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Message-ID: <dadc9d17-f311-47f1-a264-28b42bed0ab0@redhat.com>
Date:   Fri, 24 Nov 2023 20:35:47 +0100
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Subject: Re: [PATCH RFC v2 05/27] mm: page_alloc: Add an arch hook to allow
 prep_new_page() to fail
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To:     Alexandru Elisei <alexandru.elisei@arm.com>,
        catalin.marinas@arm.com, will@kernel.org, oliver.upton@linux.dev,
        maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com,
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        bristot@redhat.com, vschneid@redhat.com, mhiramat@kernel.org,
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References: <20231119165721.9849-1-alexandru.elisei@arm.com>
 <20231119165721.9849-6-alexandru.elisei@arm.com>
From:   David Hildenbrand <david@redhat.com>
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Precedence: bulk

On 19.11.23 17:56, Alexandru Elisei wrote:
> Introduce arch_prep_new_page(), which will be used by arm64 to reserve tag
> storage for an allocated page. Reserving tag storage can fail, for example,
> if the tag storage page has a short pin on it, so allow prep_new_page() ->
> arch_prep_new_page() to similarly fail.

But what are the side-effects of this? How does the calling code recover?

E.g., what if we need to populate a page into user space, but that 
particular page we allocated fails to be prepared? So we inject a signal 
into that poor process?

-- 
Cheers,

David / dhildenb