summaryrefslogtreecommitdiffstats
path: root/kernel/cgroup/rstat.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/cgroup/rstat.c')
-rw-r--r--kernel/cgroup/rstat.c58
1 files changed, 45 insertions, 13 deletions
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index d49bf92..3386fb2 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -2,7 +2,7 @@
#include <linux/sched/cputime.h>
-static DEFINE_MUTEX(cgroup_rstat_mutex);
+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);
@@ -132,21 +132,31 @@ static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos,
}
/* see cgroup_rstat_flush() */
-static void cgroup_rstat_flush_locked(struct cgroup *cgrp)
+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_mutex);
+ 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_irq(cpu_lock);
+ raw_spin_lock(cpu_lock);
while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu)))
cgroup_base_stat_flush(pos, cpu);
- raw_spin_unlock_irq(cpu_lock);
+ 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);
+ }
}
}
@@ -160,12 +170,31 @@ static void cgroup_rstat_flush_locked(struct cgroup *cgrp)
*
* 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)
{
- mutex_lock(&cgroup_rstat_mutex);
- cgroup_rstat_flush_locked(cgrp);
- mutex_unlock(&cgroup_rstat_mutex);
+ 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);
}
/**
@@ -174,21 +203,24 @@ void cgroup_rstat_flush(struct cgroup *cgrp)
*
* 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_mutex)
+ __acquires(&cgroup_rstat_lock)
{
- mutex_lock(&cgroup_rstat_mutex);
- cgroup_rstat_flush_locked(cgrp);
+ 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_mutex)
+ __releases(&cgroup_rstat_lock)
{
- mutex_unlock(&cgroup_rstat_mutex);
+ spin_unlock_irq(&cgroup_rstat_lock);
}
int cgroup_rstat_init(struct cgroup *cgrp)
OpenPOWER on IntegriCloud