From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC160370ACD for ; Wed, 1 Jul 2026 16:56:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782925000; cv=none; b=Va4jxTPHXNYBQAVo/HZ/K24sww4GVoQYrgj74tl3xjhMT5NoiOxPBikhaYD1AOZqJ0Hj3Lf/MBJfIHEbrnD5ZffC1XntbVCqavC8/aVKRgYEfIcG52Q/RBQPzI11qu3ZXyUUwmrePVPOEN57yEnwo2V+TpO42KXBe6kj6W0Ohkw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782925000; c=relaxed/simple; bh=zyNjoWcglY8sm1aomUGCqnlkQan6zriNLZIAldndQJA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=V1HdgMBwfiAr9QWR2tSt9JpCQu58tfb1aBPnvKb0YUhaKuRRTHkbhwNVjFd6xEedN305fuX1TVGUQRxD2FVcJAJSuLqrppU8RcaCrLsjVGQKi/XvI4BWJGUFRxWit61gaQxltQr4Hdwyv2LcTJlLroiwKvFlxeRT6xtBkPZHoIQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IFHkk/gg; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IFHkk/gg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C35C1F00A3A; Wed, 1 Jul 2026 16:56:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782924999; bh=MVimfh9ma7IjwVtqLkOayOmSpFAJVVDO3q0L4tXhqoM=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=IFHkk/gg0byfxsIlJha3EeHE2/TMP5GhSKfD/MiamrsSzQ4Kpv+OOt8w8xrZHwcz2 pLdArcQApNo3cvWjUKx8pGssj1CyNh/CMGUEcnNMbwa65VO68/zORS/6Beowdh+1rB YQdsmiqttXa366xAn3U71SIbVYQK7kuNEMf9udviiK4kF4h/Xzt3MxyIGr2gpMut8T CH2Ngkh3n4IPv+9rcxp+9gLQNV66OTYOQFCLEWLqaezl2+8LiHws2fwJqGgoQb2HIz 7Svp43Vg+LK67WbJOywLeMxf41vszHXh7+WWoSrYjsCdDogUwP8Uu26C7hMqdsrPRw BlvCqIjBEIi8g== Message-ID: <157838aa-1518-46b5-8734-feab2c42ee2a@kernel.org> Date: Wed, 1 Jul 2026 18:56:31 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/6] mm: extract mm_prepare_for_swap_entries() helper To: Usama Arif , Andrew Morton , chrisl@kernel.org, kasong@tencent.com, ljs@kernel.org, ziy@nvidia.com, linux-mm@kvack.org Cc: ying.huang@linux.alibaba.com, Baoquan He , willy@infradead.org, youngjun.park@lge.com, hannes@cmpxchg.org, riel@surriel.com, shakeel.butt@linux.dev, alex@ghiti.fr, kas@kernel.org, baohua@kernel.org, dev.jain@arm.com, baolin.wang@linux.alibaba.com, npache@redhat.com, "Liam R. Howlett" , ryan.roberts@arm.com, Vlastimil Babka , lance.yang@linux.dev, linux-kernel@vger.kernel.org, nphamcs@gmail.com, shikemeng@huaweicloud.com, kernel-team@meta.com References: <20260630164143.1595669-1-usama.arif@linux.dev> <20260630164143.1595669-3-usama.arif@linux.dev> 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: <20260630164143.1595669-3-usama.arif@linux.dev> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/30/26 18:34, Usama Arif wrote: > When a swap entry is installed in a page table, the mm must be added > to init_mm.mmlist so that swapoff can find and unuse its swap entries. > This double-checked locking pattern is currently open-coded in > try_to_unmap_one() and copy_nonpresent_pte(). > > Move it into mm_prepare_for_swap_entries() in mm/internal.h and convert > both callers so it can be reused by upcoming PMD-level swap entry code > paths that also need to register the mm with swapoff. > > copy_nonpresent_pte() previously inserted into &src_mm->mmlist rather > than &init_mm.mmlist, but the insertion point is irrelevant, mmlist > is a circular list and swapoff walks it entirely from init_mm.mmlist, > so only membership matters, not position. > > Reviewed-by: Dev Jain > Reviewed-by: Zi Yan > Signed-off-by: Usama Arif > --- > mm/internal.h | 13 +++++++++++++ > mm/memory.c | 9 +-------- > mm/rmap.c | 7 +------ > 3 files changed, 15 insertions(+), 14 deletions(-) > > diff --git a/mm/internal.h b/mm/internal.h > index 8e0df3d1c6f9..0e3db9451e5c 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -1956,4 +1956,17 @@ static inline int get_sysctl_max_map_count(void) > bool may_expand_vm(struct mm_struct *mm, const vma_flags_t *vma_flags, > unsigned long npages); > > +/* > + * Ensure @mm is on the init_mm.mmlist so swapoff can find it. > + */ Comment fits into a single line and I don't think we need it (function name is self-explaining enough). > +static inline void mm_prepare_for_swap_entries(struct mm_struct *mm) > +{ > + if (list_empty(&mm->mmlist)) { > + spin_lock(&mmlist_lock); > + if (list_empty(&mm->mmlist)) > + list_add(&mm->mmlist, &init_mm.mmlist); > + spin_unlock(&mmlist_lock); > + } > +} > + Acked-by: David Hildenbrand (Arm) -- Cheers, David