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,URIBL_BLOCKED,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 225A2C433E2 for ; Tue, 1 Sep 2020 03:13:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DE37320719 for ; Tue, 1 Sep 2020 03:13:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DE37320719 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 530916B0003; Mon, 31 Aug 2020 23:13:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4E19F6B0037; Mon, 31 Aug 2020 23:13:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3F6986B0055; Mon, 31 Aug 2020 23:13:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0210.hostedemail.com [216.40.44.210]) by kanga.kvack.org (Postfix) with ESMTP id 25A846B0003 for ; Mon, 31 Aug 2020 23:13:36 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id D05C4181AEF15 for ; Tue, 1 Sep 2020 03:13:35 +0000 (UTC) X-FDA: 77213022390.24.drum61_06083a227095 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id A5B791A4A0 for ; Tue, 1 Sep 2020 03:13:35 +0000 (UTC) X-HE-Tag: drum61_06083a227095 X-Filterd-Recvd-Size: 3695 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf03.hostedemail.com (Postfix) with ESMTP for ; Tue, 1 Sep 2020 03:13:35 +0000 (UTC) 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 594C330E; Mon, 31 Aug 2020 20:13:34 -0700 (PDT) Received: from [192.168.0.130] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 820923F68F; Mon, 31 Aug 2020 20:13:29 -0700 (PDT) From: Anshuman Khandual Subject: Re: [PATCH v3 01/13] powerpc/mm: Add DEBUG_VM WARN for pmd_clear To: "Aneesh Kumar K.V" , linux-mm@kvack.org, akpm@linux-foundation.org Cc: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, linux-snps-arc@lists.infradead.org, x86@kernel.org, linux-arch@vger.kernel.org, Gerald Schaefer , Christophe Leroy , Vineet Gupta , Mike Rapoport , Qian Cai References: <20200827080438.315345-1-aneesh.kumar@linux.ibm.com> <20200827080438.315345-2-aneesh.kumar@linux.ibm.com> Message-ID: Date: Tue, 1 Sep 2020 08:42:56 +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: <20200827080438.315345-2-aneesh.kumar@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: A5B791A4A0 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 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: On 08/27/2020 01:34 PM, Aneesh Kumar K.V wrote: > With the hash page table, the kernel should not use pmd_clear for clearing > huge pte entries. Add a DEBUG_VM WARN to catch the wrong usage. > > Signed-off-by: Aneesh Kumar K.V > --- > arch/powerpc/include/asm/book3s/64/pgtable.h | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h > index 6de56c3b33c4..079211968987 100644 > --- a/arch/powerpc/include/asm/book3s/64/pgtable.h > +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h > @@ -868,6 +868,13 @@ static inline bool pte_ci(pte_t pte) > > static inline void pmd_clear(pmd_t *pmdp) > { > + if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) { > + /* > + * Don't use this if we can possibly have a hash page table > + * entry mapping this. > + */ > + WARN_ON((pmd_val(*pmdp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE)); > + } > *pmdp = __pmd(0); > } > > @@ -916,6 +923,13 @@ static inline int pmd_bad(pmd_t pmd) > > static inline void pud_clear(pud_t *pudp) > { > + if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) { > + /* > + * Don't use this if we can possibly have a hash page table > + * entry mapping this. > + */ > + WARN_ON((pud_val(*pudp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE)); > + } > *pudp = __pud(0); > } There are two checkpatch.pl warnings for this patch. WARNING: line length of 105 exceeds 100 columns #27: FILE: arch/powerpc/include/asm/book3s/64/pgtable.h:876: + WARN_ON((pmd_val(*pmdp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE)); WARNING: line length of 105 exceeds 100 columns #41: FILE: arch/powerpc/include/asm/book3s/64/pgtable.h:931: + WARN_ON((pud_val(*pudp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE)); total: 0 errors, 2 warnings, 26 lines checked