aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/trace
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/ftrace.c5
-rw-r--r--kernel/trace/ring_buffer.c38
-rw-r--r--kernel/trace/trace.c5
-rw-r--r--kernel/trace/trace.h48
-rw-r--r--kernel/trace/trace_clock.c5
-rw-r--r--kernel/trace/trace_events.c5
-rw-r--r--kernel/trace/trace_functions.c6
-rw-r--r--kernel/trace/trace_sched_wakeup.c5
-rw-r--r--kernel/trace/trace_stack.c6
9 files changed, 24 insertions, 99 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 6d2cb14..0d88ce9 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1883,7 +1883,6 @@ function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
struct hlist_head *hhd;
struct hlist_node *n;
unsigned long key;
- int resched;
key = hash_long(ip, FTRACE_HASH_BITS);
@@ -1897,12 +1896,12 @@ function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
* period. This syncs the hash iteration and freeing of items
* on the hash. rcu_read_lock is too dangerous here.
*/
- resched = ftrace_preempt_disable();
+ preempt_disable_notrace();
hlist_for_each_entry_rcu(entry, n, hhd, node) {
if (entry->ip == ip)
entry->ops->func(ip, parent_ip, &entry->data);
}
- ftrace_preempt_enable(resched);
+ preempt_enable_notrace();
}
static struct ftrace_ops trace_probe_ops __read_mostly =
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 1da7b6e..28d0615 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2242,8 +2242,6 @@ static void trace_recursive_unlock(void)
#endif
-static DEFINE_PER_CPU(int, rb_need_resched);
-
/**
* ring_buffer_lock_reserve - reserve a part of the buffer
* @buffer: the ring buffer to reserve from
@@ -2264,13 +2262,13 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length)
{
struct ring_buffer_per_cpu *cpu_buffer;
struct ring_buffer_event *event;
- int cpu, resched;
+ int cpu;
if (ring_buffer_flags != RB_BUFFERS_ON)
return NULL;
/* If we are tracing schedule, we don't want to recurse */
- resched = ftrace_preempt_disable();
+ preempt_disable_notrace();
if (atomic_read(&buffer->record_disabled))
goto out_nocheck;
@@ -2295,21 +2293,13 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length)
if (!event)
goto out;
- /*
- * Need to store resched state on this cpu.
- * Only the first needs to.
- */
-
- if (preempt_count() == 1)
- per_cpu(rb_need_resched, cpu) = resched;
-
return event;
out:
trace_recursive_unlock();
out_nocheck:
- ftrace_preempt_enable(resched);
+ preempt_enable_notrace();
return NULL;
}
EXPORT_SYMBOL_GPL(ring_buffer_lock_reserve);
@@ -2355,13 +2345,7 @@ int ring_buffer_unlock_commit(struct ring_buffer *buffer,
trace_recursive_unlock();
- /*
- * Only the last preempt count needs to restore preemption.
- */
- if (preempt_count() == 1)
- ftrace_preempt_enable(per_cpu(rb_need_resched, cpu));
- else
- preempt_enable_no_resched_notrace();
+ preempt_enable_notrace();
return 0;
}
@@ -2469,13 +2453,7 @@ void ring_buffer_discard_commit(struct ring_buffer *buffer,
trace_recursive_unlock();
- /*
- * Only the last preempt count needs to restore preemption.
- */
- if (preempt_count() == 1)
- ftrace_preempt_enable(per_cpu(rb_need_resched, cpu));
- else
- preempt_enable_no_resched_notrace();
+ preempt_enable_notrace();
}
EXPORT_SYMBOL_GPL(ring_buffer_discard_commit);
@@ -2501,12 +2479,12 @@ int ring_buffer_write(struct ring_buffer *buffer,
struct ring_buffer_event *event;
void *body;
int ret = -EBUSY;
- int cpu, resched;
+ int cpu;
if (ring_buffer_flags != RB_BUFFERS_ON)
return -EBUSY;
- resched = ftrace_preempt_disable();
+ preempt_disable_notrace();
if (atomic_read(&buffer->record_disabled))
goto out;
@@ -2536,7 +2514,7 @@ int ring_buffer_write(struct ring_buffer *buffer,
ret = 0;
out:
- ftrace_preempt_enable(resched);
+ preempt_enable_notrace();
return ret;
}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 086d363..644ab74 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1404,7 +1404,6 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
struct bprint_entry *entry;
unsigned long flags;
int disable;
- int resched;
int cpu, len = 0, size, pc;
if (unlikely(tracing_selftest_running || tracing_disabled))
@@ -1414,7 +1413,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
pause_graph_tracing();
pc = preempt_count();
- resched = ftrace_preempt_disable();
+ preempt_disable_notrace();
cpu = raw_smp_processor_id();
data = tr->data[cpu];
@@ -1452,7 +1451,7 @@ out_unlock:
out:
atomic_dec_return(&data->disabled);
- ftrace_preempt_enable(resched);
+ preempt_enable_notrace();
unpause_graph_tracing();
return len;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 2cd9639..6c45e55 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -628,54 +628,6 @@ enum trace_iterator_flags {
extern struct tracer nop_trace;
-/**
- * ftrace_preempt_disable - disable preemption scheduler safe
- *
- * When tracing can happen inside the scheduler, there exists
- * cases that the tracing might happen before the need_resched
- * flag is checked. If this happens and the tracer calls
- * preempt_enable (after a disable), a schedule might take place
- * causing an infinite recursion.
- *
- * To prevent this, we read the need_resched flag before
- * disabling preemption. When we want to enable preemption we
- * check the flag, if it is set, then we call preempt_enable_no_resched.
- * Otherwise, we call preempt_enable.
- *
- * The rational for doing the above is that if need_resched is set
- * and we have yet to reschedule, we are either in an atomic location
- * (where we do not need to check for scheduling) or we are inside
- * the scheduler and do not want to resched.
- */
-static inline int ftrace_preempt_disable(void)
-{
- int resched;
-
- resched = need_resched();
- preempt_disable_notrace();
-
- return resched;
-}
-
-/**
- * ftrace_preempt_enable - enable preemption scheduler safe
- * @resched: the return value from ftrace_preempt_disable
- *
- * This is a scheduler safe way to enable preemption and not miss
- * any preemption checks. The disabled saved the state of preemption.
- * If resched is set, then we are either inside an atomic or
- * are inside the scheduler (we would have already scheduled
- * otherwise). In this case, we do not want to call normal
- * preempt_enable, but preempt_enable_no_resched instead.
- */
-static inline void ftrace_preempt_enable(int resched)
-{
- if (resched)
- preempt_enable_no_resched_notrace();
- else
- preempt_enable_notrace();
-}
-
#ifdef CONFIG_BRANCH_TRACER
extern int enable_branch_tracing(struct trace_array *tr);
extern void disable_branch_tracing(void);
diff --git a/kernel/trace/trace_clock.c b/kernel/trace/trace_clock.c
index 9d589d8..52fda6c 100644
--- a/kernel/trace/trace_clock.c
+++ b/kernel/trace/trace_clock.c
@@ -32,16 +32,15 @@
u64 notrace trace_clock_local(void)
{
u64 clock;
- int resched;
/*
* sched_clock() is an architecture implemented, fast, scalable,
* lockless clock. It is not guaranteed to be coherent across
* CPUs, nor across CPU idle events.
*/
- resched = ftrace_preempt_disable();
+ preempt_disable_notrace();
clock = sched_clock();
- ftrace_preempt_enable(resched);
+ preempt_enable_notrace();
return clock;
}
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 53cffc0..a594f9a 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1524,12 +1524,11 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip)
struct ftrace_entry *entry;
unsigned long flags;
long disabled;
- int resched;
int cpu;
int pc;
pc = preempt_count();
- resched = ftrace_preempt_disable();
+ preempt_disable_notrace();
cpu = raw_smp_processor_id();
disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
@@ -1551,7 +1550,7 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip)
out:
atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
- ftrace_preempt_enable(resched);
+ preempt_enable_notrace();
}
static struct ftrace_ops trace_ops __initdata =
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index b3f3776..16aee4d 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -54,14 +54,14 @@ function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip)
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
- int cpu, resched;
+ int cpu;
int pc;
if (unlikely(!ftrace_function_enabled))
return;
pc = preempt_count();
- resched = ftrace_preempt_disable();
+ preempt_disable_notrace();
local_save_flags(flags);
cpu = raw_smp_processor_id();
data = tr->data[cpu];
@@ -71,7 +71,7 @@ function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip)
trace_function(tr, ip, parent_ip, flags, pc);
atomic_dec(&data->disabled);
- ftrace_preempt_enable(resched);
+ preempt_enable_notrace();
}
static void
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 0e73bc2..c9fd5bd 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -46,7 +46,6 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip)
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
- int resched;
int cpu;
int pc;
@@ -54,7 +53,7 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip)
return;
pc = preempt_count();
- resched = ftrace_preempt_disable();
+ preempt_disable_notrace();
cpu = raw_smp_processor_id();
if (cpu != wakeup_current_cpu)
@@ -74,7 +73,7 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip)
out:
atomic_dec(&data->disabled);
out_enable:
- ftrace_preempt_enable(resched);
+ preempt_enable_notrace();
}
static struct ftrace_ops trace_ops __read_mostly =
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index f4bc9b2..056468e 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -110,12 +110,12 @@ static inline void check_stack(void)
static void
stack_trace_call(unsigned long ip, unsigned long parent_ip)
{
- int cpu, resched;
+ int cpu;
if (unlikely(!ftrace_enabled || stack_trace_disabled))
return;
- resched = ftrace_preempt_disable();
+ preempt_disable_notrace();
cpu = raw_smp_processor_id();
/* no atomic needed, we only modify this variable by this cpu */
@@ -127,7 +127,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip)
out:
per_cpu(trace_active, cpu)--;
/* prevent recursion in schedule */
- ftrace_preempt_enable(resched);
+ preempt_enable_notrace();
}
static struct ftrace_ops trace_ops __read_mostly =