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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 012F1C35249 for ; Tue, 28 Jan 2020 06:13:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A74822468B for ; Tue, 28 Jan 2020 06:13:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="C70j0unK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A74822468B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6A4356B0006; Tue, 28 Jan 2020 01:13:11 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6565D6B0008; Tue, 28 Jan 2020 01:13:11 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 544BE6B000A; Tue, 28 Jan 2020 01:13:11 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0098.hostedemail.com [216.40.44.98]) by kanga.kvack.org (Postfix) with ESMTP id 3E25E6B0006 for ; Tue, 28 Jan 2020 01:13:11 -0500 (EST) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id B16198248D7C for ; Tue, 28 Jan 2020 06:13:10 +0000 (UTC) X-FDA: 76426025340.09.hole58_900de16b63259 X-HE-Tag: hole58_900de16b63259 X-Filterd-Recvd-Size: 7057 Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Tue, 28 Jan 2020 06:13:09 +0000 (UTC) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 486GWR2cqXz9v22Q; Tue, 28 Jan 2020 07:13:07 +0100 (CET) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=C70j0unK; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id tf9SBshBmIx8; Tue, 28 Jan 2020 07:13:07 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 486GWR19WTz9v22N; Tue, 28 Jan 2020 07:13:07 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1580191987; bh=pcrCnDSka2qoXBfBeA3afQal2h0amq4PFi2jmMQwdpk=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=C70j0unKrMF6yDixdWedTQC2P5T5/vAYpEmpZheamqM8tUIvuDuoyzTfclHpLcmBs zFelibkah4ATRqmpbd//5eGzB63dcgYhxVJrzK4IvtVG6rBysf1zACi5HU+mamJ97b k3ddSc1LOjJeLmYIAzLxKGYzTukejGmyrGraiJB8= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id DCAFB8B7C2; Tue, 28 Jan 2020 07:13:07 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id UqMMVHvL2Had; Tue, 28 Jan 2020 07:13:07 +0100 (CET) Received: from [192.168.4.90] (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 1FF9D8B75B; Tue, 28 Jan 2020 07:13:05 +0100 (CET) Subject: Re: [PATCH V12] mm/debug: Add tests validating architecture page table helpers To: Qian Cai , Anshuman Khandual Cc: Linux-MM , Andrew Morton , Vlastimil Babka , Greg Kroah-Hartman , Thomas Gleixner , Mike Rapoport , Jason Gunthorpe , Dan Williams , Peter Zijlstra , Michal Hocko , Mark Rutland , Mark Brown , Steven Price , Ard Biesheuvel , Masahiro Yamada , Kees Cook , Tetsuo Handa , Matthew Wilcox , Sri Krishna chowdary , Dave Hansen , Russell King - ARM Linux , Michael Ellerman , Paul Mackerras , Martin Schwidefsky , Heiko Carstens , "David S. Miller" , Vineet Gupta , James Hogan , Paul Burton , Ralf Baechle , "Kirill A . Shutemov" , Gerald Schaefer , Ingo Molnar , linux-snps-arc@lists.infradead.org, linux-mips@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org References: <1580174873-18117-1-git-send-email-anshuman.khandual@arm.com> <14882A91-17DE-4ABD-ABF2-08E7CCEDF660@lca.pw> <214c0d53-eb34-9b0c-2e4e-1aa005146331@arm.com> <016A776F-EFD9-4D2B-A3A9-788008617D95@lca.pw> From: Christophe Leroy Message-ID: Date: Tue, 28 Jan 2020 07:13:04 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: <016A776F-EFD9-4D2B-A3A9-788008617D95@lca.pw> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Le 28/01/2020 =C3=A0 04:33, Qian Cai a =C3=A9crit=C2=A0: >=20 >=20 >> On Jan 27, 2020, at 10:06 PM, Anshuman Khandual wrote: >> >> >> >> On 01/28/2020 07:41 AM, Qian Cai wrote: >>> >>> >>>> On Jan 27, 2020, at 8:28 PM, Anshuman Khandual wrote: >>>> >>>> This adds tests which will validate architecture page table helpers = and >>>> other accessors in their compliance with expected generic MM semanti= cs. >>>> This will help various architectures in validating changes to existi= ng >>>> page table helpers or addition of new ones. >>>> >>>> This test covers basic page table entry transformations including bu= t not >>>> limited to old, young, dirty, clean, write, write protect etc at var= ious >>>> level along with populating intermediate entries with next page tabl= e page >>>> and validating them. >>>> >>>> Test page table pages are allocated from system memory with required= size >>>> and alignments. The mapped pfns at page table levels are derived fro= m a >>>> real pfn representing a valid kernel text symbol. This test gets cal= led >>>> right after page_alloc_init_late(). >>>> >>>> This gets build and run when CONFIG_DEBUG_VM_PGTABLE is selected alo= ng with >>>> CONFIG_VM_DEBUG. Architectures willing to subscribe this test also n= eed to >>>> select CONFIG_ARCH_HAS_DEBUG_VM_PGTABLE which for now is limited to = x86 and >>>> arm64. Going forward, other architectures too can enable this after = fixing >>>> build or runtime problems (if any) with their page table helpers. >> >> Hello Qian, >> >>> >>> What=E2=80=99s the value of this block of new code? It only supports = x86 and arm64 >>> which are supposed to be good now. >> >> We have been over the usefulness of this code many times before as the= patch is >> already in it's V12. Currently it is enabled on arm64, x86 (except PAE= ), arc and >> ppc32. There are build time or runtime problems with other archs which= prevent >=20 > I am not sure if I care too much about arc and ppc32 which are pretty m= uch legacy > platforms. >=20 >> enablement of this test (for the moment) but then the goal is to integ= rate all >> of them going forward. The test not only validates platform's adherenc= e to the >> expected semantics from generic MM but also helps in keeping it that w= ay during >> code changes in future as well. >=20 > Another option maybe to get some decent arches on board first before me= rging this > thing, so it have more changes to catch regressions for developers who = might run this. >=20 ppc32 an indecent / legacy platform ? Are you kidying ? Powerquicc II PRO for instance is fully supported by the manufacturer=20 and widely used in many small networking devices. Christophe