Sender: Paolo Bonzini <paolo.bonzini@gmail.com>
Message-ID: <2f3e9d7e-ce15-e47b-54c6-3ca3d7195d70@redhat.com>
Date:   Tue, 23 Nov 2021 10:09:28 +0100
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To:     Chao Peng <chao.p.peng@linux.intel.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>
Cc:     Wanpeng Li <wanpengli@tencent.com>, jun.nakajima@intel.com,
        kvm@vger.kernel.org, david@redhat.com, qemu-devel@nongnu.org,
        "J . Bruce Fields" <bfields@fieldses.org>, dave.hansen@intel.com,
        "H . Peter Anvin" <hpa@zytor.com>, ak@linux.intel.com,
        Jonathan Corbet <corbet@lwn.net>,
        Joerg Roedel <joro@8bytes.org>, x86@kernel.org,
        Hugh Dickins <hughd@google.com>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        luto@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jim Mattson <jmattson@google.com>, linux-mm@kvack.org,
        Sean Christopherson <seanjc@google.com>, susie.li@intel.com,
        Jeff Layton <jlayton@kernel.org>, linux-kernel@vger.kernel.org,
        john.ji@intel.com, Yu Zhang <yu.c.zhang@linux.intel.com>,
        linux-fsdevel@vger.kernel.org,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
References: <20211119134739.20218-1-chao.p.peng@linux.intel.com>
 <20211119134739.20218-14-chao.p.peng@linux.intel.com>
 <20211122141647.3pcsywilrzcoqvbf@box.shutemov.name>
 <20211123010639.GA32088@chaop.bj.intel.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [RFC v2 PATCH 13/13] KVM: Enable memfd based page
 invalidation/fallocate
In-Reply-To: <20211123010639.GA32088@chaop.bj.intel.com>
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Precedence: bulk

On 11/23/21 02:06, Chao Peng wrote:
>> Maybe the kvm has to be tagged with a sequential id that incremented every
>> allocation. This id can be checked here.
> Sounds like a sequential id will be needed, no existing fields in struct
> kvm can work for this.

There's no need to new concepts when there's a perfectly usable 
reference count. :)

Paolo