Commit ca268da6 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
Browse files

tracing: Add internal ftrace trace_puts() for ftrace to use 



There's a few places that ftrace uses trace_printk() for internal
use, but this requires context (normal, softirq, irq, NMI) buffers
to keep things lockless. But the trace_puts() does not, as it can
write the string directly into the ring buffer. Make a internal helper
for trace_puts() and have the internal functions use that.

This way the extra context buffers are not used.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 9d3c752c

kernel/trace/trace.c

+4 −4
Original line number Diff line number Diff line
@@ -443,16 +443,16 @@ void tracing_snapshot(void) 
	unsigned long flags;



	if (!tr->allocated_snapshot) {

		trace_printk("*** SNAPSHOT NOT ALLOCATED ***\n");

		trace_printk("*** stopping trace here!   ***\n");

		internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");

		internal_trace_puts("*** stopping trace here!   ***\n");

		tracing_off();

		return;

	}



	/* Note, snapshot can not be used when the tracer uses it */

	if (tracer->use_max_tr) {

		trace_printk("*** LATENCY TRACER ACTIVE ***\n");

		trace_printk("*** Can not use snapshot (sorry) ***\n");

		internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");

		internal_trace_puts("*** Can not use snapshot (sorry) ***\n");

		return;

	}

kernel/trace/trace.h

+11 −0
Original line number Diff line number Diff line
@@ -1040,6 +1040,17 @@ void trace_printk_start_comm(void); 
int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set);

int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled);



/*

 * Normal trace_printk() and friends allocates special buffers

 * to do the manipulation, as well as saves the print formats

 * into sections to display. But the trace infrastructure wants

 * to use these without the added overhead at the price of being

 * a bit slower (used mainly for warnings, where we don't care

 * about performance). The internal_trace_puts() is for such

 * a purpose.

 */

#define internal_trace_puts(str) __trace_puts(_THIS_IP_, str, strlen(str))



#undef FTRACE_ENTRY

#define FTRACE_ENTRY(call, struct_name, id, tstruct, print, filter)	\

	extern struct ftrace_event_call					\

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