From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx123.postini.com [74.125.245.123]) by kanga.kvack.org (Postfix) with SMTP id 0E35F6B004D for ; Thu, 1 Nov 2012 20:05:41 -0400 (EDT) Date: Thu, 1 Nov 2012 17:05:39 -0700 From: Andrew Morton Subject: Re: [PATCH v6 11/29] memcg: allow a memcg with kmem charges to be destructed. Message-Id: <20121101170539.2e09dc8e.akpm@linux-foundation.org> In-Reply-To: <1351771665-11076-12-git-send-email-glommer@parallels.com> References: <1351771665-11076-1-git-send-email-glommer@parallels.com> <1351771665-11076-12-git-send-email-glommer@parallels.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Glauber Costa Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com, Johannes Weiner , Tejun Heo , Michal Hocko , Christoph Lameter , Pekka Enberg , David Rientjes , Pekka Enberg , Suleiman Souhlal On Thu, 1 Nov 2012 16:07:27 +0400 Glauber Costa wrote: > Because the ultimate goal of the kmem tracking in memcg is to track slab > pages as well, we can't guarantee that we'll always be able to point a > page to a particular process, and migrate the charges along with it - > since in the common case, a page will contain data belonging to multiple > processes. > > Because of that, when we destroy a memcg, we only make sure the > destruction will succeed by discounting the kmem charges from the user > charges when we try to empty the cgroup. There was a significant conflict with the sched/numa changes in linux-next, which I resolved as below. Please check it. static int mem_cgroup_reparent_charges(struct mem_cgroup *memcg) { struct cgroup *cgrp = memcg->css.cgroup; int node, zid; u64 usage; do { if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) return -EBUSY; /* This is for making all *used* pages to be on LRU. */ lru_add_drain_all(); drain_all_stock_sync(memcg); mem_cgroup_start_move(memcg); for_each_node_state(node, N_HIGH_MEMORY) { for (zid = 0; zid < MAX_NR_ZONES; zid++) { enum lru_list lru; for_each_lru(lru) { mem_cgroup_force_empty_list(memcg, node, zid, lru); } } } mem_cgroup_end_move(memcg); memcg_oom_recover(memcg); cond_resched(); /* * Kernel memory may not necessarily be trackable to a specific * process. So they are not migrated, and therefore we can't * expect their value to drop to 0 here. * Having res filled up with kmem only is enough. * * This is a safety check because mem_cgroup_force_empty_list * could have raced with mem_cgroup_replace_page_cache callers * so the lru seemed empty but the page could have been added * right after the check. RES_USAGE should be safe as we always * charge before adding to the LRU. */ usage = res_counter_read_u64(&memcg->res, RES_USAGE) - res_counter_read_u64(&memcg->kmem, RES_USAGE); } while (usage > 0); return 0; } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org