perf_counter: Add event overlow handling

[safe/jmp/linux-2.6] / kernel / trace / trace_functions_graph.c

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index d28687e..8b59241 100644 (file)
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -65,6 +65,12 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth)
        if (!current->ret_stack)
                return -EBUSY;
 
+       /*
+        * We must make sure the ret_stack is tested before we read
+        * anything else.
+        */
+       smp_rmb();
+
        /* The return trace stack is full */
        if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
                atomic_inc(&current->trace_overrun);
@@ -78,13 +84,14 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth)
        current->ret_stack[index].ret = ret;
        current->ret_stack[index].func = func;
        current->ret_stack[index].calltime = calltime;
+       current->ret_stack[index].subtime = 0;
        *depth = index;
 
        return 0;
 }
 
 /* Retrieve a function return address to the trace stack on thread info.*/
-void
+static void
 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
 {
        int index;
@@ -104,9 +111,6 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
        trace->calltime = current->ret_stack[index].calltime;
        trace->overrun = atomic_read(&current->trace_overrun);
        trace->depth = index;
-       barrier();
-       current->curr_ret_stack--;
-
 }
 
 /*
@@ -121,6 +125,8 @@ unsigned long ftrace_return_to_handler(void)
        ftrace_pop_return_trace(&trace, &ret);
        trace.rettime = trace_clock_local();
        ftrace_graph_return(&trace);
+       barrier();
+       current->curr_ret_stack--;
 
        if (unlikely(!ret)) {
                ftrace_graph_stop();
@@ -426,8 +432,8 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr,
        return TRACE_TYPE_HANDLED;
 }
 
-static enum print_line_t
-print_graph_duration(unsigned long long duration, struct trace_seq *s)
+enum print_line_t
+trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 {
        unsigned long nsecs_rem = do_div(duration, 1000);
        /* log10(ULONG_MAX) + '\0' */
@@ -464,12 +470,23 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s)
                if (!ret)
                        return TRACE_TYPE_PARTIAL_LINE;
        }
+       return TRACE_TYPE_HANDLED;
+}
+
+static enum print_line_t
+print_graph_duration(unsigned long long duration, struct trace_seq *s)
+{
+       int ret;
+
+       ret = trace_print_graph_duration(duration, s);
+       if (ret != TRACE_TYPE_HANDLED)
+               return ret;
 
        ret = trace_seq_printf(s, "|  ");
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;
-       return TRACE_TYPE_HANDLED;
 
+       return TRACE_TYPE_HANDLED;
 }
 
 /* Case of a leaf function on its call entry */