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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]:45580 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kX3JP-0000ib-QJ for qemu-devel@archiver.kernel.org; Mon, 26 Oct 2020 10:17:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41168) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kX30k-0004bT-0u for qemu-devel@nongnu.org; Mon, 26 Oct 2020 09:58:10 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:31867) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kX30i-0002g6-1R for qemu-devel@nongnu.org; Mon, 26 Oct 2020 09:58:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1603720687; 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=Ze5ZIO/PE/Fr+ZgJUryp5L48YVFnh9Sh3NG4sVbpK8w=; b=ULPvRPhS5sBxpbL25mFgI85PIGjkdycBQNZewfyb30OPQr5I6OROBBEx7jTan33EQXUZp5 ZNrOMKCSSSyKi81KA0aGRIY4x4YJFkx9Yx1r52z5BQZszzjXEpJiMYfknOUedT7QNAPCuB nBE21Lyzz9EwFG99Bo0JqMCdcckidYI= 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-287-zMfhMhP0MVyR7EiqjCUA1w-1; Mon, 26 Oct 2020 09:58:05 -0400 X-MC-Unique: zMfhMhP0MVyR7EiqjCUA1w-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6E76B61239; Mon, 26 Oct 2020 13:58:04 +0000 (UTC) Received: from work-vm (ovpn-112-208.ams2.redhat.com [10.36.112.208]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0DFE060C07; Mon, 26 Oct 2020 13:57:59 +0000 (UTC) Date: Mon, 26 Oct 2020 13:57:56 +0000 From: "Dr. David Alan Gilbert" To: Peter Xu Subject: Re: [PATCH v6 0/6] migration/postcopy: Sync faulted addresses after network recovered Message-ID: <20201026135756.GC28658@work-vm> References: <20201021212721.440373-1-peterx@redhat.com> MIME-Version: 1.0 In-Reply-To: <20201021212721.440373-1-peterx@redhat.com> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 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 = 2020/10/26 02:39:09 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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_H4=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: Peter Maydell , Thomas Huth , 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: > v6: > - fix page mask to use ramblock psize [Dave] > > v5: > - added one test patch for easier debugging for migration-test > - added one fix patch [1] for another postcopy race > - fixed a bug that could trigger when host/guest page size differs > > v4: > - use "void */ulong" instead of "uint64_t" where proper in patch 3/4 [Dave] > > v3: > - fix build on 32bit hosts & rebase > - remove r-bs for the last 2 patches for Dave due to the changes > > v2: > - 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. Queued Dave > > Peter Xu (6): > 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/postcopy: Release fd before going into 'postcopy-pause' > migration-test: Only hide error if !QTEST_LOG > > migration/migration.c | 55 ++++++++++++++++++++++++++++++---- > migration/migration.h | 21 ++++++++++++- > migration/postcopy-ram.c | 25 ++++++++++++---- > migration/savevm.c | 57 ++++++++++++++++++++++++++++++++++++ > migration/trace-events | 3 ++ > tests/qtest/migration-test.c | 6 +++- > 6 files changed, 154 insertions(+), 13 deletions(-) > > -- > 2.26.2 > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK