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Commit 03e88ae6 authored by Dmitry Safonov's avatar Dmitry Safonov Committed by Steven Rostedt
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tracing: Remove unused ftrace_cpu_disabled per cpu variable 

Since the ring buffer is lockless, there is no need to disable ftrace on
CPU. And no one doing so: after commit 68179686 ("tracing: Remove
ftrace_disable/enable_cpu()") ftrace_cpu_disabled stays the same after
initialization, nothing changes it.
ftrace_cpu_disabled shouldn't be used by any external module since it
disables only function and graph_function tracers but not any other
tracer.

Link: http://lkml.kernel.org/r/1446836846-22239-1-git-send-email-0x7f454c46@gmail.com



Signed-off-by: default avatarDmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 8b129199

kernel/trace/trace.c

+0 −6
Original line number Diff line number Diff line
@@ -100,8 +100,6 @@ static DEFINE_PER_CPU(bool, trace_cmdline_save); 
 */

static int tracing_disabled = 1;



DEFINE_PER_CPU(int, ftrace_cpu_disabled);



cpumask_var_t __read_mostly	tracing_buffer_mask;



/*
@@ -1775,10 +1773,6 @@ trace_function(struct trace_array *tr, 
	struct ring_buffer_event *event;

	struct ftrace_entry *entry;



	/* If we are reading the ring buffer, don't trace */

	if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))

		return;



	event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),

					  flags, pc);

	if (!event)

kernel/trace/trace.h

+0 −1
Original line number Diff line number Diff line
@@ -667,7 +667,6 @@ extern int DYN_FTRACE_TEST_NAME2(void); 


extern bool ring_buffer_expanded;

extern bool tracing_selftest_disabled;

DECLARE_PER_CPU(int, ftrace_cpu_disabled);



#ifdef CONFIG_FTRACE_STARTUP_TEST

extern int trace_selftest_startup_function(struct tracer *trace,

kernel/trace/trace_functions_graph.c

+0 −6
Original line number Diff line number Diff line
@@ -288,9 +288,6 @@ int __trace_graph_entry(struct trace_array *tr, 
	struct ring_buffer *buffer = tr->trace_buffer.buffer;

	struct ftrace_graph_ent_entry *entry;



	if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))

		return 0;



	event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,

					  sizeof(*entry), flags, pc);

	if (!event)
@@ -403,9 +400,6 @@ void __trace_graph_return(struct trace_array *tr, 
	struct ring_buffer *buffer = tr->trace_buffer.buffer;

	struct ftrace_graph_ret_entry *entry;



	if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))

		return;



	event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,

					  sizeof(*entry), flags, pc);

	if (!event)