linux-kernel - Re: [PATCH v2 0/6] mm: Optimize mseal checks

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Message-ID: <CAKbZUD0_BSv6KOgaRuqjLWGnttzcprcUu5WysSZeX8FXAvui5w@mail.gmail.com>
Date: Fri, 9 Aug 2024 01:34:37 +0100
From: Pedro Falcato <pedro.falcato@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: "Liam R. Howlett" <Liam.Howlett@...cle.com>, Vlastimil Babka <vbabka@...e.cz>, 
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>, linux-mm@...ck.org, 
	linux-kernel@...r.kernel.org, oliver.sang@...el.com, 
	torvalds@...ux-foundation.org, jeffxu@...gle.com, 
	Michael Ellerman <mpe@...erman.id.au>
Subject: Re: [PATCH v2 0/6] mm: Optimize mseal checks

On Fri, Aug 9, 2024 at 12:12 AM Andrew Morton <akpm@...ux-foundation.org> wrote:
>
> On Wed,  7 Aug 2024 22:13:03 +0100 Pedro Falcato <pedro.falcato@...il.com> wrote:
>
> > This series also depends on (and will eventually very slightly conflict with)
> > the powerpc series that removes arch_unmap[2].
>
> That's awkward.  Please describe the dependency?

One of the transformations done in this patch series (patch 2) assumes
that arch_unmap either doesn't exist or does nothing.
PPC is the only architecture with an arch_unmap implementation, and
through the series I linked they're going to make it work via
->close().

What's the easiest way to deal with this? Can the PPC series go
through the mm tree?

I could also possibly work around this on my end, and either limit the
terribleness to the ppc arch_unmap code or limit the effectiveness of
the patch set a bit. But both of these options feel like somewhat
fighting the inevitable.

What do you think?

Thanks,
Pedro