mm: mm_event: make capture period configurable

[GitHub/LineageOS/android_kernel_motorola_exynos9610.git] / mm / mm_event.c

#include <linux/mm.h>
#include <linux/mm_event.h>
#include <linux/sched.h>
#include <linux/vmalloc.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>

#define CREATE_TRACE_POINTS
#include <trace/events/mm_event.h>
/* msec */
static unsigned long period_ms = 500;

void mm_event_task_init(struct task_struct *tsk)
{
	memset(tsk->mm_event, 0, sizeof(tsk->mm_event));
	tsk->next_period = 0;
}

static void record_stat(void)
{
	if (time_is_before_eq_jiffies(current->next_period)) {
		int i;

		for (i = 0; i < MM_TYPE_NUM; i++) {
			if (current->mm_event[i].count == 0)
				continue;

			trace_mm_event_record(i, &current->mm_event[i]);
			memset(&current->mm_event[i], 0,
					sizeof(struct mm_event_task));
		}
		current->next_period = jiffies + msecs_to_jiffies(period_ms);
	}
}

void mm_event_start(ktime_t *time)
{
	*time = ktime_get();
}

void mm_event_end(enum mm_event_type event, ktime_t start)
{
	s64 elapsed = ktime_us_delta(ktime_get(), start);

	current->mm_event[event].count++;
	current->mm_event[event].accm_lat += elapsed;
	if (elapsed > current->mm_event[event].max_lat)
		current->mm_event[event].max_lat = elapsed;
	record_stat();
}

static struct dentry *mm_event_root;

static int period_ms_set(void *data, u64 val)
{
	if (val < 1 || val > ULONG_MAX)
		return -EINVAL;

	period_ms = (unsigned long)val;
	return 0;
}

static int period_ms_get(void *data, u64 *val)
{
	*val = period_ms;
	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(period_ms_operations, period_ms_get,
			period_ms_set, "%llu\n");

static int __init mm_event_init(void)
{
	struct dentry *entry;

	mm_event_root = debugfs_create_dir("mm_event", NULL);
	if (!mm_event_root) {
		pr_warn("debugfs dir <mm_event> creation failed\n");
		return PTR_ERR(mm_event_root);
	}

	entry = debugfs_create_file("period_ms", 0644,
			mm_event_root, NULL, &period_ms_operations);

	if (IS_ERR(entry)) {
		pr_warn("debugfs file mm_event_task creation failed\n");
		debugfs_remove_recursive(mm_event_root);
		return PTR_ERR(entry);
	}

	return 0;
}
subsys_initcall(mm_event_init);