OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help

virtio-dev message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]

Subject: Re: [PATCH v9 5/8] migration/ram.c: add a notifier chain for precopy

On 11/29/2018 01:10 PM, Peter Xu wrote:
On Thu, Nov 29, 2018 at 11:40:57AM +0800, Wei Wang wrote:
I think this precopy notifier callchain is expected to be used only for
the precopy mode. Postcopy has its dedicated notifier callchain that
users could use.

How about changing the migrate_postcopy() check to "ms->start_postcopy":

bool migration_postcopy_start(void)
     MigrationState *s;

     s = migrate_get_current();

     return atomic_read(&s->start_postcopy);

static void precopy_notify(PrecopyNotifyReason reason)
     if (migration_postcopy_start())

     notifier_list_notify(&precopy_notifier_list, &reason);

If postcopy started with precopy, the precopy optimization feature
could still be used until it switches to the postcopy mode.
I'm not sure we can use start_postcopy.  It's a variable being set in
the QMP handler but it does not mean postcopy has started.  I'm afraid
there can be race where it's still precopy but the variable is set so
event could be missed...

I just found that migration_bitmap_sync is also called by ram_postcopy_send_discard_bitmap().
But we don't expect notifier_list_notify to be called in the postcopy mode.

So, probably we still need the start_postcopy check in notifier_list_notify though we have
the COMPLETE notifier.


[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]