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Donenfeld" To: Linus Torvalds Cc: David Hildenbrand , 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> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: C35B518000E X-Stat-Signature: 6e3e3o8ztaonxzkiia943c656htugyn8 X-Rspam-User: X-HE-Tag: 1720446686-958613 X-HE-Meta: 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 bjXggBnN 9kv6eWnoLWF6rzWN9YQ57sxR7Daoxas6lbOqXhMfdMVfOv7ptw/HWw2LNbFwQF4mgtA1eSoJmpUnOTPlgqa2rT2P7skFSeeWi6AeZS41Wf62/Oj3t1/82dgAHJ3kTOW2nJjqRL72gI/zodXBawKjZpYM9DaFwfiO76EeqgxnIspYJjSQacrokOQ/aNnBugHc6wzhgTyN4QaeEl/OO0q4SHTPg16aJGWoUllKZOogIj+THnR0icV7FE8sc8jPOgdNNyRuWphULZBRto8TfvdbAXa1+V/+ZjPoNK2PByzJRWAfctzSyc7edy6Ga6Fl6/TJC5gCk+jnkUNlAcIt5LmSGHpZqcmFj0gcAaz7VlxndjXuNaTNg/nvWpm4takt+dOsTMkzDH13qph521j+jLEvy0F10KTrj1za6YtPEKMjSqAlVhk6kpPyv9GBANqyTUh9sZ5BE0tDSmspgUZQ= 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: Hi Linus, On Sun, Jul 07, 2024 at 05:08:29PM -0700, Linus Torvalds wrote: > + vm_flags |= VM_DROPPABLE; > + vm_flags |= VM_WIPEONFORK | VM_DONTDUMP; > which looks rather simple. That is nice, though I would add that if we're implying things that are sensible to imply, it really also needs to add VM_NORESERVE too. DROPPABLE doesn't make sense semantically without it. Anyway, rather than adding PROT_xyz for v+1, I'll try adding this MAP_DROPPABLE (or a different name for David) with the implications as you've suggested. Jason