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[91.12.102.2]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-438dcc81589sm218117945e9.33.2025.02.04.01.44.04 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 04 Feb 2025 01:44:05 -0800 (PST) Message-ID: Date: Tue, 4 Feb 2025 10:44:03 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [LSF/MM/BPF TOPIC] KSM Enhancements: Selective KSM To: Sourav Panda , lsf-pc@lists.linux-foundation.org, Linux-MM , Pavel Tatashin , Yu Zhao , shr@devkernel.io, David Rientjes References: 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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: UnfpCdP0sZ91aBjxNyTwxO89EFTXvg9T4cvhHasRbTE_1738662246 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: 8C65780013 X-Stat-Signature: jtk3fmq6maezgg46ncwb8tmg1c3bi3z6 X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1738662249-783271 X-HE-Meta: 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 WbGZVNdS 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.057608, 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 01.02.25 03:15, Sourav Panda wrote: > Hi, Hi, > > > KSM is a powerful tool for deduplicating memory, reducing usage by merging > > identical pages across processes. However, there are certain interface and > > implementation aspect that prevents its deployment in our use case; wherein > > security and efficiency (CPU overhead - due to background scanning) are of > > greater importance. > > > We propose Selective KSM, a mechanism to control when the merging takes > > place and what pages can be merged together. We do this by partitioning the > > merge-space as per security-domains and carryout the merging as part of a > > synchronous syscall. Doing so, we ensure sensitive-content is not merged > > with non-sensitive content. I'll note that there was an RFC for uKSM [1] last year. Unfortunately, I didn't have time to look into it in more detail, and there was never any push for it. In particular, it proposed an interface: - /proc/uksm/merge enables the merging of two pages given their process IDs and addresses. - /proc/uksm/unmerge allows unmerging a previously merged KSM page. - /proc/uksm/cmp provides a lightweight mechanism to check page content equivalence before invoking a merge operation. [1] https://lore.kernel.org/linux-mm/20240329104035.62942-1-teawater@antgroup.com/T/ -- Cheers, David / dhildenb