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Date: Thu, 7 May 2015 10:42:46 -0700
Message-ID: <CAPcyv4hHwW4U8x1_VLGj2Q4a3HxWgK4F4n9qXg8009_n7sxkmg@mail.gmail.com>
Subject: Re: [PATCH v2 00/10] evacuate struct page from the block layer,
 introduce __pfn_t
From: Dan Williams <dan.j.williams@intel.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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On Thu, May 7, 2015 at 10:36 AM, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Dan Williams <dan.j.williams@intel.com> wrote:
>
>> > Anyway, I did want to say that while I may not be convinced about
>> > the approach, I think the patches themselves don't look horrible.
>> > I actually like your "__pfn_t". So while I (very obviously) have
>> > some doubts about this approach, it may be that the most
>> > convincing argument is just in the code.
>>
>> Ok, I'll keep thinking about this and come back when we have a
>> better story about passing mmap'd persistent memory around in
>> userspace.
>
> So is there anything fundamentally wrong about creating struct page
> backing at mmap() time (and making sure aliased mmaps share struct
> page arrays)?

Something like "get_user_pages() triggers memory hotplug for
persistent memory", so they are actual real struct pages?  Can we do
memory hotplug at that granularity?
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