Commit-ID: 81698831bc462ff16f76bc11249a1e492424da4c
Gitweb: http://git.kernel.org/tip/81698831bc462ff16f76bc11249a1e492424da4c
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Thu, 11 Oct 2012 10:15:05 -0400
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Wed, 31 Oct 2012 16:45:29 -0400
tracing: Enable comm recording if trace_printk() is used
If comm recording is not enabled when trace_printk() is used then
you just get this type of output:
[ adding trace_printk("hello! %d", irq); in do_IRQ ]
<...>-2843 [001] d.h. 80.812300: do_IRQ: hello! 14
<...>-2734 [002] d.h2 80.824664: do_IRQ: hello! 14
<...>-2713 [003] d.h. 80.829971: do_IRQ: hello! 14
<...>-2814 [000] d.h. 80.833026: do_IRQ: hello! 14
By enabling the comm recorder when trace_printk is enabled:
hackbench-6715 [001] d.h. 193.233776: do_IRQ: hello! 21
sshd-2659 [001] d.h. 193.665862: do_IRQ: hello! 21
<idle>-0 [001] d.h1 193.665996: do_IRQ: hello! 21
Suggested-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace.c | 36 ++++++++++++++++++++++++++++++++++--
kernel/trace/trace.h | 1 +
kernel/trace/trace_events.c | 3 +++
3 files changed, 38 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a5411b7..b90a827 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1559,10 +1559,10 @@ static int alloc_percpu_trace_buffer(void)
return -ENOMEM;
}
+static int buffers_allocated;
+
void trace_printk_init_buffers(void)
{
- static int buffers_allocated;
-
if (buffers_allocated)
return;
@@ -1575,6 +1575,34 @@ void trace_printk_init_buffers(void)
tracing_update_buffers();
buffers_allocated = 1;
+
+ /*
+ * trace_printk_init_buffers() can be called by modules.
+ * If that happens, then we need to start cmdline recording
+ * directly here. If the global_trace.buffer is already
+ * allocated here, then this was called by module code.
+ */
+ if (global_trace.buffer)
+ tracing_start_cmdline_record();
+}
+
+void trace_printk_start_comm(void)
+{
+ /* Start tracing comms if trace printk is set */
+ if (!buffers_allocated)
+ return;
+ tracing_start_cmdline_record();
+}
+
+static void trace_printk_start_stop_comm(int enabled)
+{
+ if (!buffers_allocated)
+ return;
+
+ if (enabled)
+ tracing_start_cmdline_record();
+ else
+ tracing_stop_cmdline_record();
}
/**
@@ -2797,6 +2825,9 @@ static void set_tracer_flags(unsigned int mask, int enabled)
if (mask == TRACE_ITER_OVERWRITE)
ring_buffer_change_overwrite(global_trace.buffer, enabled);
+
+ if (mask == TRACE_ITER_PRINTK)
+ trace_printk_start_stop_comm(enabled);
}
static ssize_t
@@ -5099,6 +5130,7 @@ __init static int tracer_alloc_buffers(void)
/* Only allocate trace_printk buffers if a trace_printk exists */
if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
+ /* Must be called before global_trace.buffer is allocated */
trace_printk_init_buffers();
/* To save memory, keep the ring buffer size to its minimum */
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index c56a233..7824a55 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -841,6 +841,7 @@ extern const char *__start___trace_bprintk_fmt[];
extern const char *__stop___trace_bprintk_fmt[];
void trace_printk_init_buffers(void);
+void trace_printk_start_comm(void);
#undef FTRACE_ENTRY
#define FTRACE_ENTRY(call, struct_name, id, tstruct, print, filter) \
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index d608d09..dec47e7 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1489,6 +1489,9 @@ static __init int event_trace_enable(void)
if (ret)
pr_warn("Failed to enable trace event: %s\n", token);
}
+
+ trace_printk_start_comm();
+
return 0;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|