perf tools: Introduce pstack_peek()
The pstack_peek() is to get the topmost entry without removing it.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1429838133-14001-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/pstack.c b/tools/perf/util/pstack.c
index a126e6c..b234a6e 100644
--- a/tools/perf/util/pstack.c
+++ b/tools/perf/util/pstack.c
@@ -74,3 +74,10 @@
pstack->entries[pstack->top] = NULL;
return ret;
}
+
+void *pstack__peek(struct pstack *pstack)
+{
+ if (pstack->top == 0)
+ return NULL;
+ return pstack->entries[pstack->top - 1];
+}
