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b=IC0bYdjTaLnYXvKhfLlUnPms9FmtHm4xOtQJJVSO6DQpdytk6rYZjHGnqqjYm4HVj S0XuCekWHj19c74E0buaHpy/u5gTOdn6UTiV83sq+04+OGJLP7bgv/RUseKsFBRMi3 vVIqEHGk6iuEZB8ayAg27GHA387gsmzPtP4xor3EyrLiwtysE9lhJAHYiWWSaSCSGG owfP7we/gtmDXLd4HPbSkHxEMfF2vJXqLD1ixH/6jvietSz7mE8dVU8pn8PcBgZ2Io SrqpD2E5Yh/tSDxNqdGRKr3r/PoVWLPQLLUH5bx4dQxbxEvDKrYHOlDen3eoSeGW0W T6JnpKlHJIwdQ== Date: Mon, 1 Sep 2025 19:23:13 +0300 From: Mike Rapoport To: Jason Gunthorpe Cc: Pasha Tatashin , pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com, changyuanl@google.com, dmatlack@google.com, rientjes@google.com, corbet@lwn.net, rdunlap@infradead.org, ilpo.jarvinen@linux.intel.com, kanie@linux.alibaba.com, ojeda@kernel.org, aliceryhl@google.com, masahiroy@kernel.org, akpm@linux-foundation.org, tj@kernel.org, yoann.congal@smile.fr, mmaurer@google.com, roman.gushchin@linux.dev, chenridong@huawei.com, axboe@kernel.dk, mark.rutland@arm.com, jannh@google.com, vincent.guittot@linaro.org, hannes@cmpxchg.org, dan.j.williams@intel.com, david@redhat.com, joel.granados@kernel.org, rostedt@goodmis.org, anna.schumaker@oracle.com, song@kernel.org, zhangguopeng@kylinos.cn, linux@weissschuh.net, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, gregkh@linuxfoundation.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, rafael@kernel.org, dakr@kernel.org, bartosz.golaszewski@linaro.org, cw00.choi@samsung.com, myungjoo.ham@samsung.com, yesanishhere@gmail.com, Jonathan.Cameron@huawei.com, quic_zijuhu@quicinc.com, aleksander.lobakin@intel.com, ira.weiny@intel.com, andriy.shevchenko@linux.intel.com, leon@kernel.org, lukas@wunner.de, bhelgaas@google.com, wagi@kernel.org, djeffery@redhat.com, stuart.w.hayes@gmail.com, ptyadav@amazon.de, lennart@poettering.net, brauner@kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, saeedm@nvidia.com, ajayachandra@nvidia.com, parav@nvidia.com, leonro@nvidia.com, witu@nvidia.com Subject: Re: [PATCH v3 29/30] luo: allow preserving memfd Message-ID: References: <20250807014442.3829950-1-pasha.tatashin@soleen.com> <20250807014442.3829950-30-pasha.tatashin@soleen.com> <20250826162019.GD2130239@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250826162019.GD2130239@nvidia.com> X-Rspamd-Queue-Id: 9F13B180011 X-Rspam-User: X-Stat-Signature: u5kounm6bn36kihjhcjqt7w81ybkpfjk X-Rspamd-Server: rspam09 X-HE-Tag: 1756743819-297863 X-HE-Meta: U2FsdGVkX19F5JjK9w16JTa8g23Mhoz+RpjGX75wdoQ2f/5g4ZfmKA2kq6uWTX/xyt+rGePtCIsXjn78GWJucVjp4ieMVtw3ijgTwZHcUmf9wfx85+IqmCAfsm8uRI4iT4jKW0HvWI0IlmqrFKzy4ure3gWF1du1i/thuSNrE4v13KS0e9+MscN5fbfKl3TEyr0WoKp7jP3Qr5iuoU0h3FYp0pThTrcv/PggLbdsLusMITu5+wKnZP+NKF9jgS4V8jY31JoQAxVU8AzZ+D56fygx+zEq2E2nP53zCiZciOY6UHE7BpwhEs3vDj7yU61BL6hwhcItcdoeQIvuEN+Rj6TmozFkfs2df3HTY+ghYhkl8aP9pwm1Ew8MAjKB5XK+koZwNjeMAXK1ZqmrEREwFHXjDj+GLBNtel+kyKkGcbaTj4k2O3I601JFRTDwO38ZpovjKvUun5u62kGxeOqtS0t5EBSc5n7T48ijJx1OlswJMGB0CSbAgfSgoOim2E762F+/hJk1xVCT9qgADi/8EQlvepUDaxrFLoq1JKCZAUgGOit5UmqITTPkN4Wx/C70pAffdAFTj0qYLAbN6w48S7OSqIR7EAR7IQMgZAQ1BhtUKAq2FfUUsNJrlPTT/aNYH1nAx84vKUOj99/rC0aMuB3FLA/8uivFngp9L9kuLulPUiqytY2x591UywgNzwKsxe8nSMkUanSN+y5wkKgwtHXwQiwQYEScaSCWQnPzzlj8Da2HtPsiKuz1vFChcs190iV1LtAYaa18ScanjMbtfIZfsSpnW8jr2zHkKiPOFzH49dUTVUz0vvREay4tW7x99OUwEBpa7YwGKCjP32/xVUFfp0YJsRijMAkG1IhJwLE/rLnrS2Hzh5PWy+FhrxovEHDfbVvuzbH1X3xmW/WwG766KRfi1BF9IkFpgbvbw2WPeOhZ5TWvyBr36Ozw1+gXPhoS/ldXbI3h4x1LXpU GuznGRQ5 yImO3/SLESrRF3SaDdlraNaF02XITscsaahJAfS7ruOaTtVGg/Wsd0odA5wyJUffP9cuOC67yTfXypqx4GcRCAn3CWEaTQXULff59f+GRy8l/NcnVPag3ptlpFTqahy4O+rMO5L85r2pCSuMLzbboKBla5PNs6W0XpUvs92CHnYkpQdgrfUPLjchGDDhPCg0NOD326yz1F/H42b4wigvk3UzNxvsF9rIgt4Q3+Q7tiTv1H3ekIeH9pAxJEszfgacbQnObHd7Lw4M89N08liBtDNfZpwOJBAYH2fPeKOKT4x/AxyyBzmQLcusVzHQirW7kacfn+XltzZvpbw8LEdNUXKngcXdfCTeNAgbG 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 Tue, Aug 26, 2025 at 01:20:19PM -0300, Jason Gunthorpe wrote: > On Thu, Aug 07, 2025 at 01:44:35AM +0000, Pasha Tatashin wrote: > > > + /* > > + * Most of the space should be taken by preserved folios. So take its > > + * size, plus a page for other properties. > > + */ > > + fdt = memfd_luo_create_fdt(PAGE_ALIGN(preserved_size) + PAGE_SIZE); > > + if (!fdt) { > > + err = -ENOMEM; > > + goto err_unpin; > > + } > > This doesn't seem to have any versioning scheme, it really should.. > > > + err = fdt_property_placeholder(fdt, "folios", preserved_size, > > + (void **)&preserved_folios); > > + if (err) { > > + pr_err("Failed to reserve folios property in FDT: %s\n", > > + fdt_strerror(err)); > > + err = -ENOMEM; > > + goto err_free_fdt; > > + } > > Yuk. > > This really wants some luo helper > > 'luo alloc array' > 'luo restore array' > 'luo free array' We can just add kho_{preserve,restore}_vmalloc(). I've drafted it here: https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/log/?h=kho/vmalloc/v1 Will wait for kbuild and then send proper patches. -- Sincerely yours, Mike.