mm, memcg: prevent memory.min load/store tearing (c3d53200) · Commits · 戴 / test

mm/memcontrol.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -6389,7 +6389,7 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root,
		return MEMCG_PROT_NONE;

		if (parent == root) {
		memcg->memory.emin = memcg->memory.min;
		memcg->memory.emin = READ_ONCE(memcg->memory.min);
		memcg->memory.elow = memcg->memory.low;
		goto out;
		}
		@@ -6397,7 +6397,8 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root,
		parent_usage = page_counter_read(&parent->memory);

		memcg->memory.emin = effective_protection(usage, parent_usage,
		memcg->memory.min, READ_ONCE(parent->memory.emin),
		READ_ONCE(memcg->memory.min),
		READ_ONCE(parent->memory.emin),
		atomic_long_read(&parent->memory.children_min_usage));

		memcg->memory.elow = effective_protection(usage, parent_usage,

+5 −4

Original line number	Diff line number	Diff line
		@@ -17,14 +17,15 @@ static void propagate_protected_usage(struct page_counter *c,
		unsigned long usage)
		{
		unsigned long protected, old_protected;
		unsigned long low;
		unsigned long low, min;
		long delta;

		if (!c->parent)
		return;

		if (c->min \|\| atomic_long_read(&c->min_usage)) {
		protected = min(usage, c->min);
		min = READ_ONCE(c->min);
		if (min \|\| atomic_long_read(&c->min_usage)) {
		protected = min(usage, min);
		old_protected = atomic_long_xchg(&c->min_usage, protected);
		delta = protected - old_protected;
		if (delta)
		@@ -207,7 +208,7 @@ void page_counter_set_min(struct page_counter *counter, unsigned long nr_pages)
		{
		struct page_counter *c;

		counter->min = nr_pages;
		WRITE_ONCE(counter->min, nr_pages);

		for (c = counter; c; c = c->parent)
		propagate_protected_usage(c, atomic_long_read(&c->usage));