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(p200300d82f3f4b00ee138c225cc5d169.dip0.t-ipconnect.de. [2003:d8:2f3f:4b00:ee13:8c22:5cc5:d169]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-429c110037asm9461926f8f.3.2025.11.01.05.22.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 01 Nov 2025 05:22:45 -0700 (PDT) Message-ID: Date: Sat, 1 Nov 2025 13:22:42 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 07/12] mm: enable lazy_mmu sections to nest To: Kevin Brodsky , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Alexander Gordeev , Andreas Larsson , Andrew Morton , Boris Ostrovsky , Borislav Petkov , Catalin Marinas , Christophe Leroy , Dave Hansen , "David S. Miller" , David Woodhouse , "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, x86@kernel.org References: <20251029100909.3381140-1-kevin.brodsky@arm.com> <20251029100909.3381140-8-kevin.brodsky@arm.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: <20251029100909.3381140-8-kevin.brodsky@arm.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: qiw-Qez_vyGPgtZ5K94LKkcq2vmkkoDWPTZPBg8EgEk_1761999766 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: 0FFD3180002 X-Rspamd-Server: rspam11 X-Rspam-User: X-Stat-Signature: 3krf9mogyfb7fjmpxqqnbotdbd4kjps7 X-HE-Tag: 1761999768-593083 X-HE-Meta: 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 IHskmFh0 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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: > static inline void lazy_mmu_mode_pause(void) > { > + struct lazy_mmu_state *state = ¤t->lazy_mmu_state; > + > + VM_WARN_ON(state->nesting_level == 0 || !state->active); > + > + state->active = false; > arch_leave_lazy_mmu_mode(); Just one question: Don't we want to allow for pause/resume when not enabled? Would seem valid to me, because pause/resume code should actually not worry about that, right? if (!state->nesting_level) { VM_WARN_ON(state->active); return; } VM_WARN_ON(!state->active); state->active = false; arch_leave_lazy_mmu_mode(); -- Cheers David / dhildenb