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To: Matthew Wilcox , Zi Yan CC: , , , Lorenzo Stoakes , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , , , , , , , , References: <20251010173906.3128789-1-ziy@nvidia.com> <20251010173906.3128789-3-ziy@nvidia.com> <934db898-5244-50b9-7ef7-b42f1e40ddca@huawei.com> From: Miaohe Lin Message-ID: <35d00740-0aa4-1d6d-87b8-ee973bcff792@huawei.com> Date: Sat, 11 Oct 2025 17:07:38 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.173.125.37] X-ClientProxiedBy: kwepems500001.china.huawei.com (7.221.188.70) To kwepemq500010.china.huawei.com (7.202.194.235) X-Rspamd-Queue-Id: 62F7F180005 X-Rspamd-Server: rspam11 X-Rspam-User: X-Stat-Signature: qjajkxc4q5prsgae8zfii8yips7bcg9x X-HE-Tag: 1760173679-465546 X-HE-Meta: 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 2BzGrwpI HGTwPvpD+5RQ/1ZvoKtIoCg5MPTa4b8p0Y3EFr0DTB2R3svk80LmHirtwrXOZLj8cNap/Da9rS9CVWUo3xRa/0Dbwui70zBHEk2v6ehlK3YIhBqEb/YAY06pdfFdOXuzeYZhMU6MEGxCZHoy9nbHXxgJ0t7kPfWRvUdHnph05VFneJZe40vYzl3dSL7ZXRHSHC2nJhHrQvjobPiNvJWzNV29LjIr1KEx6n4qwDoU+A95gSyy1JOimn0pWo53U5vMHKduLolhf0JIx821eBtPLj2LIZ1N3ZHiuChC48c/wRvdQowLJIZxzfVTrEbyAOVGKJNUwcTtLAtnE61eVSAh/R9pwhK8kyEHEqODyk+ueh98ZuJ+Kg95nSVTGEA== 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 2025/10/11 13:00, Matthew Wilcox wrote: > On Sat, Oct 11, 2025 at 12:12:12PM +0800, Miaohe Lin wrote: >>> folio_set_has_hwpoisoned(folio); >>> - if (try_to_split_thp_page(p, false) < 0) { >>> + /* >>> + * If the folio cannot be split to order-0, kill the process, >>> + * but split the folio anyway to minimize the amount of unusable >>> + * pages. >>> + */ >>> + if (try_to_split_thp_page(p, new_order, false) || new_order) { >>> + /* get folio again in case the original one is split */ >>> + folio = page_folio(p); >> >> If original folio A is split and the after-split new folio is B (A != B), will the >> refcnt of folio A held above be missing? I.e. get_hwpoison_page() held the extra refcnt >> of folio A, but we put the refcnt of folio B below. Is this a problem or am I miss >> something? > > That's how split works. I read the code and see how split works. Thanks for point this out. > > Zi Yan, the kernel-doc for folio_split() could use some attention. That would be really helpful. Thanks. . > First, it's not kernel-doc; the comment opens with /* instead of /**. > Second, it says: > > * After split, folio is left locked for caller. > > which isn't actually true, right? The folio which contains > @split_at will be locked. Also, it will contain the additional > reference which was taken on @folio by the caller. > > . >