@@ -509,6 +509,20 @@ int postcopy_ram_incoming_init(MigrationIncomingState *mis)
return 0;
}
+/*
+ * Manage a single vote to the QEMU balloon inhibitor for all postcopy usage,
+ * last caller wins.
+ */
+static void postcopy_balloon_inhibit(bool state)
+{
+ static bool cur_state = false;
+
+ if (state != cur_state) {
+ qemu_balloon_inhibit(state);
+ cur_state = state;
+ }
+}
+
/*
* At the end of a migration where postcopy_ram_incoming_init was called.
*/
@@ -539,7 +553,7 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
mis->have_fault_thread = false;
}
- qemu_balloon_inhibit(false);
+ postcopy_balloon_inhibit(false);
if (enable_mlock) {
if (os_mlock() < 0) {
@@ -1107,7 +1121,7 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis)
* Ballooning can mark pages as absent while we're postcopying
* that would cause false userfaults.
*/
- qemu_balloon_inhibit(true);
+ postcopy_balloon_inhibit(true);
trace_postcopy_ram_enable_notify();
While the qemu_balloon_inhibit() interface appears rather general purpose, postcopy uses it in a last-caller-wins approach with no guarantee of balanced inhibits and de-inhibits. Wrap postcopy's usage of the inhibitor to give it one vote overall, using the same last-caller-wins approach as previously implemented at the balloon level. Fixes: 01ccbec7bdf6 ("balloon: Allow multiple inhibit users") Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> --- migration/postcopy-ram.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-)