Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 11 Aug 2022 21:39:14 +0800
From:   Chao Peng <chao.p.peng@linux.intel.com>
To:     Quentin Perret <qperret@google.com>
Cc:     Sean Christopherson <seanjc@google.com>,
        David Hildenbrand <david@redhat.com>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
        linux-doc@vger.kernel.org, qemu-devel@nongnu.org,
        linux-kselftest@vger.kernel.org,
        Paolo Bonzini <pbonzini@redhat.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
        Hugh Dickins <hughd@google.com>,
        Jeff Layton <jlayton@kernel.org>,
        "J . Bruce Fields" <bfields@fieldses.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Shuah Khan <shuah@kernel.org>, Mike Rapoport <rppt@kernel.org>,
        Steven Price <steven.price@arm.com>,
        "Maciej S . Szmigiero" <mail@maciej.szmigiero.name>,
        Vlastimil Babka <vbabka@suse.cz>,
        Vishal Annapurve <vannapurve@google.com>,
        Yu Zhang <yu.c.zhang@linux.intel.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com,
        ak@linux.intel.com, aarcange@redhat.com, ddutile@redhat.com,
        dhildenb@redhat.com, Michael Roth <michael.roth@amd.com>,
        mhocko@suse.com, Muchun Song <songmuchun@bytedance.com>,
        Will Deacon <will@kernel.org>, Fuad Tabba <tabba@google.com>
Subject: Re: [PATCH v7 03/14] mm: Introduce memfile_notifier
Message-ID: <20220811133914.GC916119@chaop.bj.intel.com>
Reply-To: Chao Peng <chao.p.peng@linux.intel.com>
References: <20220706082016.2603916-1-chao.p.peng@linux.intel.com>
 <20220706082016.2603916-4-chao.p.peng@linux.intel.com>
 <13394075-fca0-6f2b-92a2-f1291fcec9a3@redhat.com>
 <20220810092232.GC862421@chaop.bj.intel.com>
 <00f1aa03-bc82-ffce-569b-e2d5c459992c@redhat.com>
 <YvPC87FMgF7uac7z@google.com>
 <YvT1zOQtTQl2t300@google.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <YvT1zOQtTQl2t300@google.com>
Precedence: bulk

On Thu, Aug 11, 2022 at 12:27:56PM +0000, Quentin Perret wrote:
> +CC Fuad
> 
> On Wednesday 10 Aug 2022 at 14:38:43 (+0000), Sean Christopherson wrote:
> > > I understand Sean's suggestion about abstracting, but if the new name
> > > makes it harder to grasp and there isn't really an alternative to memfd
> > > in sight, I'm not so sure I enjoy the tried abstraction here.
> > 
> > ARM's pKVM implementation is potentially (hopefully) going to switch to this API
> > (as a consumer) sooner than later.  If they anticipate being able to use memfd,
> > then there's unlikely to be a second backing type any time soon.
> > 
> > Quentin, Will?
> 
> Yep, Fuad is currently trying to port the pKVM mm stuff on top of this
> series to see how well it fits, so stay tuned.

Good to hear that.

>I think there is still
> some room for discussion around page conversions (private->shared etc),
> and we'll need a clearer idea of what the code might look like to have a
> constructive discussion,

That's fine. Looking forward to your feedbacks.

>but so far it does seem like using a memfd (the
> new private one or perhaps just memfd_secret, to be discussed) + memfd
> notifiers is a promising option.

If it still memfd (even memfd_secret), maybe we can use the name
memfd_notifier?

Chao