blkg->q = disk->queue;
INIT_LIST_HEAD(&blkg->q_node);
blkg->blkcg = blkcg;
+ blkg->iostat.blkg = blkg;
#ifdef CONFIG_BLK_CGROUP_PUNT_BIO
spin_lock_init(&blkg->async_bio_lock);
bio_list_init(&blkg->async_bios);
smp_mb();
WRITE_ONCE(bisc->lqueued, false);
+ if (bisc == &blkg->iostat)
+ goto propagate_up; /* propagate up to parent only */
/* fetch the current per-cpu values */
do {
blkcg_iostat_update(blkg, &cur, &bisc->last);
+propagate_up:
/* propagate global delta to parent (unless that's root) */
- if (parent && parent->parent)
+ if (parent && parent->parent) {
blkcg_iostat_update(parent, &blkg->iostat.cur,
&blkg->iostat.last);
+ /*
+ * Queue parent->iostat to its blkcg's lockless
+ * list to propagate up to the grandparent if the
+ * iostat hasn't been queued yet.
+ */
+ if (!parent->iostat.lqueued) {
+ struct llist_head *plhead;
+
+ plhead = per_cpu_ptr(parent->blkcg->lhead, cpu);
+ llist_add(&parent->iostat.lnode, plhead);
+ parent->iostat.lqueued = true;
+ }
+ }
}
raw_spin_unlock_irqrestore(&blkg_stat_lock, flags);
out: