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b=sb7lZpEezHU+Dj2cD7bFRkIjB+iHDbLuvnpMkgJ0BF2dj9Kwj/V4bejmL++M8/31LhrtRX bGmwnC4CG+1c9vow6rhaEVfDw1yYgivU61bZlJV/oP81vIGhDbdI6XoNftkaT+dQDf8jVa CG10ew7P11CfHMETEa35VEQCvl+83Q8= X-Stat-Signature: mx5j8yueow9r3hqf43f6g94a77pgjhxn X-Rspamd-Queue-Id: 21388C0023 X-Rspam-User: X-Rspamd-Server: rspam06 Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=clQxFgS5; spf=pass (imf28.hostedemail.com: domain of jhubbard@nvidia.com designates 40.107.236.41 as permitted sender) smtp.mailfrom=jhubbard@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector9901:i=1") X-HE-Tag: 1661648873-250114 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: On 8/27/22 17:31, John Hubbard wrote: > On 8/27/22 17:12, Andrew Morton wrote: >> On Sat, 27 Aug 2022 16:59:32 -0700 John Hubbard wrote: >> >>> Anyway, I'll change my patch locally for now, to this: >>> >>> static inline void dio_w_unpin_user_pages(struct page **pages, >>> unsigned long npages) >>> { >>> /* Careful, release_pages() uses a smaller integer type for npages: */ >>> if (WARN_ON_ONCE(npages > (unsigned long)INT_MAX)) >>> return; >>> >>> release_pages(pages, (int)npages); >>> } >> >> Well, it might be slower. release_pages() has a ton of fluff. >> >> As mentioned, the above might be faster if the pages tend >> to have page_count()==1?? >> > > I don't think we can know the answer to that. This code is called To clarify: I mean, I don't think we can know whether or not these pages usually have page_count()==1. thanks, -- John Hubbard NVIDIA