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AJvYcCXYE/d4iv8czoPtIejiF0DGQQYVLb9H1wqU4Btb9Go+H4MDLPDKbmkXkzdMAzYQWx57wmZt8C9hMw==@kvack.org X-Gm-Message-State: AOJu0YwuCEYRumfuD/y9XniS1KxyuoZ9D1QcxgbA7m4nunmwTUN3xnO6 NXoD3ETFawBygFpP4ZWeZ72CQAgAY/o/M1reejuC8jJVb3jBNFD9ayHWlNJAxi/mknw1xbULwm+ Y9YXrMJF+oqqxyR4mwA0Sdx256jW6Ulx9d1YrnfdV0A== X-Gm-Gg: ASbGncucdQ85F2OUTw+2pKynOMyoorLuq3JeVFyV0nUqy15KxGPbp+yU3WH9lDVDZrD UqyqlJ/ffaNXyyOUCE+7Ijt2Nv66zcjpjwsA2osqHWuxUD116eFLFbM1FnN/VrNAK6XeQSJxfzz zxPucUsJjet9IdF79tqgisOGtgNPjZXhoBJw77IcPhTu9CZ3S7Q84Q9QeEXW3IfQBalaG3FkoRy 8wMZdgvG6toSgme6uSL2OYHQwhJlw9N9ePMNBUrZ43YdO2mablGb6fxweGjwx+GqSEh X-Google-Smtp-Source: AGHT+IF7MT7H/N1FGVv2fGcWDDSq4G0lsAr/9izNZqOxycuQNiS8y26Pa9vU+efWnOrN6wB/Co4CNJQLTQPPNB+6gYM= X-Received: by 2002:a05:6402:20d5:20b0:640:6650:9173 with SMTP id 4fb4d7f45d1cf-6431a5906c4mr5014541a12.33.1763052961708; Thu, 13 Nov 2025 08:56:01 -0800 (PST) MIME-Version: 1.0 References: <20251107210526.257742-1-pasha.tatashin@soleen.com> <20251107210526.257742-19-pasha.tatashin@soleen.com> In-Reply-To: <20251107210526.257742-19-pasha.tatashin@soleen.com> From: Pasha Tatashin Date: Thu, 13 Nov 2025 11:55:25 -0500 X-Gm-Features: AWmQ_bncXGN-eqIRVfciSwqz1sfkpOsYp0SxgOx72ZS1NRyOW1CKwiM1xe3CWB4 Message-ID: Subject: Re: [PATCH v5 18/22] docs: add documentation for memfd preservation via LUO To: pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com, pasha.tatashin@soleen.com, rppt@kernel.org, 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, jgg@nvidia.com, parav@nvidia.com, leonro@nvidia.com, witu@nvidia.com, hughd@google.com, skhawaja@google.com, chrisl@kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 4C2E24000E X-Stat-Signature: 1c973sbfygpgmyk7cozxq8ten5hpyxwk X-HE-Tag: 1763052964-115608 X-HE-Meta: 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 0WHQPDWJ Og2hP6VoLmapMfCurhlCFMvcjhN1oUeXHpMGJuSSayutKciY7mDd8W9HsSQztnoOqmRfdRdBfiE6jSl1+xFQrsf22CSP1tC8y0DHg09vJ1q445m4mE+kbH7edHukznPq5ymJVvzFYI/RK25HYLQL0fqQkefKHupyd72AdmJJD+GV6faBPwAHaNZKRn+svuWLLmq6xZhkHUoWiJd+jOGLhj24xYKhLEBFGQnzGKKLhCFWOikAAPx++N2DZXAviV4wUJQXX 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: > +Limitations > +=========== > + > +The current implementation has the following limitations: > + > +Size > + Currently the size of the file is limited by the size of the FDT. The FDT can > + be at of most ``MAX_PAGE_ORDER`` order. By default this is 4 MiB with 4K > + pages. Each page in the file is tracked using 16 bytes. This limits the > + maximum size of the file to 1 GiB. The above should be removed, as we are using KHO vmalloc that resolves this limitation. Pratyush, I suggest for v6 let's move memfd documnetation right into the code: memfd_luo.c and liveupdate/abi/memfd.h, and source it from there. Keeping documentation with the code helps reduce code/doc divergence. Pasha