ftrace: change buffers to producer consumer
This patch changes the way the CPU trace buffers are handled.
Instead of always starting from the trace page head, the logic
is changed to a producer consumer logic. This allows for the
buffers to be drained while they are alive.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 5df8ff2..0ce1274 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -53,13 +53,15 @@
* the trace, etc.)
*/
struct trace_array_cpu {
- void *trace_current;
struct list_head trace_pages;
atomic_t disabled;
cycle_t time_offset;
/* these fields get copied into max-trace: */
- unsigned trace_current_idx;
+ unsigned trace_head_idx;
+ unsigned trace_tail_idx;
+ void *trace_head; /* producer */
+ void *trace_tail; /* consumer */
unsigned long trace_idx;
unsigned long saved_latency;
unsigned long critical_start;