On 2/20/2024 2:33 AM, Peter Xu wrote:
> On Thu, Feb 08, 2024 at 10:54:03AM -0800, Steve Sistare wrote:
>> When migration for cpr is initiated, stop the vm and set state
>> RUN_STATE_FINISH_MIGRATE before ram is saved. This eliminates the
>> possibility of ram and device state being out of sync, and guarantees
>> that a guest in the suspended state remains suspended, because qmp_cont
>> rejects a cont command in the RUN_STATE_FINISH_MIGRATE state.
>>
>> Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
>> ---
>> include/migration/misc.h | 1 +
>> migration/migration.c | 32 +++++++++++++++++++++++++-------
>> 2 files changed, 26 insertions(+), 7 deletions(-)
>>
>> diff --git a/include/migration/misc.h b/include/migration/misc.h
>> index 6dc234b..54c99a3 100644
>> --- a/include/migration/misc.h
>> +++ b/include/migration/misc.h
>> @@ -60,6 +60,7 @@ void migration_object_init(void);
>> void migration_shutdown(void);
>> bool migration_is_idle(void);
>> bool migration_is_active(MigrationState *);
>> +bool migrate_mode_is_cpr(MigrationState *);
>>
>> typedef enum MigrationEventType {
>> MIG_EVENT_PRECOPY_SETUP,
>> diff --git a/migration/migration.c b/migration/migration.c
>> index d1fce9e..fc5c587 100644
>> --- a/migration/migration.c
>> +++ b/migration/migration.c
>> @@ -1603,6 +1603,11 @@ bool migration_is_active(MigrationState *s)
>> s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE);
>> }
>>
>> +bool migrate_mode_is_cpr(MigrationState *s)
>> +{
>> + return s->parameters.mode == MIG_MODE_CPR_REBOOT;
>> +}
>> +
>> int migrate_init(MigrationState *s, Error **errp)
>> {
>> int ret;
>> @@ -2651,13 +2656,14 @@ static int
>> migration_completion_precopy(MigrationState *s,
>> bql_lock();
>> migration_downtime_start(s);
>>
>> - s->vm_old_state = runstate_get();
>> - global_state_store();
>> -
>> - ret = migration_stop_vm(RUN_STATE_FINISH_MIGRATE);
>> - trace_migration_completion_vm_stop(ret);
>> - if (ret < 0) {
>> - goto out_unlock;
>> + if (!migrate_mode_is_cpr(s)) {
>> + s->vm_old_state = runstate_get();
>> + global_state_store();
>> + ret = migration_stop_vm(RUN_STATE_FINISH_MIGRATE);
>> + trace_migration_completion_vm_stop(ret);
>> + if (ret < 0) {
>> + goto out_unlock;
>> + }
>> }
>>
>> ret = migration_maybe_pause(s, current_active_state,
>> @@ -3576,6 +3582,7 @@ void migrate_fd_connect(MigrationState *s, Error
>> *error_in)
>> Error *local_err = NULL;
>> uint64_t rate_limit;
>> bool resume = s->state == MIGRATION_STATUS_POSTCOPY_PAUSED;
>> + int ret;
>>
>> /*
>> * If there's a previous error, free it and prepare for another one.
>> @@ -3651,6 +3658,17 @@ void migrate_fd_connect(MigrationState *s, Error
>> *error_in)
>> goto fail;
>> }
>>
>> + if (migrate_mode_is_cpr(s)) {
>> + s->vm_old_state = runstate_get();
>> + global_state_store();
>> + ret = migration_stop_vm(RUN_STATE_FINISH_MIGRATE);
>> + trace_migration_completion_vm_stop(ret);
>> + if (ret < 0) {
>> + error_setg(&local_err, "migration_stop_vm failed, error %d",
>> -ret);
>> + goto fail;
>> + }
>> + }
>
> Could we have a helper function for the shared codes?
I propose to add code to migration_stop_vm to make it the helper. Some call
sites emit
more traces (via migration_stop_vm) as a result of my refactoring, and postcopy
start sets
vm_old_state, which is not used thereafter in that path. Those changes seem
harmless to me.
Tell me what you think:
-------------------------------------------------------
diff --git a/migration/migration.c b/migration/migration.c
index fc5c587..30d2b08 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -107,12 +107,6 @@ static int migration_maybe_pause(MigrationState *s,
static void migrate_fd_cancel(MigrationState *s);
static bool close_return_path_on_source(MigrationState *s);
-static void migration_downtime_start(MigrationState *s)
-{
- trace_vmstate_downtime_checkpoint("src-downtime-start");
- s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
-}
-
static void migration_downtime_end(MigrationState *s)
{
int64_t now = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
@@ -161,11 +155,20 @@ static gint page_request_addr_cmp(gconstpointer ap,
gconstpo
return (a > b) - (a < b);
}
-int migration_stop_vm(RunState state)
+static int migration_stop_vm(MigrationState *s, RunState state)
{
- int ret = vm_stop_force_state(state);
+ int ret;
+
+ trace_vmstate_downtime_checkpoint("src-downtime-start");
+ s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+
+ s->vm_old_state = runstate_get();
+ global_state_store();
+
+ ret = vm_stop_force_state(state);
trace_vmstate_downtime_checkpoint("src-vm-stopped");
+ trace_migration_completion_vm_stop(ret);
return ret;
}
@@ -2454,10 +2457,7 @@ static int postcopy_start(MigrationState *ms, Error
**errp)
bql_lock();
trace_postcopy_start_set_run();
- migration_downtime_start(ms);
-
- global_state_store();
- ret = migration_stop_vm(RUN_STATE_FINISH_MIGRATE);
+ ret = migration_stop_vm(ms, RUN_STATE_FINISH_MIGRATE);
if (ret < 0) {
goto fail;
}
@@ -2654,13 +2654,9 @@ static int migration_completion_precopy(MigrationState
*s,
int ret;
bql_lock();
- migration_downtime_start(s);
if (!migrate_mode_is_cpr(s)) {
- s->vm_old_state = runstate_get();
- global_state_store();
- ret = migration_stop_vm(RUN_STATE_FINISH_MIGRATE);
- trace_migration_completion_vm_stop(ret);
+ ret = migration_stop_vm(s, RUN_STATE_FINISH_MIGRATE);
if (ret < 0) {
goto out_unlock;
}
@@ -3498,15 +3494,10 @@ static void *bg_migration_thread(void *opaque)
s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
trace_migration_thread_setup_complete();
- migration_downtime_start(s);
bql_lock();
- s->vm_old_state = runstate_get();
-
- global_state_store();
- /* Forcibly stop VM before saving state of vCPUs and devices */
- if (migration_stop_vm(RUN_STATE_PAUSED)) {
+ if (migration_stop_vm(s, RUN_STATE_PAUSED)) {
goto fail;
}
/*
@@ -3659,10 +3650,7 @@ void migrate_fd_connect(MigrationState *s, Error
*error_in)
}
if (migrate_mode_is_cpr(s)) {
- s->vm_old_state = runstate_get();
- global_state_store();
- ret = migration_stop_vm(RUN_STATE_FINISH_MIGRATE);
- trace_migration_completion_vm_stop(ret);
+ ret = migration_stop_vm(s, RUN_STATE_FINISH_MIGRATE);
if (ret < 0) {
error_setg(&local_err, "migration_stop_vm failed, error %d", -ret);
goto fail;
diff --git a/migration/migration.h b/migration/migration.h
index aef8afb..65c0b61 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -541,6 +541,4 @@ int migration_rp_wait(MigrationState *s);
*/
void migration_rp_kick(MigrationState *s);
-int migration_stop_vm(RunState state);
-
#endif
-------------------------------------------------------
- Steve
