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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F1722C61DA4 for ; Thu, 23 Feb 2023 20:17:25 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pVI1R-00039V-Gh; Thu, 23 Feb 2023 15:16:57 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pVI1I-000388-Uc for qemu-devel@nongnu.org; Thu, 23 Feb 2023 15:16:50 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pVI1F-0008VW-8K for qemu-devel@nongnu.org; Thu, 23 Feb 2023 15:16:46 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677183404; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZhEAhg+gVumsM/eyaB8hov+QmlvtrVjqSST+g/tyyjM=; b=OJTWANHKzPOux6HcaboMWZYKchJqbf90tl6PJrPFfcXosdP4ih6h1HNYU0E6aE8+JVj60N yieU4RyL8P/bVLCPPTXjsIs5vbX+YkRXrt85uBpj9ygV6nPkYHqIBjedF/tJwQbA57a4Y/ RxAmwwPA9/vWJ2QGIsoqtRdcMyB3++U= Received: from mail-il1-f199.google.com (mail-il1-f199.google.com [209.85.166.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-29-ul3fvUjhPd2WRzlaz2xW2g-1; Thu, 23 Feb 2023 15:16:42 -0500 X-MC-Unique: ul3fvUjhPd2WRzlaz2xW2g-1 Received: by mail-il1-f199.google.com with SMTP id l5-20020a92d8c5000000b00316f26477d6so2996875ilo.10 for ; Thu, 23 Feb 2023 12:16:42 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ZhEAhg+gVumsM/eyaB8hov+QmlvtrVjqSST+g/tyyjM=; b=YALBi3vggbx40FlryFIn3nZsP+FK7ThWdnpBF1JbKTuAKbd18Aj5zzuMoJm5wsV7By 6bySzpBsFbd69bFCHu6OAVP06khZqDZKTP5lV9pM4uWyaMA64aU9jmJPYp4/9KIIkzxS BZFEP+fqPFan0HdgzI44370M8+o6nl5FHF0QLou9ZKsGbXLf7BE4REDp5r7PtX9sz+/w Okj+1eEaT5w20qZ/Tae7DPd5yoFdnHUfNfqYUuk6Q30ZnMJs31zV3O9QnFNIoNWFEMzP i8p2Hfa7J0v93Sw4hV553WC38HISj6QWrs1f/0Qi8FtOFm1ESBfWP3OIoMFvF/2qpWAw Hl+A== X-Gm-Message-State: AO0yUKVKP0uS2M4nmf/FhEztL5FvzBp6nVGhVia9eqWFcUahxkqWWybf QxHo3FnGxaZRbRHjcSF5o+w/iKmn/l8Rb3imzDcldia2O8NS1kiI1Jga87WX4FFA4XzxbYxti2f zZ2V7lJ7AJgI1B94= X-Received: by 2002:a05:6e02:216a:b0:313:cd79:adcb with SMTP id s10-20020a056e02216a00b00313cd79adcbmr14401682ilv.18.1677183401790; Thu, 23 Feb 2023 12:16:41 -0800 (PST) X-Google-Smtp-Source: AK7set8LM0GXCGB+vHEwG0UE6L+PYjBCcyjg9MxIZztYGooaAyTiVrMmK2OZMIVpC9R+wmgfmykWIQ== X-Received: by 2002:a05:6e02:216a:b0:313:cd79:adcb with SMTP id s10-20020a056e02216a00b00313cd79adcbmr14401665ilv.18.1677183401563; Thu, 23 Feb 2023 12:16:41 -0800 (PST) Received: from redhat.com ([38.15.36.239]) by smtp.gmail.com with ESMTPSA id g14-20020a056638060e00b003c502198ffbsm2525339jar.22.2023.02.23.12.16.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Feb 2023 12:16:41 -0800 (PST) Date: Thu, 23 Feb 2023 13:16:40 -0700 From: Alex Williamson To: Jason Gunthorpe Cc: Avihai Horon , qemu-devel@nongnu.org, =?UTF-8?B?Q8OpZHJpYw==?= Le Goater , Juan Quintela , "Dr. David Alan Gilbert" , "Michael S. Tsirkin" , Peter Xu , Jason Wang , Marcel Apfelbaum , Paolo Bonzini , Richard Henderson , Eduardo Habkost , David Hildenbrand , Philippe =?UTF-8?B?TWF0aGlldS1EYXVk?= =?UTF-8?B?w6k=?= , Yishai Hadas , Maor Gottlieb , Kirti Wankhede , Tarun Gupta , Joao Martins Subject: Re: [PATCH v2 11/20] vfio/common: Add device dirty page tracking start/stop Message-ID: <20230223131640.515451b2.alex.williamson@redhat.com> In-Reply-To: References: <20230222174915.5647-1-avihaih@nvidia.com> <20230222174915.5647-12-avihaih@nvidia.com> <20230222154043.35644d31.alex.williamson@redhat.com> <20230223122723.6a204e1b.alex.williamson@redhat.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.35; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=alex.williamson@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Thu, 23 Feb 2023 15:30:28 -0400 Jason Gunthorpe wrote: > On Thu, Feb 23, 2023 at 12:27:23PM -0700, Alex Williamson wrote: > > So again, I think I'm just looking for a better comment that doesn't > > add FUD to the reasoning behind switching to a single range, > > It isn't a single range, it is a single page of ranges, right? Exceeding a single page of ranges is the inflection point at which we switch to a single range. > The comment should say > > "Keep the implementation simple and use at most a PAGE_SIZE of ranges > because the kernel is guaranteed to be able to parse that" Something along those lines, yeah. And bonus points for noting that the kernel implementation is currently hard coded at this limit, so there's no point in trying larger arrays as implied in the uAPI. Thanks, Alex