diff mbox series

[V4,05/11] migration: preserve suspended for bg_migration

Message ID 1693333086-392798-6-git-send-email-steven.sistare@oracle.com (mailing list archive)
State New, archived
Headers show
Series fix migration of suspended runstate | expand

Commit Message

Steven Sistare Aug. 29, 2023, 6:18 p.m. UTC
Do not wake a suspended guest during bg_migration.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 migration/migration.c | 12 +++++-------
 softmmu/runstate.c    |  1 +
 2 files changed, 6 insertions(+), 7 deletions(-)

Comments

Peter Xu Aug. 30, 2023, 4:35 p.m. UTC | #1
On Tue, Aug 29, 2023 at 11:18:00AM -0700, Steve Sistare wrote:
> Do not wake a suspended guest during bg_migration.
> 
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> ---
>  migration/migration.c | 12 +++++-------
>  softmmu/runstate.c    |  1 +
>  2 files changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index a9ecb66..303d5a6 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -3064,7 +3064,9 @@ static void bg_migration_vm_start_bh(void *opaque)
>      qemu_bh_delete(s->vm_start_bh);
>      s->vm_start_bh = NULL;
>  
> -    vm_start();
> +    if (!runstate_check(RUN_STATE_SUSPENDED)) {
> +        vm_start();
> +    }
>      s->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - s->downtime_start;
>  }
>  
> @@ -3134,16 +3136,12 @@ static void *bg_migration_thread(void *opaque)
>  
>      qemu_mutex_lock_iothread();
>  
> -    /*
> -     * If VM is currently in suspended state, then, to make a valid runstate
> -     * transition in vm_stop_force_state() we need to wakeup it up.
> -     */
> -    qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
>      s->vm_old_state = runstate_get();
>  
>      global_state_store();
>      /* Forcibly stop VM before saving state of vCPUs and devices */
> -    if (vm_stop_force_state(RUN_STATE_PAUSED)) {
> +    if (!runstate_check(RUN_STATE_SUSPENDED) &&
> +        vm_stop_force_state(RUN_STATE_PAUSED)) {

IIUC we need the vm_stop even for SUSPENDED?  I think we need to make sure
all backends are stopped before we start wr-protect the guest pages, so
when wr-protect happens the guest pages should be in a consistent state.

I'd think it proper to juse reuse the helper you introduced in the previous
patches, but maybe you have a reason to not do so (I didn't see it
mentioned anywhere, though)?

>          goto fail;
>      }
>      /*
> diff --git a/softmmu/runstate.c b/softmmu/runstate.c
> index 21d7407..4417527 100644
> --- a/softmmu/runstate.c
> +++ b/softmmu/runstate.c
> @@ -163,6 +163,7 @@ static const RunStateTransition runstate_transitions_def[] = {
>      { RUN_STATE_SUSPENDED, RUN_STATE_FINISH_MIGRATE },
>      { RUN_STATE_SUSPENDED, RUN_STATE_PRELAUNCH },
>      { RUN_STATE_SUSPENDED, RUN_STATE_COLO},
> +    { RUN_STATE_SUSPENDED, RUN_STATE_PAUSED },
>  
>      { RUN_STATE_WATCHDOG, RUN_STATE_RUNNING },
>      { RUN_STATE_WATCHDOG, RUN_STATE_FINISH_MIGRATE },
> -- 
> 1.8.3.1
>
Steven Sistare Nov. 13, 2023, 6:32 p.m. UTC | #2
On 8/30/2023 12:35 PM, Peter Xu wrote:
> On Tue, Aug 29, 2023 at 11:18:00AM -0700, Steve Sistare wrote:
>> Do not wake a suspended guest during bg_migration.
>>
>> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
>> ---
>>  migration/migration.c | 12 +++++-------
>>  softmmu/runstate.c    |  1 +
>>  2 files changed, 6 insertions(+), 7 deletions(-)
>>
>> diff --git a/migration/migration.c b/migration/migration.c
>> index a9ecb66..303d5a6 100644
>> --- a/migration/migration.c
>> +++ b/migration/migration.c
>> @@ -3064,7 +3064,9 @@ static void bg_migration_vm_start_bh(void *opaque)
>>      qemu_bh_delete(s->vm_start_bh);
>>      s->vm_start_bh = NULL;
>>  
>> -    vm_start();
>> +    if (!runstate_check(RUN_STATE_SUSPENDED)) {
>> +        vm_start();
>> +    }
>>      s->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - s->downtime_start;
>>  }
>>  
>> @@ -3134,16 +3136,12 @@ static void *bg_migration_thread(void *opaque)
>>  
>>      qemu_mutex_lock_iothread();
>>  
>> -    /*
>> -     * If VM is currently in suspended state, then, to make a valid runstate
>> -     * transition in vm_stop_force_state() we need to wakeup it up.
>> -     */
>> -    qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
>>      s->vm_old_state = runstate_get();
>>  
>>      global_state_store();
>>      /* Forcibly stop VM before saving state of vCPUs and devices */
>> -    if (vm_stop_force_state(RUN_STATE_PAUSED)) {
>> +    if (!runstate_check(RUN_STATE_SUSPENDED) &&
>> +        vm_stop_force_state(RUN_STATE_PAUSED)) {
> 
> IIUC we need the vm_stop even for SUSPENDED?  I think we need to make sure
> all backends are stopped before we start wr-protect the guest pages, so
> when wr-protect happens the guest pages should be in a consistent state.

Agreed, I stop everything for suspended in V5.

> I'd think it proper to juse reuse the helper you introduced in the previous
> patches, but maybe you have a reason to not do so (I didn't see it
> mentioned anywhere, though)?

This code is outgoing. The helper applies to the incoming side.

- Steve

>>          goto fail;
>>      }
>>      /*
>> diff --git a/softmmu/runstate.c b/softmmu/runstate.c
>> index 21d7407..4417527 100644
>> --- a/softmmu/runstate.c
>> +++ b/softmmu/runstate.c
>> @@ -163,6 +163,7 @@ static const RunStateTransition runstate_transitions_def[] = {
>>      { RUN_STATE_SUSPENDED, RUN_STATE_FINISH_MIGRATE },
>>      { RUN_STATE_SUSPENDED, RUN_STATE_PRELAUNCH },
>>      { RUN_STATE_SUSPENDED, RUN_STATE_COLO},
>> +    { RUN_STATE_SUSPENDED, RUN_STATE_PAUSED },
>>  
>>      { RUN_STATE_WATCHDOG, RUN_STATE_RUNNING },
>>      { RUN_STATE_WATCHDOG, RUN_STATE_FINISH_MIGRATE },
>> -- 
>> 1.8.3.1
>>
>
diff mbox series

Patch

diff --git a/migration/migration.c b/migration/migration.c
index a9ecb66..303d5a6 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -3064,7 +3064,9 @@  static void bg_migration_vm_start_bh(void *opaque)
     qemu_bh_delete(s->vm_start_bh);
     s->vm_start_bh = NULL;
 
-    vm_start();
+    if (!runstate_check(RUN_STATE_SUSPENDED)) {
+        vm_start();
+    }
     s->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - s->downtime_start;
 }
 
@@ -3134,16 +3136,12 @@  static void *bg_migration_thread(void *opaque)
 
     qemu_mutex_lock_iothread();
 
-    /*
-     * If VM is currently in suspended state, then, to make a valid runstate
-     * transition in vm_stop_force_state() we need to wakeup it up.
-     */
-    qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
     s->vm_old_state = runstate_get();
 
     global_state_store();
     /* Forcibly stop VM before saving state of vCPUs and devices */
-    if (vm_stop_force_state(RUN_STATE_PAUSED)) {
+    if (!runstate_check(RUN_STATE_SUSPENDED) &&
+        vm_stop_force_state(RUN_STATE_PAUSED)) {
         goto fail;
     }
     /*
diff --git a/softmmu/runstate.c b/softmmu/runstate.c
index 21d7407..4417527 100644
--- a/softmmu/runstate.c
+++ b/softmmu/runstate.c
@@ -163,6 +163,7 @@  static const RunStateTransition runstate_transitions_def[] = {
     { RUN_STATE_SUSPENDED, RUN_STATE_FINISH_MIGRATE },
     { RUN_STATE_SUSPENDED, RUN_STATE_PRELAUNCH },
     { RUN_STATE_SUSPENDED, RUN_STATE_COLO},
+    { RUN_STATE_SUSPENDED, RUN_STATE_PAUSED },
 
     { RUN_STATE_WATCHDOG, RUN_STATE_RUNNING },
     { RUN_STATE_WATCHDOG, RUN_STATE_FINISH_MIGRATE },