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b=RyWrUZmiPavdad5/L4Ku4XTi4TroUF34qqpGQ2vIK5Mb+GKYPyKWzhjiNLEd4eT2e UVXjYV9X+p75gEgGgQGz51BDugj6dLOcRxf/VtpXcPTXatrH+9uNm5doI0218B3bwk Y2Hg7roLrSqqgo25csIUK5gOEatcZZsUU3dkiavyuOFbjg48aE5Y2hvGJyyrDDRWsj 2xMxNTw5GvJRhE3w7q4MlB5q8T2wrOI7/qyovv4wx3MUPDtocUVMtWPmRVLXtriwQC 7MQ0J/Goo7rfaJLwR7Of0FxWUIrNKVvaNp8SDsUNbxX54AOCr97HvybItXlgCaUcSZ u1xzn7yEwSdHw== Date: Fri, 14 Nov 2025 18:15:59 +0200 From: Mike Rapoport To: Pasha Tatashin Cc: akpm@linux-foundation.org, bhe@redhat.com, jasonmiu@google.com, arnd@arndb.de, coxu@redhat.com, dave@vasilevsky.ca, ebiggers@google.com, graf@amazon.com, kees@kernel.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org Subject: Re: [PATCH v1 13/13] kho: Introduce high-level memory allocation API Message-ID: References: <20251114155358.2884014-1-pasha.tatashin@soleen.com> <20251114155358.2884014-14-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251114155358.2884014-14-pasha.tatashin@soleen.com> X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: CC1FDC000B X-Stat-Signature: k3tdk9xgsbhofobhz3bdjbjpwin1p3gn X-Rspam-User: X-HE-Tag: 1763136968-10791 X-HE-Meta: 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 w8K4WqHz Iu/l8kYnUQdMBOZaVjbxVZYuZVPuLkqN7yLiN3FRCXpXuSwPOBTaZYGneukBaJEvuTk3SiZea2kYKAcjwS1jaCn1QypFyScijqh7Bk+qmMNckVByPHeuTdVWPn+ANXZtco1Ql2QoLSC6wxFJyFtXl/INyVgOPw1IRe7rFK/WwfXJBQE90HNoLr4NztKN7JLLm/CXg3DweijVzlvqLiUh+oYoZIsZR8sheLQ0/dca03FuBYjaw8n9DkcIspTRB6/Am16oWlQq4oyerGOqrJ4TQaNMLlx5+7i6xvZdRvUL8PHUXMUQYHVxibW4LlQ== 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 Fri, Nov 14, 2025 at 10:53:58AM -0500, Pasha Tatashin wrote: > Currently, clients of KHO must manually allocate memory (e.g., via > alloc_pages), calculate the page order, and explicitly call > kho_preserve_folio(). Similarly, cleanup requires separate calls to > unpreserve and free the memory. > > Introduce a high-level API to streamline this common pattern: > > - kho_alloc_preserve(size): Allocates physically contiguous, zeroed > memory and immediately marks it for preservation. > - kho_free_unpreserve(ptr, size): Unpreserves and frees the memory > in the current kernel. > - kho_free_restore(ptr, size): Restores the struct page state of > preserved memory in the new kernel and immediately frees it to the > page allocator. It would have been nice to have it before patch 3 (Preserve FDT folio only once during initialization) and use kho_alloc_preserve() for KHO's own FDT. > Signed-off-by: Pasha Tatashin > --- > include/linux/kexec_handover.h | 22 +++++-- > kernel/liveupdate/kexec_handover.c | 101 +++++++++++++++++++++++++++++ > 2 files changed, 116 insertions(+), 7 deletions(-) -- Sincerely yours, Mike.