage (deleted)");
+ !strncmp(filename, "/dev/zero", sizeof("/dev/zero") - 1) ||
+ !strncmp(filename, "/anon_hugepage", sizeof("/anon_hugepage") - 1);
}

static inline int is_no_dso_memory(const char *filename)