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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, T_HK_NAME_DR,USER_AGENT_MUTT 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 E33DAC28CC6 for ; Mon, 3 Jun 2019 09:50:21 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BB5DB28042 for ; Mon, 3 Jun 2019 09:50:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BB5DB28042 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 ([127.0.0.1]:60640 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hXjbh-0006K6-3Z for qemu-devel@archiver.kernel.org; Mon, 03 Jun 2019 05:50:21 -0400 Received: from eggs.gnu.org ([209.51.188.92]:57990) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hXjak-0005tm-15 for qemu-devel@nongnu.org; Mon, 03 Jun 2019 05:49:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hXjai-00053w-Sh for qemu-devel@nongnu.org; Mon, 03 Jun 2019 05:49:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34274) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hXjai-00052a-Kc for qemu-devel@nongnu.org; Mon, 03 Jun 2019 05:49:20 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DD86185546 for ; Mon, 3 Jun 2019 09:49:19 +0000 (UTC) Received: from work-vm (ovpn-117-145.ams2.redhat.com [10.36.117.145]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B17632DE67; Mon, 3 Jun 2019 09:49:16 +0000 (UTC) Date: Mon, 3 Jun 2019 10:49:14 +0100 From: "Dr. David Alan Gilbert" To: Peter Xu Message-ID: <20190603094913.GE2640@work-vm> References: <20190603065056.25211-1-peterx@redhat.com> <20190603065056.25211-9-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190603065056.25211-9-peterx@redhat.com> User-Agent: Mutt/1.11.4 (2019-03-13) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 03 Jun 2019 09:49:19 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v4 08/11] kvm: Persistent per kvmslot dirty bitmap X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurent Vivier , Paolo Bonzini , 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: > When synchronizing dirty bitmap from kernel KVM we do it in a > per-kvmslot fashion and we allocate the userspace bitmap for each of > the ioctl. This patch instead make the bitmap cache be persistent > then we don't need to g_malloc0() every time. > > More importantly, the cached per-kvmslot dirty bitmap will be further > used when we want to add support for the KVM_CLEAR_DIRTY_LOG and this > cached bitmap will be used to guarantee we won't clear any unknown > dirty bits otherwise that can be a severe data loss issue for > migration code. > > Signed-off-by: Peter Xu OK, so this will use a little more memory, but probably fragment stuff less. Reviewed-by: Dr. David Alan Gilbert > --- > accel/kvm/kvm-all.c | 10 +++++++--- > include/sysemu/kvm_int.h | 2 ++ > 2 files changed, 9 insertions(+), 3 deletions(-) > > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c > index b686531586..9fb0694772 100644 > --- a/accel/kvm/kvm-all.c > +++ b/accel/kvm/kvm-all.c > @@ -511,17 +511,19 @@ static int kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml, > */ > size = ALIGN(((mem->memory_size) >> TARGET_PAGE_BITS), > /*HOST_LONG_BITS*/ 64) / 8; > - d.dirty_bitmap = g_malloc0(size); > + if (!mem->dirty_bmap) { > + /* Allocate on the first log_sync, once and for all */ > + mem->dirty_bmap = g_malloc0(size); > + } > > + d.dirty_bitmap = mem->dirty_bmap; > d.slot = mem->slot | (kml->as_id << 16); > if (kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d) == -1) { > DPRINTF("ioctl failed %d\n", errno); > - g_free(d.dirty_bitmap); > return -1; > } > > kvm_get_dirty_pages_log_range(section, d.dirty_bitmap); > - g_free(d.dirty_bitmap); > } > > return 0; > @@ -796,6 +798,8 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml, > } > > /* unregister the slot */ > + g_free(mem->dirty_bmap); > + mem->dirty_bmap = NULL; > mem->memory_size = 0; > mem->flags = 0; > err = kvm_set_user_memory_region(kml, mem, false); > diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h > index f838412491..687a2ee423 100644 > --- a/include/sysemu/kvm_int.h > +++ b/include/sysemu/kvm_int.h > @@ -21,6 +21,8 @@ typedef struct KVMSlot > int slot; > int flags; > int old_flags; > + /* Dirty bitmap cache for the slot */ > + unsigned long *dirty_bmap; > } KVMSlot; > > typedef struct KVMMemoryListener { > -- > 2.17.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK