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 B6D18C83F1A for ; Thu, 10 Jul 2025 05:32:21 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uZjsw-0000Xq-0g; Thu, 10 Jul 2025 01:31:54 -0400 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 1uZjse-0000Up-Rp for qemu-devel@nongnu.org; Thu, 10 Jul 2025 01:31:45 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uZjsY-0007aa-2M for qemu-devel@nongnu.org; Thu, 10 Jul 2025 01:31:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1752125488; 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: in-reply-to:in-reply-to:references:references; bh=489ojv2XPS0VBvvpj3mZRJIjnGi5tzYd+qBFkgsD6H0=; b=KPUr0h7br7fuVpupEemf27XGHSM0ecrO4A8uqVjWGProNl6RIWX7qH72MWGruEjy+6+kov srex/EMchQS9EENKoBNfj+da2krHqI8wMrRqsjir9ndTyS91Q2DBvptq0DhOyYJOD5tTyE W6J1P2oXuS1tMxIef0dYptOzN9+00Kk= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-148-iQvU18BCNFSs-LWodQzX6w-1; Thu, 10 Jul 2025 01:31:27 -0400 X-MC-Unique: iQvU18BCNFSs-LWodQzX6w-1 X-Mimecast-MFC-AGG-ID: iQvU18BCNFSs-LWodQzX6w_1752125485 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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 mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5293E1956077; Thu, 10 Jul 2025 05:31:25 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.45.242.6]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B9DD1180035C; Thu, 10 Jul 2025 05:31:24 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id E255421E6A27; Thu, 10 Jul 2025 07:31:21 +0200 (CEST) From: Markus Armbruster To: Jonah Palmer Cc: Jason Wang , qemu-devel@nongnu.org, eperezma@redhat.com, peterx@redhat.com, mst@redhat.com, lvivier@redhat.com, dtatulea@nvidia.com, leiyang@redhat.com, parav@mellanox.com, sgarzare@redhat.com, lingshan.zhu@intel.com, boris.ostrovsky@oracle.com, Si-Wei Liu Subject: Re: [PATCH v4 0/7] Move memory listener register to vhost_vdpa_init In-Reply-To: <71ae1a0a-a697-4199-ab57-426f6252e224@oracle.com> (Jonah Palmer's message of "Wed, 9 Jul 2025 15:57:52 -0400") References: <20250507184647.15580-1-jonah.palmer@oracle.com> <87plg9ukgq.fsf@pond.sub.org> <50a648fa-76ab-47bf-9f6e-c07da913cb52@oracle.com> <87frgr7mvk.fsf@pond.sub.org> <87o6v6muq4.fsf@pond.sub.org> <8734cimtqa.fsf@pond.sub.org> <1e58dd8c-3418-4843-9620-3819e9ee31f3@oracle.com> <87o6uau2lj.fsf@pond.sub.org> <69bc738c-90fd-4a48-9bee-bb7372388810@oracle.com> <87frfcj904.fsf@pond.sub.org> <874ivnxfj6.fsf@pond.sub.org> <71ae1a0a-a697-4199-ab57-426f6252e224@oracle.com> Date: Thu, 10 Jul 2025 07:31:21 +0200 Message-ID: <87ikk0ipcm.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@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, 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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 Jonah Palmer writes: [...] >> I think I finally know enough to give you constructive feedback. >> >> Your commit messages should answer the questions I had. Specifically: >> >> * Why are we doing this? To shorten guest-visible downtime. >> >> * How are we doing this? We additionally pin memory before entering the >> main loop. This speeds up the pinning we still do in the main loop. >> >> * Drawback: slower startup. In particular, QMP becomes >> available later. >> >> * Secondary benefit: main loop responsiveness improves, in particular >> QMP. >> >> * What uses of QEMU are affected? Only with vhost-vDPA. Spell out all >> the ways to get vhost-vDPA, please. >> >> * There's a tradeoff. Show your numbers. Discuss whether this needs to >> be configurable. >> >> If you can make a case for pinning memory this way always, do so. If >> you believe making it configurable would be a good idea, do so. If >> you're not sure, say so in the cover letter, and add a suitable TODO >> comment. >> >> Questions? > > No questions, understood. > > As I was writing the responses to your questions I was thinking to > myself that this stuff should've been in the cover letter / commit > messages in the first place. > > Definitely a learning moment for me. Thanks for your time on this Markus! You're welcome!