From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 71BDC6B0007 for ; Sun, 22 Apr 2018 16:26:50 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id e14so8696973pfi.9 for ; Sun, 22 Apr 2018 13:26:50 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id q13sor2233692pfi.105.2018.04.22.13.26.49 for (Google Transport Security); Sun, 22 Apr 2018 13:26:49 -0700 (PDT) From: Greg Thelen Subject: [RFC PATCH 1/2] memcg: fix memory.low Date: Sun, 22 Apr 2018 13:26:11 -0700 Message-Id: <20180422202612.127760-2-gthelen@google.com> In-Reply-To: <20180422202612.127760-1-gthelen@google.com> References: <20180320223353.5673-1-guro@fb.com> <20180422202612.127760-1-gthelen@google.com> Sender: owner-linux-mm@kvack.org List-ID: To: guro@fb.com, Johannes Weiner , Andrew Morton , Michal Hocko Cc: Vladimir Davydov , Tejun Heo , Cgroups , kernel-team@fb.com, Linux MM , LKML , Greg Thelen When targeting reclaim to a memcg, protect that memcg from reclaim is memory consumption of any level is below respective memory.low. Signed-off-by: Greg Thelen --- mm/memcontrol.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 670e99b68aa6..9668f620203a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5341,8 +5341,8 @@ struct cgroup_subsys memory_cgrp_subsys = { * @root: the top ancestor of the sub-tree being checked * @memcg: the memory cgroup to check * - * Returns %true if memory consumption of @memcg, and that of all - * ancestors up to (but not including) @root, is below the normal range. + * Returns %true if memory consumption of @memcg, or any of its ancestors + * up to (but not including) @root, is below the normal range. * * @root is exclusive; it is never low when looked at directly and isn't * checked when traversing the hierarchy. @@ -5379,12 +5379,12 @@ bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg) if (memcg == root) return false; + /* If any level is under, then protect @memcg from reclaim */ for (; memcg != root; memcg = parent_mem_cgroup(memcg)) { - if (page_counter_read(&memcg->memory) >= memcg->low) - return false; + if (page_counter_read(&memcg->memory) <= memcg->low) + return true; /* protect from reclaim */ } - - return true; + return false; /* not protected from reclaim */ } /** -- 2.17.0.484.g0c8726318c-goog