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b=JuraNp+nvV/FZss9GmTbljR4/DaII9mHJtQWBFTelkHUiQcSU7fCvzP37CNPGJRhd C/c2V+VkfbeA3CCEG4w/P2FdKzN8IsPUxVQ4ivVSQ2cwIwaGecFeKOHs1dDm8WoeiH UVYJkvkT1S4g/6F7fN53c/ZrV5QJ8bKdLPvZoRtxdOCQlIcgeDl60GCrcTuPwUvo3O +32fw8ZaPtMXA7tXYenmVzm1czbVytuhRVfUj6f8we9GNSMDz1bGIsbGIb56elCa6h U72rn2bjrd7apVIWAtaSfa14kzTxvTV5ZKJly8SPLWgJ4QSbQUhh9XCdSJg3pvHHVV rtBr6ac1LFYDg== Message-ID: Date: Sun, 31 May 2026 22:18:16 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH mm-unstable v18 10/14] mm/khugepaged: introduce collapse_allowable_orders helper function To: Nico Pache , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Cc: aarcange@redhat.com, akpm@linux-foundation.org, anshuman.khandual@arm.com, apopple@nvidia.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, byungchul@sk.com, catalin.marinas@arm.com, cl@gentwo.org, corbet@lwn.net, dave.hansen@linux.intel.com, dev.jain@arm.com, gourry@gourry.net, hannes@cmpxchg.org, hughd@google.com, jack@suse.cz, jackmanb@google.com, jannh@google.com, jglisse@google.com, joshua.hahnjy@gmail.com, kas@kernel.org, lance.yang@linux.dev, liam@infradead.org, ljs@kernel.org, mathieu.desnoyers@efficios.com, matthew.brost@intel.com, mhiramat@kernel.org, mhocko@suse.com, peterx@redhat.com, pfalcato@suse.de, rakie.kim@sk.com, raquini@redhat.com, rdunlap@infradead.org, richard.weiyang@gmail.com, rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org, ryan.roberts@arm.com, shivankg@amd.com, sunnanyong@huawei.com, surenb@google.com, thomas.hellstrom@linux.intel.com, tiwai@suse.de, usamaarif642@gmail.com, vbabka@suse.cz, vishal.moola@gmail.com, wangkefeng.wang@huawei.com, will@kernel.org, willy@infradead.org, yang@os.amperecomputing.com, ying.huang@linux.alibaba.com, ziy@nvidia.com, zokeefe@google.com References: <20260522150009.121603-1-npache@redhat.com> <20260522150009.121603-11-npache@redhat.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: <20260522150009.121603-11-npache@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: x5smyze4tytnjmgouym9t78cwft5kta5 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 5BF0840008 X-Rspam-User: X-HE-Tag: 1780258711-544895 X-HE-Meta: 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 lZyqWhUK E16B0NTEt3JQn7E9s4+pf7tv9rfNva04Gk6ZW2Xn1JW3ZXuINHvKd6EMhIIREsWWcj0C1bd/4BtrI5ofM2bsGvutfCKtz12DYY3tIOtL6NK11rO+gE9z5vx6QLtqL9E8bRqoWYFayAQ+/W2m7ZxDB8mhA5L59+q21R6rkfBpvA9VoZpf/9u4C9SQXUxTGk3E0RKUnrQ6DCwaJefd2WOU4sJcz6bvZDF/F8oBdAOSKu5uABVESNw36x1E+PDGXWjVTohg4xfU4rJ7jekHHoOnKAuJHsEENiZlnu2RF5Ha35P/HmX6lpFozgoupiNa8ZBoPoRvxg7CH3rySV4QKhYNTkPD3pL0cNeqvmXY1ORftfAqo6rfdW2wNgtiq8c99DGe2YJSIsd6Xq7YM+VHiufu3qA7d3Q== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 5/22/26 17:00, Nico Pache wrote: > Add collapse_allowable_orders() to generalize THP order eligibility. The > function determines which THP orders are permitted based on collapse > context (khugepaged vs madv_collapse). > > This consolidates collapse configuration logic and provides a clean > interface for future mTHP collapse support where the orders may be > different. It would have been good to describe here that, for now, it only ever returns PMDs, and that it will be extended next. Logically, this patch belongs to #12, not #11 ... so seeing it before #11 was a bit ... and there, it is clear that we don't even want to know the orders? So can we just call this function "collapse_possible" and make it return a boolean? > > Reviewed-by: Baolin Wang > Signed-off-by: Nico Pache > --- > mm/khugepaged.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 4534025bc81d..64ceebc9d8a7 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -552,12 +552,21 @@ void __khugepaged_enter(struct mm_struct *mm) > wake_up_interruptible(&khugepaged_wait); > } > > +/* Check what orders are allowed based on the vma and collapse type */ > +static unsigned long collapse_allowable_orders(struct vm_area_struct *vma, > + vm_flags_t vm_flags, enum tva_type tva_flags) > +{ > + unsigned long orders = BIT(HPAGE_PMD_ORDER); > + > + return thp_vma_allowable_orders(vma, vm_flags, tva_flags, orders); > +} > + > void khugepaged_enter_vma(struct vm_area_struct *vma, > vm_flags_t vm_flags) > { > if (!mm_flags_test(MMF_VM_HUGEPAGE, vma->vm_mm) && > hugepage_pmd_enabled()) { > - if (thp_vma_allowable_order(vma, vm_flags, TVA_KHUGEPAGED, PMD_ORDER)) > + if (collapse_allowable_orders(vma, vm_flags, TVA_KHUGEPAGED)) > __khugepaged_enter(vma->vm_mm); > } > } > @@ -2680,7 +2689,7 @@ static void collapse_scan_mm_slot(unsigned int progress_max, > cc->progress++; > break; > } > - if (!thp_vma_allowable_order(vma, vma->vm_flags, TVA_KHUGEPAGED, PMD_ORDER)) { > + if (!collapse_allowable_orders(vma, vma->vm_flags, TVA_KHUGEPAGED)) { > cc->progress++; > continue; > } > @@ -2989,7 +2998,7 @@ int madvise_collapse(struct vm_area_struct *vma, unsigned long start, > BUG_ON(vma->vm_start > start); > BUG_ON(vma->vm_end < end); > > - if (!thp_vma_allowable_order(vma, vma->vm_flags, TVA_FORCED_COLLAPSE, PMD_ORDER)) > + if (!collapse_allowable_orders(vma, vma->vm_flags, TVA_FORCED_COLLAPSE)) > return -EINVAL; > > cc = kmalloc_obj(*cc); Having a simple static bool collapse_possible(...) { return collapse_allowable_orders(...) } Would make the above slightly more readable. Acked-by: David Hildenbrand (Arm) -- Cheers, David