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Received: from 30.74.144.119(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0XAeKi9D_1788942115 cluster:ay36) by smtp.aliyun-inc.com; Wed, 09 Sep 2026 16:21:56 +0800 Message-ID: <95ada031-0fe3-4191-b09e-56b324247456@linux.alibaba.com> Date: Wed, 9 Sep 2026 16:21:54 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 04/19] selftests/mm: skip khugepaged page cache cases without a PMD folio To: Kiryl Shutsemau , akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, rppt@kernel.org Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, usama.anjum@arm.com, usama.arif@linux.dev, nico.pache@linux.dev, ziy@nvidia.com, baohua@kernel.org, dev.jain@arm.com, hughd@google.com, lance.yang@linux.dev, liam@infradead.org, mhocko@suse.com, ryan.roberts@arm.com, shuah@kernel.org, surenb@google.com, vbabka@kernel.org, agordeev@linux.ibm.com, jgg@ziepe.ca, leon@kernel.org, kernel-team@meta.com, "Kiryl Shutsemau (Meta)" References: <20260908125105.1510704-1-kirill@shutemov.name> <20260908125105.1510704-5-kirill@shutemov.name> From: Baolin Wang In-Reply-To: <20260908125105.1510704-5-kirill@shutemov.name> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: hms3afj1ba88bd3ydt9s8buzpxhft3t5 X-Rspam-User: X-Rspamd-Queue-Id: 38355C0004 X-Rspamd-Server: rspam03 X-HE-Tag: 1788942123-446860 X-HE-Meta: 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 W/kjH/JZ kSJJVr8/P94ep6oDNANNr74N1hb+lQ5OphUiebyzoCP8itPMUwIqYVNallEdkXQdI42UficRzru5oP7BxCnZ3ZgZGSrPhBuGps0ueAbZocH33kFjziVpGIcOzAFqsICGFW2ewi6G5ktpmH5GEgfCTjaHbImXfQMcYuMGNVzqI7/cBIFRR8l7Tj7vwAJVBF0ia/WGlyeztqqqnLxuuH7F5Q6FqwDai9AAFTg2u8lpmeis+rouevYFAMxXY2NzN64ffa8raqSA75muMsSBX4B1p69qMBFIasByvhLpYrqlBL32gPC8UjU1sMU2n2xfi3CNLUGrojbsigyErJ2FjAGAiopDs09hP8gANMhM7DTGB5C6puMKHgCVDpr6jw73RvXM5r/Kb Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/8/26 8:50 PM, Kiryl Shutsemau wrote: > From: "Kiryl Shutsemau (Meta)" > > The page cache caps folio order at MAX_PAGECACHE_ORDER, which is below the > PMD order on arm64 with 64K pages, where a PMD is 512M. A PMD-sized page > cache folio is impossible there, so the kernel refuses these collapses: > MADV_COLLAPSE answers -EINVAL and khugepaged passes over the range. Four > shmem cases ask for a PMD-sized folio anyway, fail, and the run bails out > in the middle. > > Skip the shmem and file mem types where the cap is below the PMD order. > > The cap is not shmem-specific: it applies to every file folio. Add > thp_file_supported_orders() to read the orders the page cache allows. > > Anonymous collapse is unaffected: its orders are not capped this way. > > Assisted-by: LLM > Reviewed-by: Mike Rapoport (Microsoft) > Tested-by: Muhammad Usama Anjum > Signed-off-by: Kiryl Shutsemau (Meta) > --- LGTM. Reviewed-by: Baolin Wang