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b=mCZgaD6KOl4NSTvradsDqu9gM/HxUVIdrWrJzFCG3NpmQRzxXB6cpFVf7i0XSNUsU sBBhdtVC3l6lOJ6gKK9nyDiKxhm7+JhNmY3pMoBWtjsfFWPR3xt8E5iBfgXdibGoL6 C2d2zx/FUoHViLg4+OOcVbYNrXtg+72aw7pDXGnEsQ4xx72BH5L5eweQQB6EcMhZzC jUjYJkPeMtkj26MK8yF35s38QTxuf9lHnHoAtlI+pgUyqBuI7YS8bc6UVDhWYF4tgn 0VrUCQIQtzOGZY4IS5H2EruN/PN4SICGCPHyUshAIx5ayU6jIV4J539TcrC3l2IFIa Az3X55mxCQJ1g== From: Pratyush Yadav To: Mike Rapoport Cc: Pratyush Yadav , Alexander Graf , Pasha Tatashin , Andrew Morton , kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] kho: drop restriction on maximum page order In-Reply-To: (Mike Rapoport's message of "Tue, 10 Mar 2026 12:33:38 +0200") References: <20260309123410.382308-1-pratyush@kernel.org> <20260309123410.382308-2-pratyush@kernel.org> Date: Tue, 17 Mar 2026 09:12:19 +0000 Message-ID: <2vxzo6kmddl8.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Stat-Signature: ryort6xy3rzepjndnyw3xirr9zax4bk6 X-Rspamd-Server: rspam09 X-Rspam-User: X-Rspamd-Queue-Id: 89C1C40005 X-HE-Tag: 1773738744-102804 X-HE-Meta: U2FsdGVkX1+S/ihG+XBFFoxGWB7Jh4kXm2ZavSv/BCdXB6Be7SNsy4C86Vka2kqOMGPgHh4EnfggrAJdU8jKyakU9Qh9lKX/CJpUNpcVAqLZn+TyJ75BMxjE9nFwMs8YdK6iTQOFNpM5FNjE+FxYw1Ga2O6EvT6Mg75g3btJa7nKv13W/plgmQDGcsCocXZXOPmK3qsxGTYlA5nys/zK+jUwaFVPtkJCZwEy1oTYxblkFXhBdxSRFUxm42I02uDVKjBbZiEydob6KN+qgMtOIFoOcHUfSjURHkTKywIwgrU0RnWqVafeTZwbEY2Y8rnWZ7ZDXug7Ec+SZOscgwaqQ6ZMRVN5PrQFeOZtgDhR5/7ZkM6gtRGfFeCSG1YBmNzWrZWEcw9I+3HjrsbJUdKYWN/2y21BYIM9S6PtPm/q+G8sRE31pE1HKg3VxY6SQUl3ZtVEoNT76pqxzL+Pq7vb4lN9XD1d4x/XwsPcCfJ5wNqLQfnsOslR5jOCbVAx5bQgUBxnviCq4M5NgR8ratP/NUo96YxQHWtaGQAC7fuqQQYx4vW7EA7J1XnqREeQvjGusY5BNzTq3N8DsbHKrHH1YCaCbamoxXR8oyZgTQq1O7rNbtU4SoOZceX9bKTCHSfQH5A5O1ZhMypqhUKKu2PgWmUwcWIYjAxUtbZW+b6ZVXss83bl3YHk/cDaioDTx+JoujfdkzttZre4Wxd96twTWW0i6KblVbWOQBUmFcoVDsIode9CP7GAYBvA6M7vtNxiibAC/LEoLS6oQ6fN9fV/JSJJrmF3mfN+/STTVWdntwyALPuwh4q4GzVvV6KlmbK2AW4jSTKd5zVegRLnkdZ26hnoFSAGxvY+tkR81+rDY0HfKtIbbi98n0cY7oPuU0bl+tfRnaJbmd4GULYYPSGV8B0Qyjg13O30Izku2AD4M0sqsnWR4bY9qHJRPp2DvzqbzuSKdxIbEx/xjRNKifi EGm9VJBU c7A0VtF5saNntiDaEXzjfGqIpReugSLswdXPuxTw0Hl1hBhWdUNwukUuV19vzzNxeaWuYAo9xMz3I4jfKsH63c7rDCkGIBRnRNsu3BnuFKmkcdNM3o0UyEwDsMADC3Sd7KD4WK7rIybPP3lXUsa5iFCTFdbHwIjHl+b3tKnjx6Obmuj5tDTwJMTZWke/z6Q0flvTd Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Mar 10 2026, Mike Rapoport wrote: > On Mon, Mar 09, 2026 at 12:34:07PM +0000, Pratyush Yadav wrote: >> KHO currently restricts the maximum order of a restored page to the >> maximum order supported by the buddy allocator. While this works fine >> for much of the data passed across kexec, it is possible to have pages >> larger than MAX_PAGE_ORDER. >> >> For one, it is possible to get a larger order when using >> kho_preserve_pages() if the number of pages is large enough, since it >> tries to combine multiple aligned 0-order preservations into one higher >> order preservation. >> >> For another, upcoming support for hugepages can have gigantic hugepages >> being preserved over KHO. >> >> There is no real reason for this limit. The KHO preservation machinery >> can handle any page order. Remove this artificial restriction on max >> page order. >> >> Signed-off-by: Pratyush Yadav >> Signed-off-by: Pratyush Yadav (Google) > > One SOB should be enough ;-) Hmm, I figured the unemployed me (who originally wrote the patch) and the employed-by-google me (who is doing this new version) would count as two separate entities and there should be a S-o-b for both. Anyway, I am fine with dropping either one of the two. > > Reviewed-by: Mike Rapoport (Microsoft) Thanks! [...] -- Regards, Pratyush Yadav