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From: Juan Quintela <quintela@redhat.com>
In-Reply-To: <507FBF24.8060100@redhat.com> (Paolo Bonzini's message of "Thu,
	18 Oct 2012 10:34:44 +0200")
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Date: Fri, 26 Oct 2012 13:43:14 +0200
Message-ID: <87mwz9xxv1.fsf@elfo.mitica>
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Subject: Re: [Qemu-devel] [PATCH 21/30] migration: move exit condition to
	migration thread
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org

Paolo Bonzini <pbonzini@redhat.com> wrote:
> Il 18/10/2012 09:30, Juan Quintela ha scritto:
>> -        if (s->migration_state->complete) {
>> +        qemu_mutex_lock_iothread();
>
> So, was it a bug that we were accessing ->complete without the BQL?
>
>> +        if (m->state != MIG_STATE_ACTIVE) {
>> +            DPRINTF("put_ready returning because of non-active state\n");
>
> The contents of the debug message obsolete.  Besides, I would just put
> the two branches in the same "if (m->state != MIG_STATE_ACTIVE ||
> m->complete)".

BQL is not needed.  Complete is only used by the migration thread.  but
maintaing it outside of the iothread lock, makes locking even more complicated.

>
>> +            qemu_mutex_unlock_iothread();
>>              break;
>>          }
>> +        if (m->complete) {
>> +            qemu_mutex_unlock_iothread();
>> +            break;
>> +        }
>> +        qemu_mutex_unlock_iothread();
>> +
>
> Paolo