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dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:36876 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kL8oq-0007uF-Hg for qemu-devel@archiver.kernel.org; Wed, 23 Sep 2020 13:44:40 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44518) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kL8nd-00079x-Pq for qemu-devel@nongnu.org; Wed, 23 Sep 2020 13:43:25 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:27052) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kL8nb-0003R9-LU for qemu-devel@nongnu.org; Wed, 23 Sep 2020 13:43:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600883001; 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=irRmAPpOSKuEJA5u0loT/xQhprsI7nR15RQ88k5+2mU=; b=A89BihMbSZmVEgNEsnrLcRvp3dgaqdTQ3bKT3Tu7V3CLRp0YMw1ofchPgX6Bxcqj1S6k14 pzRUJMJegNTHEOtXMLmNRxUhHLK+M0DVXoq/baVsJ2+DMtWAo4/f4AZgn23qLLvLFGCD7g k8m8MmTMK8HDWFx32QC8xFffTM5wR/k= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-231-dmASnb-WO9WJehMZiGYpdw-1; Wed, 23 Sep 2020 13:43:20 -0400 X-MC-Unique: dmASnb-WO9WJehMZiGYpdw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4996C107464E for ; Wed, 23 Sep 2020 17:43:19 +0000 (UTC) Received: from work-vm (ovpn-113-46.ams2.redhat.com [10.36.113.46]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2882F5C230; Wed, 23 Sep 2020 17:43:13 +0000 (UTC) Date: Wed, 23 Sep 2020 18:43:11 +0100 From: "Dr. David Alan Gilbert" To: Peter Xu Subject: Re: [PATCH v2 0/6] migration/postcopy: Sync faulted addresses after network recovered Message-ID: <20200923174311.GA124840@work-vm> References: <20200908203022.341615-1-peterx@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200908203022.341615-1-peterx@redhat.com> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/22 23:02:20 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -32 X-Spam_score: -3.3 X-Spam_bar: --- X-Spam_report: (-3.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.228, 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, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Xiaohui Li , qemu-devel@nongnu.org, Juan Quintela Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Peter Xu (peterx@redhat.com) wrote: > v2: Queued > - add r-bs for Dave > - add patch "migration: Properly destroy variables on incoming side" as patch 1 > - destroy page_request_mutex in migration_incoming_state_destroy() too [Dave] > - use WITH_QEMU_LOCK_GUARD in two places where we can [Dave] > > We've seen conditional guest hangs on destination VM after postcopy recovered. > However the hang will resolve itself after a few minutes. > > The problem is: after a postcopy recovery, the prioritized postcopy queue on > the source VM is actually missing. So all the faulted threads before the > postcopy recovery happened will keep halted until (accidentally) the page got > copied by the background precopy migration stream. > > The solution is to also refresh this information after postcopy recovery. To > achieve this, we need to maintain a list of faulted addresses on the > destination node, so that we can resend the list when necessary. This work is > done via patch 2-5. > > With that, the last thing we need to do is to send this extra information to > source VM after recovered. Very luckily, this synchronization can be > "emulated" by sending a bunch of page requests (although these pages have been > sent previously!) to source VM just like when we've got a page fault. Even in > the 1st version of the postcopy code we'll handle duplicated pages well. So > this fix does not even need a new capability bit and it'll work smoothly on old > QEMUs when we migrate from them to the new QEMUs. > > Please review, thanks. > > Peter Xu (6): > migration: Properly destroy variables on incoming side > migration: Rework migrate_send_rp_req_pages() function > migration: Pass incoming state into qemu_ufd_copy_ioctl() > migration: Introduce migrate_send_rp_message_req_pages() > migration: Maintain postcopy faulted addresses > migration: Sync requested pages after postcopy recovery > > migration/migration.c | 79 +++++++++++++++++++++++++++++++++++----- > migration/migration.h | 23 +++++++++++- > migration/postcopy-ram.c | 46 ++++++++++------------- > migration/savevm.c | 57 +++++++++++++++++++++++++++++ > migration/trace-events | 3 ++ > 5 files changed, 171 insertions(+), 37 deletions(-) > > -- > 2.26.2 > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK