From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753638AbeDVU0v (ORCPT ); Sun, 22 Apr 2018 16:26:51 -0400 Received: from mail-pg0-f65.google.com ([74.125.83.65]:35661 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753586AbeDVU0t (ORCPT ); Sun, 22 Apr 2018 16:26:49 -0400 X-Google-Smtp-Source: AIpwx49I1g+BNW8K1UpE1m9FOnm78lYV8XvGXoYF32x/EzAl0WAi2f7V4Xk3P4CVdPixtkguBioxjg== From: Greg Thelen 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 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> X-Mailer: git-send-email 2.17.0.484.g0c8726318c-goog In-Reply-To: <20180422202612.127760-1-gthelen@google.com> References: <20180320223353.5673-1-guro@fb.com> <20180422202612.127760-1-gthelen@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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