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Commit 6162cef0 authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: Factor out and expose cgroup_rstat_*() interface functions 



cgroup_rstat is being generalized so that controllers can use it too.
This patch factors out and exposes the following interface functions.

* cgroup_rstat_updated(): Renamed from cgroup_rstat_cpu_updated() for
  consistency.

* cgroup_rstat_flush_hold/release(): Factored out from base stat
  implementation.

* cgroup_rstat_flush(): Verbatim expose.

While at it, drop assert on cgroup_rstat_mutex in
cgroup_base_stat_flush() as it crosses layers and make a minor comment
update.

v2: Added EXPORT_SYMBOL_GPL(cgroup_rstat_updated) to fix a build bug.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent a17556f8

include/linux/cgroup.h

+9 −2
Original line number Diff line number Diff line
@@ -690,11 +690,18 @@ static inline void cgroup_path_from_kernfs_id(const union kernfs_node_id *id, 
	char *buf, size_t buflen) {}

#endif /* !CONFIG_CGROUPS */



#ifdef CONFIG_CGROUPS

/*

 * Basic resource stats.

 * cgroup scalable recursive statistics.

 */

#ifdef CONFIG_CGROUPS

void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);

void cgroup_rstat_flush(struct cgroup *cgrp);

void cgroup_rstat_flush_hold(struct cgroup *cgrp);

void cgroup_rstat_flush_release(void);



/*

 * Basic resource stats.

 */

#ifdef CONFIG_CGROUP_CPUACCT

void cpuacct_charge(struct task_struct *tsk, u64 cputime);

void cpuacct_account_field(struct task_struct *tsk, int index, u64 val);

kernel/cgroup/cgroup-internal.h

+0 −1
Original line number Diff line number Diff line
@@ -203,7 +203,6 @@ int cgroup_task_count(const struct cgroup *cgrp); 
/*

 * rstat.c

 */

void cgroup_rstat_flush(struct cgroup *cgrp);

int cgroup_rstat_init(struct cgroup *cgrp);

void cgroup_rstat_exit(struct cgroup *cgrp);

void cgroup_rstat_boot(void);

kernel/cgroup/rstat.c

+30 −12
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ static struct cgroup_rstat_cpu *cgroup_rstat_cpu(struct cgroup *cgrp, int cpu) 
}



/**

 * cgroup_rstat_cpu_updated - keep track of updated rstat_cpu

 * cgroup_rstat_updated - keep track of updated rstat_cpu

 * @cgrp: target cgroup

 * @cpu: cpu on which rstat_cpu was updated

 *
@@ -21,7 +21,7 @@ static struct cgroup_rstat_cpu *cgroup_rstat_cpu(struct cgroup *cgrp, int cpu) 
 * rstat_cpu->updated_children list.  See the comment on top of

 * cgroup_rstat_cpu definition for details.

 */

static void cgroup_rstat_cpu_updated(struct cgroup *cgrp, int cpu)

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;
@@ -59,6 +59,7 @@ static void cgroup_rstat_cpu_updated(struct cgroup *cgrp, int cpu) 


	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
@@ -167,6 +168,29 @@ void cgroup_rstat_flush(struct cgroup *cgrp) 
	mutex_unlock(&cgroup_rstat_mutex);

}



/**

 * 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().

 */

void cgroup_rstat_flush_hold(struct cgroup *cgrp)

	__acquires(&cgroup_rstat_mutex)

{

	mutex_lock(&cgroup_rstat_mutex);

	cgroup_rstat_flush_locked(cgrp);

}



/**

 * cgroup_rstat_flush_release - release cgroup_rstat_flush_hold()

 */

void cgroup_rstat_flush_release(void)

	__releases(&cgroup_rstat_mutex)

{

	mutex_unlock(&cgroup_rstat_mutex);

}



int cgroup_rstat_init(struct cgroup *cgrp)

{

	int cpu;
@@ -239,15 +263,13 @@ static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu) 
	struct cgroup_base_stat delta;

	unsigned seq;



	lockdep_assert_held(&cgroup_rstat_mutex);



	/* 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));



	/* accumulate the deltas to propgate */

	/* 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 -
@@ -278,7 +300,7 @@ static void cgroup_base_stat_cputime_account_end(struct cgroup *cgrp, 
						 struct cgroup_rstat_cpu *rstatc)

{

	u64_stats_update_end(&rstatc->bsync);

	cgroup_rstat_cpu_updated(cgrp, smp_processor_id());

	cgroup_rstat_updated(cgrp, smp_processor_id());

	put_cpu_ptr(rstatc);

}
@@ -323,14 +345,10 @@ void cgroup_base_stat_cputime_show(struct seq_file *seq) 
	if (!cgroup_parent(cgrp))

		return;



	mutex_lock(&cgroup_rstat_mutex);



	cgroup_rstat_flush_locked(cgrp);



	cgroup_rstat_flush_hold(cgrp);

	usage = cgrp->bstat.cputime.sum_exec_runtime;

	cputime_adjust(&cgrp->bstat.cputime, &cgrp->prev_cputime, &utime, &stime);



	mutex_unlock(&cgroup_rstat_mutex);

	cgroup_rstat_flush_release();



	do_div(usage, NSEC_PER_USEC);

	do_div(utime, NSEC_PER_USEC);