From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753808Ab1KHV0O (ORCPT ); Tue, 8 Nov 2011 16:26:14 -0500 Received: from mx1.redhat.com ([209.132.183.28]:16189 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753109Ab1KHV0M (ORCPT ); Tue, 8 Nov 2011 16:26:12 -0500 From: Johannes Weiner To: Andrew Morton Cc: KAMEZAWA Hiroyuki , Michal Hocko , "Kirill A. Shutemov" , Daisuke Nishimura , Balbir Singh , Ying Han , Greg Thelen , Michel Lespinasse , Rik van Riel , Minchan Kim , Christoph Hellwig , Hugh Dickins , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [patch 06/10] mm: memcg: remove optimization of keeping the root_mem_cgroup LRU lists empty Date: Tue, 8 Nov 2011 22:23:24 +0100 Message-Id: <1320787408-22866-7-git-send-email-jweiner@redhat.com> In-Reply-To: <1320787408-22866-1-git-send-email-jweiner@redhat.com> References: <1320787408-22866-1-git-send-email-jweiner@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org root_mem_cgroup, lacking a configurable limit, was never subject to limit reclaim, so the pages charged to it could be kept off its LRU lists. They would be found on the global per-zone LRU lists upon physical memory pressure and it made sense to avoid uselessly linking them to both lists. The global per-zone LRU lists are about to go away on memcg-enabled kernels, with all pages being exclusively linked to their respective per-memcg LRU lists. As a result, pages of the root_mem_cgroup must also be linked to its LRU lists again. This is purely about the LRU list, root_mem_cgroup is still not charged. The overhead is temporary until the double-LRU scheme is going away completely. Signed-off-by: Johannes Weiner Reviewed-by: KAMEZAWA Hiroyuki Reviewed-by: Michal Hocko Reviewed-by: Kirill A. Shutemov --- mm/memcontrol.c | 12 ++---------- 1 files changed, 2 insertions(+), 10 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4305686..bf84e2b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -965,8 +965,6 @@ void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru) mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); /* huge page split is done under lru_lock. so, we have no races. */ MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page); - if (mem_cgroup_is_root(pc->mem_cgroup)) - return; VM_BUG_ON(list_empty(&pc->lru)); list_del_init(&pc->lru); } @@ -991,13 +989,11 @@ void mem_cgroup_rotate_reclaimable_page(struct page *page) return; pc = lookup_page_cgroup(page); - /* unused or root page is not rotated. */ + /* unused page is not rotated. */ if (!PageCgroupUsed(pc)) return; /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ smp_rmb(); - if (mem_cgroup_is_root(pc->mem_cgroup)) - return; mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); list_move_tail(&pc->lru, &mz->lists[lru]); } @@ -1011,13 +1007,11 @@ void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru) return; pc = lookup_page_cgroup(page); - /* unused or root page is not rotated. */ + /* unused page is not rotated. */ if (!PageCgroupUsed(pc)) return; /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ smp_rmb(); - if (mem_cgroup_is_root(pc->mem_cgroup)) - return; mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); list_move(&pc->lru, &mz->lists[lru]); } @@ -1049,8 +1043,6 @@ void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru) /* huge page split is done under lru_lock. so, we have no races. */ MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page); SetPageCgroupAcctLRU(pc); - if (mem_cgroup_is_root(pc->mem_cgroup)) - return; list_add(&pc->lru, &mz->lists[lru]); } -- 1.7.6.4