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=-13.6 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 3A965C433E2 for ; Tue, 1 Sep 2020 03:47:12 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E190C205F4 for ; Tue, 1 Sep 2020 03:47:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E190C205F4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4BgY0s4KG3zDqWN for ; Tue, 1 Sep 2020 13:47:09 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=anshuman.khandual@arm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=arm.com Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 4BgXyg6vk4zDq9G for ; Tue, 1 Sep 2020 13:45:15 +1000 (AEST) 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 00C2F30E; Mon, 31 Aug 2020 20:45:14 -0700 (PDT) Received: from [10.163.69.171] (unknown [10.163.69.171]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 806F83F68F; Mon, 31 Aug 2020 20:45:09 -0700 (PDT) From: Anshuman Khandual Subject: Re: [PATCH v3 10/13] mm/debug_vm_pgtable/locks: Take correct page table lock To: "Aneesh Kumar K.V" , linux-mm@kvack.org, akpm@linux-foundation.org References: <20200827080438.315345-1-aneesh.kumar@linux.ibm.com> <20200827080438.315345-11-aneesh.kumar@linux.ibm.com> Message-ID: <7da0de4c-8fc8-7e40-c9f7-a8f2d875e364@arm.com> Date: Tue, 1 Sep 2020 09:14:37 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20200827080438.315345-11-aneesh.kumar@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Christophe Leroy , x86@kernel.org, Mike Rapoport , Qian Cai , Gerald Schaefer , Vineet Gupta , linux-snps-arc@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 08/27/2020 01:34 PM, Aneesh Kumar K.V wrote: > Make sure we call pte accessors with correct lock held. > > Signed-off-by: Aneesh Kumar K.V > --- > mm/debug_vm_pgtable.c | 34 ++++++++++++++++++++-------------- > 1 file changed, 20 insertions(+), 14 deletions(-) > > diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c > index 78c8af3445ac..0a6e771ebd13 100644 > --- a/mm/debug_vm_pgtable.c > +++ b/mm/debug_vm_pgtable.c > @@ -1039,33 +1039,39 @@ static int __init debug_vm_pgtable(void) > pmd_thp_tests(pmd_aligned, prot); > pud_thp_tests(pud_aligned, prot); > > + hugetlb_basic_tests(pte_aligned, prot); > + This moved back again. As pointed out earlier, there will be a bisect problem and so this patch must be folded back with the previous one. > /* > * Page table modifying tests > */ > - pte_clear_tests(mm, ptep, vaddr); > - pmd_clear_tests(mm, pmdp); > - pud_clear_tests(mm, pudp); > - p4d_clear_tests(mm, p4dp); > - pgd_clear_tests(mm, pgdp); > > ptep = pte_alloc_map_lock(mm, pmdp, vaddr, &ptl); > + pte_clear_tests(mm, ptep, vaddr); > pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot); > - pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot, saved_ptep); > - pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot); > - hugetlb_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot); > - > + pte_unmap_unlock(ptep, ptl); > > + ptl = pmd_lock(mm, pmdp); > + pmd_clear_tests(mm, pmdp); > + pmd_advanced_tests(mm, vma, pmdp, pmd_aligned, vaddr, prot, saved_ptep); > pmd_huge_tests(pmdp, pmd_aligned, prot); > + pmd_populate_tests(mm, pmdp, saved_ptep); > + spin_unlock(ptl); > + > + ptl = pud_lock(mm, pudp); > + pud_clear_tests(mm, pudp); > + pud_advanced_tests(mm, vma, pudp, pud_aligned, vaddr, prot); > pud_huge_tests(pudp, pud_aligned, prot); > + pud_populate_tests(mm, pudp, saved_pmdp); > + spin_unlock(ptl); > > - pte_unmap_unlock(ptep, ptl); > + hugetlb_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot); > > - pmd_populate_tests(mm, pmdp, saved_ptep); > - pud_populate_tests(mm, pudp, saved_pmdp); > + spin_lock(&mm->page_table_lock); > + p4d_clear_tests(mm, p4dp); > + pgd_clear_tests(mm, pgdp); > p4d_populate_tests(mm, p4dp, saved_pudp); > pgd_populate_tests(mm, pgdp, saved_p4dp); > - > - hugetlb_basic_tests(pte_aligned, prot); > + spin_unlock(&mm->page_table_lock); > > p4d_free(mm, saved_p4dp); > pud_free(mm, saved_pudp); > Overall, grouping together dynamic tests at various page table levels and taking a corresponding lock, makes sense. Commit message for the resultant patch should include (a) Test classification (b) Grouping by function for the static tests, by page table level for the dynamic tests (c) Locking requirement for the dynamic tests each level etc.