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,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 D9839C4338F for ; Tue, 3 Aug 2021 06:49:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B24CB60F35 for ; Tue, 3 Aug 2021 06:49:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233982AbhHCGtt (ORCPT ); Tue, 3 Aug 2021 02:49:49 -0400 Received: from foss.arm.com ([217.140.110.172]:43746 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231386AbhHCGtr (ORCPT ); Tue, 3 Aug 2021 02:49:47 -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 0A939D6E; Mon, 2 Aug 2021 23:49:37 -0700 (PDT) Received: from [10.163.67.68] (unknown [10.163.67.68]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 866F03F70D; Mon, 2 Aug 2021 23:49:33 -0700 (PDT) Subject: Re: [PATCH v5 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, vgupta@synopsys.com, akpm@linux-foundation.org, chuhu@redhat.com, shan.gavin@gmail.com References: <20210802060419.1360913-1-gshan@redhat.com> From: Anshuman Khandual Message-ID: Date: Tue, 3 Aug 2021 12:20:24 +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: <20210802060419.1360913-1-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 8/2/21 11:34 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 accessing 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 > ========= > v5: > * Pick r-bs from Anshuman and rebase to 5.14.rc4 (Gavin) > * Use args->start_p4dp to free p4d entries (Anshuman) > * Introduce helper to allocate huge page in init_arg() (Anshuman) > * Bail early if the allocated page doesn't exist in > swap_migration_tests() and correct the comments (Anshuman) > * Add fixes tag to PATCH[v4 12/12] (Christophe) > * Address misc comments (Anshuman) Apart from the proposed changes discussed for the first patch [PATCH 1/12], this series overall looks good now. It clears build tests on all supported platforms. I was able to test this on arm64 and x86 platforms with various functional config combinations. It would be still great if others can take a look as well. - Anshuman