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b=i9oQMpZIY1uhH0+44ae33445UDB7IEPaoe2usB9oftVTiBX8AcKxOtWv8uH66qByp XySy4CfY73X8OEb4xzEKEvLyvipLaEFw7NCEIlLzX/Y7EE8N5c5YePSRIGkvJFPR49 evHp/0KXRFY5FuLpU3yi0OwUYfKSh/fiPrAcn7LV4FpGV0u+i8BWXUUK/Mq+M7y+2s qozO7v8Lm/LBKkeNIqaS3JLEYCg0p3PpyERV+sXgIaLDIuZCNjNsTiSUeViGLhrBGO DSgnJWiHAdi3rHLNfo6jq3bI4a1Lt/AaAy1QHnF1TMBQcJYpT2s8I+eaS68VakM/Fq 8M3L04tqtNvcA== Message-ID: <3daccad8-cf08-4543-b9ec-b34711a4ed14@kernel.org> Date: Tue, 21 Apr 2026 16:15:44 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/6] mm: Make lazy MMU mode context-aware To: Alexander Gordeev , Kevin Brodsky , Andrew Morton , Gerald Schaefer , Heiko Carstens , Christian Borntraeger , Vasily Gorbik , Claudio Imbrenda Cc: linux-s390@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <8809412aaed8a515fe2e149c822543d640060936.1776264097.git.agordeev@linux.ibm.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+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: <8809412aaed8a515fe2e149c822543d640060936.1776264097.git.agordeev@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: jskibrwt9kiazk4wdbo5561k6kxmxt1q X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: EA740140002 X-Rspam-User: X-HE-Tag: 1776780950-732132 X-HE-Meta: U2FsdGVkX18Oq43vsbwnafAu7xcJhcTZrAVACS1kXSlMvD2B5FmvpY4XbWv/kkqZSCSiEuiu8OUMA6wSw0rrt1i6YCRJ6s4N3hLVfmm7EG9jXooTCGnctvLD/h8pedGwT1qqOWIxd2QHgS04ZDPwNdPYOXr3ShJTGgDgNXK4c4muShTWarRzsIjbJftl1jRNZzApSdjE/n/qDJ58LY0002v8aOxRZOxDM3WzK3nEr6eVJES6JKgT8esd397zWhNhTjh0VGoiYEbwDZ9GbTJH6jsuNfa+d6Jt3evktx6sDa9op8AT0C7GiLrjtgzBE+XfLCczFvraEKg27U3DzswB7KUUCP1u3GX6yVnxVnuCnJSqkCPALGstN6aDYKzFn+Iudpl7ttPK/wkXI1+PJCjYKgS1gnSoEfVFj4GAJLOGDL3zw1GRJVteVkDnTumk2lacFhq78fjeH0IqEFlgdbj4XlzX6lCp9ZFt01ol6rtZt+ThqE8OoDugmWkxde5izXbPhp5zYWyDh5bIA4l/4kY+3LbFTUM3ZykM9Rxb9uSkTC+V0vBbhb0JMNk5cVYPwfK9+Yfq8Vm6bEuu/MWeveVc4o2Zty/xu4szzcMSQZm5P9U5zqUdqIIFY+XQi8xv3/0hUkcWLYA90GmGEaVQiZfet5RVy/y1RXP218OmN9I5OjFLtx/5ZpYagK6960GmrnJ1X1OYiqBlThSLjSy5+yEV05UxATMWZiLI2U0ZvwjvrG+AcRn4MHtC37zjkv7UKf/c1IgqKL4KqNmmY/Gm+5KWXQi6wzWSNSWMAq8JSFU9T+1EugvegeezON83qJvTYHeVAfcF4VcZwDuYo14RuZsXAd79eLs1wlY3b62a8EV/s2dfRHKrnzB73Er2O14RV42FS1JsJ9qfeV/FC8bZkcxH2UMGPFwGPjtBy0giU7qkAJvdKt45T6aD/79cybqi63PAp+VR7LOcyo929l9EB0t cmUYpApc zBA9qDQ3LyyDNvCqm8wCwEFYXc7CXcc1Kav0qF8gq1w7+uK6q6QWDJQXLF087pmSbez4YgyNoCZO9pnId82AjLssGTatyjk8vSJFCSwP//ESmDOZro32Kkzs8yfq5/QQPyvgziTMNBjQrsu/yWJpXMjstDpV1wBmriKbk0riu7Rl2JoHonMT5W1+XjmFF5D8Z+7yDVBp6QdxKEo73ZWk/fLnkfy6y/psYkClDBiwSY3GsRVOzGhOAt12Se6dzHGqyjuJA33Uj6lZDbxIh69CuPOX+e/qSYiWH5/aiEHSXv8K7GUlsxeSnDJ3+/CSKtI4QOQto Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: > +/** > + * lazy_mmu_mode_enable_for_pte_range() - Enable the lazy MMU mode with a speedup hint. > + * @mm: Address space the pages are mapped into. > + * @addr: Start address of the range. > + * @end: End address of the range. > + * @ptep: Page table pointer for the first entry. > + * > + * Enters a new lazy MMU mode section; if the mode was not already enabled, > + * enables it and calls arch_enter_lazy_mmu_mode_for_pte_range(). > + * > + * PTEs that fall within the specified range might observe update speedups. > + * The PTE range must belong to the specified memory space and not cross > + * a page table boundary. > + * > + * There are no requirements on the order or range completeness of PTE > + * updates for the specified range. > + * > + * Must be paired with a call to lazy_mmu_mode_disable(). > + * > + * Has no effect if called: > + * - While paused - see lazy_mmu_mode_pause() > + * - In interrupt context > + */ > +static inline void lazy_mmu_mode_enable_for_pte_range(struct mm_struct *mm, I'm still wondering about a better name for this. "enable_for" indeed sounds like it's only for that range. Maybe really something including a hint like you previously proposed lazy_mmu_mode_enable_with_ptes() lazy_mmu_mode_enable_with_pte_hints() I think lazy_mmu_mode_enable_with_ptes() is neat. Thoughts? In any case, on the general approach + semantics: Acked-by: David Hildenbrand (Arm) > + unsigned long addr, unsigned long end, pte_t *ptep) > +{ > + struct lazy_mmu_state *state = ¤t->lazy_mmu_state; > + > + if (in_interrupt() || state->pause_count > 0) > + return; > + > + VM_WARN_ON_ONCE(state->enable_count == U8_MAX); > + > + if (state->enable_count++ == 0) > + arch_enter_lazy_mmu_mode_for_pte_range(mm, addr, end, ptep); Okay, so the "hint" is ignored for nesting levels, that works. -- Cheers, David