From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78F19C04EB8 for ; Tue, 4 Dec 2018 22:44:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3A93D206B6 for ; Tue, 4 Dec 2018 22:44:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="5fxPzjdQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3A93D206B6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726519AbeLDWoE (ORCPT ); Tue, 4 Dec 2018 17:44:04 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:55356 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726031AbeLDWoC (ORCPT ); Tue, 4 Dec 2018 17:44:02 -0500 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id wB4Md6Sb150470; Tue, 4 Dec 2018 22:42:47 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id; s=corp-2018-07-02; bh=X9/RoA88m1xINqvMc/YZ1hMWuRFEDathW8WcQhLsLO4=; b=5fxPzjdQlcl0pkfzHqubR4iRBbvALOrjnohTQfkOnQhS+dXdaD0pMfLw3O4AYgqaFDm6 WmUZWC6JDjrMJ3IAgZhvobnRzV3M1jCYlTSUHURME43dex/q2c+bfsbWUh5YKNsvv+hE RPm8Zv7BXC3RU5wTHwbJbMwAfvtWuIHyqdev1PO0hzC1cOiFHAA01mgntl6DPIXdaqtU rv82VDEaxLibIEs88t6a7gAMoFVuf5tJEXKGqllAF3dVWVrO7+chHxEcHVJYPPnhfnVv edjQnKFD+s06OJTWeIvZsFoVRDAGiJCrzkFWOq9xthjWuZJBP63riBEuTAWlouXewkV0 0Q== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2120.oracle.com with ESMTP id 2p3jxrf6un-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 04 Dec 2018 22:42:46 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id wB4Mgial008623 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 4 Dec 2018 22:42:45 GMT Received: from abhmp0004.oracle.com (abhmp0004.oracle.com [141.146.116.10]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id wB4MggCR023869; Tue, 4 Dec 2018 22:42:42 GMT Received: from ayz-linux.us.oracle.com (/10.39.194.56) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 04 Dec 2018 22:42:41 +0000 From: Anthony Yznaga To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: adobriyan@gmail.com, akpm@linux-foundation.org, vbabka@suse.cz, sfr@canb.auug.org.au, willy@infradead.org, kirill.shutemov@linux.intel.com, rppt@linux.vnet.ibm.com, mhocko@suse.com, alexander.h.duyck@linux.intel.com, hannes@cmpxchg.org, miles.chen@mediatek.com, n-horiguchi@ah.jp.nec.com Subject: [PATCH] /proc/kpagecount: return 0 for special pages that are never mapped Date: Tue, 4 Dec 2018 14:45:26 -0800 Message-Id: <1543963526-27917-1-git-send-email-anthony.yznaga@oracle.com> X-Mailer: git-send-email 1.8.3.1 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9097 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=890 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1812040194 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Certain pages that are never mapped to userspace have a type indicated in the page_type field of their struct pages (e.g. PG_buddy). page_type overlaps with _mapcount so set the count to 0 and avoid calling page_mapcount() for these pages. Signed-off-by: Anthony Yznaga --- fs/proc/page.c | 2 +- include/linux/page-flags.h | 7 +++++++ 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/proc/page.c b/fs/proc/page.c index 6c517b11acf8..40b05e0d4274 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -46,7 +46,7 @@ static ssize_t kpagecount_read(struct file *file, char __user *buf, ppage = pfn_to_page(pfn); else ppage = NULL; - if (!ppage || PageSlab(ppage)) + if (!ppage || PageSlab(ppage) || page_has_type(ppage)) pcount = 0; else pcount = page_mapcount(ppage); diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 50ce1bddaf56..f9a1c50ccefc 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -673,10 +673,17 @@ static inline int TestClearPageDoubleMap(struct page *page) #define PG_balloon 0x00000100 #define PG_kmemcg 0x00000200 #define PG_table 0x00000400 +#define PAGE_TYPE_ALL (PG_buddy | PG_balloon | PG_kmemcg | PG_table) #define PageType(page, flag) \ ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE) +static inline int page_has_type(struct page *page) +{ + return (PageType(page, 0) && + ((page->page_type & PAGE_TYPE_ALL) != PAGE_TYPE_ALL)); +} + #define PAGE_TYPE_OPS(uname, lname) \ static __always_inline int Page##uname(struct page *page) \ { \ -- 1.8.3.1