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b=YM0QqjqdUWbm50XeI0p+NG1eLf0kzunlAOfcRNZ0NB853n0+RKvlIUwYvlshIg0+W Zk3SQfmJqf89mLGzySXSdjkp+9F0et7hr7pZgBbHWzx4FMbWHAImWbAfe27haI2Fce NredufFmP9X9HwEpeZbpxUfaZi7kF1xM56WGMid0jC6/4zEVdDLBXriJ6k+jZmw1IY 1j7yON5Qk3ZJa4NtiBder0W/z//vg4Ss6OM4tywuYtvl7lZW8T4eVoKzXwYKHxiORs HyGK2e5M6HQfm11Y4SqNf21eieyjng6xKG/NVn/0xs/YcJj2ucoOlLy/LIWX2aG2nf BEcLSVND6WvFQ== Date: Mon, 19 Jan 2026 20:43:10 +0200 From: Mike Rapoport To: Jason Miu Cc: Alexander Graf , Andrew Morton , Baoquan He , Changyuan Lyu , David Matlack , David Rientjes , Jason Gunthorpe , Pasha Tatashin , Pratyush Yadav , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v7 0/2] Make KHO Stateless Message-ID: References: <20260116034432.1520731-1-jasonmiu@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260116034432.1520731-1-jasonmiu@google.com> X-Stat-Signature: c5m49xw9dgmukjyd3mb8zhn8bz9exmta X-Rspam-User: X-Rspamd-Queue-Id: 12ECBA000B X-Rspamd-Server: rspam08 X-HE-Tag: 1768848199-232797 X-HE-Meta: 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 NLJknMXa f3v2ImmE/ZOA/47Oj/SR4qXq43icEFIy3rOJFdr4myLl6TOyMjKzxRiO9vs8/i0LFjmkToeqWTSlHClz1fCS5IeC3pCOXWjI9K6HTc0jJMieRrqFM2jchoPPGC6qeiHcTL1otWiu4CLDv8SukCWEsN8dXERTvzDbNSeg1w4IuyZfSD7Dh3iuvnFmQ2hU+b8ycWjtFHTbkxmrIRYCniJ3t1rL2c/ew1UdEOl4jBJNTNlo5dJd2tI7hJIMSKU8oWWNl2CwaBdx6b3fbt6/HReQ6dz3MioGKsT880chvd5T/41fCQOs= 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 Jason, On Thu, Jan 15, 2026 at 07:44:30PM -0800, Jason Miu wrote: > This series transitions KHO from an xarray-based metadata tracking system > with serialization to a radix tree data structure that can be passed > directly to the next kernel. > > The key motivations for this change are to: > - Eliminate the need for data serialization before kexec. > - Remove the KHO finalize state. > - Pass preservation metadata more directly to the next kernel via the FDT. > > The new approach uses a radix tree to mark preserved pages. A page's > physical address and its order are encoded into a single value. The tree > is composed of multiple levels of page-sized tables, with leaf nodes > being bitmaps where each set bit represents a preserved page. The > physical address of the radix tree's root is passed in the FDT, allowing > the next kernel to reconstruct the preserved memory map. > > This series is broken down into the following patches: > > 1. kho: Adopt radix tree for preserved memory tracking: > Replaces the xarray-based tracker with the new radix tree > implementation and increments the ABI version. > > 2. kho: Remove finalize state and clients: > Removes the now-obsolete kho_finalize() function and its usage > from client code and debugfs. > > --- > > Changelog since v6 [1]: > - Fixed a potential dangling pointer in kho_radix_add_page() on allocation failure > - Fixed a premature return in __kho_radix_walk_tree() > - Corrected the size type in kho_preserved_memory_reserve() to match memblock_reserve() git range-diff claims that v5, v6 and v7 are identical. Can you please verify that it's the latest version you intended to send? > [1] https://lore.kernel.org/lkml/20260115230047.1220580-1-jasonmiu@google.com/ > > --- > > Jason Miu (2): > kho: Adopt radix tree for preserved memory tracking > kho: Remove finalize state and clients > > Documentation/admin-guide/mm/kho.rst | 53 +- > Documentation/core-api/kho/abi.rst | 6 + > Documentation/core-api/kho/index.rst | 18 +- > include/linux/kho/abi/kexec_handover.h | 144 +++- > include/linux/kho_radix_tree.h | 70 ++ > kernel/liveupdate/kexec_handover.c | 695 ++++++++++---------- > kernel/liveupdate/kexec_handover_debugfs.c | 23 - > kernel/liveupdate/kexec_handover_internal.h | 3 - > kernel/liveupdate/luo_core.c | 12 +- > kernel/liveupdate/luo_flb.c | 2 +- > tools/testing/selftests/kho/init.c | 20 - > 11 files changed, 573 insertions(+), 473 deletions(-) > create mode 100644 include/linux/kho_radix_tree.h > > > base-commit: 9b7977f9e39b7768c70c2aa497f04e7569fd3e00 > -- > 2.52.0.457.g6b5491de43-goog > -- Sincerely yours, Mike.