From patchwork Mon Jul 30 23:13:46 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 951321 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 41fb4X31QCz9s1x for ; Tue, 31 Jul 2018 09:14:36 +1000 (AEST) Received: from localhost ([::1]:56262 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fkHN4-00012i-4p for incoming@patchwork.ozlabs.org; Mon, 30 Jul 2018 19:14:34 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60501) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fkHMb-00011s-DI for qemu-devel@nongnu.org; Mon, 30 Jul 2018 19:14:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fkHMY-0006PP-8o for qemu-devel@nongnu.org; Mon, 30 Jul 2018 19:14:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48810) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fkHMY-0006P6-1b for qemu-devel@nongnu.org; Mon, 30 Jul 2018 19:14:02 -0400 Received: from smtp.corp.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4E839307D861; Mon, 30 Jul 2018 23:14:01 +0000 (UTC) Received: from gimli.home (ovpn-116-35.phx2.redhat.com [10.3.116.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id DAD483083322; Mon, 30 Jul 2018 23:13:46 +0000 (UTC) From: Alex Williamson To: qemu-devel@nongnu.org Date: Mon, 30 Jul 2018 17:13:46 -0600 Message-ID: <153299242656.14411.14216251294160965283.stgit@gimli.home> In-Reply-To: <153299204130.14411.11438396195753743913.stgit@gimli.home> References: <153299204130.14411.11438396195753743913.stgit@gimli.home> User-Agent: StGit/0.18-136-gffd7-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Mon, 30 Jul 2018 23:14:01 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v2 1/4] balloon: Allow nested inhibits 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: cohuck@redhat.com, david@redhat.com, peterx@redhat.com, kvm@vger.kernel.org, mst@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" A simple true/false internal state does not allow multiple users. Fix this within the existing interface by converting to a counter, so long as the counter is elevated, ballooning is inhibited. Signed-off-by: Alex Williamson Reviewed-by: David Hildenbrand Reviewed-by: Peter Xu Reviewed-by: Cornelia Huck --- balloon.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/balloon.c b/balloon.c index 6bf0a9681377..931987983858 100644 --- a/balloon.c +++ b/balloon.c @@ -26,6 +26,7 @@ #include "qemu/osdep.h" #include "qemu-common.h" +#include "qemu/atomic.h" #include "exec/cpu-common.h" #include "sysemu/kvm.h" #include "sysemu/balloon.h" @@ -37,16 +38,22 @@ static QEMUBalloonEvent *balloon_event_fn; static QEMUBalloonStatus *balloon_stat_fn; static void *balloon_opaque; -static bool balloon_inhibited; +static int balloon_inhibit_count; bool qemu_balloon_is_inhibited(void) { - return balloon_inhibited; + return atomic_read(&balloon_inhibit_count) > 0; } void qemu_balloon_inhibit(bool state) { - balloon_inhibited = state; + if (state) { + atomic_inc(&balloon_inhibit_count); + } else { + atomic_dec(&balloon_inhibit_count); + } + + assert(atomic_read(&balloon_inhibit_count) >= 0); } static bool have_balloon(Error **errp)