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authorTejun Heo <tj@kernel.org>2018-04-26 14:29:05 -0700
committerTejun Heo <tj@kernel.org>2018-04-26 14:29:05 -0700
commit6162cef0f741c70eb0c7ac7e6142f85808d8abc4 (patch)
tree355935993063eb4aa28ff6e8491d40380a83db7f /kernel/cgroup
parenta17556f8d9798e8feff9e34d746e489e78ee1dab (diff)
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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: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup')
-rw-r--r--kernel/cgroup/cgroup-internal.h1
-rw-r--r--kernel/cgroup/rstat.c42
2 files changed, 30 insertions, 13 deletions
diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
index 2bf6fb417588..b68e1a7c146c 100644
--- a/kernel/cgroup/cgroup-internal.h
+++ b/kernel/cgroup/cgroup-internal.h
@@ -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);
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index 87d7252769e7..d49bf92ac3d4 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -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);