qemu/migration/colo-failover.c

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/*
* COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
* (a.k.a. Fault Tolerance or Continuous Replication)
*
* Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
* Copyright (c) 2016 FUJITSU LIMITED
* Copyright (c) 2016 Intel Corporation
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "migration/colo.h"
#include "migration/failover.h"
#include "qmp-commands.h"
#include "qapi/qmp/qerror.h"
#include "qemu/error-report.h"
#include "trace.h"
static QEMUBH *failover_bh;
static FailoverStatus failover_state;
static void colo_failover_bh(void *opaque)
{
int old_state;
qemu_bh_delete(failover_bh);
failover_bh = NULL;
old_state = failover_set_state(FAILOVER_STATUS_REQUIRE,
FAILOVER_STATUS_ACTIVE);
if (old_state != FAILOVER_STATUS_REQUIRE) {
error_report("Unknown error for failover, old_state = %s",
FailoverStatus_lookup[old_state]);
return;
}
colo_do_failover(NULL);
}
void failover_request_active(Error **errp)
{
if (failover_set_state(FAILOVER_STATUS_NONE,
FAILOVER_STATUS_REQUIRE) != FAILOVER_STATUS_NONE) {
error_setg(errp, "COLO failover is already actived");
return;
}
failover_bh = qemu_bh_new(colo_failover_bh, NULL);
qemu_bh_schedule(failover_bh);
}
void failover_init_state(void)
{
failover_state = FAILOVER_STATUS_NONE;
}
FailoverStatus failover_set_state(FailoverStatus old_state,
FailoverStatus new_state)
{
FailoverStatus old;
old = atomic_cmpxchg(&failover_state, old_state, new_state);
if (old == old_state) {
trace_colo_failover_set_state(FailoverStatus_lookup[new_state]);
}
return old;
}
FailoverStatus failover_get_state(void)
{
return atomic_read(&failover_state);
}
void qmp_x_colo_lost_heartbeat(Error **errp)
{
if (get_colo_mode() == COLO_MODE_UNKNOWN) {
error_setg(errp, QERR_FEATURE_DISABLED, "colo");
return;
}
failover_request_active(errp);
}