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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1rJ8YC-0064Xi-Oe; Fri, 29 Dec 2023 08:49:04 +0000 Date: Fri, 29 Dec 2023 08:49:04 +0000 From: Matthew Wilcox To: Kefeng Wang Cc: Andrew Morton , ziy@nvidia.com, linux-mm@kvack.org Subject: Re: [PATCH] mm: memory: use nth_page() in clear/copy_subpage() Message-ID: References: <20231229082207.60235-1-wangkefeng.wang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231229082207.60235-1-wangkefeng.wang@huawei.com> X-Rspamd-Queue-Id: EFE9340002 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: fueqynckbnxtx765kntyx7zis887fqy3 X-HE-Tag: 1703839752-481729 X-HE-Meta: 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 sYnoXoKD JCLpmHxMqlJa+LCNkPyg50kjPgkZoUQWZsdGpmh8If6ldU7UNM7WPP3FfaA+MIRKR7/vAquKxn7bFxuLUoOHQRmrjQHXiq2Vmqw26CpbfesSSEu2Lnti2mdG4Y2sXS9PTojZfTGIrsEmYm84+DbKJZRfIp70Nx5/zGR4djSmmPd0whZU+YQAB5cJLdg== 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 Fri, Dec 29, 2023 at 04:22:07PM +0800, Kefeng Wang wrote: > The clear and copy of huge gigantic page has converted to use nth_page() > to handle the possible discontinuous struct page(SPARSEMEM without VMEMMAP), > but not change for the non-gigantic part, fix it too. Can there be discontiguities within a non-gigantic huge page? My impression was that you can't have a discontiguity at such a small boundary.