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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 v22 1/4] mm: add MAP_DROPPABLE for designating always lazily freeable mappings Message-ID: References: <378f23cb-362e-413a-b221-09a5352e79f2@redhat.com> <9b400450-46bc-41c7-9e89-825993851101@redhat.com> <98798483-dfcd-451e-94bb-57d830bf68d8@redhat.com> <54b6de32-f127-4928-9f4a-acb8653e5c81@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <54b6de32-f127-4928-9f4a-acb8653e5c81@redhat.com> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 25BEB180024 X-Stat-Signature: eg6fkjkaacdauxj8n8w9x3faw6n4odug X-Rspam-User: X-HE-Tag: 1720720480-613197 X-HE-Meta: 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 nGrUjb3J P6mu3P0kjWfdytm3K5tVDOiDMuBLKODPn81kjY96+wpIuE+tSBZDd0uKykdNm38dZxpdBdvHAFeMlefr3/8Fu1hUtAhIfbToTS150/IYFAjywyBoKMjH5PFJJz/sKrWwQ0yeIUSgy8Srkx92mAODW6wbbi0HOlgT+l9bRn8R40QOnkU35m30yAXoMw8yQfZHrEkARiFoRhd2yeYvb1lJa95cSd/uWaG6w/eCzWVlbCQS10y/FWxlLZY/dwpAks3noTkFONeNDrk286XT3/rQ5PLCv5LT4ODQ6EIKu8V/b3J+eCROea0VzNk99UwjkF8CEtPEuRH57BYiN2n7NU5w8IrDnHwE/eC1mdjwLo3mK2BVMrVK4AGBb+Gg7qBxV07P6GiB4jIqD3iBtSTUCsvIGJtVRI8RDPIA7NsULdXb9Az157vwi5rTXTmPn61aT8fVdFLTGkI2vgXmXFpY= 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 Thu, Jul 11, 2024 at 07:27:27PM +0200, David Hildenbrand wrote: > > PG_owner_priv_1 maps to PG_swapcache? :) > > Maybe the combination !swapbacked && swapcache could be used to indicate > such folios. (we will never set swapbacked) > > But likely we have to be a bit careful here. We don't want > folio_test_swapcache() to return for folios that ... are not in the > swapcache. I was thinking that too, but I'm afraid it's going to be another whack-a-mole nightmare. Even for things like task_mmu in procfs that show stats, that's going to be wonky. Any other flags we can overload that aren't going to be already used in our case? Jason