From patchwork Fri Jun 23 07:13:00 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Ying" X-Patchwork-Id: 9805829 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id CE3F7600C5 for ; Fri, 23 Jun 2017 07:15:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BF1172872A for ; Fri, 23 Jun 2017 07:15:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B3D5C2872E; Fri, 23 Jun 2017 07:15:03 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 7763C2872A for ; Fri, 23 Jun 2017 07:15:03 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id BBFD421A00ACF; Fri, 23 Jun 2017 00:13:31 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id F17B121BBC43C for ; Fri, 23 Jun 2017 00:13:28 -0700 (PDT) Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga105.fm.intel.com with ESMTP; 23 Jun 2017 00:14:54 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.39,376,1493708400"; d="scan'208";a="116565886" Received: from yhuang-dev.sh.intel.com ([10.239.13.13]) by orsmga005.jf.intel.com with ESMTP; 23 Jun 2017 00:14:25 -0700 From: "Huang, Ying" To: Andrew Morton Subject: [PATCH -mm -v2 09/12] memcg, THP, swap: Avoid to duplicated charge THP in swap cache Date: Fri, 23 Jun 2017 15:13:00 +0800 Message-Id: <20170623071303.13469-10-ying.huang@intel.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170623071303.13469-1-ying.huang@intel.com> References: <20170623071303.13469-1-ying.huang@intel.com> X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrea Arcangeli , linux-nvdimm@lists.01.org, Huang Ying , linux-kernel@vger.kernel.org, Michal Hocko , linux-mm@kvack.org, Johannes Weiner , Minchan Kim , "Kirill A . Shutemov" MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP From: Huang Ying For a THP (Transparent Huge Page), tail_page->mem_cgroup is NULL. So to check whether the page is charged already, we need to check the head page. This is not an issue before because it is impossible for a THP to be in the swap cache before. But after we add delaying splitting THP after swapped out support, it is possible now. Signed-off-by: "Huang, Ying" Cc: Johannes Weiner Cc: Minchan Kim Cc: Michal Hocko Cc: Andrea Arcangeli Cc: "Kirill A . Shutemov" --- mm/memcontrol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 99e96ae59cd3..123564bcdd77 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5407,7 +5407,7 @@ int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, * in turn serializes uncharging. */ VM_BUG_ON_PAGE(!PageLocked(page), page); - if (page->mem_cgroup) + if (compound_head(page)->mem_cgroup) goto out; if (do_swap_account) {