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(p200300d82f20da00b70ad5023b511f2d.dip0.t-ipconnect.de. [2003:d8:2f20:da00:b70a:d502:3b51:1f2d]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-45e0372ae57sm60050545e9.8.2025.09.12.05.40.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 12 Sep 2025 05:40:58 -0700 (PDT) Message-ID: <74d1f275-23c3-4fd8-b665-503c7fc87df0@redhat.com> Date: Fri, 12 Sep 2025 14:40:55 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/7] mm: introduce local state for lazy_mmu sections To: Alexander Gordeev Cc: Kevin Brodsky , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andreas Larsson , Andrew Morton , Boris Ostrovsky , Borislav Petkov , Catalin Marinas , Christophe Leroy , Dave Hansen , "David S. Miller" , "H. Peter Anvin" , Ingo Molnar , Jann Horn , Juergen Gross , "Liam R. Howlett" , Lorenzo Stoakes , Madhavan Srinivasan , Michael Ellerman , Michal Hocko , Mike Rapoport , Nicholas Piggin , Peter Zijlstra , Ryan Roberts , Suren Baghdasaryan , Thomas Gleixner , Vlastimil Babka , Will Deacon , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, Mark Rutland References: <47ee1df7-1602-4200-af94-475f84ca8d80@arm.com> <29383ee2-d6d6-4435-9052-d75a263a5c45@redhat.com> <9de08024-adfc-421b-8799-62653468cf63@arm.com> <4b4971fd-0445-4d86-8f3a-6ba3d68d15b7@arm.com> <4aa28016-5678-4c66-8104-8dcc3fa2f5ce@redhat.com> <15d01c8b-5475-442e-9df5-ca37b0d5dc04@arm.com> <7953a735-6129-4d22-be65-ce736630d539@redhat.com> <781a6450-1c0b-4603-91cf-49f16cd78c28@arm.com> <9ed5441f-cc03-472a-adc6-b9d3ad525664-agordeev@linux.ibm.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: <9ed5441f-cc03-472a-adc6-b9d3ad525664-agordeev@linux.ibm.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: w6MC4SdshJIoPibQ4NW0SYg_CzuZUGpDT84oX1-qL9Q_1757680859 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 09107180007 X-Stat-Signature: pfi96ua9njxbjm36gsgm5inrmcbsj48h X-HE-Tag: 1757680863-40660 X-HE-Meta: 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 mvzuV/5o Ao9Ni1Lk9/gnzShygVipKvQ0x761AE7Psz8q7MI7nDdYq7XSHqP2YXu/Ad/jiBt0de9tw2hx+z8MZK+Ta4Z4SkREpVavdTLecxgBsgJL+1PNrioao5crWWQHoWFUB3dY7d5u1z9BrFHwsgUIpE3ZTATmINz11wPJghvrm1FsPv+LHTnuZUr+AXwNzpgAhIy/IhhvbzzdzSpsvbeR3/LjsTkSzrXDwpcUNABzBjFjvqvnTYb6/kyso1NW39dUeLPE53dLL6NU1mIWp4Ct+0/yMnPQUte5UPhtZhukIOyQcyeARKOLDh9weF5F822VCNTQ0wnQmoAKTfAeX3MZLAbbwVOL8zDWyOJIum5Tj06ll6/0qCzQPYRR5EvKcPWhZYYug4mETTG9rwFCG7zMyMi1mVBETb59pgMNpyA9pIL+3uxmzXOIwu69JtGtTi/oAXDy8/sSo9vX6KWLMqIRT8aVm50evem5x+sjDsS8Z 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 12.09.25 14:37, Alexander Gordeev wrote: > On Fri, Sep 12, 2025 at 10:55:50AM +0200, David Hildenbrand wrote: > > Hi David, Kevin, > >> Great, looking forward to seeing this all getting cleaned up and done >> properly for good. > > I am currently working on lazy mmu for s390 and this nesting > initiative kind of interferres. Well, in fact it looks like > it does not, but I am bit lost in last couple of iterations ;) > > The prerequisite for s390 would be something like the change > below. With that change I can store the context in a per-cpu > structure and use it later in arch-specific ptep_* primitives. > > Moreover, with a further (experimental) rework we could use > a custom kasan sanitizer to spot false directly compiled > PTE accesses, as opposed to set_pte()/ptep_get() accessors. > > I am not quite sure see whether this could be derailed by > the new lazy mmu API. At least I do not immediately see any > obvious problem. But may be you do? It would just be passing more context down to the architecture, right? -- Cheers David / dhildenb