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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 6FFAFC43381 for ; Thu, 14 Mar 2019 09:50:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 449D92070D for ; Thu, 14 Mar 2019 09:50:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726898AbfCNJuW (ORCPT ); Thu, 14 Mar 2019 05:50:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48116 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726629AbfCNJuW (ORCPT ); Thu, 14 Mar 2019 05:50:22 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4649F30832CB; Thu, 14 Mar 2019 09:50:22 +0000 (UTC) Received: from localhost (ovpn-12-22.pek2.redhat.com [10.72.12.22]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A5A2917CEB; Thu, 14 Mar 2019 09:50:21 +0000 (UTC) Date: Thu, 14 Mar 2019 17:50:19 +0800 From: Baoquan He To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, keescook@chromium.org, kirill@shutemov.name, yamada.masahiro@socionext.com, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, x86@kernel.org, thgarnie@google.com Subject: Re: [PATCH v4 3/6] mm: Add build time sanity check for struct page size Message-ID: <20190314095019.GA12200@MiWiFi-R3L-srv> References: <20190314094645.4883-1-bhe@redhat.com> <20190314094645.4883-4-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190314094645.4883-4-bhe@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Thu, 14 Mar 2019 09:50:22 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/14/19 at 05:46pm, Baoquan He wrote: > Size of struct page might be larger than 64 bytes if debug options > enabled, or fields added for debugging intentionally. Yet an upper > limit need be added at build time to trigger an alert in case the > size is too big to boot up system, warning people to check if it's > be done on purpose in advance. > > Here 1/4 of PAGE_SIZE is chosen since system must have been insane > with this value. For those systems with PAGE_SIZE larger than 4KB, > 1KB is simply taken. > > Signed-off-by: Baoquan He > Kirill A. Shutemov Sorry, I forgot adding 'Acked-by' tag here. > --- > mm/page_alloc.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 3eb01dedfb50..eddf96c137f2 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -67,6 +67,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -7170,6 +7171,7 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn) > unsigned long start_pfn, end_pfn; > int i, nid; > > + BUILD_BUG_ON(sizeof(struct page) > min_t(size_t, SZ_1K, PAGE_SIZE/4)); > /* Record where the zone boundaries are */ > memset(arch_zone_lowest_possible_pfn, 0, > sizeof(arch_zone_lowest_possible_pfn)); > -- > 2.17.2 >