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Thu, 23 Apr 2026 07:50:09 -0700 (PDT) X-Received: by 2002:a05:620a:4084:b0:8dc:eca0:35bd with SMTP id af79cd13be357-8e78fa1dd25mr4108105885a.5.1776955809008; Thu, 23 Apr 2026 07:50:09 -0700 (PDT) Received: from x1.local ([142.189.10.167]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8e7d98c15a9sm1850297485a.43.2026.04.23.07.50.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Apr 2026 07:50:08 -0700 (PDT) Date: Thu, 23 Apr 2026 10:50:06 -0400 From: Peter Xu To: Kiryl Shutsemau Cc: "David Hildenbrand (Arm)" , Andrew Morton , Lorenzo Stoakes , Mike Rapoport , Suren Baghdasaryan , Vlastimil Babka , "Liam R . Howlett" , Zi Yan , Jonathan Corbet , Shuah Khan , Sean Christopherson , Paolo Bonzini , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [RFC, PATCH 00/12] userfaultfd: working set tracking for VM guest memory Message-ID: References: <1a499781-1115-44bc-adbf-2ac3769354ca@kernel.org> <4c635703-3d8d-4cfa-bb98-7f6f5fcbe547@kernel.org> <34f75083-29a3-4860-8a6e-94551d37ac6a@kernel.org> MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: tmfcu6d4t0a774KO3vOaEELYlfGG2VUxBf7lrML_bJI_1776955810 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Stat-Signature: itisrqa48s8qo3dp6rs996kpinf6nkyq X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 8E325180010 X-HE-Tag: 1776955813-546489 X-HE-Meta: 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 LS4kG5u+ VE1dTgESNi++p5a1vw8NZSFU7ioxMnsaO7UUZwJt+kEKHB0MIfzUlqDdVCLBU2YrT6zeidsxqBOluvsW/gqZ6opgBKKZbcoxtZ+ndMfAv8usxZyx4u0t5aVWUTnuggHJ/08DWD26DtavvDyE+YSVZGimxSggEw58oR38hiS0D/TfMQLixBc+puEt1Y+y9jlCEvWx5L4u5+97dOyExAMM+xz35J3PVqMAxmifBxLb6HHGSMPxceJVSBe+ep0FcXHCheo5KfrWqi2fAANvESU6nxXTx2d3JxsX6sE0/IrC+ZHrKEhbtySRJHyFbbzvuIn3vbBDo2ZNiKssNeyD0aWSiTXQOA61OYKaju1u3nOo68oozZMMkUuiwxBiS2rrnklLBvyS11p4uQwMeeCkay3lHGY1yAti0GzFyv4ba Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hello, Kiryl, On Thu, Apr 23, 2026 at 03:27:11PM +0100, Kiryl Shutsemau wrote: > The patchet is pretty good shape in my eyes and will probably drop RFC > tag. I still have some high level questions not yet got answered. Do you want to answer them? https://lore.kernel.org/all/ad59TxAHNwFWH7Cc@x1.local/ In summary, it's about: - Whether we have explored other approaches on page hotness tracking - Whether read protection is required for an userspace swap system (e.g. did you get time to have a look at umap?) Thanks, -- Peter Xu