On 2015/6/27 16:49, Hou Pengyang wrote:
Maps for JIT is helpful for symbols-parsing for anon-executable-memory.
What we need to do is to add (START, SIZE, symbolname) to /tmp/perf-%d.map
(%d = pid of process), and perf would parse symbol located in this area
according to /tmp/perf-%d.map. It works well for normal mmap.
However, when we alloc such memory from hugetlbfs by the following code:
......
fd = open("/mnt/huge/hugepagefile", O_CREAT | O_RDWR, 0755);
if (fd < 0) {
perror("Open failed");
exit(1);
}
addr = mmap(ADDR, LENGTH, PROT_READ | PROT_WRITE | \
PROT_EXEC, MAP_SHARED, fd, 0);
......
where hugetlbfs is mounted in /mnt/huge. Symbols could not be parsed correctly:
#perf report
86.96% 0.00% hugepage-mmap hugepagefile [.] 0xffffffe00000005c
86.96% 0.00% hugepage-mmap hugepagefile [.] 0xffffffe0000000ac
This is because such mmap area's file backed is "/mnt/huge/hugepagefile", a node
in pseudo filesystem, it is useless for symbol-parsing. so wo had better
recognize
such hugetlbfs area, and rename it's filename to /tmp/perf-%d.map, just as
anon-memory
and no_dso_memory do.
This patch imports a new function named is_hugetlb_memory to check if this
memory
is from hugetlbfs. If true, change its name.
After this patch:
#perf report
86.96% 0.00% hugepage-mmap perf-182.map [.] 0x000000200000005c
86.96% 0.00% hugepage-mmap perf-182.map [.] 0x00000020000000ac
We can add maps info to perf-182.map for further symbols-parsing.
Signed-off-by: Hou Pengyang <houpengy...@huawei.com>
---
tools/perf/util/map.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index b5a5e9c..796db08 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -15,6 +15,7 @@
#include "debug.h"
#include "machine.h"
#include <linux/string.h>
+#include <sys/mman.h>
static void __maps__insert(struct maps *maps, struct map *map);
@@ -43,6 +44,11 @@ static inline int is_android_lib(const char *filename)
!strncmp(filename, "/system/lib", 11);
}
+static inline int is_hugetlb_memory(u32 flags)
+{
+ return flags & MAP_HUGETLB;
+}
There is something about MAP_HUGETLB.
In this patch, we check if a mmap area is hugetlbfs area by MAP_HUGETLB,
a bit in MMAP2 event.
However, if mmap area is hugetlb related, MAP_HUGETLB does not always
appear. Because, there are two ways generating MMAP2 event.
1) when a new vm_area_struct is created, its info would be exported
as a MMAP2 event.
2) perf reads /proc/pid/maps for generating MMAP2 event.
MAP_HUGETLB appears if MMAP2 event is generated on situation 1),
while not on situation 2).
This is because on situation 2), perf reads /proc/pid/maps, which
contains only PROT_READ/WRITE/EXEC, MAP_SHARED/MAP_PRIVATE, while more
details appear in /proc/pid/smaps, such as MAP_HUGETLB.
So I wonder if there is a need to read /proc/pid/smaps instead of
/proc/pid/maps to generate MMAP2 event. Or we should solve the problem
by another way?
Thanks!
+
static inline bool replace_android_lib(const char *filename, char
*newfilename)
{
const char *libname;
@@ -151,12 +157,13 @@ struct map *map__new(struct machine *machine, u64 start,
u64 len,
if (map != NULL) {
char newfilename[PATH_MAX];
struct dso *dso;
- int anon, no_dso, vdso, android;
+ int anon, no_dso, vdso, android, hugetlb;
android = is_android_lib(filename);
anon = is_anon_memory(filename);
vdso = is_vdso_map(filename);
no_dso = is_no_dso_memory(filename);
+ hugetlb = is_hugetlb_memory(flags);
map->maj = d_maj;
map->min = d_min;
@@ -165,7 +172,7 @@ struct map *map__new(struct machine *machine, u64 start,
u64 len,
map->prot = prot;
map->flags = flags;
- if ((anon || no_dso) && type == MAP__FUNCTION) {
+ if ((anon || no_dso || hugetlb) && type == MAP__FUNCTION) {
snprintf(newfilename, sizeof(newfilename),
"/tmp/perf-%d.map", pid);
filename = newfilename;
}
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