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b=ou7Su6GC0HgcXE91A7ybE8rVrAL/ds7lBgRUPKFdr8xf8W+ro3p5Rf0JTKAuV/7pM tav/40d80NMF8uKrh1eiYH4tUq9156kNTU+Zhe4c/4v8n76653PSTWQPQwsSJAAfdH n+ikFBTgaZHETW3x/XzFgaNcAq4+I8uZk5lVqZ5FVFr5JvgAdDBhGohZqXw6BJKvWx cUUMNRCLxMQJc5eIcMOsfGzUj3u+E/590ZdrPxib7whbxMhb3GKMN4G4uGXbfqKcYA RqdfcClr06xWf6PGxHO6MenJi67hnRqmmGPrGpglmeCA1YstxY1n4HfRCZnZWkHIMd QDw1JYkizpolQ== From: Pratyush Yadav To: Pasha Tatashin Cc: akpm@linux-foundation.org, brauner@kernel.org, corbet@lwn.net, graf@amazon.com, jgg@ziepe.ca, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, masahiroy@kernel.org, ojeda@kernel.org, pratyush@kernel.org, rdunlap@infradead.org, rppt@kernel.org, tj@kernel.org Subject: Re: [PATCHv7 5/7] kho: don't unpreserve memory during abort In-Reply-To: <20251022005719.3670224-6-pasha.tatashin@soleen.com> (Pasha Tatashin's message of "Tue, 21 Oct 2025 20:57:17 -0400") References: <20251022005719.3670224-1-pasha.tatashin@soleen.com> <20251022005719.3670224-6-pasha.tatashin@soleen.com> Date: Wed, 22 Oct 2025 13:15:30 +0200 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 9B6141A0007 X-Stat-Signature: nh4woucdtp6xj9w5m1s5zdrfsangjr8u X-Rspam-User: X-HE-Tag: 1761131734-510759 X-HE-Meta: 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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 Tue, Oct 21 2025, Pasha Tatashin wrote: > KHO allows clients to preserve memory regions at any point before the > KHO state is finalized. The finalization process itself involves KHO > performing its own actions, such as serializing the overall > preserved memory map. > > If this finalization process is aborted, the current implementation > destroys KHO's internal memory tracking structures > (`kho_out.ser.track.orders`). This behavior effectively unpreserves > all memory from KHO's perspective, regardless of whether those > preservations were made by clients before the finalization attempt > or by KHO itself during finalization. > > This premature unpreservation is incorrect. An abort of the > finalization process should only undo actions taken by KHO as part of > that specific finalization attempt. Individual memory regions > preserved by clients prior to finalization should remain preserved, > as their lifecycle is managed by the clients themselves. These > clients might still need to call kho_unpreserve_folio() or > kho_unpreserve_phys() based on their own logic, even after a KHO > finalization attempt is aborted. I think you also need to update test_kho and reserve_mem to do this since right now they assume all memory gets unpreserved on failure. > > Signed-off-by: Pasha Tatashin > --- [...] -- Regards, Pratyush Yadav