// SPDX-License-Identifier: GPL-2.0-or-later/* delayacct.c - per-task delay accounting * * Copyright (C) Shailabh Nagar, IBM Corp. 2006 */ #include <linux/sched.h>#include <linux/sched/task.h>#include <linux/sched/cputime.h>#include <linux/sched/clock.h>#include <linux/slab.h>#include <linux/taskstats.h>#include <linux/sysctl.h>#include <linux/delayacct.h>#include <linux/module.h> DEFINE_STATIC_KEY_FALSE(delayacct_key);int delayacct_on __read_mostly;	/* Delay accounting turned on/off */struct kmem_cache *delayacct_cache; static void set_delayacct(bool enabled){	if (enabled) {		static_branch_enable(&delayacct_key);		delayacct_on = 1;	} else {		delayacct_on = 0;		static_branch_disable(&delayacct_key);	}} static int __init delayacct_setup_enable(char *str){	delayacct_on = 1;	return 1;}__setup("delayacct", delayacct_setup_enable); void delayacct_init(void){	delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT);	delayacct_tsk_init(&init_task);	set_delayacct(delayacct_on);} #ifdef CONFIG_PROC_SYSCTLstatic int sysctl_delayacct(const struct ctl_table *table, int write, void *buffer,		     size_t *lenp, loff_t *ppos){	int state = delayacct_on;	struct ctl_table t;	int err; 	if (write && !capable(CAP_SYS_ADMIN))		return -EPERM; 	t = *table;	t.data = &state;	err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);	if (err < 0)		return err;	if (write)		set_delayacct(state);	return err;} static const struct ctl_table kern_delayacct_table[] = {	{		.procname       = "task_delayacct",		.data           = NULL,		.maxlen         = sizeof(unsigned int),		.mode           = 0644,		.proc_handler   = sysctl_delayacct,		.extra1         = SYSCTL_ZERO,		.extra2         = SYSCTL_ONE,	},}; static __init int kernel_delayacct_sysctls_init(void){	register_sysctl_init("kernel", kern_delayacct_table);	return 0;}late_initcall(kernel_delayacct_sysctls_init);#endif void __delayacct_tsk_init(struct task_struct *tsk){	tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);	if (tsk->delays)		raw_spin_lock_init(&tsk->delays->lock);} /* * Finish delay accounting for a statistic using its timestamps (@start), * accumulator (@total) and @count */static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, u32 *count, u64 *max, u64 *min){	s64 ns = local_clock() - *start;	unsigned long flags; 	if (ns > 0) {		raw_spin_lock_irqsave(lock, flags);		*total += ns;		(*count)++;		if (ns > *max)			*max = ns;		if (*min == 0 || ns < *min)			*min = ns;		raw_spin_unlock_irqrestore(lock, flags);	}} void __delayacct_blkio_start(void){	current->delays->blkio_start = local_clock();} /* * We cannot rely on the `current` macro, as we haven't yet switched back to * the process being woken. */void __delayacct_blkio_end(struct task_struct *p){	delayacct_end(&p->delays->lock,		      &p->delays->blkio_start,		      &p->delays->blkio_delay,		      &p->delays->blkio_count,		      &p->delays->blkio_delay_max,		      &p->delays->blkio_delay_min);} int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk){	u64 utime, stime, stimescaled, utimescaled;	unsigned long long t2, t3;	unsigned long flags, t1;	s64 tmp; 	task_cputime(tsk, &utime, &stime);	tmp = (s64)d->cpu_run_real_total;	tmp += utime + stime;	d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp; 	task_cputime_scaled(tsk, &utimescaled, &stimescaled);	tmp = (s64)d->cpu_scaled_run_real_total;	tmp += utimescaled + stimescaled;	d->cpu_scaled_run_real_total =		(tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp; 	/*	 * No locking available for sched_info (and too expensive to add one)	 * Mitigate by taking snapshot of values	 */	t1 = tsk->sched_info.pcount;	t2 = tsk->sched_info.run_delay;	t3 = tsk->se.sum_exec_runtime; 	d->cpu_count += t1; 	d->cpu_delay_max = tsk->sched_info.max_run_delay;	d->cpu_delay_min = tsk->sched_info.min_run_delay;	tmp = (s64)d->cpu_delay_total + t2;	d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;	tmp = (s64)d->cpu_run_virtual_total + t3; 	d->cpu_run_virtual_total =		(tmp < (s64)d->cpu_run_virtual_total) ?	0 : tmp; 	if (!tsk->delays)		return 0; 	/* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */	raw_spin_lock_irqsave(&tsk->delays->lock, flags);	d->blkio_delay_max = tsk->delays->blkio_delay_max;	d->blkio_delay_min = tsk->delays->blkio_delay_min;	tmp = d->blkio_delay_total + tsk->delays->blkio_delay;	d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;	d->swapin_delay_max = tsk->delays->swapin_delay_max;	d->swapin_delay_min = tsk->delays->swapin_delay_min;	tmp = d->swapin_delay_total + tsk->delays->swapin_delay;	d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;	d->freepages_delay_max = tsk->delays->freepages_delay_max;	d->freepages_delay_min = tsk->delays->freepages_delay_min;	tmp = d->freepages_delay_total + tsk->delays->freepages_delay;	d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;	d->thrashing_delay_max = tsk->delays->thrashing_delay_max;	d->thrashing_delay_min = tsk->delays->thrashing_delay_min;	tmp = d->thrashing_delay_total + tsk->delays->thrashing_delay;	d->thrashing_delay_total = (tmp < d->thrashing_delay_total) ? 0 : tmp;	d->compact_delay_max = tsk->delays->compact_delay_max;	d->compact_delay_min = tsk->delays->compact_delay_min;	tmp = d->compact_delay_total + tsk->delays->compact_delay;	d->compact_delay_total = (tmp < d->compact_delay_total) ? 0 : tmp;	d->wpcopy_delay_max = tsk->delays->wpcopy_delay_max;	d->wpcopy_delay_min = tsk->delays->wpcopy_delay_min;	tmp = d->wpcopy_delay_total + tsk->delays->wpcopy_delay;	d->wpcopy_delay_total = (tmp < d->wpcopy_delay_total) ? 0 : tmp;	d->irq_delay_max = tsk->delays->irq_delay_max;	d->irq_delay_min = tsk->delays->irq_delay_min;	tmp = d->irq_delay_total + tsk->delays->irq_delay;	d->irq_delay_total = (tmp < d->irq_delay_total) ? 0 : tmp;	d->blkio_count += tsk->delays->blkio_count;	d->swapin_count += tsk->delays->swapin_count;	d->freepages_count += tsk->delays->freepages_count;	d->thrashing_count += tsk->delays->thrashing_count;	d->compact_count += tsk->delays->compact_count;	d->wpcopy_count += tsk->delays->wpcopy_count;	d->irq_count += tsk->delays->irq_count;	raw_spin_unlock_irqrestore(&tsk->delays->lock, flags); 	return 0;} __u64 __delayacct_blkio_ticks(struct task_struct *tsk){	__u64 ret;	unsigned long flags; 	raw_spin_lock_irqsave(&tsk->delays->lock, flags);	ret = nsec_to_clock_t(tsk->delays->blkio_delay);	raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);	return ret;} void __delayacct_freepages_start(void){	current->delays->freepages_start = local_clock();} void __delayacct_freepages_end(void){	delayacct_end(&current->delays->lock,		      &current->delays->freepages_start,		      &current->delays->freepages_delay,		      &current->delays->freepages_count,		      &current->delays->freepages_delay_max,		      &current->delays->freepages_delay_min);} void __delayacct_thrashing_start(bool *in_thrashing){	*in_thrashing = !!current->in_thrashing;	if (*in_thrashing)		return; 	current->in_thrashing = 1;	current->delays->thrashing_start = local_clock();} void __delayacct_thrashing_end(bool *in_thrashing){	if (*in_thrashing)		return; 	current->in_thrashing = 0;	delayacct_end(&current->delays->lock,		      &current->delays->thrashing_start,		      &current->delays->thrashing_delay,		      &current->delays->thrashing_count,		      &current->delays->thrashing_delay_max,		      &current->delays->thrashing_delay_min);} void __delayacct_swapin_start(void){	current->delays->swapin_start = local_clock();} void __delayacct_swapin_end(void){	delayacct_end(&current->delays->lock,		      &current->delays->swapin_start,		      &current->delays->swapin_delay,		      &current->delays->swapin_count,		      &current->delays->swapin_delay_max,		      &current->delays->swapin_delay_min);} void __delayacct_compact_start(void){	current->delays->compact_start = local_clock();} void __delayacct_compact_end(void){	delayacct_end(&current->delays->lock,		      &current->delays->compact_start,		      &current->delays->compact_delay,		      &current->delays->compact_count,		      &current->delays->compact_delay_max,		      &current->delays->compact_delay_min);} void __delayacct_wpcopy_start(void){	current->delays->wpcopy_start = local_clock();} void __delayacct_wpcopy_end(void){	delayacct_end(&current->delays->lock,		      &current->delays->wpcopy_start,		      &current->delays->wpcopy_delay,		      &current->delays->wpcopy_count,		      &current->delays->wpcopy_delay_max,		      &current->delays->wpcopy_delay_min);} void __delayacct_irq(struct task_struct *task, u32 delta){	unsigned long flags; 	raw_spin_lock_irqsave(&task->delays->lock, flags);	task->delays->irq_delay += delta;	task->delays->irq_count++;	if (delta > task->delays->irq_delay_max)		task->delays->irq_delay_max = delta;	if (delta && (!task->delays->irq_delay_min || delta < task->delays->irq_delay_min))		task->delays->irq_delay_min = delta;	raw_spin_unlock_irqrestore(&task->delays->lock, flags);}