linux-kernel - Re: [PATCH RFC v2 18/27] arm64: mte: Reserve tag block for the zero page

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Message-ID: <c027ea00-a955-4c3c-b1ea-2c3f6906790d@redhat.com>
Date:   Tue, 28 Nov 2023 18:06:54 +0100
From:   David Hildenbrand <david@...hat.com>
To:     Alexandru Elisei <alexandru.elisei@....com>,
        catalin.marinas@....com, will@...nel.org, oliver.upton@...ux.dev,
        maz@...nel.org, james.morse@....com, suzuki.poulose@....com,
        yuzenghui@...wei.com, arnd@...db.de, akpm@...ux-foundation.org,
        mingo@...hat.com, peterz@...radead.org, juri.lelli@...hat.com,
        vincent.guittot@...aro.org, dietmar.eggemann@....com,
        rostedt@...dmis.org, bsegall@...gle.com, mgorman@...e.de,
        bristot@...hat.com, vschneid@...hat.com, mhiramat@...nel.org,
        rppt@...nel.org, hughd@...gle.com
Cc:     pcc@...gle.com, steven.price@....com, anshuman.khandual@....com,
        vincenzo.frascino@....com, eugenis@...gle.com, kcc@...gle.com,
        hyesoo.yu@...sung.com, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, kvmarm@...ts.linux.dev,
        linux-fsdevel@...r.kernel.org, linux-arch@...r.kernel.org,
        linux-mm@...ck.org, linux-trace-kernel@...r.kernel.org
Subject: Re: [PATCH RFC v2 18/27] arm64: mte: Reserve tag block for the zero
 page

On 19.11.23 17:57, Alexandru Elisei wrote:
> On arm64, the zero page receives special treatment by having the tagged
> flag set on MTE initialization, not when the page is mapped in a process
> address space. Reserve the corresponding tag block when tag storage
> management is being activated.

Out of curiosity: why does the shared zeropage require tagged storage? 
What about the huge zeropage?

-- 
Cheers,

David / dhildenb