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aef060850b
qemu/migration/colo.c
zhanghailiang aef060850b COLO: Introduce state to record failover process 
When handling failover, COLO processes differently according to
the different stage of failover process, here we introduce a global
atomic variable to record the status of failover.

We add four failover status to indicate the different stage of failover process.
You should use the helpers to get and set the value.

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Amit Shah <amit@amitshah.net>
2016-10-30 15:17:39 +05:30

446 lines
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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 "qemu/timer.h"
#include "sysemu/sysemu.h"
#include "migration/colo.h"
#include "io/channel-buffer.h"
#include "trace.h"
#include "qemu/error-report.h"
#include "qapi/error.h"
#include "migration/failover.h"
#define COLO_BUFFER_BASE_SIZE (4 * 1024 * 1024)
bool colo_supported(void)
{
return false;
}
bool migration_in_colo_state(void)
{
MigrationState *s = migrate_get_current();
return (s->state == MIGRATION_STATUS_COLO);
}
bool migration_incoming_in_colo_state(void)
{
MigrationIncomingState *mis = migration_incoming_get_current();
return mis && (mis->state == MIGRATION_STATUS_COLO);
}
static void colo_send_message(QEMUFile *f, COLOMessage msg,
Error **errp)
{
int ret;
if (msg >= COLO_MESSAGE__MAX) {
error_setg(errp, "%s: Invalid message", __func__);
return;
}
qemu_put_be32(f, msg);
qemu_fflush(f);
ret = qemu_file_get_error(f);
if (ret < 0) {
error_setg_errno(errp, -ret, "Can't send COLO message");
}
trace_colo_send_message(COLOMessage_lookup[msg]);
}
static void colo_send_message_value(QEMUFile *f, COLOMessage msg,
uint64_t value, Error **errp)
{
Error *local_err = NULL;
int ret;
colo_send_message(f, msg, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
qemu_put_be64(f, value);
qemu_fflush(f);
ret = qemu_file_get_error(f);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to send value for message:%s",
COLOMessage_lookup[msg]);
}
}
static COLOMessage colo_receive_message(QEMUFile *f, Error **errp)
{
COLOMessage msg;
int ret;
msg = qemu_get_be32(f);
ret = qemu_file_get_error(f);
if (ret < 0) {
error_setg_errno(errp, -ret, "Can't receive COLO message");
return msg;
}
if (msg >= COLO_MESSAGE__MAX) {
error_setg(errp, "%s: Invalid message", __func__);
return msg;
}
trace_colo_receive_message(COLOMessage_lookup[msg]);
return msg;
}
static void colo_receive_check_message(QEMUFile *f, COLOMessage expect_msg,
Error **errp)
{
COLOMessage msg;
Error *local_err = NULL;
msg = colo_receive_message(f, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
if (msg != expect_msg) {
error_setg(errp, "Unexpected COLO message %d, expected %d",
msg, expect_msg);
}
}
static uint64_t colo_receive_message_value(QEMUFile *f, uint32_t expect_msg,
Error **errp)
{
Error *local_err = NULL;
uint64_t value;
int ret;
colo_receive_check_message(f, expect_msg, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return 0;
}
value = qemu_get_be64(f);
ret = qemu_file_get_error(f);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to get value for COLO message: %s",
COLOMessage_lookup[expect_msg]);
}
return value;
}
static int colo_do_checkpoint_transaction(MigrationState *s,
QIOChannelBuffer *bioc,
QEMUFile *fb)
{
Error *local_err = NULL;
int ret = -1;
colo_send_message(s->to_dst_file, COLO_MESSAGE_CHECKPOINT_REQUEST,
&local_err);
if (local_err) {
goto out;
}
colo_receive_check_message(s->rp_state.from_dst_file,
COLO_MESSAGE_CHECKPOINT_REPLY, &local_err);
if (local_err) {
goto out;
}
/* Reset channel-buffer directly */
qio_channel_io_seek(QIO_CHANNEL(bioc), 0, 0, NULL);
bioc->usage = 0;
qemu_mutex_lock_iothread();
vm_stop_force_state(RUN_STATE_COLO);
qemu_mutex_unlock_iothread();
trace_colo_vm_state_change("run", "stop");
/* Disable block migration */
s->params.blk = 0;
s->params.shared = 0;
qemu_savevm_state_header(fb);
qemu_savevm_state_begin(fb, &s->params);
qemu_mutex_lock_iothread();
qemu_savevm_state_complete_precopy(fb, false);
qemu_mutex_unlock_iothread();
qemu_fflush(fb);
colo_send_message(s->to_dst_file, COLO_MESSAGE_VMSTATE_SEND, &local_err);
if (local_err) {
goto out;
}
/*
* We need the size of the VMstate data in Secondary side,
* With which we can decide how much data should be read.
*/
colo_send_message_value(s->to_dst_file, COLO_MESSAGE_VMSTATE_SIZE,
bioc->usage, &local_err);
if (local_err) {
goto out;
}
qemu_put_buffer(s->to_dst_file, bioc->data, bioc->usage);
qemu_fflush(s->to_dst_file);
ret = qemu_file_get_error(s->to_dst_file);
if (ret < 0) {
goto out;
}
colo_receive_check_message(s->rp_state.from_dst_file,
COLO_MESSAGE_VMSTATE_RECEIVED, &local_err);
if (local_err) {
goto out;
}
colo_receive_check_message(s->rp_state.from_dst_file,
COLO_MESSAGE_VMSTATE_LOADED, &local_err);
if (local_err) {
goto out;
}
ret = 0;
qemu_mutex_lock_iothread();
vm_start();
qemu_mutex_unlock_iothread();
trace_colo_vm_state_change("stop", "run");
out:
if (local_err) {
error_report_err(local_err);
}
return ret;
}
static void colo_process_checkpoint(MigrationState *s)
{
QIOChannelBuffer *bioc;
QEMUFile *fb = NULL;
int64_t current_time, checkpoint_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
Error *local_err = NULL;
int ret;
failover_init_state();
s->rp_state.from_dst_file = qemu_file_get_return_path(s->to_dst_file);
if (!s->rp_state.from_dst_file) {
error_report("Open QEMUFile from_dst_file failed");
goto out;
}
/*
* Wait for Secondary finish loading VM states and enter COLO
* restore.
*/
colo_receive_check_message(s->rp_state.from_dst_file,
COLO_MESSAGE_CHECKPOINT_READY, &local_err);
if (local_err) {
goto out;
}
bioc = qio_channel_buffer_new(COLO_BUFFER_BASE_SIZE);
fb = qemu_fopen_channel_output(QIO_CHANNEL(bioc));
object_unref(OBJECT(bioc));
qemu_mutex_lock_iothread();
vm_start();
qemu_mutex_unlock_iothread();
trace_colo_vm_state_change("stop", "run");
while (s->state == MIGRATION_STATUS_COLO) {
current_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
if (current_time - checkpoint_time <
s->parameters.x_checkpoint_delay) {
int64_t delay_ms;
delay_ms = s->parameters.x_checkpoint_delay -
(current_time - checkpoint_time);
g_usleep(delay_ms * 1000);
}
ret = colo_do_checkpoint_transaction(s, bioc, fb);
if (ret < 0) {
goto out;
}
checkpoint_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
}
out:
/* Throw the unreported error message after exited from loop */
if (local_err) {
error_report_err(local_err);
}
if (fb) {
qemu_fclose(fb);
}
if (s->rp_state.from_dst_file) {
qemu_fclose(s->rp_state.from_dst_file);
}
}
void migrate_start_colo_process(MigrationState *s)
{
qemu_mutex_unlock_iothread();
migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_COLO);
colo_process_checkpoint(s);
qemu_mutex_lock_iothread();
}
static void colo_wait_handle_message(QEMUFile *f, int *checkpoint_request,
Error **errp)
{
COLOMessage msg;
Error *local_err = NULL;
msg = colo_receive_message(f, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
switch (msg) {
case COLO_MESSAGE_CHECKPOINT_REQUEST:
*checkpoint_request = 1;
break;
default:
*checkpoint_request = 0;
error_setg(errp, "Got unknown COLO message: %d", msg);
break;
}
}
void *colo_process_incoming_thread(void *opaque)
{
MigrationIncomingState *mis = opaque;
QEMUFile *fb = NULL;
QIOChannelBuffer *bioc = NULL; /* Cache incoming device state */
uint64_t total_size;
uint64_t value;
Error *local_err = NULL;
migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_COLO);
failover_init_state();
mis->to_src_file = qemu_file_get_return_path(mis->from_src_file);
if (!mis->to_src_file) {
error_report("COLO incoming thread: Open QEMUFile to_src_file failed");
goto out;
}
/*
* Note: the communication between Primary side and Secondary side
* should be sequential, we set the fd to unblocked in migration incoming
* coroutine, and here we are in the COLO incoming thread, so it is ok to
* set the fd back to blocked.
*/
qemu_file_set_blocking(mis->from_src_file, true);
bioc = qio_channel_buffer_new(COLO_BUFFER_BASE_SIZE);
fb = qemu_fopen_channel_input(QIO_CHANNEL(bioc));
object_unref(OBJECT(bioc));
colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_READY,
&local_err);
if (local_err) {
goto out;
}
while (mis->state == MIGRATION_STATUS_COLO) {
int request;
colo_wait_handle_message(mis->from_src_file, &request, &local_err);
if (local_err) {
goto out;
}
assert(request);
/* FIXME: This is unnecessary for periodic checkpoint mode */
colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_REPLY,
&local_err);
if (local_err) {
goto out;
}
colo_receive_check_message(mis->from_src_file,
COLO_MESSAGE_VMSTATE_SEND, &local_err);
if (local_err) {
goto out;
}
value = colo_receive_message_value(mis->from_src_file,
COLO_MESSAGE_VMSTATE_SIZE, &local_err);
if (local_err) {
goto out;
}
/*
* Read VM device state data into channel buffer,
* It's better to re-use the memory allocated.
* Here we need to handle the channel buffer directly.
*/
if (value > bioc->capacity) {
bioc->capacity = value;
bioc->data = g_realloc(bioc->data, bioc->capacity);
}
total_size = qemu_get_buffer(mis->from_src_file, bioc->data, value);
if (total_size != value) {
error_report("Got %" PRIu64 " VMState data, less than expected"
" %" PRIu64, total_size, value);
goto out;
}
bioc->usage = total_size;
qio_channel_io_seek(QIO_CHANNEL(bioc), 0, 0, NULL);
colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_RECEIVED,
&local_err);
if (local_err) {
goto out;
}
qemu_mutex_lock_iothread();
qemu_system_reset(VMRESET_SILENT);
if (qemu_loadvm_state(fb) < 0) {
error_report("COLO: loadvm failed");
qemu_mutex_unlock_iothread();
goto out;
}
qemu_mutex_unlock_iothread();
colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_LOADED,
&local_err);
if (local_err) {
goto out;
}
}
out:
/* Throw the unreported error message after exited from loop */
if (local_err) {
error_report_err(local_err);
}
if (fb) {
qemu_fclose(fb);
}
if (mis->to_src_file) {
qemu_fclose(mis->to_src_file);
}
migration_incoming_exit_colo();
return NULL;
}
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