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Date:   Fri, 19 Jul 2019 05:00:43 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Jason Gunthorpe <jgg@ziepe.ca>
Cc:     Pavel Machek <pavel@ucw.cz>, Christoph Hellwig <hch@infradead.org>,
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        sgutti@nvidia.com, torvalds@linux-foundation.org,
        vdavydov.dev@gmail.com
Subject: Re: [PATCH] mm/Kconfig: additional help text for HMM_MIRROR option
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On Fri, Jul 19, 2019 at 08:48:53AM -0300, Jason Gunthorpe wrote:
> It is like MMU_NOTIFIERS, if something needs it, then it will select
> it.
> 
> Maybe it should just be a hidden kconfig anyhow as there is no reason
> to turn it on without also turning on a using driver.

We can't just select it due to the odd X86_64 || PPC64 dependency.

Which also answers Pavels question:  you never really need it, as we
can only use it for optional functionality due to that.