From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49371) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ffYkv-0005Qz-FS for qemu-devel@nongnu.org; Tue, 17 Jul 2018 18:47:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ffYku-0000l5-OI for qemu-devel@nongnu.org; Tue, 17 Jul 2018 18:47:41 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:39674 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ffYku-0000kw-Ix for qemu-devel@nongnu.org; Tue, 17 Jul 2018 18:47:40 -0400 From: Alex Williamson Date: Tue, 17 Jul 2018 16:47:37 -0600 Message-ID: <20180717224737.14019.3324.stgit@gimli.home> In-Reply-To: <20180717222721.14019.27548.stgit@gimli.home> References: <20180717222721.14019.27548.stgit@gimli.home> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] [RFC PATCH 1/3] balloon: Allow nested inhibits List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org 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 --- balloon.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/balloon.c b/balloon.c index 6bf0a9681377..2a6a7e1a22a0 100644 --- a/balloon.c +++ b/balloon.c @@ -37,16 +37,17 @@ static QEMUBalloonEvent *balloon_event_fn; static QEMUBalloonStatus *balloon_stat_fn; static void *balloon_opaque; -static bool balloon_inhibited; +static int balloon_inhibited; bool qemu_balloon_is_inhibited(void) { - return balloon_inhibited; + return balloon_inhibited > 0; } void qemu_balloon_inhibit(bool state) { - balloon_inhibited = state; + balloon_inhibited += (state ? 1 : -1); + assert(balloon_inhibited >= 0); } static bool have_balloon(Error **errp)