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[2003:d8:2f4e:3200:c99d:a38b:3f3a:d4b3]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-475c427f77bsm107646305e9.3.2025.10.23.09.16.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 23 Oct 2025 09:16:01 -0700 (PDT) Message-ID: Date: Thu, 23 Oct 2025 18:16:00 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 0/1] mm/ksm: recover from memory failure on KSM page by migrating to healthy duplicate To: Long long Xia , linmiaohe@huawei.com, lance.yang@linux.dev Cc: markus.elfring@web.de, nao.horiguchi@gmail.com, akpm@linux-foundation.org, wangkefeng.wang@huawei.com, qiuxu.zhuo@intel.com, xu.xin16@zte.com.cn, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20251016101813.484565-1-xialonglong2025@163.com> <7e533422-1707-4fea-9350-0e832cf24a83@redhat.com> <122ef241-787d-4e8c-82cf-01ff318293a6@163.com> 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: <122ef241-787d-4e8c-82cf-01ff318293a6@163.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: O8j1ZEy9ycG_WuRVMmeH1Lv7UswGEakQI4mA8v-nlJ0_1761236163 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Stat-Signature: as8aw9pj1kfw14pxxe8ik63pznez3rok X-Rspamd-Queue-Id: 484D320003 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1761236166-896811 X-HE-Meta: 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 lFjEc2SM 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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 21.10.25 16:00, Long long Xia wrote: > Thanks for the reply. > > I do some simple tests. > I hope these findings are helpful for the community's review. > > 1.Test VM > Configuration > Hardware: x86_64 QEMU VM, 1 vCPU, 256MB RAM per guest > Kernel: 6.6.89 > > Testcase1: Single VM and enable KSM > > - VM Memory Usage: >   * RSS Total  = 275028 KB (268 MB) >   * RSS Anon   = 253656 KB (247 MB) >   * RSS File   = 21372 KB (20 MB) >   * RSS Shmem  = 0 KB (0 MB) > > a.Traverse the stable tree > b. pages on the chain > 2 chains detected > Chain #1: 51 duplicates, 12,956 pages (~51 MB) > Chain #2: 15 duplicates, 3,822 pages (~15 MB) > Average: 8,389 pages per chain > Sum: 16778 pages (64.6% of ksm_pages_sharing + ksm_pages_shared) > c. pages on the chain > Non-chain pages: 9,209 pages > d.chain_count = 2, not_chain_count = 4200 > e. > /sys/kernel/mm/ksm/ksm_pages_sharing = 21721 > /sys/kernel/mm/ksm/ksm_pages_shared = 4266 > /sys/kernel/mm/ksm/ksm_pages_unshared = 38098 > > > Testcase2: 10 VMs and enable KSM > a.Traverse the stable tree > b.Pages on the chain > 8 chains detected > Chain #1: 458 duplicates, 117,012 pages (~457 MB) > Chain #2: 150 duplicates, 38,231 pages (~149 MB) > Chain #3: 10 duplicates, 2,320 pages (~9 MB) > Chain #4: 8 duplicates, 1,814 pages (~7 MB) > Chain #5-8: 4, 3, 3, 2 duplicates (920, 720, 600, 260 pages) Thanks, so I assume the top candidates is mostly zeropages and stuff like that. Makes sense to me then, it would be great to add that as motivation to the cover letter! -- Cheers David / dhildenb