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b=i9MOrYmHgSH7Y+7qHtX1Byvl1ufAKEXc1Ej/VzGCte2ENcbxl6Mjs/y7IuxfEcCQ3 lkRNGXjyWdOWAjOORBHFnPRA/tQO7cxQGyxoKmvFfmz4u8IXtmkl7ciAUTWgFT+GAP myO6mgfBUImeuJUAz/Pp3nRZc3rbxvf5UZr3Y0Bck70j808roKhLMObuwp5KEXxApA xpPMEoC4Z5WrmciOCLArypa7JShIxMw4iOYxs4tM20apqeuHeoOTbvLYZ/wTsANFrj 0RU+AInyj9lCuH+cdHwn1+LLbCI7dNSEn4Q4fm9jFierntGz1oHAM9EVt+WbDdjGQ+ uvggoCCmg/h4g== From: Pratyush Yadav To: Mike Rapoport Cc: Pratyush Yadav , Jason Gunthorpe , Pasha Tatashin , 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, 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 In-Reply-To: References: <20250807014442.3829950-1-pasha.tatashin@soleen.com> <20250807014442.3829950-30-pasha.tatashin@soleen.com> <20250826162019.GD2130239@nvidia.com> Date: Thu, 04 Sep 2025 14:39:13 +0200 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Stat-Signature: 8h3qj6n5qn1ygb677u5qihkxy9dy5mz3 X-Rspam-User: X-Rspamd-Queue-Id: 538F11C000E X-Rspamd-Server: rspam05 X-HE-Tag: 1756989565-237827 X-HE-Meta: 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 2BT3lZlT rTx4DK3pURvffAJdDdbkHelXz8ngj/xKOkaSM7U6nwDueSgXd4zqA7USZKYiC6vdSTLy4XL+nEqLwwY3MPLttGufhJqzAGhsoLwyEmT7p3th2f/Z9qAdhxRlV7feimMM+Omx2I2JEzY3ztjJa+DkIHxlOfJOmsMtYC4mkWqzv0ms55bcgXkAwp7ICKDoV9RMbZJ/qN3fdHurl+hyjyJMTkH2DaRUzWnt2sFKrFSCmWOv5fU8= 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 Mike, On Wed, Sep 03 2025, Mike Rapoport wrote: > On Wed, Sep 03, 2025 at 04:17:15PM +0200, Pratyush Yadav wrote: >> On Tue, Sep 02 2025, Mike Rapoport wrote: >> > >> > As for porting kho_preserve_vmalloc() to kho_array, I also feel that it >> > would just make kho_preserve_vmalloc() more complex and I'd rather simplify >> > it even more, e.g. with preallocating all the pages that preserve indices >> > in advance. [...] > >> Beyond that, I think KHO array will actually make kho_preserve_vmalloc() >> simpler since it won't have to deal with the linked list traversal >> logic. It can just do ka_for_each() and just get all the pages. >> >> We can also convert the preservation bitmaps to use it so the linked list >> logic is in one place, and others just build on top of it. > > I disagree. The boilerplate to initialize and iterate the kho_array will > not make neither vmalloc nor bitmaps preservation simpler IMO. I have done 80% of the work on this already, so let's do this: I will do the rest of the 20% and publish the patches. Then you and Jason can have a look and if you still think it's not worth it, I am fine shelving it for now and revisiting later when there might be a stronger case. > > And for bitmaps Pasha and Jason M. are anyway working on a different data > structure already, so if their proposal moves forward converting bitmap > preservation to anything would be a wasted effort. -- Regards, Pratyush Yadav