mm: memcontrol: switch soft limit default back to infinity (24d404dc) · Commits · 戴 / test

Commit ("mm: memcontrol: lockless page counters") accidentally switched the soft limit default from infinity to zero, which turns all memcgs with even a single page into soft limit excessors and engages soft limit reclaim on all of them during global memory pressure. This makes global reclaim generally more aggressive, but also inverts the meaning of existing soft limit configurations where unset soft limits are usually more generous than set ones. Signed-off-by:

Johannes Weiner <hannes@cmpxchg.org> Acked-by:

Michal Hocko <mhocko@suse.cz> Acked-by:

Vladimir Davydov <vdavydov@parallels.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/memcontrol.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -4679,6 +4679,7 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
		if (parent_css == NULL) {
		root_mem_cgroup = memcg;
		page_counter_init(&memcg->memory, NULL);
		memcg->soft_limit = PAGE_COUNTER_MAX;
		page_counter_init(&memcg->memsw, NULL);
		page_counter_init(&memcg->kmem, NULL);
		}
		@@ -4724,6 +4725,7 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css)

		if (parent->use_hierarchy) {
		page_counter_init(&memcg->memory, &parent->memory);
		memcg->soft_limit = PAGE_COUNTER_MAX;
		page_counter_init(&memcg->memsw, &parent->memsw);
		page_counter_init(&memcg->kmem, &parent->kmem);

		@@ -4733,6 +4735,7 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css)
		*/
		} else {
		page_counter_init(&memcg->memory, NULL);
		memcg->soft_limit = PAGE_COUNTER_MAX;
		page_counter_init(&memcg->memsw, NULL);
		page_counter_init(&memcg->kmem, NULL);
		/*
		@@ -4807,7 +4810,7 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
		mem_cgroup_resize_limit(memcg, PAGE_COUNTER_MAX);
		mem_cgroup_resize_memsw_limit(memcg, PAGE_COUNTER_MAX);
		memcg_update_kmem_limit(memcg, PAGE_COUNTER_MAX);
		memcg->soft_limit = 0;
		memcg->soft_limit = PAGE_COUNTER_MAX;
		}

		#ifdef CONFIG_MMU

Admin message