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 54343C3DA4A for ; Thu, 8 Aug 2024 15:26:28 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sc51H-0003ub-En; Thu, 08 Aug 2024 11:25:39 -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 1sc51F-0003qj-Pj for qemu-devel@nongnu.org; Thu, 08 Aug 2024 11:25:37 -0400 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 1sc51E-00055L-2L for qemu-devel@nongnu.org; Thu, 08 Aug 2024 11:25:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1723130734; 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=40s7y3yjiQ3kcoKbH3z2AlAuLczFr+zYkcJIoHqFbLk=; b=WCBg20fBRLEO82FvJtADtQHSVXSmDVrXlBgfAk43WGaOEnmflCUn4bcIDCMkEHtqQwG/uV D57fG2wcoVoKf3ts3tCf+lbwWoOc2IORboRr5bB4NnkaF8JKVeU2pkSqVwug6s4GntIG2w 3SNUCIUkzAuwTEJQNw8/JH0qfQzzwSY= Received: from mail-oo1-f72.google.com (mail-oo1-f72.google.com [209.85.161.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-353-mrzz_CJaMp-R3Vgucgq-qA-1; Thu, 08 Aug 2024 11:25:33 -0400 X-MC-Unique: mrzz_CJaMp-R3Vgucgq-qA-1 Received: by mail-oo1-f72.google.com with SMTP id 006d021491bc7-5d5b4ffa0c8so149970eaf.1 for ; Thu, 08 Aug 2024 08:25:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723130732; x=1723735532; 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=40s7y3yjiQ3kcoKbH3z2AlAuLczFr+zYkcJIoHqFbLk=; b=lOivg7ewQM8hREmui+u7zSHGmB4grOyomurS5cGEXS6c6cBDcsw6hw+0Kw/ras56GM kF/51Suw9FBOL7XxIMj77EwcMlYYLK+Ys9Azys6BNLspe6011g+UyM60yMUX8MsORqLC cgLeZZmArg3F0O5nYwJlQM5WQrS+QlDwStxRsDjjxHFUvIXWolfyUF/wCZ+O/+3Pvagg Vw8eeVWhW6ATBUdDQ//kO8N/J3y12k8nn148lL8vq75Vz+Zyc/EPo0UhOMQZd+UxhF+F 1DXIpDZq4SDmbLUJ/e60V+NEtk1kdB3RqdFckq7LGfjQAi0XurXJJ9mCLIvC6Y4dyFGR BukA== X-Forwarded-Encrypted: i=1; AJvYcCXrjsGb21g5yAiu++bLRaxc79uYMo7o2jkI5S+MywNIZ7Sg7uxMa/ur0jQh8pOCkg9f5yXr0kWXSLlVg68a6JU0B0taMHk= X-Gm-Message-State: AOJu0YzOM0ueToUNczvHXRVCYR6toYbN0fVr2I+dZhgCRr16XqBZYgJZ 0LN87x1vcEg86kwAMy7gcfiR8g0W3Gb1C2woy5++GCNuipfLw3noO5P2PkvuV5BYOFple7EPpGh 9n3safZhTx7StXhwBDIa3AnJ2pTuyIVgzRzeQM1Qz5Z6yJPdC6lTe X-Received: by 2002:a4a:ea99:0:b0:5cd:13e0:b0d3 with SMTP id 006d021491bc7-5d855ba00bcmr1435749eaf.2.1723130732638; Thu, 08 Aug 2024 08:25:32 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGHGPhZCEe+IegUokZrqMGVnnhh0mLBCfHI2VXEJbhwMqkUCEpyEJEU8GMEXbL/Up15ltHiEw== X-Received: by 2002:a4a:ea99:0:b0:5cd:13e0:b0d3 with SMTP id 006d021491bc7-5d855ba00bcmr1435728eaf.2.1723130732167; Thu, 08 Aug 2024 08:25:32 -0700 (PDT) Received: from x1n (pool-99-254-121-117.cpe.net.cable.rogers.com. [99.254.121.117]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6bb9c7c0fe7sm67865246d6.71.2024.08.08.08.25.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Aug 2024 08:25:31 -0700 (PDT) Date: Thu, 8 Aug 2024 11:25:29 -0400 From: Peter Xu To: "Michael S. Tsirkin" Cc: Akihiko Odaki , Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= , Thomas Huth , Yuri Benditovich , eduardo@habkost.net, marcel.apfelbaum@gmail.com, philmd@linaro.org, wangyanan55@huawei.com, dmitry.fleytman@gmail.com, jasowang@redhat.com, sriram.yagnaraman@est.tech, sw@weilnetz.de, qemu-devel@nongnu.org, yan@daynix.com, Fabiano Rosas , devel@lists.libvirt.org Subject: Re: [PATCH v2 4/4] virtio-net: Add support for USO features Message-ID: References: <20240805060544-mutt-send-email-mst@kernel.org> <2b62780c-a6cb-4262-beb5-81d54c14f545@daynix.com> <20240806092822-mutt-send-email-mst@kernel.org> <890f9d0a-3ded-488d-b274-8be9c38b5df3@daynix.com> <20240808065339-mutt-send-email-mst@kernel.org> <274ccd97-a473-4937-a57b-0029a18069c9@daynix.com> <20240808070912-mutt-send-email-mst@kernel.org> <20240808104559-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240808104559-mutt-send-email-mst@kernel.org> Received-SPF: pass client-ip=170.10.129.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.141, 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_H3=0.001, RCVD_IN_MSPIKE_WL=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, Aug 08, 2024 at 10:47:28AM -0400, Michael S. Tsirkin wrote: > On Thu, Aug 08, 2024 at 10:15:36AM -0400, Peter Xu wrote: > > On Thu, Aug 08, 2024 at 07:12:14AM -0400, Michael S. Tsirkin wrote: > > > This is too big of a hammer. People already use what you call "cross > > > migrate" and have for years. We are not going to stop developing > > > features just because someone suddenly became aware of some such bit. > > > If you care, you will have to work to solve the problem properly - > > > nacking half baked hacks is the only tool maintainers have to make > > > people work on hard problems. > > > > IMHO this is totally different thing. It's not about proposing a new > > feature yet so far, it's about how we should fix a breakage first. > > > > And that's why I think we should fix it even in the simple way first, then > > we consider anything more benefitial from perf side without breaking > > anything, which should be on top of that. > > > > Thanks, > > As I said, once the quick hack is merged people stop caring. IMHO it's not a hack. It's a proper fix to me to disable it by default for now. OTOH, having it ON always even knowing it can break migration is a hack to me, when we don't have anything else to guard the migration. > Mixing different kernel versions in migration is esoteric enough for > this not to matter to most people. There's no rush I think, address > it properly. Exactly mixing kernel versions will be tricky to users to identify, but that's, AFAICT, exactly happening everywhere. We can't urge user to always use the exact same kernels when we're talking about a VM cluster. That's why I think allowing migration to work across those kernels matter. I will agree there's no rush iff RHEL9 kernel won't backport TAP at all, otherwise this will trigger between y-stream after people upgrades partial of the clusters. Thanks, -- Peter Xu