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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 5211EC433E0 for ; Wed, 20 May 2020 15:53:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 336D320759 for ; Wed, 20 May 2020 15:53:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="jBdHwLzX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726789AbgETPxJ (ORCPT ); Wed, 20 May 2020 11:53:09 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:40951 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726596AbgETPxI (ORCPT ); Wed, 20 May 2020 11:53:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589989987; 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=MWxes5zfMaG9o/8NEN/0d/Rm32meUmr2iQZPwMdi3lg=; b=jBdHwLzXf2D1d+8swKSSZ29XBhIOvKmhnTPnd/SmsmTA5X3jXIDGFKOl/Qfa145wb207hf CHjQho7IWSH/G7kBxu72bNW2AqlrTK8e0KCpw7P+3S+Nr5+5cfGf8PqhP8Ctb+TnrQMoek tKP4apx0A9eRUHjSD38RlHEmErCV4p8= 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-133-d951aKoFOkGPom9rMP8BQg-1; Wed, 20 May 2020 11:53:05 -0400 X-MC-Unique: d951aKoFOkGPom9rMP8BQg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4AA531005510; Wed, 20 May 2020 15:53:04 +0000 (UTC) Received: from work-vm (ovpn-114-169.ams2.redhat.com [10.36.114.169]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A7C455D9E2; Wed, 20 May 2020 15:52:56 +0000 (UTC) Date: Wed, 20 May 2020 16:52:54 +0100 From: "Dr. David Alan Gilbert" To: David Hildenbrand Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, qemu-s390x@nongnu.org, Richard Henderson , Paolo Bonzini , Eduardo Habkost , "Michael S . Tsirkin" , Juan Quintela Subject: Re: [PATCH v2 07/19] migration/rdma: Use ram_block_discard_disable() Message-ID: <20200520155254.GE2820@work-vm> References: <20200520123152.60527-1-david@redhat.com> <20200520123152.60527-8-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200520123152.60527-8-david@redhat.com> User-Agent: Mutt/1.13.4 (2020-02-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org * David Hildenbrand (david@redhat.com) wrote: > RDMA will pin all guest memory (as documented in docs/rdma.txt). We want > to disable RAM block discards - however, to keep it simple use > ram_block_discard_is_required() instead of inhibiting. > > Note: It is not sufficient to limit disabling to pin_all. Even when only > conditionally pinning 1 MB chunks, as soon as one page within such a > chunk was discarded and one page not, the discarded pages will be pinned > as well. > > Cc: "Michael S. Tsirkin" > Cc: Juan Quintela > Cc: "Dr. David Alan Gilbert" > Signed-off-by: David Hildenbrand Reviewed-by: Dr. David Alan Gilbert > --- > migration/rdma.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/migration/rdma.c b/migration/rdma.c > index 967fda5b0c..57e2cbc8ca 100644 > --- a/migration/rdma.c > +++ b/migration/rdma.c > @@ -29,6 +29,7 @@ > #include "qemu/sockets.h" > #include "qemu/bitmap.h" > #include "qemu/coroutine.h" > +#include "exec/memory.h" > #include > #include > #include > @@ -4017,8 +4018,14 @@ void rdma_start_incoming_migration(const char *host_port, Error **errp) > Error *local_err = NULL; > > trace_rdma_start_incoming_migration(); > - rdma = qemu_rdma_data_init(host_port, &local_err); > > + /* Avoid ram_block_discard_disable(), cannot change during migration. */ > + if (ram_block_discard_is_required()) { > + error_setg(errp, "RDMA: cannot disable RAM discard"); > + return; > + } > + > + rdma = qemu_rdma_data_init(host_port, &local_err); > if (rdma == NULL) { > goto err; > } > @@ -4065,10 +4072,17 @@ void rdma_start_outgoing_migration(void *opaque, > const char *host_port, Error **errp) > { > MigrationState *s = opaque; > - RDMAContext *rdma = qemu_rdma_data_init(host_port, errp); > RDMAContext *rdma_return_path = NULL; > + RDMAContext *rdma; > int ret = 0; > > + /* Avoid ram_block_discard_disable(), cannot change during migration. */ > + if (ram_block_discard_is_required()) { > + error_setg(errp, "RDMA: cannot disable RAM discard"); > + return; > + } > + > + rdma = qemu_rdma_data_init(host_port, errp); > if (rdma == NULL) { > goto err; > } > -- > 2.25.4 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK