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Donenfeld" To: David Hildenbrand Cc: Linus Torvalds , linux-kernel@vger.kernel.org, patches@lists.linux.dev, tglx@linutronix.de, linux-crypto@vger.kernel.org, linux-api@vger.kernel.org, x86@kernel.org, Greg Kroah-Hartman , Adhemerval Zanella Netto , Carlos O'Donell , Florian Weimer , Arnd Bergmann , Jann Horn , Christian Brauner , David Hildenbrand , linux-mm@kvack.org Subject: Re: [PATCH v21 1/4] mm: add VM_DROPPABLE for designating always lazily freeable mappings Message-ID: References: <20240707002658.1917440-1-Jason@zx2c4.com> <20240707002658.1917440-2-Jason@zx2c4.com> <1583c837-a4d5-4a8a-9c1d-2c64548cd199@redhat.com> <6705c6c8-8b6a-4d03-ae0f-aa83442ec0ab@redhat.com> <7439da2e-4a60-4643-9804-17e99ce6e312@redhat.com> <8bf64731-9e5c-4c8c-b46b-5b18ae3110a1@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <8bf64731-9e5c-4c8c-b46b-5b18ae3110a1@redhat.com> X-Rspamd-Queue-Id: 3D336100012 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: we8htbj4m5s63hnnizk3qxy8711ioyth X-HE-Tag: 1720447047-51697 X-HE-Meta: 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 x8sCoGhx HoRdCEcTOxjiSeFlF24RQxARPLIxyDm1tnuZyCJVRgti10FBOsjPkFbKq7yHNzvim/9Y8UlJwEbqGBfFreHXbpA6mTmX7qVrcFSxSle+zYXzJU3/S6UhPS3OcEv65ns67o1itL+8b2O7ovJh5B8SIDoagNOOz8jAZ6R+koESYOF4iWxhUSLICUz3S17gDZxxOFrKuaBWm7/jaqR52wYYubn/llf/lTA3/odFAb+QwwmFCfNfbRa+sMr/gWtxit4ftKvejnf6vyhbC9Rz+vIhVpHkQEoSQeEW2NMLODMYRskn230Q/y66Jl3OCBKHxr9Sv96sfXnR5/w22RhIy7jFXgzyFDWIxKsCpFuwOomyRRbO03rqNVmzR5Ho4kUf3wD5YCJC4k7xkMARIaDRTIbauS9hdaSPKY6DLqU/vGAvLpEVSmV48mSf24TKrpholCUi25Feja+vuAdtUIj8= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jul 08, 2024 at 10:23:10AM +0200, David Hildenbrand wrote: > > As a side note, I'll raise that I am not a particular fan of the > > "droppable" terminology, at least with the "read 0s" approach. > > > > From a user perspective, the memory might suddenly lose its state and > > read as 0s just like volatile memory when it loses power. "dropping > > pages" sounds more like an implementation detail. > > Long story short: it's the hypervisor that could be effectively > dropping/zeroing out that memory, not the guest VM. "NONVOLATILE" might > be clearer than "DROPPABLE". Surely you mean "VOLATILE", not "NONVOLATILE", right? Jason