balloon: Allow multiple inhibit users

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 <david@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Alex Williamson 2018-08-17 09:27:15 -06:00
parent 0abaa41d93
commit 01ccbec7bd

View File

@ -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)