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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 C02FDC31E40 for ; Tue, 6 Aug 2019 11:53:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 97FF220C01 for ; Tue, 6 Aug 2019 11:53:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="Z0mI1c0b" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730094AbfHFLxU (ORCPT ); Tue, 6 Aug 2019 07:53:20 -0400 Received: from mail-qk1-f196.google.com ([209.85.222.196]:40845 "EHLO mail-qk1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726243AbfHFLxU (ORCPT ); Tue, 6 Aug 2019 07:53:20 -0400 Received: by mail-qk1-f196.google.com with SMTP id s145so62595962qke.7 for ; Tue, 06 Aug 2019 04:53:19 -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:user-agent; bh=eo4243fxJunv120eldJ+yINhsaoHQ/b07ic+MhyUnUY=; b=Z0mI1c0biLAyuHhq5HIH9liJ9V9NmYB6TCZCXG/MS5n6b7MXngGDqXWAvW9Q3wU70f Yuj4Gf5hmNpwIefJdv3jpcVqzwrm17rlQpqCpa8h75KznnlVcHW+bOQ8mi52XzW32i5X xMyKUlZMHS1zgPqQftCrIwo83eGAnrddpriXhq4ERkbDt3WwCS0upZb4/WtoahuAO8kW rLLLe/brCqzVyuGIKUWxPpcJJrKlwgWXPRE3jAKSeJ2mD0cdUXjpM0rJYi2yNTADYoYQ aDzSN7ZZQHTrS2/K7nALIkgZpt7+fyciFkxjLncICC8fqlQT1qsJ9jdY2CtN6k6kVuIQ kuUg== 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:user-agent; bh=eo4243fxJunv120eldJ+yINhsaoHQ/b07ic+MhyUnUY=; b=T8aFqzjoqPBOxkk5gxNY1G+QEn7NZ3EytTSXnxccO9HY4FEPR5LDm9b4Wc3wjhKdYw JGR06mI3suJI2t0ZBfCSajVwz9CNyg+mqQS1/xIVGZHc51Difr/a0pp8YunP6uE0gAck Kf0a4hDaG4luJ24wfQfueRR35uCv6YH4XTc3mw+pelnulM3sW/lppKFu16RCf+HcLbcA OdymSdUPKWioT4Eqx5K/DBh+F4Xe43fAIaV57lDwdmvt6FqoM4mT4v3kuEeg/nlFrFCC dMqeJtdxT1cqacfkZo7kqkDhqLOH3sJLix6+/qPKlJL8CRbIlc5PfIRc8pYfeL/3iS/e 9VOQ== X-Gm-Message-State: APjAAAXwKwJNv49TbpFN2bY3I28DbPTia+JYznH30rhAWeBwvBiu+CmB Mn8l29YRqPvtWsg4WqAb0vrjWw== X-Google-Smtp-Source: APXvYqw8Kp97Codo4loFeh85jsMCmVqW5Bh1vzUEuORvgfGzgHvIynQzybQA5mb0rqsqpydwn040qg== X-Received: by 2002:a05:620a:127c:: with SMTP id b28mr2606352qkl.299.1565092399391; Tue, 06 Aug 2019 04:53:19 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-156-34-55-100.dhcp-dynamic.fibreop.ns.bellaliant.net. [156.34.55.100]) by smtp.gmail.com with ESMTPSA id r14sm40128814qke.47.2019.08.06.04.53.18 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 06 Aug 2019 04:53:18 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1huy1l-0003cs-Vr; Tue, 06 Aug 2019 08:53:17 -0300 Date: Tue, 6 Aug 2019 08:53:17 -0300 From: Jason Gunthorpe To: "Michael S. Tsirkin" Cc: Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH V2 7/9] vhost: do not use RCU to synchronize MMU notifier with worker Message-ID: <20190806115317.GA11627@ziepe.ca> References: <20190731193057.GG3946@ziepe.ca> <20190801141512.GB23899@ziepe.ca> <42ead87b-1749-4c73-cbe4-29dbeb945041@redhat.com> <20190802124613.GA11245@ziepe.ca> <20190802100414-mutt-send-email-mst@kernel.org> <20190802172418.GB11245@ziepe.ca> <20190803172944-mutt-send-email-mst@kernel.org> <20190804001400.GA25543@ziepe.ca> <20190804040034-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190804040034-mutt-send-email-mst@kernel.org> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Aug 04, 2019 at 04:07:17AM -0400, Michael S. Tsirkin wrote: > > > > Also, why can't this just permanently GUP the pages? In fact, where > > > > does it put_page them anyhow? Worrying that 7f466 adds a get_user page > > > > but does not add a put_page?? > > > > You didn't answer this.. Why not just use GUP? > > > > Jason > > Sorry I misunderstood the question. Permanent GUP breaks lots of > functionality we need such as THP and numa balancing. Really? It doesn't look like that many pages are involved.. Jason