[PATCH v7 01/10] tracing/osnoise: Variable cleanup

[Crystal Wood <crwood@redhat.com>]

Add cpu_osn_var/cpu_tmr_var() accessors and use them.

Timerlat threads aren't always kthreads, so rename the variable to just
"thread".

rel_period isn't used at all, so remove it.

Signed-off-by: Crystal Wood <crwood@redhat.com>
---
v7: Add osn variable to start_kthread(), replacing individual calls to
    cpu_osn_var(), which previously happened later in the patch set.
    This avoids a temporary build break in the next patch.
---
 kernel/trace/trace_osnoise.c | 54 +++++++++++++++++++++---------------
 1 file changed, 32 insertions(+), 22 deletions(-)

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 995da9e0b548..2f3cbe71d313 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -251,6 +251,11 @@ static inline struct osnoise_variables *this_cpu_osn_var(void)
 	return this_cpu_ptr(&per_cpu_osnoise_var);
 }
 
+static inline struct osnoise_variables *cpu_osn_var(int cpu)
+{
+	return per_cpu_ptr(&per_cpu_osnoise_var, cpu);
+}
+
 /*
  * Protect the interface.
  */
@@ -261,9 +266,8 @@ static struct mutex interface_lock;
  * Runtime information for the timer mode.
  */
 struct timerlat_variables {
-	struct task_struct	*kthread;
+	struct task_struct	*thread;
 	struct hrtimer		timer;
-	u64			rel_period;
 	u64			abs_period;
 	bool			tracing_thread;
 	u64			count;
@@ -285,6 +289,11 @@ static inline struct timerlat_variables *this_cpu_tmr_var(void)
 	return this_cpu_ptr(&per_cpu_timerlat_var);
 }
 
+static inline struct timerlat_variables *cpu_tmr_var(int cpu)
+{
+	return per_cpu_ptr(&per_cpu_timerlat_var, cpu);
+}
+
 /*
  * tlat_var_reset - Reset the values of the given timerlat_variables
  */
@@ -301,8 +310,8 @@ static inline void tlat_var_reset(void)
 	 * zeroing the structure is perfect.
 	 */
 	for_each_online_cpu(cpu) {
-		tlat_var = per_cpu_ptr(&per_cpu_timerlat_var, cpu);
-		if (tlat_var->kthread)
+		tlat_var = cpu_tmr_var(cpu);
+		if (tlat_var->thread)
 			hrtimer_cancel(&tlat_var->timer);
 		memset(tlat_var, 0, sizeof(*tlat_var));
 	}
@@ -331,7 +340,7 @@ static inline void osn_var_reset(void)
 	 * zeroing the structure is perfect.
 	 */
 	for_each_online_cpu(cpu) {
-		osn_var = per_cpu_ptr(&per_cpu_osnoise_var, cpu);
+		osn_var = cpu_osn_var(cpu);
 		memset(osn_var, 0, sizeof(*osn_var));
 	}
 }
@@ -1227,9 +1236,9 @@ static void trace_sched_migrate_callback(void *data, struct task_struct *p, int
 	struct osnoise_variables *osn_var;
 	long cpu = task_cpu(p);
 
-	osn_var = per_cpu_ptr(&per_cpu_osnoise_var, cpu);
+	osn_var = cpu_osn_var(cpu);
 	if (osn_var->pid == p->pid && dest_cpu != cpu) {
-		per_cpu_ptr(&per_cpu_timerlat_var, cpu)->uthread_migrate = 1;
+		cpu_tmr_var(cpu)->uthread_migrate = 1;
 		osnoise_taint("timerlat user-thread migrated\n");
 		osnoise_stop_exception("timerlat user-thread migrated", cpu);
 	}
@@ -1827,13 +1836,13 @@ static enum hrtimer_restart timerlat_irq(struct hrtimer *timer)
 			osnoise_stop_tracing();
 			notify_new_max_latency(diff);
 
-			wake_up_process(tlat->kthread);
+			wake_up_process(tlat->thread);
 
 			return HRTIMER_NORESTART;
 		}
 	}
 
-	wake_up_process(tlat->kthread);
+	wake_up_process(tlat->thread);
 
 	if (osnoise_data.print_stack)
 		timerlat_save_stack(0);
@@ -1926,7 +1935,7 @@ static int timerlat_main(void *data)
 	tlat->tracing_thread = false;
 
 	hrtimer_setup(&tlat->timer, timerlat_irq, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
-	tlat->kthread = current;
+	tlat->thread = current;
 	osn_var->pid = current->pid;
 	/*
 	 * Annotate the arrival time.
@@ -1981,7 +1990,7 @@ static void stop_kthread(unsigned int cpu)
 {
 	struct task_struct *kthread;
 
-	kthread = xchg_relaxed(&(per_cpu(per_cpu_osnoise_var, cpu).kthread), NULL);
+	kthread = xchg_relaxed(&cpu_osn_var(cpu)->kthread, NULL);
 	if (kthread) {
 		if (cpumask_test_and_clear_cpu(cpu, &kthread_cpumask) &&
 		    !WARN_ON(!test_bit(OSN_WORKLOAD, &osnoise_options))) {
@@ -2001,7 +2010,7 @@ static void stop_kthread(unsigned int cpu)
 			/*
 			 * This is set in the osnoise tracer case.
 			 */
-			per_cpu(per_cpu_osnoise_var, cpu).sampling = false;
+			cpu_osn_var(cpu)->sampling = false;
 			barrier();
 		}
 	}
@@ -2030,12 +2039,13 @@ static void stop_per_cpu_kthreads(void)
  */
 static int start_kthread(unsigned int cpu)
 {
+	struct osnoise_variables *osn = cpu_osn_var(cpu);
 	struct task_struct *kthread;
 	void *main = osnoise_main;
 	char comm[24];
 
 	/* Do not start a new thread if it is already running */
-	if (per_cpu(per_cpu_osnoise_var, cpu).kthread)
+	if (osn->kthread)
 		return 0;
 
 	if (timerlat_enabled()) {
@@ -2044,7 +2054,7 @@ static int start_kthread(unsigned int cpu)
 	} else {
 		/* if no workload, just return */
 		if (!test_bit(OSN_WORKLOAD, &osnoise_options)) {
-			per_cpu(per_cpu_osnoise_var, cpu).sampling = true;
+			osn->sampling = true;
 			barrier();
 			return 0;
 		}
@@ -2058,7 +2068,7 @@ static int start_kthread(unsigned int cpu)
 		return -ENOMEM;
 	}
 
-	per_cpu(per_cpu_osnoise_var, cpu).kthread = kthread;
+	osn->kthread = kthread;
 	cpumask_set_cpu(cpu, &kthread_cpumask);
 
 	return 0;
@@ -2091,7 +2101,7 @@ static int start_per_cpu_kthreads(void)
 		if (cpumask_test_and_clear_cpu(cpu, &kthread_cpumask)) {
 			struct task_struct *kthread;
 
-			kthread = xchg_relaxed(&(per_cpu(per_cpu_osnoise_var, cpu).kthread), NULL);
+			kthread = xchg_relaxed(&cpu_osn_var(cpu)->kthread, NULL);
 			if (!WARN_ON(!kthread))
 				kthread_stop(kthread);
 		}
@@ -2520,7 +2530,7 @@ timerlat_fd_read(struct file *file, char __user *ubuf, size_t count,
 			return -EINVAL;
 		}
 	} else {
-		per_cpu_ptr(&per_cpu_timerlat_var, cpu)->uthread_migrate = 1;
+		cpu_tmr_var(cpu)->uthread_migrate = 1;
 		osnoise_taint("timerlat user thread migrate\n");
 		osnoise_stop_tracing();
 		migrate_enable();
@@ -2564,7 +2574,7 @@ timerlat_fd_read(struct file *file, char __user *ubuf, size_t count,
 		}
 	} else {
 		tlat->tracing_thread = false;
-		tlat->kthread = current;
+		tlat->thread = current;
 
 		/* Annotate now to drift new period */
 		tlat->abs_period = hrtimer_cb_get_time(&tlat->timer);
@@ -2613,10 +2623,10 @@ static int timerlat_fd_release(struct inode *inode, struct file *file)
 	migrate_disable();
 	mutex_lock(&interface_lock);
 
-	osn_var = per_cpu_ptr(&per_cpu_osnoise_var, cpu);
-	tlat_var = per_cpu_ptr(&per_cpu_timerlat_var, cpu);
+	osn_var = cpu_osn_var(cpu);
+	tlat_var = cpu_tmr_var(cpu);
 
-	if (tlat_var->kthread)
+	if (tlat_var->thread)
 		hrtimer_cancel(&tlat_var->timer);
 	memset(tlat_var, 0, sizeof(*tlat_var));
 
@@ -3096,7 +3106,7 @@ static void timerlat_tracer_stop(struct trace_array *tr)
 	 */
 	if (!osnoise_has_registered_instances()) {
 		for_each_online_cpu(cpu)
-			per_cpu(per_cpu_osnoise_var, cpu).sampling = 0;
+			cpu_osn_var(cpu)->sampling = 0;
 	}
 
 	osnoise_workload_stop();
-- 
2.56.0