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s=MBO0001; t=1752505784; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=yi4MCawnQyQQdkkj277+T9j0E8vF1s1kglJELz5ZzhM=; b=qTubtvhDqrugIMwcOUyZvZGENfOqT6WpF36DT5KvFdRz4RUhvcMLrL9SjYWVVbuRSpsmI2 SW3wc27W2YIerYbH63wD95hxGOeaxPulhCy7Xvln2eVIXap4lovkVDQJ1BW133k4dem0Gr 9xOugdk2IyYq1CMyR0kF5UTihQGxZJDrD0ZXR4F/GQORX3GDI+862O2XTJI14D7mTECWyb zLfA3SJuZDISzROC5r7ptJOFL9r1QjyhDcK715mhn9xGqOIZ5Rrtvtty6//Cg6pydTilq1 VIwoHgz0DX7ACc/qhb2jxioSbnmMr0gWrr3D5UkUqPBnn3M03nFXC9K0eSpMVg== Date: Mon, 14 Jul 2025 17:09:40 +0200 From: "Pankaj Raghav (Samsung)" To: David Hildenbrand Cc: Zi Yan , Matthew Wilcox , Luis Chamberlain , Jinjiang Tu , Oscar Salvador , akpm@linux-foundation.org, linmiaohe@huawei.com, mhocko@kernel.org, linux-mm@kvack.org, wangkefeng.wang@huawei.com Subject: Re: [PATCH v2 2/2] mm/memory_hotplug: fix hwpoisoned large folio handling in do_migrate_range Message-ID: References: <61325284-d1d6-a973-8aa7-c0f226db95fa@huawei.com> <7b2c054b-fc33-4127-aaa9-9edf6a63e142@redhat.com> <924d9d25-e53c-f159-6ec0-e1fd4e96d6e2@huawei.com> <4c5d4fd5-5582-11d8-9fee-24828ac1913d@huawei.com> <8c9719f0-c072-40bb-b7f6-6f2cc41a31dc@redhat.com> <1D589FE5-3515-4ED5-B12E-D5CE23BA5D13@nvidia.com> <641F5B0B-2B48-46FA-AC58-3A8A4BEB1448@nvidia.com> <3702f6b0-27a9-4ca1-adbd-fb1e2985b2d3@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3702f6b0-27a9-4ca1-adbd-fb1e2985b2d3@redhat.com> X-Stat-Signature: g8kbyjp6hu5sk7ykzmitkhd3qeuyirj9 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 972124000C X-Rspam-User: X-HE-Tag: 1752505788-13172 X-HE-Meta: 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 +Kqk+ZEv nwWsH566LGFBeDZ7/LtcMelR1XSfy8JERUpooO5PcMcii1yr0ip1/GzgKkKQWNb5QZIDRVPaYaz9U8U5/F/Qq6zZsX5Q82xcm2lTX5iYuBxuCUmCYydyPXv5UD2p9NOrVOFHfmlUyBnITHCWkTW5Gju1MmCnQxjyQB4kTfu/7PLNM942uX52zXF1THsdvWuetlcWht8iPMzPqgUO3OT+LDZD02PDduVjhw+WQRQ9FHPFWxKg856HCqoGYu1/ZsVS2WFaqUFkxrkPvpEit3YnRR2OdT9J8Jvc5zg8g 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: > > > > So we will need to take care of madvise cold or pageout case? > > > > > > > > Hi Matthew, Pankaj, and Luis, > > > > > > > > Is it possible to partially map a min-order folio in a fs with LBS? Based on my > > > > > > Typically, FSs match the min order with the blocksize of the filesystem. > > > As a filesystem block is the smallest unit of data that the filesystem uses > > > to store file data on the disk, we cannot partially map them. > > > > > > So if I understand your question correctly, the answer is no. > > I'm confused. Shouldn't this be trivially possible? > Hmm, maybe I misunderstood the question? > E.g., just mmap() a single page of such a file? Who would make that fail? > My point was, even if you try to mmap a single page of a file, page cache will read the whole block (that corresponds to min order folio). Technically we can mmap a single page of file, but FS will always read and write **at least** in min folio order chunks. > And if it doesn't fail, who would stop us from munmap()'ing everything > except a single page. > > -- > Cheers, > > David / dhildenb > > -- Pankaj