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

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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: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tejun Heo 2018-04-26 14:29:05 -07:00
parent a17556f8d9
commit 6162cef0f7
3 changed files with 39 additions and 15 deletions
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11
include/linux/cgroup.h
View File

@ -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
/*
* cgroup scalable recursive statistics.
*/
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_CGROUPS
#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);

1
kernel/cgroup/cgroup-internal.h
View File

@ -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);

42
kernel/cgroup/rstat.c
View File

@ -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);