perf tools: Ensure thread-stack is flushed

The thread-stack represents a thread's current stack.  When a thread
exits there can still be many functions on the stack e.g. exit() can be
called many levels deep, so all the callers will never return.  To get
that information output, the thread-stack must be flushed.

Previously it was assumed the thread-stack would be flushed when the
struct thread was deleted.  With thread ref-counting it is no longer
clear when that will be, if ever. So instead explicitly flush all the
thread-stacks at the end of a session.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1432906425-9911-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 13 insertions, 5 deletions

diff --git a/tools/perf/util/thread-stack.c b/tools/perf/util/thread-stack.c
index 9ed59a452d1f..679688e70ae7 100644
--- a/tools/perf/util/thread-stack.c
+++ b/tools/perf/util/thread-stack.c
@@ -219,7 +219,7 @@ static int thread_stack__call_return(struct thread *thread,
         return crp->process(&cr, crp->data);
 }
 
-static int thread_stack__flush(struct thread *thread, struct thread_stack *ts)
+static int __thread_stack__flush(struct thread *thread, struct thread_stack *ts)
 {
         struct call_return_processor *crp = ts->crp;
         int err;
@@ -242,6 +242,14 @@ static int thread_stack__flush(struct thread *thread, struct thread_stack *ts)
         return 0;
 }
 
+int thread_stack__flush(struct thread *thread)
+{
+        if (thread->ts)
+                return __thread_stack__flush(thread, thread->ts);
+
+        return 0;
+}
+
 int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip,
                         u64 to_ip, u16 insn_len, u64 trace_nr)
 {
@@ -264,7 +272,7 @@ int thread_stack__event(struct thread *thread, u32 flags, u64 from_ip,
          */
         if (trace_nr != thread->ts->trace_nr) {
                 if (thread->ts->trace_nr)
-                        thread_stack__flush(thread, thread->ts);
+                        __thread_stack__flush(thread, thread->ts);
                 thread->ts->trace_nr = trace_nr;
         }
 
@@ -297,7 +305,7 @@ void thread_stack__set_trace_nr(struct thread *thread, u64 trace_nr)
 
         if (trace_nr != thread->ts->trace_nr) {
                 if (thread->ts->trace_nr)
-                        thread_stack__flush(thread, thread->ts);
+                        __thread_stack__flush(thread, thread->ts);
                 thread->ts->trace_nr = trace_nr;
         }
 }
@@ -305,7 +313,7 @@ void thread_stack__set_trace_nr(struct thread *thread, u64 trace_nr)
 void thread_stack__free(struct thread *thread)
 {
         if (thread->ts) {
-                thread_stack__flush(thread, thread->ts);
+                __thread_stack__flush(thread, thread->ts);
                 zfree(&thread->ts->stack);
                 zfree(&thread->ts);
         }
@@ -689,7 +697,7 @@ int thread_stack__process(struct thread *thread, struct comm *comm,
 
         /* Flush stack on exec */
         if (ts->comm != comm && thread->pid_ == thread->tid) {
-                err = thread_stack__flush(thread, ts);
+                err = __thread_stack__flush(thread, ts);
                 if (err)
                         return err;
                 ts->comm = comm;