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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 32AF6C4338F for ; Mon, 2 Aug 2021 04:52:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A6B16018A for ; Mon, 2 Aug 2021 04:52:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229718AbhHBEwu (ORCPT ); Mon, 2 Aug 2021 00:52:50 -0400 Received: from foss.arm.com ([217.140.110.172]:58620 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229457AbhHBEwt (ORCPT ); Mon, 2 Aug 2021 00:52:49 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5DED9106F; Sun, 1 Aug 2021 21:52:40 -0700 (PDT) Received: from [10.163.66.153] (unknown [10.163.66.153]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C9B563F719; Sun, 1 Aug 2021 21:52:36 -0700 (PDT) Subject: Re: [PATCH v4 00/12] mm/debug_vm_pgtable: Enhancements To: Gavin Shan , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, gerald.schaefer@linux.ibm.com, aneesh.kumar@linux.ibm.com, christophe.leroy@csgroup.eu, cai@lca.pw, catalin.marinas@arm.com, will@kernel.org, akpm@linux-foundation.org, chuhu@redhat.com, shan.gavin@gmail.com, Vineet Gupta References: <20210727061401.592616-1-gshan@redhat.com> <8b969a2a-a883-3ce2-fac4-70ac2e3fd157@arm.com> <05736d94-3bd1-3193-69b1-3c71aa22d0a7@redhat.com> From: Anshuman Khandual Message-ID: <5ef150b0-60dc-3cf6-da6e-34fe0734ee2e@arm.com> Date: Mon, 2 Aug 2021 10:23:27 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <05736d94-3bd1-3193-69b1-3c71aa22d0a7@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/2/21 5:39 AM, Gavin Shan wrote: > Hi Anshuman, > > On 7/29/21 5:14 PM, Anshuman Khandual wrote: >> On 7/27/21 11:43 AM, Gavin Shan wrote: >>> There are couple of issues with current implementations and this series >>> tries to resolve the issues: >>> >>>    (a) All needed information are scattered in variables, passed to various >>>        test functions. The code is organized in pretty much relaxed fashion. >>> >>>    (b) The page isn't allocated from buddy during page table entry modifying >>>        tests. The page can be invalid, conflicting to the implementations >>>        of set_xxx_at() on ARM64. The target page is accessed so that the iCache >>>        can be flushed when execution permission is given on ARM64. Besides, >>>        the target page can be unmapped and access to it causes kernel crash. >>> >>> "struct pgtable_debug_args" is introduced to address issue (a). For issue >>> (b), the used page is allocated from buddy in page table entry modifying >>> tests. The corresponding tets will be skipped if we fail to allocate the >>> (huge) page. For other test cases, the original page around to kernel >>> symbol (@start_kernel) is still used. >>> >>> The patches are organized as below. PATCH[2-10] could be combined to one >>> patch, but it will make the review harder: >>> >>>    PATCH[1] introduces "struct pgtable_debug_args" as place holder of all >>>             needed information. With it, the old and new implementation >>>             can coexist. >>>    PATCH[2-10] uses "struct pgtable_debug_args" in various test functions. >>>    PATCH[11] removes the unused code for old implementation. >>>    PATCH[12] fixes the issue of corrupted page flag for ARM64 >>> >>> Changelog >>> ========= >>> v4: >>>     * Determine the page allocation method according to >>>       MAX_ORDER                                                   (Anshuman) >>>     * Move existing comments to init_args()                       (Anshuman) >>>     * Code refactoring as suggested by Anshuman                   (Anshuman) >>>     * Improved commit log and add comments for flush_dcache_page() >>>       in PATCH[v4 12/12]                                          (Anshuman) >>>     * Address misc comments                                       (Anshuman >> >> This series builds ok on all supported platforms but should also be tested >> on them as well i.e s390, ppc, arc and riscv. I was able to do some tests >> on arm64 and x86 platforms. >> > > I had tests on the platforms except arc as it's not supported by QEMU yet. > The test is pretty simple to boot the kernel and see if there is any warning > raised from mm/debug_vm_pgtable. Everything looks good. Sure, that should be enough. > > The test was done on v5, which will be posted pretty soon. Thanks again for > your continuous review. Please also do copy Vineet Gupta for ARC in the next version. - Anshuman