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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 E9309C433E2 for ; Thu, 10 Sep 2020 17:21:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A5F502064B for ; Thu, 10 Sep 2020 17:21:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="R7muKjGs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725866AbgIJRVG (ORCPT ); Thu, 10 Sep 2020 13:21:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54682 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726761AbgIJRUA (ORCPT ); Thu, 10 Sep 2020 13:20:00 -0400 Received: from mail-qt1-x842.google.com (mail-qt1-x842.google.com [IPv6:2607:f8b0:4864:20::842]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21647C0613ED for ; Thu, 10 Sep 2020 10:20:00 -0700 (PDT) Received: by mail-qt1-x842.google.com with SMTP id e7so5439222qtj.11 for ; Thu, 10 Sep 2020 10:20:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=wS3Cxs+LxMo6gPPzfzs9JS4wraYUHvaNngFKImlbYPQ=; b=R7muKjGsMqQxjYn/v3laT3wxz696cPiiZUGTarCqWEmD8sEHzFMnpmRv1NbdWuvxUl ES4sa/jWMnYWk8X4X6idi0ndI491v7kNFTPa5GqC+PbSliK0PxcG7BbrKL1SGaFULExx kGCtyImpN4w3JYZEvlwpotauF+GyY/wqoWRoFKEJsIkkaaCf8ZEqmuepKdImBUgzQsFC Vc+IXldSoElxGSHRRDrr1U2IvhE0zAiCRYQ16d8EWEqzrgIPV6ZfSpzmZYP6/ZBNfv4U wV4KH/FXvtzAig33Lc4SwlzTJpcb6YSdw29FHxZ2Fklak2OM0YAdYreU9PkLtv7plyJk DE3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=wS3Cxs+LxMo6gPPzfzs9JS4wraYUHvaNngFKImlbYPQ=; b=BlISPEqZXAP7ezCWR7JR7AhAOkGounuNBvrpT5gOgcXmbaWF3S4Z8OKUMcuJD2kW9D gyP+lpBI2PZTAQJHc4B4yUNTAE2VKef/JqRNoiAR+zmOp3WVQZOZ8EZxkJvprTH3GnQf VHopRCBTMkjJfhAHAXb+Muz3ABjXOn+WAvcC4cGESayCt+kbvcIjewRlgwxUFEtPjaEk FISP7AbvFZU7MUer57h6abfj4Yw97gjArlbSRyLJXALFqibyaSSoIBjhlqcMf+XIhvcO 2kSQbMIV3jgvJGUyHfXNujhI4H/KGXneKy/17M08iJEemV0BxmUxR0Gd/iQ+UzOxeYoR fn5g== X-Gm-Message-State: AOAM532z4/vn6HjONu8vmiQSifd2gxL5OHgp6qOoLXVWLPKPNlFzY8/+ 6H127iY5Nq6oM/h/3OwUa/eg2g== X-Google-Smtp-Source: ABdhPJzOK6FcVm6akWqNTL2Hu85OsyALxMrEucVBwOeXC6OwPNTX8vss/Xw7hopiKEc6u3QVNfxIcg== X-Received: by 2002:ac8:54a:: with SMTP id c10mr9299916qth.251.1599758398248; Thu, 10 Sep 2020 10:19:58 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-156-34-48-30.dhcp-dynamic.fibreop.ns.bellaliant.net. [156.34.48.30]) by smtp.gmail.com with ESMTPSA id x126sm6934696qkb.101.2020.09.10.10.19.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Sep 2020 10:19:57 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1kGQEm-004NzL-RL; Thu, 10 Sep 2020 14:19:56 -0300 Date: Thu, 10 Sep 2020 14:19:56 -0300 From: Jason Gunthorpe To: Gerald Schaefer Cc: Anshuman Khandual , Alexander Gordeev , Dave Hansen , John Hubbard , LKML , linux-mm , linux-arch , Andrew Morton , Linus Torvalds , Russell King , Mike Rapoport , 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 , Vasily Gorbik , Heiko Carstens , Christian Borntraeger , Claudio Imbrenda Subject: Re: [RFC PATCH v2 1/3] mm/gup: fix gup_fast with dynamic page table folding Message-ID: <20200910171956.GM87483@ziepe.ca> References: <0dbc6ec8-45ea-0853-4856-2bc1e661a5a5@intel.com> <20200909142904.00b72921@thinkpad> <20200909192534.442f8984@thinkpad> <20200909180324.GI87483@ziepe.ca> <20200910093925.GB29166@oc3871087118.ibm.com> <20200910130233.GK87483@ziepe.ca> <20200910152803.1a930afc@thinkpad> <20200910151026.GL87483@ziepe.ca> <20200910190757.153319d4@thinkpad> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200910190757.153319d4@thinkpad> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 10, 2020 at 07:07:57PM +0200, Gerald Schaefer wrote: > I might have lost track a bit. Are we still talking about possible > functional impacts of either our current pagetable walking with s390 > (apart from gup_fast), or the proposed generic change (for s390, or > others?)? I'm looking for an more understandable explanation what is wrong with the S390 implementation. If the page operations require the invariant I described then it is quite easy to explain the problem and understand the solution. Jason From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Date: Thu, 10 Sep 2020 17:19:56 +0000 Subject: Re: [RFC PATCH v2 1/3] mm/gup: fix gup_fast with dynamic page table folding Message-Id: <20200910171956.GM87483@ziepe.ca> List-Id: References: <0dbc6ec8-45ea-0853-4856-2bc1e661a5a5@intel.com> <20200909142904.00b72921@thinkpad> <20200909192534.442f8984@thinkpad> <20200909180324.GI87483@ziepe.ca> <20200910093925.GB29166@oc3871087118.ibm.com> <20200910130233.GK87483@ziepe.ca> <20200910152803.1a930afc@thinkpad> <20200910151026.GL87483@ziepe.ca> <20200910190757.153319d4@thinkpad> In-Reply-To: <20200910190757.153319d4@thinkpad> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Gerald Schaefer Cc: Anshuman Khandual , Alexander Gordeev , Dave Hansen , John Hubbard , LKML , linux-mm , linux-arch , Andrew Morton , Linus Torvalds , Russell King , Mike Rapoport , 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 , Vasily Gorbik , Heiko Carstens , Christian Borntraeger , Claudio Imbrenda On Thu, Sep 10, 2020 at 07:07:57PM +0200, Gerald Schaefer wrote: > I might have lost track a bit. Are we still talking about possible > functional impacts of either our current pagetable walking with s390 > (apart from gup_fast), or the proposed generic change (for s390, or > others?)? I'm looking for an more understandable explanation what is wrong with the S390 implementation. If the page operations require the invariant I described then it is quite easy to explain the problem and understand the solution. Jason 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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,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 1A47CC43461 for ; Thu, 10 Sep 2020 17:59:48 +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 2603921D81 for ; Thu, 10 Sep 2020 17:59:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="R7muKjGs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2603921D81 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca 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 4BnQgz5vBJzDr4Q for ; Fri, 11 Sep 2020 03:22:55 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=ziepe.ca (client-ip=2607:f8b0:4864:20::842; helo=mail-qt1-x842.google.com; envelope-from=jgg@ziepe.ca; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Received: from mail-qt1-x842.google.com (mail-qt1-x842.google.com [IPv6:2607:f8b0:4864:20::842]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4BnQdt2NltzDqgS for ; Fri, 11 Sep 2020 03:21:05 +1000 (AEST) Received: by mail-qt1-x842.google.com with SMTP id r8so5416533qtp.13 for ; Thu, 10 Sep 2020 10:21:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=wS3Cxs+LxMo6gPPzfzs9JS4wraYUHvaNngFKImlbYPQ=; b=R7muKjGsMqQxjYn/v3laT3wxz696cPiiZUGTarCqWEmD8sEHzFMnpmRv1NbdWuvxUl ES4sa/jWMnYWk8X4X6idi0ndI491v7kNFTPa5GqC+PbSliK0PxcG7BbrKL1SGaFULExx kGCtyImpN4w3JYZEvlwpotauF+GyY/wqoWRoFKEJsIkkaaCf8ZEqmuepKdImBUgzQsFC Vc+IXldSoElxGSHRRDrr1U2IvhE0zAiCRYQ16d8EWEqzrgIPV6ZfSpzmZYP6/ZBNfv4U wV4KH/FXvtzAig33Lc4SwlzTJpcb6YSdw29FHxZ2Fklak2OM0YAdYreU9PkLtv7plyJk DE3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=wS3Cxs+LxMo6gPPzfzs9JS4wraYUHvaNngFKImlbYPQ=; b=G3Ckl2OxWGRrZ6UsTLxbPSdUNXzuA/oO/gyh/LUQOlzTC7OcRrTX/SVYl9Ha+6uE6h NzZxebIClTJF2PIfdaUzkT0WpfLq39vqLl52vJkHVkaJyDCK0mrso/mROOC9P2HcI6XO vXfgkp542MpaGzq+tFHx4Ga/+z5gagmo1rMQTscoCRrcwov4wpIabOXfluJqgxtPsDAL AwJo/MlR4L5IEuv3bXlifiv8dxAyAurgI9ug8Q03I9kudGYMS3T42ziNoJvQiYHj6gOD wnW/733B9y7l9vhz6NjVLHlxVaxE2tRZiykImcFeZ1aGQcKtZsn+MhqsQDTwVxPz8zK6 TLpA== X-Gm-Message-State: AOAM531T3MtASloea/ZM64nbh7PneVBNjjfB+EPyFGxYjYn3MEocUqIH 217OFqr0mJqsTicKwMqoAw4IZQ== X-Google-Smtp-Source: ABdhPJzOK6FcVm6akWqNTL2Hu85OsyALxMrEucVBwOeXC6OwPNTX8vss/Xw7hopiKEc6u3QVNfxIcg== X-Received: by 2002:ac8:54a:: with SMTP id c10mr9299916qth.251.1599758398248; Thu, 10 Sep 2020 10:19:58 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-156-34-48-30.dhcp-dynamic.fibreop.ns.bellaliant.net. [156.34.48.30]) by smtp.gmail.com with ESMTPSA id x126sm6934696qkb.101.2020.09.10.10.19.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Sep 2020 10:19:57 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1kGQEm-004NzL-RL; Thu, 10 Sep 2020 14:19:56 -0300 Date: Thu, 10 Sep 2020 14:19:56 -0300 From: Jason Gunthorpe To: Gerald Schaefer Subject: Re: [RFC PATCH v2 1/3] mm/gup: fix gup_fast with dynamic page table folding Message-ID: <20200910171956.GM87483@ziepe.ca> References: <0dbc6ec8-45ea-0853-4856-2bc1e661a5a5@intel.com> <20200909142904.00b72921@thinkpad> <20200909192534.442f8984@thinkpad> <20200909180324.GI87483@ziepe.ca> <20200910093925.GB29166@oc3871087118.ibm.com> <20200910130233.GK87483@ziepe.ca> <20200910152803.1a930afc@thinkpad> <20200910151026.GL87483@ziepe.ca> <20200910190757.153319d4@thinkpad> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200910190757.153319d4@thinkpad> 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 , Dave Hansen , Paul Mackerras , linux-sparc , Alexander Gordeev , Claudio Imbrenda , Will Deacon , linux-arch , linux-s390 , Vasily Gorbik , Richard Weinberger , linux-x86 , Russell King , Christian Borntraeger , Ingo Molnar , Catalin Marinas , Andrey Ryabinin , Heiko Carstens , Arnd Bergmann , Anshuman Khandual , John Hubbard , Jeff Dike , linux-um , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm , linux-mm , linux-power , LKML , Andrew Morton , Linus Torvalds , Mike Rapoport Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Sep 10, 2020 at 07:07:57PM +0200, Gerald Schaefer wrote: > I might have lost track a bit. Are we still talking about possible > functional impacts of either our current pagetable walking with s390 > (apart from gup_fast), or the proposed generic change (for s390, or > others?)? I'm looking for an more understandable explanation what is wrong with the S390 implementation. If the page operations require the invariant I described then it is quite easy to explain the problem and understand the solution. Jason 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,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 946C1C43461 for ; Thu, 10 Sep 2020 17:21:22 +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 0FE0B2064B for ; Thu, 10 Sep 2020 17:21:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="qJry4WQi"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="R7muKjGs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0FE0B2064B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca 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=GMw0DZpOG0hMddbEQocER0EHaSFvadvuL9B9Tm8d8QU=; b=qJry4WQizblquBVfeZMH4OQ4d fwCyjR2P1VPFKqJgrz6Bhrhuhl/T0SNjnnV5MXb6NkGIgwHWwLkogOndX4d07m44/pExXDXfo4MkQ W+RcZpVuVYXpzDmVXIt8kGasUGB0mC5du77W4FbIWgk0yLRZ3FnRxEEjhshArV/np7whb1mjtLAHC SNSMV6I4Yjh2NJzcp86wdQDoeB3b944zNNwiaVAtq+cdefjH6ozjyfKMCKOqzGG2ATjMwL9ky+P3y WPrPzzML/npq6a8bpmzM0bducLHDc5bI5tqYTfz81EGJriGenH52S4KwAWvUUfmywNi21XW1jK2CW Jw8c4hfJw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kGQEu-00037V-T5; Thu, 10 Sep 2020 17:20:04 +0000 Received: from mail-qt1-x844.google.com ([2607:f8b0:4864:20::844]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kGQEq-00034y-DS for linux-arm-kernel@lists.infradead.org; Thu, 10 Sep 2020 17:20:02 +0000 Received: by mail-qt1-x844.google.com with SMTP id z2so5421901qtv.12 for ; Thu, 10 Sep 2020 10:19:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=wS3Cxs+LxMo6gPPzfzs9JS4wraYUHvaNngFKImlbYPQ=; b=R7muKjGsMqQxjYn/v3laT3wxz696cPiiZUGTarCqWEmD8sEHzFMnpmRv1NbdWuvxUl ES4sa/jWMnYWk8X4X6idi0ndI491v7kNFTPa5GqC+PbSliK0PxcG7BbrKL1SGaFULExx kGCtyImpN4w3JYZEvlwpotauF+GyY/wqoWRoFKEJsIkkaaCf8ZEqmuepKdImBUgzQsFC Vc+IXldSoElxGSHRRDrr1U2IvhE0zAiCRYQ16d8EWEqzrgIPV6ZfSpzmZYP6/ZBNfv4U wV4KH/FXvtzAig33Lc4SwlzTJpcb6YSdw29FHxZ2Fklak2OM0YAdYreU9PkLtv7plyJk DE3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=wS3Cxs+LxMo6gPPzfzs9JS4wraYUHvaNngFKImlbYPQ=; b=bt0HMhlZf1VfrmMvBkr50R2vChIbzApGR/+NxbRv3UCR53ilmZE/Esqd9y3phVOrXQ 1qcb+F0KPG8JpO424LneL7eg3FE8qagns8YeVXJVRXJGm+KxfINqT0wfAuGpn129hhse 48o6gNo0ZNO8IJsxQSfPB9+Vq6isEg0tCcVwJ4GqA9oDKQuy8bJDAGLMSOStLBHxG4to jttweWQBlxlmhL34PQgyTxcVuz64Kb1PtrVfRDwM18Ir4JDaVcwbkSwWT5R8b/Aodvdx qUgflxumjN1JgB9/hfm9iXx3M0zUUxzzm/7Sdt+DN0nLwx816nNNj34PFtUqv1nHH5Z+ mtmQ== X-Gm-Message-State: AOAM533tSqbLphVyNPQqvvM+/iAirN6t40LHBXOajox/gNjuykikFd3j nmkqqlDWKUNgW/bQ7Wwep0IYXw== X-Google-Smtp-Source: ABdhPJzOK6FcVm6akWqNTL2Hu85OsyALxMrEucVBwOeXC6OwPNTX8vss/Xw7hopiKEc6u3QVNfxIcg== X-Received: by 2002:ac8:54a:: with SMTP id c10mr9299916qth.251.1599758398248; Thu, 10 Sep 2020 10:19:58 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-156-34-48-30.dhcp-dynamic.fibreop.ns.bellaliant.net. [156.34.48.30]) by smtp.gmail.com with ESMTPSA id x126sm6934696qkb.101.2020.09.10.10.19.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Sep 2020 10:19:57 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1kGQEm-004NzL-RL; Thu, 10 Sep 2020 14:19:56 -0300 Date: Thu, 10 Sep 2020 14:19:56 -0300 From: Jason Gunthorpe To: Gerald Schaefer Subject: Re: [RFC PATCH v2 1/3] mm/gup: fix gup_fast with dynamic page table folding Message-ID: <20200910171956.GM87483@ziepe.ca> References: <0dbc6ec8-45ea-0853-4856-2bc1e661a5a5@intel.com> <20200909142904.00b72921@thinkpad> <20200909192534.442f8984@thinkpad> <20200909180324.GI87483@ziepe.ca> <20200910093925.GB29166@oc3871087118.ibm.com> <20200910130233.GK87483@ziepe.ca> <20200910152803.1a930afc@thinkpad> <20200910151026.GL87483@ziepe.ca> <20200910190757.153319d4@thinkpad> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200910190757.153319d4@thinkpad> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200910_132000_763657_0E0DE439 X-CRM114-Status: GOOD ( 15.92 ) 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 , Dave Hansen , Paul Mackerras , linux-sparc , Alexander Gordeev , Claudio Imbrenda , Will Deacon , linux-arch , linux-s390 , Vasily Gorbik , Richard Weinberger , linux-x86 , Russell King , Christian Borntraeger , Ingo Molnar , Catalin Marinas , Andrey Ryabinin , Heiko Carstens , Arnd Bergmann , Anshuman Khandual , John Hubbard , Jeff Dike , linux-um , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm , linux-mm , linux-power , LKML , Michael Ellerman , Andrew Morton , Linus Torvalds , Mike Rapoport 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 Thu, Sep 10, 2020 at 07:07:57PM +0200, Gerald Schaefer wrote: > I might have lost track a bit. Are we still talking about possible > functional impacts of either our current pagetable walking with s390 > (apart from gup_fast), or the proposed generic change (for s390, or > others?)? I'm looking for an more understandable explanation what is wrong with the S390 implementation. If the page operations require the invariant I described then it is quite easy to explain the problem and understand the solution. Jason _______________________________________________ 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: Received: from mail-qt1-x843.google.com ([2607:f8b0:4864:20::843]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kGQEq-00034w-Cs for linux-um@lists.infradead.org; Thu, 10 Sep 2020 17:20:03 +0000 Received: by mail-qt1-x843.google.com with SMTP id n18so5485067qtw.0 for ; Thu, 10 Sep 2020 10:19:59 -0700 (PDT) Date: Thu, 10 Sep 2020 14:19:56 -0300 From: Jason Gunthorpe Subject: Re: [RFC PATCH v2 1/3] mm/gup: fix gup_fast with dynamic page table folding Message-ID: <20200910171956.GM87483@ziepe.ca> References: <0dbc6ec8-45ea-0853-4856-2bc1e661a5a5@intel.com> <20200909142904.00b72921@thinkpad> <20200909192534.442f8984@thinkpad> <20200909180324.GI87483@ziepe.ca> <20200910093925.GB29166@oc3871087118.ibm.com> <20200910130233.GK87483@ziepe.ca> <20200910152803.1a930afc@thinkpad> <20200910151026.GL87483@ziepe.ca> <20200910190757.153319d4@thinkpad> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200910190757.153319d4@thinkpad> 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 , Dave Hansen , Paul Mackerras , linux-sparc , Alexander Gordeev , Claudio Imbrenda , Will Deacon , linux-arch , linux-s390 , Vasily Gorbik , Richard Weinberger , linux-x86 , Russell King , Christian Borntraeger , Ingo Molnar , Catalin Marinas , Andrey Ryabinin , Heiko Carstens , Arnd Bergmann , Anshuman Khandual , John Hubbard , Jeff Dike , linux-um , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm , linux-mm , linux-power , LKML , Michael Ellerman , Andrew Morton , Linus Torvalds , Mike Rapoport On Thu, Sep 10, 2020 at 07:07:57PM +0200, Gerald Schaefer wrote: > I might have lost track a bit. Are we still talking about possible > functional impacts of either our current pagetable walking with s390 > (apart from gup_fast), or the proposed generic change (for s390, or > others?)? I'm looking for an more understandable explanation what is wrong with the S390 implementation. If the page operations require the invariant I described then it is quite easy to explain the problem and understand the solution. Jason _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um