From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Williamson Subject: [PATCH v3 1/4] balloon: Allow multiple inhibit users Date: Tue, 7 Aug 2018 13:31:22 -0600 Message-ID: <20180807193125.30378-2-alex.williamson@redhat.com> References: <20180807193125.30378-1-alex.williamson@redhat.com> Cc: Cornelia Huck , david@redhat.com, kvm@vger.kernel.org, peterx@redhat.com, "Michael S. Tsirkin" To: alex.williamson@redhat.com, qemu-devel@nongnu.org Return-path: In-Reply-To: <20180807193125.30378-1-alex.williamson@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel2=m.gmane.org@nongnu.org Sender: "Qemu-devel" List-Id: 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. Reviewed-by: David Hildenbrand Reviewed-by: Peter Xu Reviewed-by: Cornelia Huck Signed-off-by: Alex Williamson --- 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) -- 2.18.0