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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D8AEC433DF for ; Mon, 29 Jun 2020 08:07:08 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 56F7923134 for ; Mon, 29 Jun 2020 08:07:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WT2uuBfR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 56F7923134 Authentication-Results: mail.kernel.org; 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]:37656 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jpool-0005i3-LT for qemu-devel@archiver.kernel.org; Mon, 29 Jun 2020 04:07:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46736) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jpooC-0005HS-Hb for qemu-devel@nongnu.org; Mon, 29 Jun 2020 04:06:32 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:52132 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jpooA-0000aR-3b for qemu-devel@nongnu.org; Mon, 29 Jun 2020 04:06:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593417987; 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: content-transfer-encoding:content-transfer-encoding; bh=Quvs3auXGsiNa9bwq9vvT9IlJxvPAaxrbsRhS2i4QrE=; b=WT2uuBfRIuHTzyAqTm0OIh/sgqllOgvxdmfYGbaUtLkhfdxWrFi3P0Ol6azCzoHp4p+0Cj kXVk4EeGf8MCIuGfYXvsEfFnnn2T7YaE6UZkuoxkO/648rrm1pcjiHoWfHP+lqrvpFHImc 2Tc2HnxFXiBVOhCKgsxU7nfkRwtPKQ0= 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-60-CTox0YmYPJiuz3BNW_XxQg-1; Mon, 29 Jun 2020 04:06:26 -0400 X-MC-Unique: CTox0YmYPJiuz3BNW_XxQg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CF8B08015FD; Mon, 29 Jun 2020 08:06:24 +0000 (UTC) Received: from t480s.redhat.com (ovpn-114-157.ams2.redhat.com [10.36.114.157]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9BCAC121A56; Mon, 29 Jun 2020 08:06:16 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v2] virtio-balloon: always indicate S_DONE when migration fails Date: Mon, 29 Jun 2020 10:06:15 +0200 Message-Id: <20200629080615.26022-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=205.139.110.61; envelope-from=david@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/29 01:06:01 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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: virtio-dev@lists.oasis-open.org, David Hildenbrand , "Michael S . Tsirkin" , Alexander Duyck , Wei Wang , Alexander Duyck Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" If something goes wrong during precopy, before stopping the VM, we will never send a S_DONE indication to the VM, resulting in the hinted pages not getting released to be used by the guest OS (e.g., Linux). Easy to reproduce: 1. Start migration (e.g., HMP "migrate -d 'exec:gzip -c > STATEFILE.gz'") 2. Cancel migration (e.g., HMP "migrate_cancel") 3. Oberve in the guest (e.g., cat /proc/meminfo) that there is basically no free memory left. While at it, add similar locking to virtio_balloon_free_page_done() as done in virtio_balloon_free_page_stop. Locking is still weird, but that has to be sorted out separately. There is nothing to do in the PRECOPY_NOTIFY_COMPLETE case. Add some comments regarding S_DONE handling. Fixes: c13c4153f76d ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT") Reviewed-by: Alexander Duyck Cc: Wei Wang Cc: Alexander Duyck Signed-off-by: David Hildenbrand --- hw/virtio/virtio-balloon.c | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index 10507b2a43..8a84718490 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -628,8 +628,13 @@ static void virtio_balloon_free_page_done(VirtIOBalloon *s) { VirtIODevice *vdev = VIRTIO_DEVICE(s); - s->free_page_report_status = FREE_PAGE_REPORT_S_DONE; - virtio_notify_config(vdev); + if (s->free_page_report_status != FREE_PAGE_REPORT_S_DONE) { + /* See virtio_balloon_free_page_stop() */ + qemu_mutex_lock(&s->free_page_lock); + s->free_page_report_status = FREE_PAGE_REPORT_S_DONE; + qemu_mutex_unlock(&s->free_page_lock); + virtio_notify_config(vdev); + } } static int @@ -653,17 +658,26 @@ virtio_balloon_free_page_report_notify(NotifierWithReturn *n, void *data) case PRECOPY_NOTIFY_SETUP: precopy_enable_free_page_optimization(); break; - case PRECOPY_NOTIFY_COMPLETE: - case PRECOPY_NOTIFY_CLEANUP: case PRECOPY_NOTIFY_BEFORE_BITMAP_SYNC: virtio_balloon_free_page_stop(dev); break; case PRECOPY_NOTIFY_AFTER_BITMAP_SYNC: if (vdev->vm_running) { virtio_balloon_free_page_start(dev); - } else { - virtio_balloon_free_page_done(dev); + break; } + /* + * Set S_DONE before migrating the vmstate, so the guest will reuse + * all hinted pages once running on the destination. Fall through. + */ + case PRECOPY_NOTIFY_CLEANUP: + /* + * Especially, if something goes wrong during precopy or if migration + * is canceled, we have to properly communicate S_DONE to the VM. + */ + virtio_balloon_free_page_done(dev); + break; + case PRECOPY_NOTIFY_COMPLETE: break; default: virtio_error(vdev, "%s: %d reason unknown", __func__, pnd->reason); -- 2.26.2