Re: [PATCH 03/11] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable()

From	Andy Lutomirski <luto@amacapital.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH 03/11] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable()
Date	2016-02-12 20:10 +0100
Message-ID	<r1rgl-2Ho-9@gated-at.bofh.it> (permalink)
References	<qbpfr-5Ff-1@gated-at.bofh.it> <qbpfs-5Ff-27@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Mon, Sep 21, 2015 at 11:23 PM, Ingo Molnar <mingo@kernel.org> wrote:
> So when memory hotplug removes a piece of physical memory from pagetable
> mappings, it also frees the underlying PGD entry.
>
> This complicates PGD management, so don't do this. We can keep the
> PGD mapped and the PUD table all clear - it's only a single 4K page
> per 512 GB of memory hotplugged.

Ressurecting an ancient thread: I want this particular change to make
it (much) easier to make vmapped stacks work correctly.  Could it be
applied by itself?

--Andy

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Re: [PATCH 03/11] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Andy Lutomirski <luto@amacapital.net> - 2016-02-12 20:10 +0100

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