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@@ -0,0 +1,416 @@
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+#include "cgroup-internal.h"
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+
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+#include <linux/sched/cputime.h>
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+
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+static DEFINE_SPINLOCK(cgroup_rstat_lock);
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+static DEFINE_PER_CPU(raw_spinlock_t, cgroup_rstat_cpu_lock);
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+
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+static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu);
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+
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+static struct cgroup_rstat_cpu *cgroup_rstat_cpu(struct cgroup *cgrp, int cpu)
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+{
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+ return per_cpu_ptr(cgrp->rstat_cpu, cpu);
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+}
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+
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+/**
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+ * cgroup_rstat_updated - keep track of updated rstat_cpu
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+ * @cgrp: target cgroup
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+ * @cpu: cpu on which rstat_cpu was updated
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+ *
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+ * @cgrp's rstat_cpu on @cpu was updated. Put it on the parent's matching
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+ * rstat_cpu->updated_children list. See the comment on top of
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+ * cgroup_rstat_cpu definition for details.
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+ */
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+void cgroup_rstat_updated(struct cgroup *cgrp, int cpu)
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+{
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+ raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu);
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+ struct cgroup *parent;
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+ unsigned long flags;
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+
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+ /* nothing to do for root */
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+ if (!cgroup_parent(cgrp))
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+ return;
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+
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+ /*
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+ * Paired with the one in cgroup_rstat_cpu_pop_upated(). Either we
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+ * see NULL updated_next or they see our updated stat.
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+ */
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+ smp_mb();
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+
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+ /*
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+ * Because @parent's updated_children is terminated with @parent
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+ * instead of NULL, we can tell whether @cgrp is on the list by
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+ * testing the next pointer for NULL.
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+ */
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+ if (cgroup_rstat_cpu(cgrp, cpu)->updated_next)
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+ return;
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+
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+ raw_spin_lock_irqsave(cpu_lock, flags);
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+
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+ /* put @cgrp and all ancestors on the corresponding updated lists */
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+ for (parent = cgroup_parent(cgrp); parent;
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+ cgrp = parent, parent = cgroup_parent(cgrp)) {
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+ struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
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+ struct cgroup_rstat_cpu *prstatc = cgroup_rstat_cpu(parent, cpu);
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+
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+ /*
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+ * Both additions and removals are bottom-up. If a cgroup
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+ * is already in the tree, all ancestors are.
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+ */
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+ if (rstatc->updated_next)
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+ break;
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+
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+ rstatc->updated_next = prstatc->updated_children;
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+ prstatc->updated_children = cgrp;
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+ }
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+
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+ raw_spin_unlock_irqrestore(cpu_lock, flags);
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+}
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+EXPORT_SYMBOL_GPL(cgroup_rstat_updated);
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+
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+/**
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+ * cgroup_rstat_cpu_pop_updated - iterate and dismantle rstat_cpu updated tree
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+ * @pos: current position
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+ * @root: root of the tree to traversal
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+ * @cpu: target cpu
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+ *
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+ * Walks the udpated rstat_cpu tree on @cpu from @root. %NULL @pos starts
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+ * the traversal and %NULL return indicates the end. During traversal,
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+ * each returned cgroup is unlinked from the tree. Must be called with the
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+ * matching cgroup_rstat_cpu_lock held.
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+ *
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+ * The only ordering guarantee is that, for a parent and a child pair
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+ * covered by a given traversal, if a child is visited, its parent is
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+ * guaranteed to be visited afterwards.
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+ */
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+static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos,
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+ struct cgroup *root, int cpu)
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+{
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+ struct cgroup_rstat_cpu *rstatc;
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+ struct cgroup *parent;
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+
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+ if (pos == root)
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+ return NULL;
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+
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+ /*
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+ * We're gonna walk down to the first leaf and visit/remove it. We
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+ * can pick whatever unvisited node as the starting point.
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+ */
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+ if (!pos)
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+ pos = root;
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+ else
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+ pos = cgroup_parent(pos);
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+
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+ /* walk down to the first leaf */
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+ while (true) {
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+ rstatc = cgroup_rstat_cpu(pos, cpu);
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+ if (rstatc->updated_children == pos)
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+ break;
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+ pos = rstatc->updated_children;
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+ }
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+
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+ /*
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+ * Unlink @pos from the tree. As the updated_children list is
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+ * singly linked, we have to walk it to find the removal point.
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+ * However, due to the way we traverse, @pos will be the first
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+ * child in most cases. The only exception is @root.
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+ */
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+ parent = cgroup_parent(pos);
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+ if (parent && rstatc->updated_next) {
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+ struct cgroup_rstat_cpu *prstatc = cgroup_rstat_cpu(parent, cpu);
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+ struct cgroup_rstat_cpu *nrstatc;
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+ struct cgroup **nextp;
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+
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+ nextp = &prstatc->updated_children;
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+ while (true) {
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+ nrstatc = cgroup_rstat_cpu(*nextp, cpu);
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+ if (*nextp == pos)
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+ break;
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+
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+ WARN_ON_ONCE(*nextp == parent);
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+ nextp = &nrstatc->updated_next;
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+ }
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+
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+ *nextp = rstatc->updated_next;
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+ rstatc->updated_next = NULL;
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+
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+ /*
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+ * Paired with the one in cgroup_rstat_cpu_updated().
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+ * Either they see NULL updated_next or we see their
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+ * updated stat.
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+ */
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+ smp_mb();
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+ }
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+
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+ return pos;
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+}
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+
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+/* see cgroup_rstat_flush() */
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+static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep)
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+ __releases(&cgroup_rstat_lock) __acquires(&cgroup_rstat_lock)
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+{
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+ int cpu;
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+
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+ lockdep_assert_held(&cgroup_rstat_lock);
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+
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+ for_each_possible_cpu(cpu) {
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+ raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock,
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+ cpu);
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+ struct cgroup *pos = NULL;
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+
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+ raw_spin_lock(cpu_lock);
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+ while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu))) {
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+ struct cgroup_subsys_state *css;
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+
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+ cgroup_base_stat_flush(pos, cpu);
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+
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+ rcu_read_lock();
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+ list_for_each_entry_rcu(css, &pos->rstat_css_list,
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+ rstat_css_node)
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+ css->ss->css_rstat_flush(css, cpu);
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+ rcu_read_unlock();
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+ }
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+ raw_spin_unlock(cpu_lock);
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+
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+ /* if @may_sleep, play nice and yield if necessary */
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+ if (may_sleep && (need_resched() ||
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+ spin_needbreak(&cgroup_rstat_lock))) {
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+ spin_unlock_irq(&cgroup_rstat_lock);
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+ if (!cond_resched())
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+ cpu_relax();
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+ spin_lock_irq(&cgroup_rstat_lock);
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+ }
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+ }
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+}
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+
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+/**
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+ * cgroup_rstat_flush - flush stats in @cgrp's subtree
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+ * @cgrp: target cgroup
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+ *
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+ * Collect all per-cpu stats in @cgrp's subtree into the global counters
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+ * and propagate them upwards. After this function returns, all cgroups in
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+ * the subtree have up-to-date ->stat.
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+ *
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+ * This also gets all cgroups in the subtree including @cgrp off the
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+ * ->updated_children lists.
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+ *
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+ * This function may block.
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+ */
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+void cgroup_rstat_flush(struct cgroup *cgrp)
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+{
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+ might_sleep();
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+
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+ spin_lock_irq(&cgroup_rstat_lock);
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+ cgroup_rstat_flush_locked(cgrp, true);
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+ spin_unlock_irq(&cgroup_rstat_lock);
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+}
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+
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+/**
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+ * cgroup_rstat_flush_irqsafe - irqsafe version of cgroup_rstat_flush()
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+ * @cgrp: target cgroup
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+ *
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+ * This function can be called from any context.
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+ */
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+void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp)
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+{
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+ unsigned long flags;
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+
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+ spin_lock_irqsave(&cgroup_rstat_lock, flags);
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+ cgroup_rstat_flush_locked(cgrp, false);
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+ spin_unlock_irqrestore(&cgroup_rstat_lock, flags);
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+}
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+
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+/**
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+ * cgroup_rstat_flush_begin - flush stats in @cgrp's subtree and hold
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+ * @cgrp: target cgroup
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+ *
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+ * Flush stats in @cgrp's subtree and prevent further flushes. Must be
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+ * paired with cgroup_rstat_flush_release().
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+ *
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+ * This function may block.
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+ */
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+void cgroup_rstat_flush_hold(struct cgroup *cgrp)
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+ __acquires(&cgroup_rstat_lock)
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+{
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+ might_sleep();
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+ spin_lock_irq(&cgroup_rstat_lock);
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+ cgroup_rstat_flush_locked(cgrp, true);
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+}
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+
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+/**
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+ * cgroup_rstat_flush_release - release cgroup_rstat_flush_hold()
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+ */
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+void cgroup_rstat_flush_release(void)
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+ __releases(&cgroup_rstat_lock)
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+{
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+ spin_unlock_irq(&cgroup_rstat_lock);
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+}
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+
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+int cgroup_rstat_init(struct cgroup *cgrp)
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+{
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+ int cpu;
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+
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+ /* the root cgrp has rstat_cpu preallocated */
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+ if (!cgrp->rstat_cpu) {
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+ cgrp->rstat_cpu = alloc_percpu(struct cgroup_rstat_cpu);
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+ if (!cgrp->rstat_cpu)
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+ return -ENOMEM;
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+ }
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+
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+ /* ->updated_children list is self terminated */
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+ for_each_possible_cpu(cpu) {
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+ struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
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+
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+ rstatc->updated_children = cgrp;
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+ u64_stats_init(&rstatc->bsync);
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+ }
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+
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+ return 0;
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+}
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+
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+void cgroup_rstat_exit(struct cgroup *cgrp)
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+{
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+ int cpu;
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+
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+ cgroup_rstat_flush(cgrp);
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+
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+ /* sanity check */
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+ for_each_possible_cpu(cpu) {
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+ struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
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+
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+ if (WARN_ON_ONCE(rstatc->updated_children != cgrp) ||
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+ WARN_ON_ONCE(rstatc->updated_next))
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+ return;
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+ }
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+
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+ free_percpu(cgrp->rstat_cpu);
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+ cgrp->rstat_cpu = NULL;
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+}
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+
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+void __init cgroup_rstat_boot(void)
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+{
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+ int cpu;
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+
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+ for_each_possible_cpu(cpu)
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+ raw_spin_lock_init(per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu));
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+
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+ BUG_ON(cgroup_rstat_init(&cgrp_dfl_root.cgrp));
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+}
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+
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+/*
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+ * Functions for cgroup basic resource statistics implemented on top of
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+ * rstat.
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+ */
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+static void cgroup_base_stat_accumulate(struct cgroup_base_stat *dst_bstat,
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+ struct cgroup_base_stat *src_bstat)
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+{
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+ dst_bstat->cputime.utime += src_bstat->cputime.utime;
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+ dst_bstat->cputime.stime += src_bstat->cputime.stime;
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+ dst_bstat->cputime.sum_exec_runtime += src_bstat->cputime.sum_exec_runtime;
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+}
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+
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+static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
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+{
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+ struct cgroup *parent = cgroup_parent(cgrp);
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+ struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
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+ struct task_cputime *last_cputime = &rstatc->last_bstat.cputime;
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+ struct task_cputime cputime;
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+ struct cgroup_base_stat delta;
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+ unsigned seq;
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+
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+ /* fetch the current per-cpu values */
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+ do {
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+ seq = __u64_stats_fetch_begin(&rstatc->bsync);
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+ cputime = rstatc->bstat.cputime;
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+ } while (__u64_stats_fetch_retry(&rstatc->bsync, seq));
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+
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+ /* calculate the delta to propgate */
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+ delta.cputime.utime = cputime.utime - last_cputime->utime;
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+ delta.cputime.stime = cputime.stime - last_cputime->stime;
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+ delta.cputime.sum_exec_runtime = cputime.sum_exec_runtime -
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+ last_cputime->sum_exec_runtime;
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+ *last_cputime = cputime;
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+
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+ /* transfer the pending stat into delta */
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+ cgroup_base_stat_accumulate(&delta, &cgrp->pending_bstat);
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+ memset(&cgrp->pending_bstat, 0, sizeof(cgrp->pending_bstat));
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+
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+ /* propagate delta into the global stat and the parent's pending */
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+ cgroup_base_stat_accumulate(&cgrp->bstat, &delta);
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+ if (parent)
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+ cgroup_base_stat_accumulate(&parent->pending_bstat, &delta);
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+}
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+
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+static struct cgroup_rstat_cpu *
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+cgroup_base_stat_cputime_account_begin(struct cgroup *cgrp)
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+{
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+ struct cgroup_rstat_cpu *rstatc;
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+
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+ rstatc = get_cpu_ptr(cgrp->rstat_cpu);
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+ u64_stats_update_begin(&rstatc->bsync);
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+ return rstatc;
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+}
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+
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+static void cgroup_base_stat_cputime_account_end(struct cgroup *cgrp,
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+ struct cgroup_rstat_cpu *rstatc)
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+{
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+ u64_stats_update_end(&rstatc->bsync);
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+ cgroup_rstat_updated(cgrp, smp_processor_id());
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+ put_cpu_ptr(rstatc);
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+}
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+
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+void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec)
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+{
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+ struct cgroup_rstat_cpu *rstatc;
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+
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+ rstatc = cgroup_base_stat_cputime_account_begin(cgrp);
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+ rstatc->bstat.cputime.sum_exec_runtime += delta_exec;
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+ cgroup_base_stat_cputime_account_end(cgrp, rstatc);
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+}
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+
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+void __cgroup_account_cputime_field(struct cgroup *cgrp,
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+ enum cpu_usage_stat index, u64 delta_exec)
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+{
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+ struct cgroup_rstat_cpu *rstatc;
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+
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+ rstatc = cgroup_base_stat_cputime_account_begin(cgrp);
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+
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+ switch (index) {
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+ case CPUTIME_USER:
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+ case CPUTIME_NICE:
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+ rstatc->bstat.cputime.utime += delta_exec;
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+ break;
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+ case CPUTIME_SYSTEM:
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+ case CPUTIME_IRQ:
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+ case CPUTIME_SOFTIRQ:
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+ rstatc->bstat.cputime.stime += delta_exec;
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+ break;
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+ default:
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+ break;
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+ }
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+
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+ cgroup_base_stat_cputime_account_end(cgrp, rstatc);
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+}
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+
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+void cgroup_base_stat_cputime_show(struct seq_file *seq)
|
|
|
+{
|
|
|
+ struct cgroup *cgrp = seq_css(seq)->cgroup;
|
|
|
+ u64 usage, utime, stime;
|
|
|
+
|
|
|
+ if (!cgroup_parent(cgrp))
|
|
|
+ return;
|
|
|
+
|
|
|
+ cgroup_rstat_flush_hold(cgrp);
|
|
|
+ usage = cgrp->bstat.cputime.sum_exec_runtime;
|
|
|
+ cputime_adjust(&cgrp->bstat.cputime, &cgrp->prev_cputime, &utime, &stime);
|
|
|
+ cgroup_rstat_flush_release();
|
|
|
+
|
|
|
+ do_div(usage, NSEC_PER_USEC);
|
|
|
+ do_div(utime, NSEC_PER_USEC);
|
|
|
+ do_div(stime, NSEC_PER_USEC);
|
|
|
+
|
|
|
+ seq_printf(seq, "usage_usec %llu\n"
|
|
|
+ "user_usec %llu\n"
|
|
|
+ "system_usec %llu\n",
|
|
|
+ usage, utime, stime);
|
|
|
+}
|
Linus Torvalds