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([2a02:6b6f:e750:1800:450:cba3:aec3:a1fd]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-479311ece7asm145085065e9.12.2025.12.06.09.27.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 06 Dec 2025 09:27:30 -0800 (PST) Message-ID: <17002374-e135-46a5-9e4c-c317ac9823ae@gmail.com> Date: Sat, 6 Dec 2025 17:27:29 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 07/11] mm: Drop fake head checks and fix a race condition Content-Language: en-GB To: Kiryl Shutsemau , Andrew Morton , Muchun Song Cc: David Hildenbrand , Oscar Salvador , Mike Rapoport , Vlastimil Babka , Lorenzo Stoakes , Matthew Wilcox , Zi Yan , Baoquan He , Michal Hocko , Johannes Weiner , Jonathan Corbet , kernel-team@meta.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org References: <20251205194351.1646318-1-kas@kernel.org> <20251205194351.1646318-8-kas@kernel.org> From: Usama Arif In-Reply-To: <20251205194351.1646318-8-kas@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 8D26B20005 X-Stat-Signature: zdudywp1p7nhw6ntjrtbh49176ix5fpq X-Rspam-User: X-HE-Tag: 1765042053-125260 X-HE-Meta: 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 KNnskir1 pLwk2X2vdbyl9ftQ33Te9mpfPHEr0W3MXG/OWvkBApKHBe5geauhDOJh7COJw2mGaTy0WdoITM4qtndCZdyGU1u/roewxIpzLD50vfzvTYcBSEuP9G2U//kyrtARtbCnzNuAhWlsgkuEs+8QNQyggYvWKiLCqmcWnosULUVZsdnyvC42fKeUU1FMIatB8gaoH4TIvYgYEx+uoVSH9VuP7pdJN2WrH2QRqpw7WYSUpotjnBf3StrNVJZvND+J04PfzwXsCSTVEIrYliXEW8NDNkfVoXMOvh3UzzrZcUGtNhf6jhuwVLvwrGByinGvBUdoSEZGHjmtvVD8mb0SE8CozhDKV6YAWMlYPKwmv0nj6Lj1da4hH2FRRL50isBdmDy5NYLwDT2QvoEBaVws3RtM4MgmIvwd7aYKxrmch4y4730W0NroOFMi/qKVaqD1Xbb/nl+NZ9C4kn6JM+U8jBEM4aU6hWw== 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 05/12/2025 19:43, Kiryl Shutsemau wrote: > Fake heads are no longer in use, so checks for them should be removed. > > It simplifies compound_head() and page_ref_add_unless() substantially. > Would be good to mention in the commit message what the race condition is as its there in the subject. Probably can copy some text from the cover letter.