// SPDX-License-Identifier: GPL-2.0-only#include "cgroup-internal.h" #include <linux/sched/cputime.h> static DEFINE_SPINLOCK(cgroup_rstat_lock);static DEFINE_PER_CPU(raw_spinlock_t, cgroup_rstat_cpu_lock); static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu); static struct cgroup_rstat_cpu *cgroup_rstat_cpu(struct cgroup *cgrp, int cpu){	return per_cpu_ptr(cgrp->rstat_cpu, cpu);} /** * cgroup_rstat_updated - keep track of updated rstat_cpu * @cgrp: target cgroup * @cpu: cpu on which rstat_cpu was updated * * @cgrp's rstat_cpu on @cpu was updated.  Put it on the parent's matching * rstat_cpu->updated_children list.  See the comment on top of * cgroup_rstat_cpu definition for details. */void cgroup_rstat_updated(struct cgroup *cgrp, int cpu){	raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu);	struct cgroup *parent;	unsigned long flags; 	/* nothing to do for root */	if (!cgroup_parent(cgrp))		return; 	/*	 * Paired with the one in cgroup_rstat_cpu_pop_upated().  Either we	 * see NULL updated_next or they see our updated stat.	 */	smp_mb(); 	/*	 * Because @parent's updated_children is terminated with @parent	 * instead of NULL, we can tell whether @cgrp is on the list by	 * testing the next pointer for NULL.	 */	if (cgroup_rstat_cpu(cgrp, cpu)->updated_next)		return; 	raw_spin_lock_irqsave(cpu_lock, flags); 	/* put @cgrp and all ancestors on the corresponding updated lists */	for (parent = cgroup_parent(cgrp); parent;	     cgrp = parent, parent = cgroup_parent(cgrp)) {		struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);		struct cgroup_rstat_cpu *prstatc = cgroup_rstat_cpu(parent, cpu); 		/*		 * Both additions and removals are bottom-up.  If a cgroup		 * is already in the tree, all ancestors are.		 */		if (rstatc->updated_next)			break; 		rstatc->updated_next = prstatc->updated_children;		prstatc->updated_children = cgrp;	} 	raw_spin_unlock_irqrestore(cpu_lock, flags);}EXPORT_SYMBOL_GPL(cgroup_rstat_updated); /** * cgroup_rstat_cpu_pop_updated - iterate and dismantle rstat_cpu updated tree * @pos: current position * @root: root of the tree to traversal * @cpu: target cpu * * Walks the udpated rstat_cpu tree on @cpu from @root.  %NULL @pos starts * the traversal and %NULL return indicates the end.  During traversal, * each returned cgroup is unlinked from the tree.  Must be called with the * matching cgroup_rstat_cpu_lock held. * * The only ordering guarantee is that, for a parent and a child pair * covered by a given traversal, if a child is visited, its parent is * guaranteed to be visited afterwards. */static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos,						   struct cgroup *root, int cpu){	struct cgroup_rstat_cpu *rstatc; 	if (pos == root)		return NULL; 	/*	 * We're gonna walk down to the first leaf and visit/remove it.  We	 * can pick whatever unvisited node as the starting point.	 */	if (!pos)		pos = root;	else		pos = cgroup_parent(pos); 	/* walk down to the first leaf */	while (true) {		rstatc = cgroup_rstat_cpu(pos, cpu);		if (rstatc->updated_children == pos)			break;		pos = rstatc->updated_children;	} 	/*	 * Unlink @pos from the tree.  As the updated_children list is	 * singly linked, we have to walk it to find the removal point.	 * However, due to the way we traverse, @pos will be the first	 * child in most cases. The only exception is @root.	 */	if (rstatc->updated_next) {		struct cgroup *parent = cgroup_parent(pos);		struct cgroup_rstat_cpu *prstatc = cgroup_rstat_cpu(parent, cpu);		struct cgroup_rstat_cpu *nrstatc;		struct cgroup **nextp; 		nextp = &prstatc->updated_children;		while (true) {			nrstatc = cgroup_rstat_cpu(*nextp, cpu);			if (*nextp == pos)				break; 			WARN_ON_ONCE(*nextp == parent);			nextp = &nrstatc->updated_next;		} 		*nextp = rstatc->updated_next;		rstatc->updated_next = NULL; 		/*		 * Paired with the one in cgroup_rstat_cpu_updated().		 * Either they see NULL updated_next or we see their		 * updated stat.		 */		smp_mb(); 		return pos;	} 	/* only happens for @root */	return NULL;} /* see cgroup_rstat_flush() */static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep)	__releases(&cgroup_rstat_lock) __acquires(&cgroup_rstat_lock){	int cpu; 	lockdep_assert_held(&cgroup_rstat_lock); 	for_each_possible_cpu(cpu) {		raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock,						       cpu);		struct cgroup *pos = NULL; 		raw_spin_lock(cpu_lock);		while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu))) {			struct cgroup_subsys_state *css; 			cgroup_base_stat_flush(pos, cpu); 			rcu_read_lock();			list_for_each_entry_rcu(css, &pos->rstat_css_list,						rstat_css_node)				css->ss->css_rstat_flush(css, cpu);			rcu_read_unlock();		}		raw_spin_unlock(cpu_lock); 		/* if @may_sleep, play nice and yield if necessary */		if (may_sleep && (need_resched() ||				  spin_needbreak(&cgroup_rstat_lock))) {			spin_unlock_irq(&cgroup_rstat_lock);			if (!cond_resched())				cpu_relax();			spin_lock_irq(&cgroup_rstat_lock);		}	}} /** * cgroup_rstat_flush - flush stats in @cgrp's subtree * @cgrp: target cgroup * * Collect all per-cpu stats in @cgrp's subtree into the global counters * and propagate them upwards.  After this function returns, all cgroups in * the subtree have up-to-date ->stat. * * This also gets all cgroups in the subtree including @cgrp off the * ->updated_children lists. * * This function may block. */void cgroup_rstat_flush(struct cgroup *cgrp){	might_sleep(); 	spin_lock_irq(&cgroup_rstat_lock);	cgroup_rstat_flush_locked(cgrp, true);	spin_unlock_irq(&cgroup_rstat_lock);} /** * cgroup_rstat_flush_irqsafe - irqsafe version of cgroup_rstat_flush() * @cgrp: target cgroup * * This function can be called from any context. */void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp){	unsigned long flags; 	spin_lock_irqsave(&cgroup_rstat_lock, flags);	cgroup_rstat_flush_locked(cgrp, false);	spin_unlock_irqrestore(&cgroup_rstat_lock, flags);} /** * cgroup_rstat_flush_begin - flush stats in @cgrp's subtree and hold * @cgrp: target cgroup * * Flush stats in @cgrp's subtree and prevent further flushes.  Must be * paired with cgroup_rstat_flush_release(). * * This function may block. */void cgroup_rstat_flush_hold(struct cgroup *cgrp)	__acquires(&cgroup_rstat_lock){	might_sleep();	spin_lock_irq(&cgroup_rstat_lock);	cgroup_rstat_flush_locked(cgrp, true);} /** * cgroup_rstat_flush_release - release cgroup_rstat_flush_hold() */void cgroup_rstat_flush_release(void)	__releases(&cgroup_rstat_lock){	spin_unlock_irq(&cgroup_rstat_lock);} int cgroup_rstat_init(struct cgroup *cgrp){	int cpu; 	/* the root cgrp has rstat_cpu preallocated */	if (!cgrp->rstat_cpu) {		cgrp->rstat_cpu = alloc_percpu(struct cgroup_rstat_cpu);		if (!cgrp->rstat_cpu)			return -ENOMEM;	} 	/* ->updated_children list is self terminated */	for_each_possible_cpu(cpu) {		struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu); 		rstatc->updated_children = cgrp;		u64_stats_init(&rstatc->bsync);	} 	return 0;} void cgroup_rstat_exit(struct cgroup *cgrp){	int cpu; 	cgroup_rstat_flush(cgrp); 	/* sanity check */	for_each_possible_cpu(cpu) {		struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu); 		if (WARN_ON_ONCE(rstatc->updated_children != cgrp) ||		    WARN_ON_ONCE(rstatc->updated_next))			return;	} 	free_percpu(cgrp->rstat_cpu);	cgrp->rstat_cpu = NULL;} void __init cgroup_rstat_boot(void){	int cpu; 	for_each_possible_cpu(cpu)		raw_spin_lock_init(per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu)); 	BUG_ON(cgroup_rstat_init(&cgrp_dfl_root.cgrp));} /* * Functions for cgroup basic resource statistics implemented on top of * rstat. */static void cgroup_base_stat_accumulate(struct cgroup_base_stat *dst_bstat,					struct cgroup_base_stat *src_bstat){	dst_bstat->cputime.utime += src_bstat->cputime.utime;	dst_bstat->cputime.stime += src_bstat->cputime.stime;	dst_bstat->cputime.sum_exec_runtime += src_bstat->cputime.sum_exec_runtime;} static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu){	struct cgroup *parent = cgroup_parent(cgrp);	struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);	struct task_cputime *last_cputime = &rstatc->last_bstat.cputime;	struct task_cputime cputime;	struct cgroup_base_stat delta;	unsigned seq; 	/* fetch the current per-cpu values */	do {		seq = __u64_stats_fetch_begin(&rstatc->bsync);		cputime = rstatc->bstat.cputime;	} while (__u64_stats_fetch_retry(&rstatc->bsync, seq)); 	/* calculate the delta to propgate */	delta.cputime.utime = cputime.utime - last_cputime->utime;	delta.cputime.stime = cputime.stime - last_cputime->stime;	delta.cputime.sum_exec_runtime = cputime.sum_exec_runtime -					 last_cputime->sum_exec_runtime;	*last_cputime = cputime; 	/* transfer the pending stat into delta */	cgroup_base_stat_accumulate(&delta, &cgrp->pending_bstat);	memset(&cgrp->pending_bstat, 0, sizeof(cgrp->pending_bstat)); 	/* propagate delta into the global stat and the parent's pending */	cgroup_base_stat_accumulate(&cgrp->bstat, &delta);	if (parent)		cgroup_base_stat_accumulate(&parent->pending_bstat, &delta);} static struct cgroup_rstat_cpu *cgroup_base_stat_cputime_account_begin(struct cgroup *cgrp){	struct cgroup_rstat_cpu *rstatc; 	rstatc = get_cpu_ptr(cgrp->rstat_cpu);	u64_stats_update_begin(&rstatc->bsync);	return rstatc;} static void cgroup_base_stat_cputime_account_end(struct cgroup *cgrp,						 struct cgroup_rstat_cpu *rstatc){	u64_stats_update_end(&rstatc->bsync);	cgroup_rstat_updated(cgrp, smp_processor_id());	put_cpu_ptr(rstatc);} void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec){	struct cgroup_rstat_cpu *rstatc; 	rstatc = cgroup_base_stat_cputime_account_begin(cgrp);	rstatc->bstat.cputime.sum_exec_runtime += delta_exec;	cgroup_base_stat_cputime_account_end(cgrp, rstatc);} void __cgroup_account_cputime_field(struct cgroup *cgrp,				    enum cpu_usage_stat index, u64 delta_exec){	struct cgroup_rstat_cpu *rstatc; 	rstatc = cgroup_base_stat_cputime_account_begin(cgrp); 	switch (index) {	case CPUTIME_USER:	case CPUTIME_NICE:		rstatc->bstat.cputime.utime += delta_exec;		break;	case CPUTIME_SYSTEM:	case CPUTIME_IRQ:	case CPUTIME_SOFTIRQ:		rstatc->bstat.cputime.stime += delta_exec;		break;	default:		break;	} 	cgroup_base_stat_cputime_account_end(cgrp, rstatc);} void cgroup_base_stat_cputime_show(struct seq_file *seq){	struct cgroup *cgrp = seq_css(seq)->cgroup;	u64 usage, utime, stime; 	if (!cgroup_parent(cgrp))		return; 	cgroup_rstat_flush_hold(cgrp);	usage = cgrp->bstat.cputime.sum_exec_runtime;	cputime_adjust(&cgrp->bstat.cputime, &cgrp->prev_cputime, &utime, &stime);	cgroup_rstat_flush_release(); 	do_div(usage, NSEC_PER_USEC);	do_div(utime, NSEC_PER_USEC);	do_div(stime, NSEC_PER_USEC); 	seq_printf(seq, "usage_usec %llu\n"		   "user_usec %llu\n"		   "system_usec %llu\n",		   usage, utime, stime);}