From patchwork Wed Jun 3 14:49:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 11585777 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0D1031392 for ; Wed, 3 Jun 2020 14:50:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E889020870 for ; Wed, 3 Jun 2020 14:50:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JVgJH3Kt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726296AbgFCOuH (ORCPT ); Wed, 3 Jun 2020 10:50:07 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:27935 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726264AbgFCOuG (ORCPT ); Wed, 3 Jun 2020 10:50:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591195804; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=IXI8MvZBXHJ62Epbc7tcDuOnhHYwrxnOFnnNWM2DDqc=; b=JVgJH3Kt72j3/VQJRbIxVcKndHi9kiLOEmKZCjiR2qSkwxzPMIsloR1OdYaoFH/C0fOhy+ JO3FNajkGXSeDo+j60FI0NJwDWQ7A2csq8/t7E828AaO42LknSOKImleZPEkiMYKZjdP7X Un+jNJNEstYL4/c3+Wd41VreH2eIAfQ= 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-364-QdR6H76TOpSnkw2D9CQvfA-1; Wed, 03 Jun 2020 10:49:59 -0400 X-MC-Unique: QdR6H76TOpSnkw2D9CQvfA-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 B91AF19067E4; Wed, 3 Jun 2020 14:49:58 +0000 (UTC) Received: from t480s.redhat.com (ovpn-113-192.ams2.redhat.com [10.36.113.192]) by smtp.corp.redhat.com (Postfix) with ESMTP id B39815D9CD; Wed, 3 Jun 2020 14:49:56 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org, qemu-s390x@nongnu.org, Richard Henderson , Paolo Bonzini , "Dr . David Alan Gilbert" , Eduardo Habkost , "Michael S . Tsirkin" , David Hildenbrand , Juan Quintela Subject: [PATCH v3 07/20] migration/rdma: Use ram_block_discard_disable() Date: Wed, 3 Jun 2020 16:49:01 +0200 Message-Id: <20200603144914.41645-8-david@redhat.com> In-Reply-To: <20200603144914.41645-1-david@redhat.com> References: <20200603144914.41645-1-david@redhat.com> MIME-Version: 1.0 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 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. Reviewed-by: Dr. David Alan Gilbert Cc: "Michael S. Tsirkin" Cc: Juan Quintela Cc: "Dr. David Alan Gilbert" Signed-off-by: David Hildenbrand --- migration/rdma.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/migration/rdma.c b/migration/rdma.c index ec45d33ba3..bbe6f36627 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; } @@ -4067,10 +4074,17 @@ 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; }