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=-4.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 E704AC433E2 for ; Mon, 7 Sep 2020 20:13:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD03721582 for ; Mon, 7 Sep 2020 20:13:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599509598; bh=Txq0SHMAQgqfdmcGMkwaxwK8bh+LCMYp/KURZ2semt0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=rXuH6+Xv6DzNoAUVUyJDvXJRm5fI8xRISqIjTuddXEnGFyQ+B/beYPC833lFDoDQh VG68e8Z/YT7dd260t0fqGiJUt0YaqP+jlljyN3rWHzHhaaXH+olq1LkT2AfOBgA1Sc rDjo9wxUaYH5ex0ClUTM1YTV4mxxDerlALHLz3Dw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729353AbgIGUNR (ORCPT ); Mon, 7 Sep 2020 16:13:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:37976 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728834AbgIGUNP (ORCPT ); Mon, 7 Sep 2020 16:13:15 -0400 Received: from kernel.org (unknown [87.71.73.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 30E5C21556; Mon, 7 Sep 2020 20:13:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599509594; bh=Txq0SHMAQgqfdmcGMkwaxwK8bh+LCMYp/KURZ2semt0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nLpipW8sQvLhlZFZtsFQwKo1Znbs/0KAcD4LFEfe7h7JTvYMqqR6v+seDpO4Yd/cu RrfBDF0lYv41owv1h519SaLJN7kE80eKoMCgi8/Hj0LT+ao5fgTb95OgH+il6wLukz qp6QPtSS/AB4nQIMNuSph4bC4G+E+gDc26AyDbdg= Date: Mon, 7 Sep 2020 23:12:56 +0300 From: Mike Rapoport To: Gerald Schaefer Cc: Jason Gunthorpe , John Hubbard , LKML , linux-mm , linux-arch , Andrew Morton , Linus Torvalds , Russell King , Catalin Marinas , Will Deacon , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Jeff Dike , Richard Weinberger , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Arnd Bergmann , Andrey Ryabinin , linux-x86 , linux-arm , linux-power , linux-sparc , linux-um , linux-s390 , Alexander Gordeev , Vasily Gorbik , Heiko Carstens , Christian Borntraeger , Claudio Imbrenda Subject: Re: [RFC PATCH v2 0/3] mm/gup: fix gup_fast with dynamic page table folding Message-ID: <20200907201256.GC1976319@kernel.org> References: <20200907180058.64880-1-gerald.schaefer@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200907180058.64880-1-gerald.schaefer@linux.ibm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 07, 2020 at 08:00:55PM +0200, Gerald Schaefer wrote: > This is v2 of an RFC previously discussed here: > https://lore.kernel.org/lkml/20200828140314.8556-1-gerald.schaefer@linux.ibm.com/ > > Patch 1 is a fix for a regression in gup_fast on s390, after our conversion > to common gup_fast code. It will introduce special helper functions > pXd_addr_end_folded(), which have to be used in places where pagetable walk > is done w/o lock and with READ_ONCE, so currently only in gup_fast. > > Patch 2 is an attempt to make that more generic, i.e. change pXd_addr_end() > themselves by adding an extra pXd value parameter. That was suggested by > Jason during v1 discussion, because he is already thinking of some other > places where he might want to switch to the READ_ONCE logic for pagetable > walks. In general, that would be the cleanest / safest solution, but there > is some impact on other architectures and common code, hence the new and > greatly enlarged recipient list. > > Patch 3 is a "nice to have" add-on, which makes pXd_addr_end() inline > functions instead of #defines, so that we get some type checking for the > new pXd value parameter. > > Not sure about Fixes/stable tags for the generic solution. Only patch 1 > fixes a real bug on s390, and has Fixes/stable tags. Patches 2 + 3 might > still be nice to have in stable, to ease future backports, but I guess > "nice to have" does not really qualify for stable backports. I also think that adding pXd parameter to pXd_addr_end() is a cleaner way and with this patch 1 is not really required. I would even merge patches 2 and 3 into a single patch and use only it as the fix. [ /me apologises to stable@ team :-) ] > Changes in v2: > - Pick option 2 from v1 discussion (pXd_addr_end_folded helpers) > - Add patch 2 + 3 for more generic approach > > Alexander Gordeev (3): > mm/gup: fix gup_fast with dynamic page table folding > mm: make pXd_addr_end() functions page-table entry aware > mm: make generic pXd_addr_end() macros inline functions > > arch/arm/include/asm/pgtable-2level.h | 2 +- > arch/arm/mm/idmap.c | 6 ++-- > arch/arm/mm/mmu.c | 8 ++--- > arch/arm64/kernel/hibernate.c | 16 +++++---- > arch/arm64/kvm/mmu.c | 16 ++++----- > arch/arm64/mm/kasan_init.c | 8 ++--- > arch/arm64/mm/mmu.c | 25 +++++++------- > arch/powerpc/mm/book3s64/radix_pgtable.c | 7 ++-- > arch/powerpc/mm/hugetlbpage.c | 6 ++-- > arch/s390/include/asm/pgtable.h | 42 ++++++++++++++++++++++++ > arch/s390/mm/page-states.c | 8 ++--- > arch/s390/mm/pageattr.c | 8 ++--- > arch/s390/mm/vmem.c | 8 ++--- > arch/sparc/mm/hugetlbpage.c | 6 ++-- > arch/um/kernel/tlb.c | 8 ++--- > arch/x86/mm/init_64.c | 15 ++++----- > arch/x86/mm/kasan_init_64.c | 16 ++++----- > include/asm-generic/pgtable-nop4d.h | 2 +- > include/asm-generic/pgtable-nopmd.h | 2 +- > include/asm-generic/pgtable-nopud.h | 2 +- > include/linux/pgtable.h | 38 ++++++++++++--------- > mm/gup.c | 8 ++--- > mm/ioremap.c | 8 ++--- > mm/kasan/init.c | 17 +++++----- > mm/madvise.c | 4 +-- > mm/memory.c | 40 +++++++++++----------- > mm/mlock.c | 18 +++++++--- > mm/mprotect.c | 8 ++--- > mm/pagewalk.c | 8 ++--- > mm/swapfile.c | 8 ++--- > mm/vmalloc.c | 16 ++++----- > 31 files changed, 219 insertions(+), 165 deletions(-) > > -- > 2.17.1 > -- Sincerely yours, Mike. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Rapoport Date: Mon, 07 Sep 2020 20:12:56 +0000 Subject: Re: [RFC PATCH v2 0/3] mm/gup: fix gup_fast with dynamic page table folding Message-Id: <20200907201256.GC1976319@kernel.org> List-Id: References: <20200907180058.64880-1-gerald.schaefer@linux.ibm.com> In-Reply-To: <20200907180058.64880-1-gerald.schaefer@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Gerald Schaefer Cc: Jason Gunthorpe , John Hubbard , LKML , linux-mm , linux-arch , Andrew Morton , Linus Torvalds , Russell King , Catalin Marinas , Will Deacon , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Jeff Dike , Richard Weinberger , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Arnd Bergmann , Andrey Ryabinin , linux-x86 , linux-arm , linux-power , linux-sparc , linux-um , linux-s390 , Alexander Gordeev , Vasily Gorbik , Heiko Carstens , Christian Borntraeger , Claudio Imbrenda On Mon, Sep 07, 2020 at 08:00:55PM +0200, Gerald Schaefer wrote: > This is v2 of an RFC previously discussed here: > https://lore.kernel.org/lkml/20200828140314.8556-1-gerald.schaefer@linux.ibm.com/ > > Patch 1 is a fix for a regression in gup_fast on s390, after our conversion > to common gup_fast code. It will introduce special helper functions > pXd_addr_end_folded(), which have to be used in places where pagetable walk > is done w/o lock and with READ_ONCE, so currently only in gup_fast. > > Patch 2 is an attempt to make that more generic, i.e. change pXd_addr_end() > themselves by adding an extra pXd value parameter. That was suggested by > Jason during v1 discussion, because he is already thinking of some other > places where he might want to switch to the READ_ONCE logic for pagetable > walks. In general, that would be the cleanest / safest solution, but there > is some impact on other architectures and common code, hence the new and > greatly enlarged recipient list. > > Patch 3 is a "nice to have" add-on, which makes pXd_addr_end() inline > functions instead of #defines, so that we get some type checking for the > new pXd value parameter. > > Not sure about Fixes/stable tags for the generic solution. Only patch 1 > fixes a real bug on s390, and has Fixes/stable tags. Patches 2 + 3 might > still be nice to have in stable, to ease future backports, but I guess > "nice to have" does not really qualify for stable backports. I also think that adding pXd parameter to pXd_addr_end() is a cleaner way and with this patch 1 is not really required. I would even merge patches 2 and 3 into a single patch and use only it as the fix. [ /me apologises to stable@ team :-) ] > Changes in v2: > - Pick option 2 from v1 discussion (pXd_addr_end_folded helpers) > - Add patch 2 + 3 for more generic approach > > Alexander Gordeev (3): > mm/gup: fix gup_fast with dynamic page table folding > mm: make pXd_addr_end() functions page-table entry aware > mm: make generic pXd_addr_end() macros inline functions > > arch/arm/include/asm/pgtable-2level.h | 2 +- > arch/arm/mm/idmap.c | 6 ++-- > arch/arm/mm/mmu.c | 8 ++--- > arch/arm64/kernel/hibernate.c | 16 +++++---- > arch/arm64/kvm/mmu.c | 16 ++++----- > arch/arm64/mm/kasan_init.c | 8 ++--- > arch/arm64/mm/mmu.c | 25 +++++++------- > arch/powerpc/mm/book3s64/radix_pgtable.c | 7 ++-- > arch/powerpc/mm/hugetlbpage.c | 6 ++-- > arch/s390/include/asm/pgtable.h | 42 ++++++++++++++++++++++++ > arch/s390/mm/page-states.c | 8 ++--- > arch/s390/mm/pageattr.c | 8 ++--- > arch/s390/mm/vmem.c | 8 ++--- > arch/sparc/mm/hugetlbpage.c | 6 ++-- > arch/um/kernel/tlb.c | 8 ++--- > arch/x86/mm/init_64.c | 15 ++++----- > arch/x86/mm/kasan_init_64.c | 16 ++++----- > include/asm-generic/pgtable-nop4d.h | 2 +- > include/asm-generic/pgtable-nopmd.h | 2 +- > include/asm-generic/pgtable-nopud.h | 2 +- > include/linux/pgtable.h | 38 ++++++++++++--------- > mm/gup.c | 8 ++--- > mm/ioremap.c | 8 ++--- > mm/kasan/init.c | 17 +++++----- > mm/madvise.c | 4 +-- > mm/memory.c | 40 +++++++++++----------- > mm/mlock.c | 18 +++++++--- > mm/mprotect.c | 8 ++--- > mm/pagewalk.c | 8 ++--- > mm/swapfile.c | 8 ++--- > mm/vmalloc.c | 16 ++++----- > 31 files changed, 219 insertions(+), 165 deletions(-) > > -- > 2.17.1 > -- Sincerely yours, Mike. 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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 BEFF7C43461 for ; Mon, 7 Sep 2020 20:14:57 +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 8217F21556 for ; Mon, 7 Sep 2020 20:14:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="nLpipW8s" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8217F21556 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 4Blfdn1ws7zDqQG for ; Tue, 8 Sep 2020 06:14:53 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=rppt@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=default header.b=nLpipW8s; dkim-atps=neutral Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Blfby3DWtzDqN3 for ; Tue, 8 Sep 2020 06:13:17 +1000 (AEST) Received: from kernel.org (unknown [87.71.73.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 30E5C21556; Mon, 7 Sep 2020 20:13:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599509594; bh=Txq0SHMAQgqfdmcGMkwaxwK8bh+LCMYp/KURZ2semt0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nLpipW8sQvLhlZFZtsFQwKo1Znbs/0KAcD4LFEfe7h7JTvYMqqR6v+seDpO4Yd/cu RrfBDF0lYv41owv1h519SaLJN7kE80eKoMCgi8/Hj0LT+ao5fgTb95OgH+il6wLukz qp6QPtSS/AB4nQIMNuSph4bC4G+E+gDc26AyDbdg= Date: Mon, 7 Sep 2020 23:12:56 +0300 From: Mike Rapoport To: Gerald Schaefer Subject: Re: [RFC PATCH v2 0/3] mm/gup: fix gup_fast with dynamic page table folding Message-ID: <20200907201256.GC1976319@kernel.org> References: <20200907180058.64880-1-gerald.schaefer@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200907180058.64880-1-gerald.schaefer@linux.ibm.com> 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: Peter Zijlstra , Dave Hansen , linux-mm , Paul Mackerras , linux-sparc , Alexander Gordeev , Claudio Imbrenda , Will Deacon , linux-arch , linux-s390 , Vasily Gorbik , Christian Borntraeger , Richard Weinberger , linux-x86 , Russell King , Jason Gunthorpe , Ingo Molnar , Catalin Marinas , Andrey Ryabinin , Heiko Carstens , Arnd Bergmann , John Hubbard , Jeff Dike , linux-um , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm , linux-power , LKML , Andrew Morton , Linus Torvalds Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, Sep 07, 2020 at 08:00:55PM +0200, Gerald Schaefer wrote: > This is v2 of an RFC previously discussed here: > https://lore.kernel.org/lkml/20200828140314.8556-1-gerald.schaefer@linux.ibm.com/ > > Patch 1 is a fix for a regression in gup_fast on s390, after our conversion > to common gup_fast code. It will introduce special helper functions > pXd_addr_end_folded(), which have to be used in places where pagetable walk > is done w/o lock and with READ_ONCE, so currently only in gup_fast. > > Patch 2 is an attempt to make that more generic, i.e. change pXd_addr_end() > themselves by adding an extra pXd value parameter. That was suggested by > Jason during v1 discussion, because he is already thinking of some other > places where he might want to switch to the READ_ONCE logic for pagetable > walks. In general, that would be the cleanest / safest solution, but there > is some impact on other architectures and common code, hence the new and > greatly enlarged recipient list. > > Patch 3 is a "nice to have" add-on, which makes pXd_addr_end() inline > functions instead of #defines, so that we get some type checking for the > new pXd value parameter. > > Not sure about Fixes/stable tags for the generic solution. Only patch 1 > fixes a real bug on s390, and has Fixes/stable tags. Patches 2 + 3 might > still be nice to have in stable, to ease future backports, but I guess > "nice to have" does not really qualify for stable backports. I also think that adding pXd parameter to pXd_addr_end() is a cleaner way and with this patch 1 is not really required. I would even merge patches 2 and 3 into a single patch and use only it as the fix. [ /me apologises to stable@ team :-) ] > Changes in v2: > - Pick option 2 from v1 discussion (pXd_addr_end_folded helpers) > - Add patch 2 + 3 for more generic approach > > Alexander Gordeev (3): > mm/gup: fix gup_fast with dynamic page table folding > mm: make pXd_addr_end() functions page-table entry aware > mm: make generic pXd_addr_end() macros inline functions > > arch/arm/include/asm/pgtable-2level.h | 2 +- > arch/arm/mm/idmap.c | 6 ++-- > arch/arm/mm/mmu.c | 8 ++--- > arch/arm64/kernel/hibernate.c | 16 +++++---- > arch/arm64/kvm/mmu.c | 16 ++++----- > arch/arm64/mm/kasan_init.c | 8 ++--- > arch/arm64/mm/mmu.c | 25 +++++++------- > arch/powerpc/mm/book3s64/radix_pgtable.c | 7 ++-- > arch/powerpc/mm/hugetlbpage.c | 6 ++-- > arch/s390/include/asm/pgtable.h | 42 ++++++++++++++++++++++++ > arch/s390/mm/page-states.c | 8 ++--- > arch/s390/mm/pageattr.c | 8 ++--- > arch/s390/mm/vmem.c | 8 ++--- > arch/sparc/mm/hugetlbpage.c | 6 ++-- > arch/um/kernel/tlb.c | 8 ++--- > arch/x86/mm/init_64.c | 15 ++++----- > arch/x86/mm/kasan_init_64.c | 16 ++++----- > include/asm-generic/pgtable-nop4d.h | 2 +- > include/asm-generic/pgtable-nopmd.h | 2 +- > include/asm-generic/pgtable-nopud.h | 2 +- > include/linux/pgtable.h | 38 ++++++++++++--------- > mm/gup.c | 8 ++--- > mm/ioremap.c | 8 ++--- > mm/kasan/init.c | 17 +++++----- > mm/madvise.c | 4 +-- > mm/memory.c | 40 +++++++++++----------- > mm/mlock.c | 18 +++++++--- > mm/mprotect.c | 8 ++--- > mm/pagewalk.c | 8 ++--- > mm/swapfile.c | 8 ++--- > mm/vmalloc.c | 16 ++++----- > 31 files changed, 219 insertions(+), 165 deletions(-) > > -- > 2.17.1 > -- Sincerely yours, Mike. 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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 CAB9CC43461 for ; Mon, 7 Sep 2020 20:15:01 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 6DDCC21556 for ; Mon, 7 Sep 2020 20:15:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="vOshyE9A"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="nLpipW8s" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6DDCC21556 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=9DszBktUa4Na7sUmoBWtnUOiaN4NEmhyD/S63MNzUSo=; b=vOshyE9AcpNfRyTp9WUWarlGa bnQUEd8nwmQd809YyasEoIEjchioWmhBKKVzTdGdYA0BRFzvRSYW9+3uGHmqmtgmHTw+yqsD226xL 557Q7LQPO9R/aXRNVUCqwquQ14iWVRztxTKn8WaSxph5SE5Dl9/QM0GSSJGydM5C8QzBJ3srE2oR+ 0U61iP710ACLbX5Lq2HGiL2APm4xSFzi90pRB1HY9PRmvIKgE7d8QyqjsbmRyt8a6WxX9DNi3Pjl7 UViLcI37QwAwHldDXBtB+0xhQatneO3i/VmbyZAUhM/ZvYijSiKLO9UZJbZeoHxH8gevrMPPSzBr0 yHMBfEJ4Q==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFNW1-0005Tr-JO; Mon, 07 Sep 2020 20:13:25 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFNVw-0005Rv-AU; Mon, 07 Sep 2020 20:13:22 +0000 Received: from kernel.org (unknown [87.71.73.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 30E5C21556; Mon, 7 Sep 2020 20:13:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599509594; bh=Txq0SHMAQgqfdmcGMkwaxwK8bh+LCMYp/KURZ2semt0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nLpipW8sQvLhlZFZtsFQwKo1Znbs/0KAcD4LFEfe7h7JTvYMqqR6v+seDpO4Yd/cu RrfBDF0lYv41owv1h519SaLJN7kE80eKoMCgi8/Hj0LT+ao5fgTb95OgH+il6wLukz qp6QPtSS/AB4nQIMNuSph4bC4G+E+gDc26AyDbdg= Date: Mon, 7 Sep 2020 23:12:56 +0300 From: Mike Rapoport To: Gerald Schaefer Subject: Re: [RFC PATCH v2 0/3] mm/gup: fix gup_fast with dynamic page table folding Message-ID: <20200907201256.GC1976319@kernel.org> References: <20200907180058.64880-1-gerald.schaefer@linux.ibm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200907180058.64880-1-gerald.schaefer@linux.ibm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200907_161320_579422_50C01669 X-CRM114-Status: GOOD ( 29.51 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Zijlstra , Benjamin Herrenschmidt , Dave Hansen , linux-mm , Paul Mackerras , linux-sparc , Alexander Gordeev , Claudio Imbrenda , Will Deacon , linux-arch , linux-s390 , Vasily Gorbik , Christian Borntraeger , Richard Weinberger , linux-x86 , Russell King , Jason Gunthorpe , Ingo Molnar , Catalin Marinas , Andrey Ryabinin , Heiko Carstens , Arnd Bergmann , John Hubbard , Jeff Dike , linux-um , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm , linux-power , LKML , Michael Ellerman , Andrew Morton , Linus Torvalds Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Sep 07, 2020 at 08:00:55PM +0200, Gerald Schaefer wrote: > This is v2 of an RFC previously discussed here: > https://lore.kernel.org/lkml/20200828140314.8556-1-gerald.schaefer@linux.ibm.com/ > > Patch 1 is a fix for a regression in gup_fast on s390, after our conversion > to common gup_fast code. It will introduce special helper functions > pXd_addr_end_folded(), which have to be used in places where pagetable walk > is done w/o lock and with READ_ONCE, so currently only in gup_fast. > > Patch 2 is an attempt to make that more generic, i.e. change pXd_addr_end() > themselves by adding an extra pXd value parameter. That was suggested by > Jason during v1 discussion, because he is already thinking of some other > places where he might want to switch to the READ_ONCE logic for pagetable > walks. In general, that would be the cleanest / safest solution, but there > is some impact on other architectures and common code, hence the new and > greatly enlarged recipient list. > > Patch 3 is a "nice to have" add-on, which makes pXd_addr_end() inline > functions instead of #defines, so that we get some type checking for the > new pXd value parameter. > > Not sure about Fixes/stable tags for the generic solution. Only patch 1 > fixes a real bug on s390, and has Fixes/stable tags. Patches 2 + 3 might > still be nice to have in stable, to ease future backports, but I guess > "nice to have" does not really qualify for stable backports. I also think that adding pXd parameter to pXd_addr_end() is a cleaner way and with this patch 1 is not really required. I would even merge patches 2 and 3 into a single patch and use only it as the fix. [ /me apologises to stable@ team :-) ] > Changes in v2: > - Pick option 2 from v1 discussion (pXd_addr_end_folded helpers) > - Add patch 2 + 3 for more generic approach > > Alexander Gordeev (3): > mm/gup: fix gup_fast with dynamic page table folding > mm: make pXd_addr_end() functions page-table entry aware > mm: make generic pXd_addr_end() macros inline functions > > arch/arm/include/asm/pgtable-2level.h | 2 +- > arch/arm/mm/idmap.c | 6 ++-- > arch/arm/mm/mmu.c | 8 ++--- > arch/arm64/kernel/hibernate.c | 16 +++++---- > arch/arm64/kvm/mmu.c | 16 ++++----- > arch/arm64/mm/kasan_init.c | 8 ++--- > arch/arm64/mm/mmu.c | 25 +++++++------- > arch/powerpc/mm/book3s64/radix_pgtable.c | 7 ++-- > arch/powerpc/mm/hugetlbpage.c | 6 ++-- > arch/s390/include/asm/pgtable.h | 42 ++++++++++++++++++++++++ > arch/s390/mm/page-states.c | 8 ++--- > arch/s390/mm/pageattr.c | 8 ++--- > arch/s390/mm/vmem.c | 8 ++--- > arch/sparc/mm/hugetlbpage.c | 6 ++-- > arch/um/kernel/tlb.c | 8 ++--- > arch/x86/mm/init_64.c | 15 ++++----- > arch/x86/mm/kasan_init_64.c | 16 ++++----- > include/asm-generic/pgtable-nop4d.h | 2 +- > include/asm-generic/pgtable-nopmd.h | 2 +- > include/asm-generic/pgtable-nopud.h | 2 +- > include/linux/pgtable.h | 38 ++++++++++++--------- > mm/gup.c | 8 ++--- > mm/ioremap.c | 8 ++--- > mm/kasan/init.c | 17 +++++----- > mm/madvise.c | 4 +-- > mm/memory.c | 40 +++++++++++----------- > mm/mlock.c | 18 +++++++--- > mm/mprotect.c | 8 ++--- > mm/pagewalk.c | 8 ++--- > mm/swapfile.c | 8 ++--- > mm/vmalloc.c | 16 ++++----- > 31 files changed, 219 insertions(+), 165 deletions(-) > > -- > 2.17.1 > -- Sincerely yours, Mike. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 7 Sep 2020 23:12:56 +0300 From: Mike Rapoport Subject: Re: [RFC PATCH v2 0/3] mm/gup: fix gup_fast with dynamic page table folding Message-ID: <20200907201256.GC1976319@kernel.org> References: <20200907180058.64880-1-gerald.schaefer@linux.ibm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200907180058.64880-1-gerald.schaefer@linux.ibm.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: Gerald Schaefer Cc: Peter Zijlstra , Benjamin Herrenschmidt , Dave Hansen , linux-mm , Paul Mackerras , linux-sparc , Alexander Gordeev , Claudio Imbrenda , Will Deacon , linux-arch , linux-s390 , Vasily Gorbik , Christian Borntraeger , Richard Weinberger , linux-x86 , Russell King , Jason Gunthorpe , Ingo Molnar , Catalin Marinas , Andrey Ryabinin , Heiko Carstens , Arnd Bergmann , John Hubbard , Jeff Dike , linux-um , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm , linux-power , LKML , Michael Ellerman , Andrew Morton , Linus Torvalds On Mon, Sep 07, 2020 at 08:00:55PM +0200, Gerald Schaefer wrote: > This is v2 of an RFC previously discussed here: > https://lore.kernel.org/lkml/20200828140314.8556-1-gerald.schaefer@linux.ibm.com/ > > Patch 1 is a fix for a regression in gup_fast on s390, after our conversion > to common gup_fast code. It will introduce special helper functions > pXd_addr_end_folded(), which have to be used in places where pagetable walk > is done w/o lock and with READ_ONCE, so currently only in gup_fast. > > Patch 2 is an attempt to make that more generic, i.e. change pXd_addr_end() > themselves by adding an extra pXd value parameter. That was suggested by > Jason during v1 discussion, because he is already thinking of some other > places where he might want to switch to the READ_ONCE logic for pagetable > walks. In general, that would be the cleanest / safest solution, but there > is some impact on other architectures and common code, hence the new and > greatly enlarged recipient list. > > Patch 3 is a "nice to have" add-on, which makes pXd_addr_end() inline > functions instead of #defines, so that we get some type checking for the > new pXd value parameter. > > Not sure about Fixes/stable tags for the generic solution. Only patch 1 > fixes a real bug on s390, and has Fixes/stable tags. Patches 2 + 3 might > still be nice to have in stable, to ease future backports, but I guess > "nice to have" does not really qualify for stable backports. I also think that adding pXd parameter to pXd_addr_end() is a cleaner way and with this patch 1 is not really required. I would even merge patches 2 and 3 into a single patch and use only it as the fix. [ /me apologises to stable@ team :-) ] > Changes in v2: > - Pick option 2 from v1 discussion (pXd_addr_end_folded helpers) > - Add patch 2 + 3 for more generic approach > > Alexander Gordeev (3): > mm/gup: fix gup_fast with dynamic page table folding > mm: make pXd_addr_end() functions page-table entry aware > mm: make generic pXd_addr_end() macros inline functions > > arch/arm/include/asm/pgtable-2level.h | 2 +- > arch/arm/mm/idmap.c | 6 ++-- > arch/arm/mm/mmu.c | 8 ++--- > arch/arm64/kernel/hibernate.c | 16 +++++---- > arch/arm64/kvm/mmu.c | 16 ++++----- > arch/arm64/mm/kasan_init.c | 8 ++--- > arch/arm64/mm/mmu.c | 25 +++++++------- > arch/powerpc/mm/book3s64/radix_pgtable.c | 7 ++-- > arch/powerpc/mm/hugetlbpage.c | 6 ++-- > arch/s390/include/asm/pgtable.h | 42 ++++++++++++++++++++++++ > arch/s390/mm/page-states.c | 8 ++--- > arch/s390/mm/pageattr.c | 8 ++--- > arch/s390/mm/vmem.c | 8 ++--- > arch/sparc/mm/hugetlbpage.c | 6 ++-- > arch/um/kernel/tlb.c | 8 ++--- > arch/x86/mm/init_64.c | 15 ++++----- > arch/x86/mm/kasan_init_64.c | 16 ++++----- > include/asm-generic/pgtable-nop4d.h | 2 +- > include/asm-generic/pgtable-nopmd.h | 2 +- > include/asm-generic/pgtable-nopud.h | 2 +- > include/linux/pgtable.h | 38 ++++++++++++--------- > mm/gup.c | 8 ++--- > mm/ioremap.c | 8 ++--- > mm/kasan/init.c | 17 +++++----- > mm/madvise.c | 4 +-- > mm/memory.c | 40 +++++++++++----------- > mm/mlock.c | 18 +++++++--- > mm/mprotect.c | 8 ++--- > mm/pagewalk.c | 8 ++--- > mm/swapfile.c | 8 ++--- > mm/vmalloc.c | 16 ++++----- > 31 files changed, 219 insertions(+), 165 deletions(-) > > -- > 2.17.1 > -- Sincerely yours, Mike. _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um