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Date: Thu, 12 Feb 2015 14:25:06 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: KY Srinivasan <kys@microsoft.com>, Vitaly Kuznetsov <vkuznets@redhat.com>,
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Subject: Re: [PATCH RESEND 0/3] memory_hotplug: hyperv: fix deadlock between
 memory adding and onlining
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On Thu, 12 Feb 2015 23:43:17 +0100 "Rafael J. Wysocki" <rjw@rjwysocki.net> wrote:

> On Thursday, February 12, 2015 10:10:30 PM KY Srinivasan wrote:
> 
> [cut]

yay!

> > > > > >
> > > > > > This issue was first discovered by Andy Whitcroft:
> > > > > > https://lkml.org/lkml/2014/3/14/451
> > > > > > I had sent patches based on Andy's analysis that did not affect
> > > > > > the users of the kernel hot-add memory APIs:
> > > > > > https://lkml.org/lkml/2014/12/2/662
> > > > > >
> > > > > > This patch puts the burden where it needs to be and can address
> > > > > > the issue
> > > > > for all clients.
> > > > >
> > > > > That seems to mean that this series is not needed.  Is that correct?
> > > >
> > > > This patch was never committed upstream and so the issue still is there.
> > > 
> > > Well, I'm not sure what to do now to be honest.
> > > 
> > > Is this series regarded as the right way to address the problem that
> > > everybody is comfortable with?  Or is it still under discussion?
> > 
> > We need to solve this problem and that is not under discussion. I also believe this problem
> > needs to be solved in a way that addresses the problem where it belongs - not in the users of
> > the hot_add API. Both my solution and the one proposed by David https://lkml.org/lkml/2015/2/12/57
> > address this issue. You can select either patch and check it in. I just want the issue addressed and I am not
> > married to the solution I proposed.
> 
> OK, thanks!
> 
> So having looked at both your patch and the David's one I think that
> the Andrew's tree is appropriate for any of them.
> 
> Andrew?

OK, I'll wake up and take a look.  Hopefully as 3.21 material but I
need to to back and reread everything.  Is it more urgent than that?