From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id 80B8C6B026F for ; Mon, 12 Sep 2011 06:58:21 -0400 (EDT) From: Johannes Weiner Subject: [patch 06/11] mm: memcg: remove optimization of keeping the root_mem_cgroup LRU lists empty Date: Mon, 12 Sep 2011 12:57:23 +0200 Message-Id: <1315825048-3437-7-git-send-email-jweiner@redhat.com> In-Reply-To: <1315825048-3437-1-git-send-email-jweiner@redhat.com> References: <1315825048-3437-1-git-send-email-jweiner@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: KAMEZAWA Hiroyuki , Daisuke Nishimura , Balbir Singh , Ying Han , Michal Hocko , Greg Thelen , Michel Lespinasse , Rik van Riel , Minchan Kim , Christoph Hellwig , linux-mm@kvack.org, 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. The overhead is temporary until the double-LRU scheme is going away completely. Signed-off-by: Johannes Weiner --- mm/memcontrol.c | 12 ++---------- 1 files changed, 2 insertions(+), 10 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 413e1f8..518f640 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -956,8 +956,6 @@ 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); } @@ -982,13 +980,11 @@ 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]); } @@ -1002,13 +998,11 @@ 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]); } @@ -1040,8 +1034,6 @@ 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 -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org