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Date: Tue, 28 Jul 2015 11:32:14 +0530
From: Amit Shah <amit.shah@redhat.com>
Message-ID: <20150728060214.GJ12267@grmbl.mre>
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Subject: Re: [Qemu-devel] [PATCH v7 41/42] Disable mlock around incoming
	postcopy
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To: Juan Quintela <quintela@redhat.com>
Cc: aarcange@redhat.com, yamahata@private.email.ne.jp, liang.z.li@intel.com, "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>, qemu-devel@nongnu.org, luis@cs.umu.se, pbonzini@redhat.com, david@gibson.dropbear.id.au

On (Tue) 14 Jul 2015 [17:22:13], Juan Quintela wrote:
> "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote:

> > +    if (enable_mlock) {
> > +        if (os_mlock() < 0) {
> > +            error_report("mlock: %s", strerror(errno));
> > +            /*
> > +             * It doesn't feel right to fail at this point, we have a valid
> > +             * VM state.
> > +             */
> 
> realtime_init() exit in case of os_mlock() fails, so current code is:

Yea, I was wondering the same - but then I thought: would the realtime
case want a migration to happen at all?

> - we start qemu with mlock requset
> - we mlock memory
> - we start postcopy
> - we munlock memory
> - we mlock memory
> 
> I wmill really, really preffer having a check if memory is mlocked, and
> it that case, just abort migration altogether.  Or better still, wait to
> enable mlock *until* we have finished postcopy, no?

		Amit