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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762193153; bh=+64iKrvV3aelQ+MDxd4Vv/MtBZ3N2qzpU9GTaRPio/U=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=P0Q6iZmJK/NA+gbfeQInwBVD+j/Mn4E1i/RYRGFSSkO9j48VXUBSt4qX7JDbU9/sh oQaUywp3A+5CnhS2iXAStJ0jiuKL+Iz79AezYdKAOdkZHlIlnXylhHGjX+X6iqj+IF n6QlkUu4/grO0RvSCHPixVuKjT1yJPWqvv9s+/q1qzlfKkH/iNA1Tqe55xboZrNhm1 LKekEXOUMr07Yqs22nUM1noYOwUY6u3H1N1Zz1ZLfekCtPCeFvHjyRJJ3G2jxZ6raM Gsh6bOPS3mkh2oaFKdjmn7dcQlkMDUwbWf+FxdzN1FWZHRr4dNx82XokKVxrHSed4T 0zF60vTlv8V8g== 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, yanjun.zhu@linux.dev Subject: Re: [PATCH v9 3/9] kho: add interfaces to unpreserve folios, page ranges, and vmalloc In-Reply-To: <20251101142325.1326536-4-pasha.tatashin@soleen.com> (Pasha Tatashin's message of "Sat, 1 Nov 2025 10:23:19 -0400") References: <20251101142325.1326536-1-pasha.tatashin@soleen.com> <20251101142325.1326536-4-pasha.tatashin@soleen.com> Date: Mon, 03 Nov 2025 19:05:49 +0100 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 20FD218001B X-Stat-Signature: y7qsddo7sgp5dze4z34194jozccgi58w X-HE-Tag: 1762193153-188034 X-HE-Meta: U2FsdGVkX1+5BCrYmk2dd01K9zkR4hFIc2g6CuAp6t5wJRCv+PsktqexLJAjNbBj8QXUVI9t2WfEQQw7oFPslz4hvlr7rhBAY8pUZ6v8WMK6n2ABQpQXtO+gdYfbBxW+98qninWkWu8EvOL4RJRWEPo3/FuL4zR4+np4RlooHK72+BuktxzmjLeET1LfZpbE8z6QCnWI7QDCtqHgaJbcKV4MAc4ZtmyvEgGwWT0eE+F7adJ/ScgJ6GUrfyiOwGKe5cqlCdYev71aE9nH37VtoKbF4oZ4MNPfgUTWsUJmGZ4OajeWoIAjioAMLg54yU7KuzndWRXTi71NNc3XrgSOE0SAoHbdKAxJxWk4W+FQn5gEuOzvRnOW4UHoubJRe8M+MrrVB7EfADmCyJ0JgmFPEND+CkFgsrFxfSUjL/Z64PqMNRdg355vh7lVdIRMk40qCAwEBOelkUM/vfe0PO7HMS3n8rkXmQ6b87696ihMJE9I2Ftx5C96A//p+AbhfC2ARBJS4qeJJrdXhi9GOpOmuqcP0b4JpvA83xss6DUjZbIKHW3kU4FpbA9xLWWrHclaXUQUYxl+JUjF7W4o49RzKwnuhJAmU2wva3+6lrmMBCitblrpHYFfr/7VqNJa6As/bASCKHHMA1jMnqaKOTc3kc4/AIonVYXf+JMJGKN+aDPVOpvCaR6z80FXrgM8ep8IyQj81iKeeigUr1pb8oWwAWV9ouPMKdrKrNaEesLCHjvLnDk9CPbet/kxcc6luKBBeuMmBocyOQ6qkYqMxqPY2RTMS30n0ESh2CUX2vvIyAdBpSjrQetVaYrg7iGnJekyJvddM4gHxNBOq7NHLzE00AVosQ1OPQXy6TozlHcMcIRdxPq7l5rJ4MZvEZ74fXdbokO+nCWfL1Nh9sLl/l/BhPAdgPBR4siYnbq/iHmIaRWISxWAZgpVNllSaQHhmz74UtpRJW2AH5w0Xb85SRC YqQ6em/C J1DdFVXZsFPmLIK6JOsYyZBFecpTI5/zDBTBgf2YSWv4Ppj5p+GYtEyvdKQ0cJ33lPMaRhJNRNZYOabWyvb9L6P+dXIFVP3eYENR1ARALOuEh9bb982YVN7N+/9S1i9INP2jBC/VdFDNNiO1uzMS++3/x0+RJywa8DGe7sbBWHR9JaUlKTGnuDK2hQvrbdespq1egQdO4safxfiRCxQPYN3qwV3OmUzR0p7DbIKMZBfUALNj9cYPTHFqXX4pphNxUREZ8 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 Pasha, On Sat, Nov 01 2025, Pasha Tatashin wrote: > Allow users of KHO to cancel the previous preservation by adding the > necessary interfaces to unpreserve folio, pages, and vmallocs. > > Signed-off-by: Pasha Tatashin > Reviewed-by: Pratyush Yadav > Reviewed-by: Mike Rapoport (Microsoft) [...] > +/** > + * kho_unpreserve_vmalloc - unpreserve memory allocated with vmalloc() > + * @preservation: preservation metadata returned by kho_preserve_vmalloc() > + * > + * Instructs KHO to unpreserve the area in vmalloc address space that was > + * previously preserved with kho_preserve_vmalloc(). > + * > + * Return: 0 on success, error code on failure > + */ > +int kho_unpreserve_vmalloc(struct kho_vmalloc *preservation) > +{ > + if (kho_out.finalized) > + return -EBUSY; > + > + kho_vmalloc_free_chunks(preservation); When reviewing this patch, I spotted that kho_vmalloc_free_chunks() is broken. Well it happens to work if all pages are 0-order, but breaks on higher-order allocations. I have sent a separate patch [0] to fix this on top of mm-stable. It doesn't have a conflict with this patch so it shouldn't cause trouble. And I **don't** think it should block this patch either. This is mostly a heads up. [0] https://lore.kernel.org/linux-mm/20251103180235.71409-2-pratyush@kernel.org/T/#u -- Regards, Pratyush Yadav