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Date:   Wed, 27 Nov 2019 10:41:40 +0100
From:   Joerg Roedel <joro@8bytes.org>
To:     Sean Christopherson <sean.j.christopherson@intel.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Vlastimil Babka <vbabka@suse.cz>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        kvm@vger.kernel.org
Subject: Re: THP refcounting in disallowed_hugepage_adjust()?
Message-ID: <20191127094140.GA11039@8bytes.org>
References: <20191126152109.GA23850@8bytes.org>
 <20191126174603.GB22233@linux.intel.com>
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Hi Jean,

On Tue, Nov 26, 2019 at 09:46:03AM -0800, Sean Christopherson wrote:
> disallowed_hugepage_adjust() is called from __direct_map() and its
> modification of the pfn is also contained to __direct_map(), i.e. the
> updated @pfn doesn't get propagated back up to the fault handlers.  Thus,
> kvm_release_pfn_clean() is called on the original pfn and so there's no
> need to transfer the page reference.


Thanks for your explanation, makes a lot of sense to me now.


Regards,

	Joerg