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Date:   Fri, 6 May 2022 03:54:58 +0300
From:   "Kirill A. Shutemov" <kirill@shutemov.name>
To:     David Hildenbrand <david@redhat.com>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Borislav Petkov <bp@alien8.de>,
        Andy Lutomirski <luto@kernel.org>,
        Sean Christopherson <seanjc@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Joerg Roedel <jroedel@suse.de>,
        Ard Biesheuvel <ardb@kernel.org>,
        Andi Kleen <ak@linux.intel.com>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        David Rientjes <rientjes@google.com>,
        Vlastimil Babka <vbabka@suse.cz>,
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        Thomas Gleixner <tglx@linutronix.de>,
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        Paolo Bonzini <pbonzini@redhat.com>,
        Ingo Molnar <mingo@redhat.com>,
        Varad Gautam <varad.gautam@suse.com>,
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        Dave Hansen <dave.hansen@intel.com>,
        Brijesh Singh <brijesh.singh@amd.com>,
        Mike Rapoport <rppt@kernel.org>, x86@kernel.org,
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        linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
        Mike Rapoport <rppt@linux.ibm.com>
Subject: Re: [PATCHv5 02/12] mm: Add support for unaccepted memory
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On Tue, May 03, 2022 at 10:21:03PM +0200, David Hildenbrand wrote:
> 
> >  
> > +/*
> > + * Page acceptance can be very slow. Do not call under critical locks.
> > + */
> > +static void accept_page(struct page *page, unsigned int order)
> > +{
> > +	phys_addr_t start = page_to_phys(page);
> > +	int i;
> > +
> > +	accept_memory(start, start + (PAGE_SIZE << order));
> > +
> > +	for (i = 0; i < (1 << order); i++) {
> > +		if (PageUnaccepted(page + i))
> > +			__ClearPageUnaccepted(page + i);
> > +	}
> > +}
> 
> What was the rationale of leaving PageUnaccepted() set on sub-pages when
> merging pages?
> 
> I'd just clear the flag when merging and avoid the loop here. You could
> even assert here that we don't have any PageUnaccepted() on tail pages.

Okay, fair enough. I will change the code.

-- 
 Kirill A. Shutemov