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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 68179686ac ("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: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Dmitry Safonov 2015-11-06 22:07:26 +03:00 committed by Steven Rostedt
parent 8b1291994d
commit 03e88ae6b3
3 changed files with 0 additions and 13 deletions
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6
kernel/trace/trace.c
View File

@ -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)

1
kernel/trace/trace.h
View File

@ -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,

6
kernel/trace/trace_functions_graph.c
View File

@ -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)