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changyuanl@google.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, 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 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, Sep 01, 2025 at 07:10:53PM +0200, Pratyush Yadav wrote: > Building kvalloc on top of this becomes trivial. > > [0] https://git.kernel.org/pub/scm/linux/kernel/git/pratyush/linux.git/commit/?h=kho-array&id=cf4c04c1e9ac854e3297018ad6dada17c54a59af This isn't really an array, it is a non-seekable serialization of key/values with some optimization for consecutive keys. IMHO it is most useful if you don't know the size of the thing you want to serialize in advance since it has a nice dynamic append. But if you do know the size, I think it makes more sense just to do a preserving vmalloc and write out a linear array.. So, it could be useful, but I wouldn't use it for memfd, the vmalloc approach is better and we shouldn't optimize for sparsness which should never happen. > > The versioning should be first class, not hidden away as some emergent > > property of registering multiple serializers or something like that. > > That makes sense. How about some simple changes to the LUO interfaces to > make the version more prominent: > > int (*prepare)(struct liveupdate_file_handler *handler, > struct file *file, u64 *data, char **compatible); Yeah, something more integrated with the ops is better. You could list the supported versions in the ops itself const char **supported_deserialize_versions; And let the luo framework find the right versions. But for prepare I would expect an inbetween object: int (*prepare)(struct liveupdate_file_handler *handler, struct luo_object *obj, struct file *file); And then you'd do function calls on 'obj' to store 'data' per version. Jason