sched/core: Fix trace_sched_switch()

__trace_sched_switch_state() is the last remaining PREEMPT_ACTIVE
user, move trace_sched_switch() from prepare_task_switch() to
__schedule() and propagate the @preempt argument.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 539d6bc..9b90c57 100644 (file)
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -104,22 +104,17 @@ DEFINE_EVENT(sched_wakeup_template, sched_wakeup_new,
             TP_ARGS(p));
 
 #ifdef CREATE_TRACE_POINTS
-static inline long __trace_sched_switch_state(struct task_struct *p)
+static inline long __trace_sched_switch_state(bool preempt, struct task_struct *p)
 {
-       long state = p->state;
-
-#ifdef CONFIG_PREEMPT
 #ifdef CONFIG_SCHED_DEBUG
        BUG_ON(p != current);
 #endif /* CONFIG_SCHED_DEBUG */
+
        /*
-        * For all intents and purposes a preempted task is a running task.
+        * Preemption ignores task state, therefore preempted tasks are always
+        * RUNNING (we will not have dequeued if state != RUNNING).
         */
-       if (preempt_count() & PREEMPT_ACTIVE)
-               state = TASK_RUNNING | TASK_STATE_MAX;
-#endif /* CONFIG_PREEMPT */
-
-       return state;
+       return preempt ? TASK_RUNNING | TASK_STATE_MAX : p->state;
 }
 #endif /* CREATE_TRACE_POINTS */
 
@@ -128,10 +123,11 @@ static inline long __trace_sched_switch_state(struct task_struct *p)
  */
 TRACE_EVENT(sched_switch,
 
-       TP_PROTO(struct task_struct *prev,
+       TP_PROTO(bool preempt,
+                struct task_struct *prev,
                 struct task_struct *next),
 
-       TP_ARGS(prev, next),
+       TP_ARGS(preempt, prev, next),
 
        TP_STRUCT__entry(
                __array(        char,   prev_comm,      TASK_COMM_LEN   )
@@ -147,7 +143,7 @@ TRACE_EVENT(sched_switch,
                memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
                __entry->prev_pid       = prev->pid;
                __entry->prev_prio      = prev->prio;
-               __entry->prev_state     = __trace_sched_switch_state(prev);
+               __entry->prev_state     = __trace_sched_switch_state(preempt, prev);
                memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
                __entry->next_pid       = next->pid;
                __entry->next_prio      = next->prio;

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0a71f89..cfad7f5 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2470,7 +2470,6 @@ static inline void
 prepare_task_switch(struct rq *rq, struct task_struct *prev,
                    struct task_struct *next)
 {
-       trace_sched_switch(prev, next);
        sched_info_switch(rq, prev, next);
        perf_event_task_sched_out(prev, next);
        fire_sched_out_preempt_notifiers(prev, next);
@@ -3132,6 +3131,7 @@ static void __sched __schedule(bool preempt)
                rq->curr = next;
                ++*switch_count;
 
+               trace_sched_switch(preempt, prev, next);
                rq = context_switch(rq, prev, next); /* unlocks the rq */
                cpu = cpu_of(rq);
        } else {

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b0623ac..00611e9 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5697,7 +5697,7 @@ free:
 }
 
 static void
-ftrace_graph_probe_sched_switch(void *ignore,
+ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
                        struct task_struct *prev, struct task_struct *next)
 {
        unsigned long long timestamp;

diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index f270088..4c896a0 100644 (file)
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -16,7 +16,8 @@ static int                    sched_ref;
 static DEFINE_MUTEX(sched_register_mutex);
 
 static void
-probe_sched_switch(void *ignore, struct task_struct *prev, struct task_struct *next)
+probe_sched_switch(void *ignore, bool preempt,
+                  struct task_struct *prev, struct task_struct *next)
 {
        if (unlikely(!sched_ref))
                return;

diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 12cbe77..4bcfbac 100644 (file)
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -420,7 +420,7 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
 }
 
 static void notrace
-probe_wakeup_sched_switch(void *ignore,
+probe_wakeup_sched_switch(void *ignore, bool preempt,
                          struct task_struct *prev, struct task_struct *next)
 {
        struct trace_array_cpu *data;