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Date:   Tue, 10 Aug 2021 11:30:55 -0700
From:   Andi Kleen <>
To:     Dave Hansen <>,
        "Kirill A. Shutemov" <>,
        Borislav Petkov <>,
        Andy Lutomirski <>,
        Sean Christopherson <>,
        Andrew Morton <>,
        Joerg Roedel <>
Cc:     Kuppuswamy Sathyanarayanan 
        David Rientjes <>,
        Vlastimil Babka <>,
        Tom Lendacky <>,
        Thomas Gleixner <>,
        Peter Zijlstra <>,
        Paolo Bonzini <>,
        Ingo Molnar <>,
        Varad Gautam <>,
        Dario Faggioli <>,,,,,
        "Kirill A. Shutemov" <>
Subject: Re: [PATCH 1/5] mm: Add support for unaccepted memory

> So, this is right in the fast path of the page allocator.  It's a
> one-time thing per 2M page, so it's not permanent.
> *But* there's both a global spinlock and a firmware call hidden in
> clear_page_offline().  That's *GOT* to hurt if you were, for instance,
> running a benchmark while this code path is being tickled.  Not just to
> That could be just downright catastrophic for scalability, albeit
> temporarily

This would be only a short blib at initialization until the system 
reaches steady state. So yes it would be temporary, but very short at that.


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