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=-5.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 CD14EC4338F for ; Thu, 29 Jul 2021 07:13:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B5E6E61074 for ; Thu, 29 Jul 2021 07:13:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234575AbhG2HNk (ORCPT ); Thu, 29 Jul 2021 03:13:40 -0400 Received: from foss.arm.com ([217.140.110.172]:41662 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234079AbhG2HNj (ORCPT ); Thu, 29 Jul 2021 03:13:39 -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 4D8D96D; Thu, 29 Jul 2021 00:13:36 -0700 (PDT) Received: from [10.163.65.237] (unknown [10.163.65.237]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 92DF13F73D; Thu, 29 Jul 2021 00:13:32 -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 References: <20210727061401.592616-1-gshan@redhat.com> From: Anshuman Khandual Message-ID: <8b969a2a-a883-3ce2-fac4-70ac2e3fd157@arm.com> Date: Thu, 29 Jul 2021 12:44:20 +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: <20210727061401.592616-1-gshan@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.