[v4] Live update: cpr-exec

[PATCH V4 1/8] migration: multi-mode notifier

Posted by Steve Sistare 6 days, 1 hour ago

Allow a notifier to be added for multiple migration modes.
To allow a notifier to appear on multiple per-node lists, use
a generic list type.  We can no longer use NotifierWithReturnList,
because it shoe horns the notifier onto a single list.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
---
 include/migration/misc.h | 12 ++++++++++
 migration/migration.c    | 60 +++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 59 insertions(+), 13 deletions(-)

diff --git a/include/migration/misc.h b/include/migration/misc.h
index a261f99..592b930 100644
--- a/include/migration/misc.h
+++ b/include/migration/misc.h
@@ -95,7 +95,19 @@ void migration_add_notifier(NotifierWithReturn *notify,
 void migration_add_notifier_mode(NotifierWithReturn *notify,
                                  MigrationNotifyFunc func, MigMode mode);
 
+/*
+ * Same as migration_add_notifier, but applies to all @mode in the argument
+ * list.  The list is terminated by -1 or MIG_MODE_ALL.  For the latter,
+ * the notifier is added for all modes.
+ */
+void migration_add_notifier_modes(NotifierWithReturn *notify,
+                                  MigrationNotifyFunc func, MigMode mode, ...);
+
+/*
+ * Remove a notifier from all modes.
+ */
 void migration_remove_notifier(NotifierWithReturn *notify);
+
 void migration_file_set_error(int ret, Error *err);
 
 /* True if incoming migration entered POSTCOPY_INCOMING_DISCARD */
diff --git a/migration/migration.c b/migration/migration.c
index 10c216d..08a98f7 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -74,11 +74,7 @@
 
 #define INMIGRATE_DEFAULT_EXIT_ON_ERROR true
 
-static NotifierWithReturnList migration_state_notifiers[] = {
-    NOTIFIER_ELEM_INIT(migration_state_notifiers, MIG_MODE_NORMAL),
-    NOTIFIER_ELEM_INIT(migration_state_notifiers, MIG_MODE_CPR_REBOOT),
-    NOTIFIER_ELEM_INIT(migration_state_notifiers, MIG_MODE_CPR_TRANSFER),
-};
+static GSList *migration_state_notifiers[MIG_MODE__MAX];
 
 /* Messages sent on the return path from destination to source */
 enum mig_rp_message_type {
@@ -1665,23 +1661,51 @@ void migration_cancel(void)
     }
 }
 
+static int get_modes(MigMode mode, va_list ap);
+
+static void add_notifiers(NotifierWithReturn *notify, int modes)
+{
+    for (MigMode mode = 0; mode < MIG_MODE__MAX; mode++) {
+        if (modes & BIT(mode)) {
+            migration_state_notifiers[mode] =
+                g_slist_prepend(migration_state_notifiers[mode], notify);
+        }
+    }
+}
+
+void migration_add_notifier_modes(NotifierWithReturn *notify,
+                                  MigrationNotifyFunc func, MigMode mode, ...)
+{
+    int modes;
+    va_list ap;
+
+    va_start(ap, mode);
+    modes = get_modes(mode, ap);
+    va_end(ap);
+
+    notify->notify = (NotifierWithReturnFunc)func;
+    add_notifiers(notify, modes);
+}
+
 void migration_add_notifier_mode(NotifierWithReturn *notify,
                                  MigrationNotifyFunc func, MigMode mode)
 {
-    notify->notify = (NotifierWithReturnFunc)func;
-    notifier_with_return_list_add(&migration_state_notifiers[mode], notify);
+    migration_add_notifier_modes(notify, func, mode, -1);
 }
 
 void migration_add_notifier(NotifierWithReturn *notify,
                             MigrationNotifyFunc func)
 {
-    migration_add_notifier_mode(notify, func, MIG_MODE_NORMAL);
+    migration_add_notifier_modes(notify, func, MIG_MODE_NORMAL, -1);
 }
 
 void migration_remove_notifier(NotifierWithReturn *notify)
 {
     if (notify->notify) {
-        notifier_with_return_remove(notify);
+        for (MigMode mode = 0; mode < MIG_MODE__MAX; mode++) {
+            migration_blockers[mode] =
+                g_slist_remove(migration_state_notifiers[mode], notify);
+        }
         notify->notify = NULL;
     }
 }
@@ -1691,13 +1715,23 @@ int migration_call_notifiers(MigrationState *s, MigrationEventType type,
 {
     MigMode mode = s->parameters.mode;
     MigrationEvent e;
+    NotifierWithReturn *notifier;
+    GSList *elem, *next;
     int ret;
 
     e.type = type;
-    ret = notifier_with_return_list_notify(&migration_state_notifiers[mode],
-                                           &e, errp);
-    assert(!ret || type == MIG_EVENT_PRECOPY_SETUP);
-    return ret;
+
+    for (elem = migration_state_notifiers[mode]; elem; elem = next) {
+        next = elem->next;
+        notifier = (NotifierWithReturn *)elem->data;
+        ret = notifier->notify(notifier, &e, errp);
+        if (ret) {
+            assert(type == MIG_EVENT_PRECOPY_SETUP);
+            return ret;
+        }
+    }
+
+    return 0;
 }
 
 bool migration_has_failed(MigrationState *s)
-- 
1.8.3.1

Re: [PATCH V4 1/8] migration: multi-mode notifier

Posted by Cédric Le Goater 6 days ago

On 9/22/25 15:49, Steve Sistare wrote:
> Allow a notifier to be added for multiple migration modes.
> To allow a notifier to appear on multiple per-node lists, use
> a generic list type.  We can no longer use NotifierWithReturnList,
> because it shoe horns the notifier onto a single list.
> 
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> Reviewed-by: Fabiano Rosas <farosas@suse.de>
> ---
>   include/migration/misc.h | 12 ++++++++++
>   migration/migration.c    | 60 +++++++++++++++++++++++++++++++++++++-----------
>   2 files changed, 59 insertions(+), 13 deletions(-)
> 
> diff --git a/include/migration/misc.h b/include/migration/misc.h
> index a261f99..592b930 100644
> --- a/include/migration/misc.h
> +++ b/include/migration/misc.h
> @@ -95,7 +95,19 @@ void migration_add_notifier(NotifierWithReturn *notify,
>   void migration_add_notifier_mode(NotifierWithReturn *notify,
>                                    MigrationNotifyFunc func, MigMode mode);
>   
> +/*
> + * Same as migration_add_notifier, but applies to all @mode in the argument
> + * list.  The list is terminated by -1 or MIG_MODE_ALL.  For the latter,
> + * the notifier is added for all modes.
> + */
> +void migration_add_notifier_modes(NotifierWithReturn *notify,
> +                                  MigrationNotifyFunc func, MigMode mode, ...);
> +
> +/*
> + * Remove a notifier from all modes.
> + */
>   void migration_remove_notifier(NotifierWithReturn *notify);
> +
>   void migration_file_set_error(int ret, Error *err);

I think the include/migration/misc.h file should be updated with
proper documentation, like found in include/migration/blocker.h.

>   
>   /* True if incoming migration entered POSTCOPY_INCOMING_DISCARD */
> diff --git a/migration/migration.c b/migration/migration.c
> index 10c216d..08a98f7 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -74,11 +74,7 @@
>   
>   #define INMIGRATE_DEFAULT_EXIT_ON_ERROR true
>   
> -static NotifierWithReturnList migration_state_notifiers[] = {
> -    NOTIFIER_ELEM_INIT(migration_state_notifiers, MIG_MODE_NORMAL),
> -    NOTIFIER_ELEM_INIT(migration_state_notifiers, MIG_MODE_CPR_REBOOT),
> -    NOTIFIER_ELEM_INIT(migration_state_notifiers, MIG_MODE_CPR_TRANSFER),
> -};
> +static GSList *migration_state_notifiers[MIG_MODE__MAX];
>   
>   /* Messages sent on the return path from destination to source */
>   enum mig_rp_message_type {
> @@ -1665,23 +1661,51 @@ void migration_cancel(void)
>       }
>   }
>   
> +static int get_modes(MigMode mode, va_list ap);
> +
> +static void add_notifiers(NotifierWithReturn *notify, int modes)
> +{
> +    for (MigMode mode = 0; mode < MIG_MODE__MAX; mode++) {
> +        if (modes & BIT(mode)) {
> +            migration_state_notifiers[mode] =
> +                g_slist_prepend(migration_state_notifiers[mode], notify);
> +        }
> +    }
> +}
> +
> +void migration_add_notifier_modes(NotifierWithReturn *notify,
> +                                  MigrationNotifyFunc func, MigMode mode, ...)
> +{
> +    int modes;
> +    va_list ap;
> +
> +    va_start(ap, mode);
> +    modes = get_modes(mode, ap);
> +    va_end(ap);

No sanity check needed ? Could we have conflicting modes ? Just asking.


Thanks,

C.



> +    notify->notify = (NotifierWithReturnFunc)func;
> +    add_notifiers(notify, modes);
> +}
> +
>   void migration_add_notifier_mode(NotifierWithReturn *notify,
>                                    MigrationNotifyFunc func, MigMode mode)
>   {
> -    notify->notify = (NotifierWithReturnFunc)func;
> -    notifier_with_return_list_add(&migration_state_notifiers[mode], notify);
> +    migration_add_notifier_modes(notify, func, mode, -1);
>   }
>   
>   void migration_add_notifier(NotifierWithReturn *notify,
>                               MigrationNotifyFunc func)
>   {
> -    migration_add_notifier_mode(notify, func, MIG_MODE_NORMAL);
> +    migration_add_notifier_modes(notify, func, MIG_MODE_NORMAL, -1);
>   }
>   
>   void migration_remove_notifier(NotifierWithReturn *notify)
>   {
>       if (notify->notify) {
> -        notifier_with_return_remove(notify);
> +        for (MigMode mode = 0; mode < MIG_MODE__MAX; mode++) {
> +            migration_blockers[mode] =
> +                g_slist_remove(migration_state_notifiers[mode], notify);
> +        }
>           notify->notify = NULL;
>       }
>   }
> @@ -1691,13 +1715,23 @@ int migration_call_notifiers(MigrationState *s, MigrationEventType type,
>   {
>       MigMode mode = s->parameters.mode;
>       MigrationEvent e;
> +    NotifierWithReturn *notifier;
> +    GSList *elem, *next;
>       int ret;
>   
>       e.type = type;
> -    ret = notifier_with_return_list_notify(&migration_state_notifiers[mode],
> -                                           &e, errp);
> -    assert(!ret || type == MIG_EVENT_PRECOPY_SETUP);
> -    return ret;
> +
> +    for (elem = migration_state_notifiers[mode]; elem; elem = next) {
> +        next = elem->next;
> +        notifier = (NotifierWithReturn *)elem->data;
> +        ret = notifier->notify(notifier, &e, errp);
> +        if (ret) {
> +            assert(type == MIG_EVENT_PRECOPY_SETUP);
> +            return ret;
> +        }
> +    }
> +
> +    return 0;
>   }
>   
>   bool migration_has_failed(MigrationState *s)

Re: [PATCH V4 1/8] migration: multi-mode notifier

Posted by Steven Sistare 3 days, 21 hours ago

On 9/22/2025 11:18 AM, Cédric Le Goater wrote:
> On 9/22/25 15:49, Steve Sistare wrote:
>> Allow a notifier to be added for multiple migration modes.
>> To allow a notifier to appear on multiple per-node lists, use
>> a generic list type.  We can no longer use NotifierWithReturnList,
>> because it shoe horns the notifier onto a single list.
>>
>> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
>> Reviewed-by: Fabiano Rosas <farosas@suse.de>
>> ---
>>   include/migration/misc.h | 12 ++++++++++
>>   migration/migration.c    | 60 +++++++++++++++++++++++++++++++++++++-----------
>>   2 files changed, 59 insertions(+), 13 deletions(-)
>>
>> diff --git a/include/migration/misc.h b/include/migration/misc.h
>> index a261f99..592b930 100644
>> --- a/include/migration/misc.h
>> +++ b/include/migration/misc.h
>> @@ -95,7 +95,19 @@ void migration_add_notifier(NotifierWithReturn *notify,
>>   void migration_add_notifier_mode(NotifierWithReturn *notify,
>>                                    MigrationNotifyFunc func, MigMode mode);
>> +/*
>> + * Same as migration_add_notifier, but applies to all @mode in the argument
>> + * list.  The list is terminated by -1 or MIG_MODE_ALL.  For the latter,
>> + * the notifier is added for all modes.
>> + */
>> +void migration_add_notifier_modes(NotifierWithReturn *notify,
>> +                                  MigrationNotifyFunc func, MigMode mode, ...);
>> +
>> +/*
>> + * Remove a notifier from all modes.
>> + */
>>   void migration_remove_notifier(NotifierWithReturn *notify);
>> +
>>   void migration_file_set_error(int ret, Error *err);
> 
> I think the include/migration/misc.h file should be updated with
> proper documentation, like found in include/migration/blocker.h.
> 
>>   /* True if incoming migration entered POSTCOPY_INCOMING_DISCARD */
>> diff --git a/migration/migration.c b/migration/migration.c
>> index 10c216d..08a98f7 100644
>> --- a/migration/migration.c
>> +++ b/migration/migration.c
>> @@ -74,11 +74,7 @@
>>   #define INMIGRATE_DEFAULT_EXIT_ON_ERROR true
>> -static NotifierWithReturnList migration_state_notifiers[] = {
>> -    NOTIFIER_ELEM_INIT(migration_state_notifiers, MIG_MODE_NORMAL),
>> -    NOTIFIER_ELEM_INIT(migration_state_notifiers, MIG_MODE_CPR_REBOOT),
>> -    NOTIFIER_ELEM_INIT(migration_state_notifiers, MIG_MODE_CPR_TRANSFER),
>> -};
>> +static GSList *migration_state_notifiers[MIG_MODE__MAX];
>>   /* Messages sent on the return path from destination to source */
>>   enum mig_rp_message_type {
>> @@ -1665,23 +1661,51 @@ void migration_cancel(void)
>>       }
>>   }
>> +static int get_modes(MigMode mode, va_list ap);
>> +
>> +static void add_notifiers(NotifierWithReturn *notify, int modes)
>> +{
>> +    for (MigMode mode = 0; mode < MIG_MODE__MAX; mode++) {
>> +        if (modes & BIT(mode)) {
>> +            migration_state_notifiers[mode] =
>> +                g_slist_prepend(migration_state_notifiers[mode], notify);
>> +        }
>> +    }
>> +}
>> +
>> +void migration_add_notifier_modes(NotifierWithReturn *notify,
>> +                                  MigrationNotifyFunc func, MigMode mode, ...)
>> +{
>> +    int modes;
>> +    va_list ap;
>> +
>> +    va_start(ap, mode);
>> +    modes = get_modes(mode, ap);
>> +    va_end(ap);
> 
> No sanity check needed ? Could we have conflicting modes ? Just asking.

No conflicts.  A notifier can apply to one or more nodes.  Only the caller
knows what is necessary.

- Steve

>> +    notify->notify = (NotifierWithReturnFunc)func;
>> +    add_notifiers(notify, modes);
>> +}
>> +
>>   void migration_add_notifier_mode(NotifierWithReturn *notify,
>>                                    MigrationNotifyFunc func, MigMode mode)
>>   {
>> -    notify->notify = (NotifierWithReturnFunc)func;
>> -    notifier_with_return_list_add(&migration_state_notifiers[mode], notify);
>> +    migration_add_notifier_modes(notify, func, mode, -1);
>>   }
>>   void migration_add_notifier(NotifierWithReturn *notify,
>>                               MigrationNotifyFunc func)
>>   {
>> -    migration_add_notifier_mode(notify, func, MIG_MODE_NORMAL);
>> +    migration_add_notifier_modes(notify, func, MIG_MODE_NORMAL, -1);
>>   }
>>   void migration_remove_notifier(NotifierWithReturn *notify)
>>   {
>>       if (notify->notify) {
>> -        notifier_with_return_remove(notify);
>> +        for (MigMode mode = 0; mode < MIG_MODE__MAX; mode++) {
>> +            migration_blockers[mode] =
>> +                g_slist_remove(migration_state_notifiers[mode], notify);
>> +        }
>>           notify->notify = NULL;
>>       }
>>   }
>> @@ -1691,13 +1715,23 @@ int migration_call_notifiers(MigrationState *s, MigrationEventType type,
>>   {
>>       MigMode mode = s->parameters.mode;
>>       MigrationEvent e;
>> +    NotifierWithReturn *notifier;
>> +    GSList *elem, *next;
>>       int ret;
>>       e.type = type;
>> -    ret = notifier_with_return_list_notify(&migration_state_notifiers[mode],
>> -                                           &e, errp);
>> -    assert(!ret || type == MIG_EVENT_PRECOPY_SETUP);
>> -    return ret;
>> +
>> +    for (elem = migration_state_notifiers[mode]; elem; elem = next) {
>> +        next = elem->next;
>> +        notifier = (NotifierWithReturn *)elem->data;
>> +        ret = notifier->notify(notifier, &e, errp);
>> +        if (ret) {
>> +            assert(type == MIG_EVENT_PRECOPY_SETUP);
>> +            return ret;
>> +        }
>> +    }
>> +
>> +    return 0;
>>   }
>>   bool migration_has_failed(MigrationState *s)
>

[PATCH V4 1/8] migration: multi-mode notifier
[PATCH V4 2/8] migration: add cpr_walk_fd
[PATCH V4 3/8] oslib: qemu_clear_cloexec
[PATCH V4 4/8] migration: cpr-exec-command parameter
[PATCH V4 5/8] migration: cpr-exec save and load
[PATCH V4 6/8] migration: cpr-exec mode
[PATCH V4 7/8] migration: cpr-exec docs
[PATCH V4 8/8] vfio: cpr-exec mode