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 ws5-mx01.kavi.com (ws5-mx01.kavi.com [34.193.7.191]) (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 26BCDC47071 for ; Thu, 16 Nov 2023 17:26:08 +0000 (UTC) Received: from lists.oasis-open.org (oasis.ws5.connectedcommunity.org [10.110.1.242]) by ws5-mx01.kavi.com (Postfix) with ESMTP id 5420C77C4C for ; Thu, 16 Nov 2023 17:26:08 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 29968986E02 for ; Thu, 16 Nov 2023 17:26:08 +0000 (UTC) Received: from host09.ws5.connectedcommunity.org (host09.ws5.connectedcommunity.org [10.110.1.97]) by lists.oasis-open.org (Postfix) with QMQP id 11BB1986DF7; Thu, 16 Nov 2023 17:26:08 +0000 (UTC) Mailing-List: contact virtio-comment-help@lists.oasis-open.org; run by ezmlm List-ID: Sender: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 01ED2986DF8 for ; Thu, 16 Nov 2023 17:26:07 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: MrjXYxewOg-AUz7IWicP8Q-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700155564; x=1700760364; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=zUPwQ9yCkZ+3QUC2UdAqxFL2UkfGQQs7kh/g/UoAOQw=; b=oaUIZZVb4dTPgvc4CeQ1vY9r+En6pCG1UwsQPHLL1s5rGHXWrdazjeiRiZ+fQbxEVo gdf9DQTNZXt9u/Fo1+uVuh1meLpGEPnt/XRrWvl9f0YEw4rVEOzsia7QFOmMr4Pe/1Do TLgVVyHavbfTf/BwusxoKQ7X39Uernini97SIG8jQgp2Asun/lRD1S3XowRgDPx5/guv F8ixb0ByYRZzTl6A3pdeIP15bmjqPfCKFR4JxUUfFoHMnTeehY1kGM588fNtNX1X87+7 DZz97rwR20nsZsTCM7oF6JeWKIE9VAp35m1nbQ3Xrkppta7eFnZs6n01r223jzmJOf6K Lu8g== X-Gm-Message-State: AOJu0YzPewcf892Rq8nFdN0MYAd3+eL7aRwgegzIyU6WP6mtjqn99uCe r38gE9dSjxzen+K7NQ8CMvYTgKtDqSKnykxPQPBSGB+DWyjEmBvyPh2blfVLrRFsk+d6zi+jnx6 l/fOtze1/zp+erObZb7YlBNUFyjJStAB5HQ== X-Received: by 2002:a17:907:7888:b0:9be:6395:6b12 with SMTP id ku8-20020a170907788800b009be63956b12mr13930721ejc.27.1700155564220; Thu, 16 Nov 2023 09:26:04 -0800 (PST) X-Google-Smtp-Source: AGHT+IH52AbJPrHfQYp3PS2yVZhYVGHYNK052xA2pI5YUMV55MNVMwBEB8L0RJ0CBGwNKA3QXPZ2cg== X-Received: by 2002:a17:907:7888:b0:9be:6395:6b12 with SMTP id ku8-20020a170907788800b009be63956b12mr13930705ejc.27.1700155563909; Thu, 16 Nov 2023 09:26:03 -0800 (PST) Date: Thu, 16 Nov 2023 12:25:58 -0500 From: "Michael S. Tsirkin" To: Parav Pandit Cc: Jason Wang , "virtio-comment@lists.oasis-open.org" , "cohuck@redhat.com" , "sburla@marvell.com" , Shahaf Shuler , Maor Gottlieb , Yishai Hadas , "lingshan.zhu@intel.com" Message-ID: <20231116121958-mutt-send-email-mst@kernel.org> References: <20231116004037-mutt-send-email-mst@kernel.org> <20231116023443-mutt-send-email-mst@kernel.org> <20231116064611-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: [virtio-comment] Re: [PATCH v3 6/8] admin: Add theory of operation for write recording commands On Thu, Nov 16, 2023 at 04:26:53PM +0000, Parav Pandit wrote: > > From: Michael S. Tsirkin > > Sent: Thursday, November 16, 2023 5:18 PM > > > > On Thu, Nov 16, 2023 at 07:40:57AM +0000, Parav Pandit wrote: > > > > > > > From: Michael S. Tsirkin > > > > Sent: Thursday, November 16, 2023 1:06 PM > > > > > > > > On Thu, Nov 16, 2023 at 12:51:40AM -0500, Michael S. Tsirkin wrote: > > > > > On Thu, Nov 16, 2023 at 05:29:54AM +0000, Parav Pandit wrote: > > > > > > We should expose a limit of the device in the proposed > > > > WRITE_RECORD_CAP_QUERY command, that how much range it can track. > > > > > > So that future provisioning framework can use it. > > > > > > > > > > > > I will cover this in v5 early next week. > > > > > > > > > > I do worry about how this can even work though. If you want a > > > > > generic device you do not get to dictate how much memory VM has. > > > > > > > > > > Aren't we talking bit per page? With 1TByte of memory to track -> > > > > > 256Gbit -> 32Gbit -> 8Gbyte per VF? > > > > > > > > Ugh. Actually of course: > > > > With 1TByte of memory to track -> 256Mbit -> 32Mbit -> 8Mbyte per VF > > > > > > > > 8Gbyte per *PF* with 1K VFs. > > > > > > > Device may not maintain as a bitmap. > > > > However you maintain it, there's 256Mega bit of information. > There may be other data structures that device may deploy as for example hash or tree or something else. Point being? > And this is runtime memory only during the short live migration period of 400msec or less. > It is not some _always_ resident memory. No - write tracking is used in the live phase of migration. It can be enabled as long as you wish - it's a question of policy. There actually exist solutions that utilize this phase for redundancy, permanently running in this mode. -- MST This publicly archived list offers a means to provide input to the OASIS Virtual I/O Device (VIRTIO) TC. 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