Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core

1 files changed, 34 insertions, 16 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 30a94c26dcb3..3f381d0b20a8 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -278,6 +278,29 @@ struct tracer {
 };
 
 
+/* Only current can touch trace_recursion */
+#define trace_recursion_inc() do { (current)->trace_recursion++; } while (0)
+#define trace_recursion_dec() do { (current)->trace_recursion--; } while (0)
+
+/* Ring buffer has the 10 LSB bits to count */
+#define trace_recursion_buffer() ((current)->trace_recursion & 0x3ff)
+
+/* for function tracing recursion */
+#define TRACE_INTERNAL_BIT              (1<<11)
+#define TRACE_GLOBAL_BIT                (1<<12)
+/*
+ * Abuse of the trace_recursion.
+ * As we need a way to maintain state if we are tracing the function
+ * graph in irq because we want to trace a particular function that
+ * was called in irq context but we have irq tracing off. Since this
+ * can only be modified by current, we can reuse trace_recursion.
+ */
+#define TRACE_IRQ_BIT                   (1<<13)
+
+#define trace_recursion_set(bit)        do { (current)->trace_recursion |= (bit); } while (0)
+#define trace_recursion_clear(bit)      do { (current)->trace_recursion &= ~(bit); } while (0)
+#define trace_recursion_test(bit)       ((current)->trace_recursion & (bit))
+
 #define TRACE_PIPE_ALL_CPU      -1
 
 int tracer_init(struct tracer *t, struct trace_array *tr);
@@ -516,8 +539,18 @@ static inline int ftrace_graph_addr(unsigned long addr)
                 return 1;
 
         for (i = 0; i < ftrace_graph_count; i++) {
-                if (addr == ftrace_graph_funcs[i])
+                if (addr == ftrace_graph_funcs[i]) {
+                        /*
+                         * If no irqs are to be traced, but a set_graph_function
+                         * is set, and called by an interrupt handler, we still
+                         * want to trace it.
+                         */
+                        if (in_irq())
+                                trace_recursion_set(TRACE_IRQ_BIT);
+                        else
+                                trace_recursion_clear(TRACE_IRQ_BIT);
                         return 1;
+                }
         }
 
         return 0;
@@ -795,19 +828,4 @@ extern const char *__stop___trace_bprintk_fmt[];
         FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
 #include "trace_entries.h"
 
-/* Only current can touch trace_recursion */
-#define trace_recursion_inc() do { (current)->trace_recursion++; } while (0)
-#define trace_recursion_dec() do { (current)->trace_recursion--; } while (0)
-
-/* Ring buffer has the 10 LSB bits to count */
-#define trace_recursion_buffer() ((current)->trace_recursion & 0x3ff)
-
-/* for function tracing recursion */
-#define TRACE_INTERNAL_BIT              (1<<11)
-#define TRACE_GLOBAL_BIT                (1<<12)
-
-#define trace_recursion_set(bit)        do { (current)->trace_recursion |= (bit); } while (0)
-#define trace_recursion_clear(bit)      do { (current)->trace_recursion &= ~(bit); } while (0)
-#define trace_recursion_test(bit)       ((current)->trace_recursion & (bit))
-
 #endif /* _LINUX_KERNEL_TRACE_H */