From d3e302f2ab9543e1fb52c9d7b6c2167d054a62f5 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Mon, 3 Dec 2018 21:52:37 +0100 Subject: [PATCH 18/34] balloon: Allow multiple inhibit users RH-Author: Alex Williamson Message-id: <154387395708.26945.11708135028435449926.stgit@gimli.home> Patchwork-id: 83227 O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH 1/7] balloon: Allow multiple inhibit users Bugzilla: 1619778 RH-Acked-by: Peter Xu RH-Acked-by: Cornelia Huck RH-Acked-by: Auger Eric RH-Acked-by: David Hildenbrand Bugzilla: 1619778 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 (cherry picked from commit 01ccbec7bdf6f89f1b7d46dda05e4c1fd2dd5ade) Signed-off-by: Miroslav Rezanina --- balloon.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/balloon.c b/balloon.c index 6bf0a96..9319879 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) -- 1.8.3.1