From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793873879; b=K9HWOwEit1vGtaDROkaA9+ncy0rzVrvmfaTFp/5Jqwmr4XGTOgnxnHwZqwwvau2IsO0t +ZBNT/Z9BaoNv8T6Jb9eGJT2G6CMK0ARUmCwzRljixmnCeeRU/f77IxzCq7bVUG7Zt9Na sShF+AQDgRvlD051OnElWsp3vmFXFvMmvjZmzekgGQxWbs7xoS+cO7rvjDQ1xXIjBDoOG 9L4RpEQjw2WMtHp7DLPT9KKYOKHW9mJ0f/dPv28TsUuLm1Gg63U52s0PjbrRjXpMIZZ5r WA5AzDTyP1IUEpKfzmYWzThg54SkMQtl2vy69S7iNGGLRcR0N2SMANScWE3Nzu+oNWg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793873879; h=Received:DKIM-Signature:Message-ID:Date:MIME-Version:User-Agent: Subject:To:Cc:References:From:Content-Language:Autocrypt:In-Reply-To: Content-Type:Content-Transfer-Encoding; bh=ge0csq01UDr23GRywGYDdJfNDf0j4kn1jvr1l1h6C8s=; b=4H33Qd8AjwAh5sPPV67TWDqQplGvsgnFAxFQjRFYaCZGFOhFztprdaVerfpjf8zDzbFA ZZAz8OJfx54K5eoEMKSqToOfaawaWVtdOwNz37L0k/EZqZ0YRNtFeaiGXR4NUB9lhwcK+ vMVT6lcjlgf5TgiHI9sFlCbBaQ2fpAVkQ56GmvEWR5hLDZATSkB5kN1IWJRpT7UhmgF0J fm7GYNzOP1r4twzbI6idzVRU2cj96LIAdiGrLRjjt7TnQLuUeLGc8x8dxbkBs6bvM6KnK mn6x1oji8fxyI329fvlut2jZyYFxx9rRJMXPldBNolO/baBNC/6Z/j8fTTpyDJZexFQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=JjpWMhIm; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 87EA5606A31B; Thu, 5 Nov 2026 10:17:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=JjpWMhIm Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF9701F00919; Thu, 5 Nov 2026 10:17:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793873879; bh=ge0csq01UDr23GRywGYDdJfNDf0j4kn1jvr1l1h6C8s=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=JjpWMhImRu+LAmbhcVmFv2rI+GeyzSZNvjXT0r8xfZLpg331rjnt55cx0ggPww50w VXDPTlps85VpjVB00uZULQZcEnh2cw4udDrqGKTfeDTF4YLWeROIoWjdXEkimWk4Tn yTFjodeEJzt15GfJbm6XgFo3K6QcdTD9Ra2rJ7AOiUYNer7+yE8dSM5Fs+8SD2tmXw kBnJBuXCOriKvzR15xIJkefyO9T8d+PxLBK94+JuZsnNWKJGfBzp6thjdLmBqkh1pM 3BnJxbvHoP5FebNWl+CUmyjdhMGN0sDhYBj/hZARkU7onHM1zCZ1BjrkFH9Sk15uLe 8XnrcyvfAgAqQ== Message-ID: Date: Thu, 5 Nov 2026 11:17:49 +0100 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/5] Revert "mm/khugepaged: remove definition of struct khugepaged_mm_slot" To: "Lorenzo Stoakes (ARM)" , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Andrew Morton , Peter Zijlstra , Ingo Molnar , Will Deacon , Boqun Feng , Waiman Long , Suren Baghdasaryan , Vlastimil Babka , Shakeel Butt , Yonghong Song , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org References: <20261103-khugepaged-latency-fix-v1-0-a07ab16ac860@kernel.org> <20261103-khugepaged-latency-fix-v1-1-a07ab16ac860@kernel.org> 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: <20261103-khugepaged-latency-fix-v1-1-a07ab16ac860@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/3/26 09:27, Lorenzo Stoakes (ARM) wrote: > This partially reverts commit b4c9ffb54b32 ("mm/khugepaged: remove > definition of struct khugepaged_mm_slot"), as a subsequent commit needs to > resurrect this type to store additional data alongside the mm_slot. > > The stated intent of the commit was to address a NULL check in > __khugepaged_exit(): > > mm_slot = mm_slot_entry(slot, struct khugepaged_mm_slot, slot); > > slot can be NULL and mm_slot_entry() is an alias for container_of(), so > this is container_of() a NULL value. > > This was benign as there was only 1 field in khugepaged_mm_slot (offsetting > NULL at 0 results in NULL), however it was right to fix this, so retain the > fix. > > It also unwrapped KMEM_CACHE() in khugepaged_init(). This was a mistake, > and was itself reverted in commit c14bdcc9f274 ("mm/khugepaged: use > KMEM_CACHE()"). Therefore, retain the KMEM_CACHE() form in this revert. > > Signed-off-by: Lorenzo Stoakes (ARM) > --- LGTM Reviewed-by: David Hildenbrand (Arm) -- Cheers, David