From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932606AbeENPFM (ORCPT ); Mon, 14 May 2018 11:05:12 -0400 Received: from foss.arm.com ([217.140.101.70]:44604 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754530AbeENPFD (ORCPT ); Mon, 14 May 2018 11:05:03 -0400 From: Punit Agrawal To: Laurent Dufour Cc: akpm@linux-foundation.org, mhocko@kernel.org, peterz@infradead.org, kirill@shutemov.name, ak@linux.intel.com, dave@stgolabs.net, jack@suse.cz, Matthew Wilcox , benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org, Thomas Gleixner , Ingo Molnar , hpa@zytor.com, Will Deacon , Sergey Senozhatsky , Andrea Arcangeli , Alexei Starovoitov , kemi.wang@intel.com, sergey.senozhatsky.work@gmail.com, Daniel Jordan , David Rientjes , Jerome Glisse , Ganesh Mahendran , linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com, npiggin@gmail.com, bsingharora@gmail.com, paulmck@linux.vnet.ibm.com, Tim Chen , linuxppc-dev@lists.ozlabs.org, x86@kernel.org Subject: Re: [PATCH v10 02/25] x86/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT References: <1523975611-15978-1-git-send-email-ldufour@linux.vnet.ibm.com> <1523975611-15978-3-git-send-email-ldufour@linux.vnet.ibm.com> <87sh72jtmn.fsf@e105922-lin.cambridge.arm.com> Date: Mon, 14 May 2018 16:05:01 +0100 In-Reply-To: (Laurent Dufour's message of "Mon, 14 May 2018 16:47:39 +0200") Message-ID: <87o9hi46si.fsf@e105922-lin.cambridge.arm.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Laurent Dufour writes: > On 08/05/2018 13:04, Punit Agrawal wrote: >> Hi Laurent, >> >> Laurent Dufour writes: >> >>> Set ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT which turns on the >>> Speculative Page Fault handler when building for 64bit. >>> >>> Cc: Thomas Gleixner >>> Signed-off-by: Laurent Dufour >>> --- >>> arch/x86/Kconfig | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig >>> index d8983df5a2bc..ebdeb48e4a4a 100644 >>> --- a/arch/x86/Kconfig >>> +++ b/arch/x86/Kconfig >>> @@ -30,6 +30,7 @@ config X86_64 >>> select MODULES_USE_ELF_RELA >>> select X86_DEV_DMA_OPS >>> select ARCH_HAS_SYSCALL_WRAPPER >>> + select ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT >> >> I'd suggest merging this patch with the one making changes to the >> architectural fault handler towards the end of the series. >> >> The Kconfig change is closely tied to the architectural support for SPF >> and makes sense to be in a single patch. >> >> If there's a good reason to keep them as separate patches, please move >> the architecture Kconfig changes after the patch adding fault handler >> changes. >> >> It's better to enable the feature once the core infrastructure is merged >> rather than at the beginning of the series to avoid potential bad >> fallout from incomplete functionality during bisection. > > Indeed bisection was the reason why Andrew asked me to push the configuration > enablement on top of the series (https://lkml.org/lkml/2017/10/10/1229). The config options have gone through another round of splitting (between core and architecture) since that comment. I agree that it still makes sense to define the core config - CONFIG_SPECULATIVE_PAGE_FAULT early on. Just to clarify, my suggestion was to only move the architecture configs further down. > > I also think it would be better to have the architecture enablement in on patch > but that would mean that the code will not be build when bisecting without the > latest patch adding the per architecture code. I don't see that as a problem. But if I'm in the minority, I am OK with leaving things as they are as well. Thanks, Punit From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f72.google.com (mail-oi0-f72.google.com [209.85.218.72]) by kanga.kvack.org (Postfix) with ESMTP id 13F106B0007 for ; Mon, 14 May 2018 11:05:05 -0400 (EDT) Received: by mail-oi0-f72.google.com with SMTP id k13-v6so12256486oiw.3 for ; Mon, 14 May 2018 08:05:05 -0700 (PDT) Received: from foss.arm.com (foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id q185-v6si2993541oib.405.2018.05.14.08.05.03 for ; Mon, 14 May 2018 08:05:03 -0700 (PDT) From: Punit Agrawal Subject: Re: [PATCH v10 02/25] x86/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT References: <1523975611-15978-1-git-send-email-ldufour@linux.vnet.ibm.com> <1523975611-15978-3-git-send-email-ldufour@linux.vnet.ibm.com> <87sh72jtmn.fsf@e105922-lin.cambridge.arm.com> Date: Mon, 14 May 2018 16:05:01 +0100 In-Reply-To: (Laurent Dufour's message of "Mon, 14 May 2018 16:47:39 +0200") Message-ID: <87o9hi46si.fsf@e105922-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: Laurent Dufour Cc: akpm@linux-foundation.org, mhocko@kernel.org, peterz@infradead.org, kirill@shutemov.name, ak@linux.intel.com, dave@stgolabs.net, jack@suse.cz, Matthew Wilcox , benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org, Thomas Gleixner , Ingo Molnar , hpa@zytor.com, Will Deacon , Sergey Senozhatsky , Andrea Arcangeli , Alexei Starovoitov , kemi.wang@intel.com, sergey.senozhatsky.work@gmail.com, Daniel Jordan , David Rientjes , Jerome Glisse , Ganesh Mahendran , linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com, npiggin@gmail.com, bsingharora@gmail.com, paulmck@linux.vnet.ibm.com, Tim Chen , linuxppc-dev@lists., ozlabs.org, x86@kernel.org Laurent Dufour writes: > On 08/05/2018 13:04, Punit Agrawal wrote: >> Hi Laurent, >> >> Laurent Dufour writes: >> >>> Set ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT which turns on the >>> Speculative Page Fault handler when building for 64bit. >>> >>> Cc: Thomas Gleixner >>> Signed-off-by: Laurent Dufour >>> --- >>> arch/x86/Kconfig | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig >>> index d8983df5a2bc..ebdeb48e4a4a 100644 >>> --- a/arch/x86/Kconfig >>> +++ b/arch/x86/Kconfig >>> @@ -30,6 +30,7 @@ config X86_64 >>> select MODULES_USE_ELF_RELA >>> select X86_DEV_DMA_OPS >>> select ARCH_HAS_SYSCALL_WRAPPER >>> + select ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT >> >> I'd suggest merging this patch with the one making changes to the >> architectural fault handler towards the end of the series. >> >> The Kconfig change is closely tied to the architectural support for SPF >> and makes sense to be in a single patch. >> >> If there's a good reason to keep them as separate patches, please move >> the architecture Kconfig changes after the patch adding fault handler >> changes. >> >> It's better to enable the feature once the core infrastructure is merged >> rather than at the beginning of the series to avoid potential bad >> fallout from incomplete functionality during bisection. > > Indeed bisection was the reason why Andrew asked me to push the configuration > enablement on top of the series (https://lkml.org/lkml/2017/10/10/1229). The config options have gone through another round of splitting (between core and architecture) since that comment. I agree that it still makes sense to define the core config - CONFIG_SPECULATIVE_PAGE_FAULT early on. Just to clarify, my suggestion was to only move the architecture configs further down. > > I also think it would be better to have the architecture enablement in on patch > but that would mean that the code will not be build when bisecting without the > latest patch adding the per architecture code. I don't see that as a problem. But if I'm in the minority, I am OK with leaving things as they are as well. Thanks, Punit From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by lists.ozlabs.org (Postfix) with ESMTP id 40l3sG0wRWzF36W for ; Tue, 15 May 2018 01:05:05 +1000 (AEST) From: Punit Agrawal To: Laurent Dufour Cc: akpm@linux-foundation.org, mhocko@kernel.org, peterz@infradead.org, kirill@shutemov.name, ak@linux.intel.com, dave@stgolabs.net, jack@suse.cz, Matthew Wilcox , benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org, Thomas Gleixner , Ingo Molnar , hpa@zytor.com, Will Deacon , Sergey Senozhatsky , Andrea Arcangeli , Alexei Starovoitov , kemi.wang@intel.com, sergey.senozhatsky.work@gmail.com, Daniel Jordan , David Rientjes , Jerome Glisse , Ganesh Mahendran , linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com, npiggin@gmail.com, bsingharora@gmail.com, paulmck@linux.vnet.ibm.com, Tim Chen , linuxppc-dev@lists. ozlabs.org, x86@kernel.org Subject: Re: [PATCH v10 02/25] x86/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT References: <1523975611-15978-1-git-send-email-ldufour@linux.vnet.ibm.com> <1523975611-15978-3-git-send-email-ldufour@linux.vnet.ibm.com> <87sh72jtmn.fsf@e105922-lin.cambridge.arm.com> Date: Mon, 14 May 2018 16:05:01 +0100 In-Reply-To: (Laurent Dufour's message of "Mon, 14 May 2018 16:47:39 +0200") Message-ID: <87o9hi46si.fsf@e105922-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Laurent Dufour writes: > On 08/05/2018 13:04, Punit Agrawal wrote: >> Hi Laurent, >> >> Laurent Dufour writes: >> >>> Set ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT which turns on the >>> Speculative Page Fault handler when building for 64bit. >>> >>> Cc: Thomas Gleixner >>> Signed-off-by: Laurent Dufour >>> --- >>> arch/x86/Kconfig | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig >>> index d8983df5a2bc..ebdeb48e4a4a 100644 >>> --- a/arch/x86/Kconfig >>> +++ b/arch/x86/Kconfig >>> @@ -30,6 +30,7 @@ config X86_64 >>> select MODULES_USE_ELF_RELA >>> select X86_DEV_DMA_OPS >>> select ARCH_HAS_SYSCALL_WRAPPER >>> + select ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT >> >> I'd suggest merging this patch with the one making changes to the >> architectural fault handler towards the end of the series. >> >> The Kconfig change is closely tied to the architectural support for SPF >> and makes sense to be in a single patch. >> >> If there's a good reason to keep them as separate patches, please move >> the architecture Kconfig changes after the patch adding fault handler >> changes. >> >> It's better to enable the feature once the core infrastructure is merged >> rather than at the beginning of the series to avoid potential bad >> fallout from incomplete functionality during bisection. > > Indeed bisection was the reason why Andrew asked me to push the configuration > enablement on top of the series (https://lkml.org/lkml/2017/10/10/1229). The config options have gone through another round of splitting (between core and architecture) since that comment. I agree that it still makes sense to define the core config - CONFIG_SPECULATIVE_PAGE_FAULT early on. Just to clarify, my suggestion was to only move the architecture configs further down. > > I also think it would be better to have the architecture enablement in on patch > but that would mean that the code will not be build when bisecting without the > latest patch adding the per architecture code. I don't see that as a problem. But if I'm in the minority, I am OK with leaving things as they are as well. Thanks, Punit