linux-kernel - RE: [External] Re: [PATCH 2/4] mm: pgalloc: support address-conditional pmd allocation

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Message-ID: 
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Date: Wed, 21 Feb 2024 15:54:38 +0000
From: Maxwell Bland <mbland@...orola.com>
To: David Hildenbrand <david@...hat.com>,
        Christophe Leroy
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Subject: RE: [External] Re: [PATCH 2/4] mm: pgalloc: support
 address-conditional pmd allocation

> On February 21, 2024 3:27 AM David Hildenbrand wrote
> On 21.02.24 08:13, Christophe Leroy wrote:
> > Le 20/02/2024 à 21:32, Maxwell Bland a écrit :
> >>
> >> While other descriptors (e.g. pud) allow allocations conditional on
> >> which virtual address is allocated, pmd descriptor allocations do not.
> >> However, adding support for this is straightforward and is beneficial to
> >> future kernel development targeting the PMD memory granularity.
> >>
> >> As many architectures already implement pmd_populate_kernel in an
> >> address-generic manner, it is necessary to roll out support
> >> incrementally. For this purpose a preprocessor flag,
> >
> > Is it really worth it ? It is only 48 call sites that need to be
> > updated. It would avoid that processor flag and avoid introducing that
> > pmd_populate_kernel_at() in kernel core.
> 
> +1, let's avoid that if possible.

Will fix, thank you!

Maxwell