[PATCH perf/core 03/22] perf refcnt: Add refcnt debug filter

Masami Hiramatsu
2015-12-09T02:18:51Z

Add refcnt debug filter for filtering the debug objects.
Developers can set the target object name (or glob pattern)
to PERF_REFCNT_DEBUG_FILTER environment variable.

E.g.
# PERF_REFCNT_DEBUG_FILTER=dso ./perf ...

This traces only the dso object. This also removes
unused name arguments from refcnt__record API.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
tools/perf/util/refcnt.c | 29 ++++++++++++++++++-----------
tools/perf/util/refcnt.h | 14 +++++++-------
2 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/tools/perf/util/refcnt.c b/tools/perf/util/refcnt.c
index 9748dba..e83e9a8 100644
--- a/tools/perf/util/refcnt.c
+++ b/tools/perf/util/refcnt.c
@@ -16,13 +16,20 @@

/* A root of backtraces (a hash table of the list of refcnt_object)*/
static struct list_head refcnt_root[REFCNT_HASHSZ];
+static const char *refcnt_filter;

static void __attribute__((constructor)) refcnt__init_root(void)
{
int h;
+ const char *filter;

for (h = 0; h < REFCNT_HASHSZ; h++)
INIT_LIST_HEAD(&refcnt_root[h]);
+
+ /* glob matching filter */
+ filter = getenv("PERF_REFCNT_DEBUG_FILTER");
+ if (filter && *filter)
+ refcnt_filter = filter;
}

static void refcnt_object__delete(struct refcnt_object *ref)
@@ -54,11 +61,9 @@ void refcnt__delete(void *addr)
{
struct refcnt_object *ref = refcnt_object__find(addr);

- if (!ref) {
- pr_debug("REFCNT: Delete uninitialized refcnt: %p\n", addr);
- return;
- }
- refcnt_object__delete(ref);
+ /* If !ref, it is already filtered out */
+ if (ref)
+ refcnt_object__delete(ref);
}

static void refcnt_object__record(struct refcnt_object *ref, int count)
@@ -98,21 +103,23 @@ static struct refcnt_object *refcnt_object__new(void *obj, const char *name)
/* This is called via refcnt__init */
void refcnt__recordnew(void *obj, const char *name, int count)
{
- struct refcnt_object *ref = refcnt_object__new(obj, name);
+ struct refcnt_object *ref;
+
+ if (refcnt_filter && !strglobmatch(name, refcnt_filter))
+ return;

+ ref = refcnt_object__new(obj, name);
if (ref)
refcnt_object__record(ref, count);
}

/* This is called via refcnt__get/put */
-void refcnt__record(void *obj, const char *name, int count)
+void refcnt__record(void *obj, int count)
{
struct refcnt_object *ref = refcnt_object__find(obj);

- /* If no entry, allocate new one */
- if (!ref)
- refcnt__recordnew(obj, name, count);
- else
+ /* If no entry, it should be filtered out */
+ if (ref)
refcnt_object__record(ref, count);
}

diff --git a/tools/perf/util/refcnt.h b/tools/perf/util/refcnt.h
index cd5e4e4..21569e1 100644
--- a/tools/perf/util/refcnt.h
+++ b/tools/perf/util/refcnt.h
@@ -24,7 +24,7 @@ struct refcnt_buffer {
};

void refcnt__recordnew(void *obj, const char *name, int count);
-void refcnt__record(void *obj, const char *name, int count);
+void refcnt__record(void *obj, int count);
void refcnt__delete(void *obj);

static inline void __refcnt__init(atomic_t *refcnt, int n, void *obj,
@@ -34,15 +34,15 @@ static inline void __refcnt__init(atomic_t *refcnt, int n, void *obj,
refcnt__recordnew(obj, name, n);
}

-static inline void __refcnt__get(atomic_t *refcnt, void *obj, const char *name)
+static inline void __refcnt__get(atomic_t *refcnt, void *obj)
{
atomic_inc(refcnt);
- refcnt__record(obj, name, atomic_read(refcnt));
+ refcnt__record(obj, atomic_read(refcnt));
}

-static inline int __refcnt__put(atomic_t *refcnt, void *obj, const char *name)
+static inline int __refcnt__put(atomic_t *refcnt, void *obj)
{
- refcnt__record(obj, name, -atomic_read(refcnt));
+ refcnt__record(obj, -atomic_read(refcnt));
return atomic_dec_and_test(refcnt);
}

@@ -53,9 +53,9 @@ static inline int __refcnt__put(atomic_t *refcnt, void *obj, const char *name)
#define refcnt__exit(obj, member) \
refcnt__delete(obj)
#define refcnt__get(obj, member) \
- __refcnt__get(&(obj)->member, obj, #obj)
+ __refcnt__get(&(obj)->member, obj)
#define refcnt__put(obj, member) \
- __refcnt__put(&(obj)->member, obj, #obj)
+ __refcnt__put(&(obj)->member, obj)

#else /* !REFCNT_DEBUG */