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b=YZu3ijssENglOnURSerpM3JLIbhS9/hpMCoVqQhWFCXpniBu2lgaawd2xNTfv4uK0 JnpYYuGXLpWk90+FMLagcSonqqfnaooTN9wEe9SRLGVNu26OLG9/JRjYxIHB70L4ab YXcPZ5kYoapZGdwLZ4Trt5SFbW87F/uh+1nvgYFBk1X+pCOKe1FNROUDL0QkytGNTI bidl46eVofmaBxLtcF0hKniskx0ZHbbsOSS/rk8TwLp3AvHc5bzZf50IGO5UI9iUFg +P5V7b9EmaXQS7OfqIuJS3aQY0MnuaV+3wOzcKhCmp38KfTNapAH6JJpnioAoJuN/F Sg7urIoXBE0Sw== Date: Tue, 16 Sep 2025 17:41:15 +0300 From: Mike Rapoport To: Pratyush Yadav Cc: Pratyush Yadav , Andrew Morton , Alexander Graf , Baoquan He , Changyuan Lyu , Chris Li , Jason Gunthorpe , Pasha Tatashin , kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/2] kho: add support for preserving vmalloc allocations Message-ID: References: <20250908103528.2179934-1-rppt@kernel.org> <20250908103528.2179934-2-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 6237C40009 X-Stat-Signature: fnkcjyh7exx4h419dstyk1hjenkun9rz X-Rspam-User: X-HE-Tag: 1758033685-141421 X-HE-Meta: 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 llM4nID+ olMtvJ5mkX9RwEPwyClUVkUnfwTfwlBHveuAwp0eZv1vw2CsPsP3FoN8Tji7b6kXFfNwx3fFmrifwk9ujJ8CtcvHTQw/U27dCEgZZcxCUMiAXpjJN0QhLD9fKStcRJyR4I2IV3NES79hijorcwoMfOl84T5nrdWxof8FPciPkG8dgLJhvIiN6kL7SDK4CSk+f44h3Q5bLw3qHqCqneRgGDqVuVKpUnS7U/qB2RDFTEM7nGcHWoGPPnUHivzp4RwAS5OzwthuvjQcfdCi1nqszfgWfkg== 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, Sep 16, 2025 at 02:48:55PM +0200, Pratyush Yadav wrote: > On Mon, Sep 15 2025, Mike Rapoport wrote: > > > On Tue, Sep 09, 2025 at 04:33:27PM +0200, Pratyush Yadav wrote: > >> Hi Mike, > >> > >> Also, I am not a fan of using kho_restore_page() directly. I think the > >> vmalloc preservation is a layer above core KHO, and it should use the > >> public KHO APIs. It really doesn't need to poke into internal APIs. If > >> any of the public APIs are insufficient, we should add new ones. > >> > >> I don't suppose I'd insist on it, but something to consider since you > >> are likely going to do another revision anyway. > > > > I think vmalloc is as basic as folio. At some point we probably converge to > > kho_preserve(void *) that will choose the right internal handler. like > > folio, vmalloc, kmalloc etc. > > Sure, but do you need to use the internal APIs? Because doing this way > would miss some improvements for the public APIs. See my patch for > adding more sanity checking to kho_restore_folio() for example: > https://lore.kernel.org/linux-mm/20250910153443.95049-1-pratyush@kernel.org/ > > vmalloc preservation would miss this improvement since it uses the > internal API, even though it will clearly benefit from it. The core restore API is kho_restore_page() and the improvements should land there, IMO. Then whatever uses that core API will benefit from them. -- Sincerely yours, Mike.