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[80.187.80.144]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-46e61a029a0sm27915195e9.13.2025.10.01.01.31.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 01 Oct 2025 01:31:09 -0700 (PDT) Message-ID: Date: Wed, 1 Oct 2025 10:31:07 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH mm-new v2 1/1] mm/khugepaged: abort collapse scan on non-swap entries To: Lance Yang , akpm@linux-foundation.org Cc: lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, dev.jain@arm.com, hughd@google.com, ioworker0@gmail.com, kirill@shutemov.name, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mpenttil@redhat.com, npache@redhat.com, ryan.roberts@arm.com, ziy@nvidia.com, richard.weiyang@gmail.com References: <20251001032251.85888-1-lance.yang@linux.dev> From: David Hildenbrand Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20251001032251.85888-1-lance.yang@linux.dev> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 3DiMMjIRkSeHo7luwfjo2gCDuc9ZEzbA2s-3sAGB_88_1759307470 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 4951314000B X-Rspam-User: X-Rspamd-Server: rspam07 X-Stat-Signature: j5zp7qei3amdnbq9chd5wcgw58tf99pc X-HE-Tag: 1759307473-508852 X-HE-Meta: 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 QxBUZHJh 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 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 01.10.25 05:22, Lance Yang wrote: > From: Lance Yang > > Currently, special non-swap entries (like migration, hwpoison, or PTE > markers) are not caught early in hpage_collapse_scan_pmd(), leading to > failures deep in the swap-in logic. > > hpage_collapse_scan_pmd() > `- collapse_huge_page() > `- __collapse_huge_page_swapin() -> fails! > > As David suggested[1], this patch skips any such non-swap entries > early. If any one is found, the scan is aborted immediately with the > SCAN_PTE_NON_PRESENT result, as Lorenzo suggested[2], avoiding wasted > work. > > [1] https://lore.kernel.org/linux-mm/7840f68e-7580-42cb-a7c8-1ba64fd6df69@redhat.com > [2] https://lore.kernel.org/linux-mm/7df49fe7-c6b7-426a-8680-dcd55219c8bd@lucifer.local > > Suggested-by: David Hildenbrand > Suggested-by: Lorenzo Stoakes > Signed-off-by: Lance Yang > --- Could have mentioned you adjust the flow of code to resemble what we have in __collapse_huge_page_isolate(). Acked-by: David Hildenbrand -- Cheers David / dhildenb