static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS];
+static struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
+ struct request_queue *q, bool update_hint);
+
+/**
+ * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
+ * @d_blkg: loop cursor pointing to the current descendant
+ * @pos_cgrp: used for iteration
+ * @p_blkg: target blkg to walk descendants of
+ *
+ * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU
+ * read locked. If called under either blkcg or queue lock, the iteration
+ * is guaranteed to include all and only online blkgs. The caller may
+ * update @pos_cgrp by calling cgroup_rightmost_descendant() to skip
+ * subtree.
+ */
+#define blkg_for_each_descendant_pre(d_blkg, pos_cgrp, p_blkg) \
+ cgroup_for_each_descendant_pre((pos_cgrp), (p_blkg)->blkcg->css.cgroup) \
+ if (((d_blkg) = __blkg_lookup(cgroup_to_blkcg(pos_cgrp), \
+ (p_blkg)->q, false)))
+
static bool blkcg_policy_enabled(struct request_queue *q,
const struct blkcg_policy *pol)
{
return NULL;
}
+/**
+ * __blkg_lookup - internal version of blkg_lookup()
+ * @blkcg: blkcg of interest
+ * @q: request_queue of interest
+ * @update_hint: whether to update lookup hint with the result or not
+ *
+ * This is internal version and shouldn't be used by policy
+ * implementations. Looks up blkgs for the @blkcg - @q pair regardless of
+ * @q's bypass state. If @update_hint is %true, the caller should be
+ * holding @q->queue_lock and lookup hint is updated on success.
+ */
static struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
struct request_queue *q, bool update_hint)
{
{
struct blkcg *blkcg = cgroup_to_blkcg(cgroup);
struct blkcg_gq *blkg;
- struct hlist_node *n;
int i;
mutex_lock(&blkcg_pol_mutex);
* stat updates. This is a debug feature which shouldn't exist
* anyway. If you get hit by a race, retry.
*/
- hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
+ hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
*
* This function invokes @prfill on each blkg of @blkcg if pd for the
* policy specified by @pol exists. @prfill is invoked with @sf, the
- * policy data and @data. If @show_total is %true, the sum of the return
- * values from @prfill is printed with "Total" label at the end.
+ * policy data and @data and the matching queue lock held. If @show_total
+ * is %true, the sum of the return values from @prfill is printed with
+ * "Total" label at the end.
*
* This is to be used to construct print functions for
* cftype->read_seq_string method.
bool show_total)
{
struct blkcg_gq *blkg;
- struct hlist_node *n;
u64 total = 0;
- spin_lock_irq(&blkcg->lock);
- hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node)
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
+ spin_lock_irq(blkg->q->queue_lock);
if (blkcg_policy_enabled(blkg->q, pol))
total += prfill(sf, blkg->pd[pol->plid], data);
- spin_unlock_irq(&blkcg->lock);
+ spin_unlock_irq(blkg->q->queue_lock);
+ }
+ rcu_read_unlock();
if (show_total)
seq_printf(sf, "Total %llu\n", (unsigned long long)total);
seq_printf(sf, "%s Total %llu\n", dname, (unsigned long long)v);
return v;
}
+EXPORT_SYMBOL_GPL(__blkg_prfill_rwstat);
/**
* blkg_prfill_stat - prfill callback for blkg_stat
}
EXPORT_SYMBOL_GPL(blkg_prfill_rwstat);
+/**
+ * blkg_stat_recursive_sum - collect hierarchical blkg_stat
+ * @pd: policy private data of interest
+ * @off: offset to the blkg_stat in @pd
+ *
+ * Collect the blkg_stat specified by @off from @pd and all its online
+ * descendants and return the sum. The caller must be holding the queue
+ * lock for online tests.
+ */
+u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off)
+{
+ struct blkcg_policy *pol = blkcg_policy[pd->plid];
+ struct blkcg_gq *pos_blkg;
+ struct cgroup *pos_cgrp;
+ u64 sum;
+
+ lockdep_assert_held(pd->blkg->q->queue_lock);
+
+ sum = blkg_stat_read((void *)pd + off);
+
+ rcu_read_lock();
+ blkg_for_each_descendant_pre(pos_blkg, pos_cgrp, pd_to_blkg(pd)) {
+ struct blkg_policy_data *pos_pd = blkg_to_pd(pos_blkg, pol);
+ struct blkg_stat *stat = (void *)pos_pd + off;
+
+ if (pos_blkg->online)
+ sum += blkg_stat_read(stat);
+ }
+ rcu_read_unlock();
+
+ return sum;
+}
+EXPORT_SYMBOL_GPL(blkg_stat_recursive_sum);
+
+/**
+ * blkg_rwstat_recursive_sum - collect hierarchical blkg_rwstat
+ * @pd: policy private data of interest
+ * @off: offset to the blkg_stat in @pd
+ *
+ * Collect the blkg_rwstat specified by @off from @pd and all its online
+ * descendants and return the sum. The caller must be holding the queue
+ * lock for online tests.
+ */
+struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd,
+ int off)
+{
+ struct blkcg_policy *pol = blkcg_policy[pd->plid];
+ struct blkcg_gq *pos_blkg;
+ struct cgroup *pos_cgrp;
+ struct blkg_rwstat sum;
+ int i;
+
+ lockdep_assert_held(pd->blkg->q->queue_lock);
+
+ sum = blkg_rwstat_read((void *)pd + off);
+
+ rcu_read_lock();
+ blkg_for_each_descendant_pre(pos_blkg, pos_cgrp, pd_to_blkg(pd)) {
+ struct blkg_policy_data *pos_pd = blkg_to_pd(pos_blkg, pol);
+ struct blkg_rwstat *rwstat = (void *)pos_pd + off;
+ struct blkg_rwstat tmp;
+
+ if (!pos_blkg->online)
+ continue;
+
+ tmp = blkg_rwstat_read(rwstat);
+
+ for (i = 0; i < BLKG_RWSTAT_NR; i++)
+ sum.cnt[i] += tmp.cnt[i];
+ }
+ rcu_read_unlock();
+
+ return sum;
+}
+EXPORT_SYMBOL_GPL(blkg_rwstat_recursive_sum);
+
/**
* blkg_conf_prep - parse and prepare for per-blkg config update
* @blkcg: target block cgroup
git.openpandora.org / pandora-kernel.git / blobdiff