#include "cgroup-internal.h" #include <linux/sched/cputime.h> static DEFINE_MUTEX(cgroup_stat_mutex);static DEFINE_PER_CPU(raw_spinlock_t, cgroup_cpu_stat_lock); static struct cgroup_cpu_stat *cgroup_cpu_stat(struct cgroup *cgrp, int cpu){	return per_cpu_ptr(cgrp->cpu_stat, cpu);} /** * cgroup_cpu_stat_updated - keep track of updated cpu_stat * @cgrp: target cgroup * @cpu: cpu on which cpu_stat was updated * * @cgrp's cpu_stat on @cpu was updated.  Put it on the parent's matching * cpu_stat->updated_children list.  See the comment on top of * cgroup_cpu_stat definition for details. */static void cgroup_cpu_stat_updated(struct cgroup *cgrp, int cpu){	raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_cpu_stat_lock, cpu);	struct cgroup *parent;	unsigned long flags; 	/*	 * Speculative already-on-list test.  This may race leading to	 * temporary inaccuracies, which is fine.	 *	 * 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_cpu_stat(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_cpu_stat *cstat = cgroup_cpu_stat(cgrp, cpu);		struct cgroup_cpu_stat *pcstat = cgroup_cpu_stat(parent, cpu); 		/*		 * Both additions and removals are bottom-up.  If a cgroup		 * is already in the tree, all ancestors are.		 */		if (cstat->updated_next)			break; 		cstat->updated_next = pcstat->updated_children;		pcstat->updated_children = cgrp;	} 	raw_spin_unlock_irqrestore(cpu_lock, flags);} /** * cgroup_cpu_stat_pop_updated - iterate and dismantle cpu_stat updated tree * @pos: current position * @root: root of the tree to traversal * @cpu: target cpu * * Walks the udpated cpu_stat 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_cpu_stat_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_cpu_stat_pop_updated(struct cgroup *pos,						  struct cgroup *root, int cpu){	struct cgroup_cpu_stat *cstat;	struct cgroup *parent; 	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) {		cstat = cgroup_cpu_stat(pos, cpu);		if (cstat->updated_children == pos)			break;		pos = cstat->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.	 */	parent = cgroup_parent(pos);	if (parent && cstat->updated_next) {		struct cgroup_cpu_stat *pcstat = cgroup_cpu_stat(parent, cpu);		struct cgroup_cpu_stat *ncstat;		struct cgroup **nextp; 		nextp = &pcstat->updated_children;		while (true) {			ncstat = cgroup_cpu_stat(*nextp, cpu);			if (*nextp == pos)				break; 			WARN_ON_ONCE(*nextp == parent);			nextp = &ncstat->updated_next;		} 		*nextp = cstat->updated_next;		cstat->updated_next = NULL;	} 	return pos;} static void cgroup_stat_accumulate(struct cgroup_stat *dst_stat,				   struct cgroup_stat *src_stat){	dst_stat->cputime.utime += src_stat->cputime.utime;	dst_stat->cputime.stime += src_stat->cputime.stime;	dst_stat->cputime.sum_exec_runtime += src_stat->cputime.sum_exec_runtime;} static void cgroup_cpu_stat_flush_one(struct cgroup *cgrp, int cpu){	struct cgroup *parent = cgroup_parent(cgrp);	struct cgroup_cpu_stat *cstat = cgroup_cpu_stat(cgrp, cpu);	struct task_cputime *last_cputime = &cstat->last_cputime;	struct task_cputime cputime;	struct cgroup_stat delta;	unsigned seq; 	lockdep_assert_held(&cgroup_stat_mutex); 	/* fetch the current per-cpu values */	do {		seq = __u64_stats_fetch_begin(&cstat->sync);		cputime = cstat->cputime;	} while (__u64_stats_fetch_retry(&cstat->sync, seq)); 	/* accumulate the deltas 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_stat_accumulate(&delta, &cgrp->pending_stat);	memset(&cgrp->pending_stat, 0, sizeof(cgrp->pending_stat)); 	/* propagate delta into the global stat and the parent's pending */	cgroup_stat_accumulate(&cgrp->stat, &delta);	if (parent)		cgroup_stat_accumulate(&parent->pending_stat, &delta);} /* see cgroup_stat_flush() */static void cgroup_stat_flush_locked(struct cgroup *cgrp){	int cpu; 	lockdep_assert_held(&cgroup_stat_mutex); 	for_each_possible_cpu(cpu) {		raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_cpu_stat_lock, cpu);		struct cgroup *pos = NULL; 		raw_spin_lock_irq(cpu_lock);		while ((pos = cgroup_cpu_stat_pop_updated(pos, cgrp, cpu)))			cgroup_cpu_stat_flush_one(pos, cpu);		raw_spin_unlock_irq(cpu_lock);	}} /** * cgroup_stat_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. */void cgroup_stat_flush(struct cgroup *cgrp){	mutex_lock(&cgroup_stat_mutex);	cgroup_stat_flush_locked(cgrp);	mutex_unlock(&cgroup_stat_mutex);} static struct cgroup_cpu_stat *cgroup_cpu_stat_account_begin(struct cgroup *cgrp){	struct cgroup_cpu_stat *cstat; 	cstat = get_cpu_ptr(cgrp->cpu_stat);	u64_stats_update_begin(&cstat->sync);	return cstat;} static void cgroup_cpu_stat_account_end(struct cgroup *cgrp,					struct cgroup_cpu_stat *cstat){	u64_stats_update_end(&cstat->sync);	cgroup_cpu_stat_updated(cgrp, smp_processor_id());	put_cpu_ptr(cstat);} void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec){	struct cgroup_cpu_stat *cstat; 	cstat = cgroup_cpu_stat_account_begin(cgrp);	cstat->cputime.sum_exec_runtime += delta_exec;	cgroup_cpu_stat_account_end(cgrp, cstat);} void __cgroup_account_cputime_field(struct cgroup *cgrp,				    enum cpu_usage_stat index, u64 delta_exec){	struct cgroup_cpu_stat *cstat; 	cstat = cgroup_cpu_stat_account_begin(cgrp); 	switch (index) {	case CPUTIME_USER:	case CPUTIME_NICE:		cstat->cputime.utime += delta_exec;		break;	case CPUTIME_SYSTEM:	case CPUTIME_IRQ:	case CPUTIME_SOFTIRQ:		cstat->cputime.stime += delta_exec;		break;	default:		break;	} 	cgroup_cpu_stat_account_end(cgrp, cstat);} void cgroup_stat_show_cputime(struct seq_file *seq){	struct cgroup *cgrp = seq_css(seq)->cgroup;	u64 usage, utime, stime; 	if (!cgroup_parent(cgrp))		return; 	mutex_lock(&cgroup_stat_mutex); 	cgroup_stat_flush_locked(cgrp); 	usage = cgrp->stat.cputime.sum_exec_runtime;	cputime_adjust(&cgrp->stat.cputime, &cgrp->stat.prev_cputime,		       &utime, &stime); 	mutex_unlock(&cgroup_stat_mutex); 	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);} int cgroup_stat_init(struct cgroup *cgrp){	int cpu; 	/* the root cgrp has cpu_stat preallocated */	if (!cgrp->cpu_stat) {		cgrp->cpu_stat = alloc_percpu(struct cgroup_cpu_stat);		if (!cgrp->cpu_stat)			return -ENOMEM;	} 	/* ->updated_children list is self terminated */	for_each_possible_cpu(cpu) {		struct cgroup_cpu_stat *cstat = cgroup_cpu_stat(cgrp, cpu); 		cstat->updated_children = cgrp;		u64_stats_init(&cstat->sync);	} 	prev_cputime_init(&cgrp->stat.prev_cputime); 	return 0;} void cgroup_stat_exit(struct cgroup *cgrp){	int cpu; 	cgroup_stat_flush(cgrp); 	/* sanity check */	for_each_possible_cpu(cpu) {		struct cgroup_cpu_stat *cstat = cgroup_cpu_stat(cgrp, cpu); 		if (WARN_ON_ONCE(cstat->updated_children != cgrp) ||		    WARN_ON_ONCE(cstat->updated_next))			return;	} 	free_percpu(cgrp->cpu_stat);	cgrp->cpu_stat = NULL;} void __init cgroup_stat_boot(void){	int cpu; 	for_each_possible_cpu(cpu)		raw_spin_lock_init(per_cpu_ptr(&cgroup_cpu_stat_lock, cpu)); 	BUG_ON(cgroup_stat_init(&cgrp_dfl_root.cgrp));}