From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2AC3C5478C for ; Tue, 27 Feb 2024 09:14:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8E1D76B0078; Tue, 27 Feb 2024 04:14:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8922E94000C; Tue, 27 Feb 2024 04:14:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 70CB8940008; Tue, 27 Feb 2024 04:14:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 5DA316B0078 for ; Tue, 27 Feb 2024 04:14:51 -0500 (EST) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 2E316A0B7F for ; Tue, 27 Feb 2024 09:14:51 +0000 (UTC) X-FDA: 81837023982.08.FEAC20B Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf12.hostedemail.com (Postfix) with ESMTP id 08D914000D for ; Tue, 27 Feb 2024 09:14:48 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=h2Q27Mq2; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf12.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1709025289; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=2/gjWd2qDKmet6I9PBwA50r61BeuZ2ughk1QxC4Mh80=; b=R/XV835yIx97Lzs81glcO9egA107eaS7gNsqo0DHkCft5BZ/xm64VzQ40qUKCLKBSRI6HF 61sl7VevRcYI6+lLk+acpXw01yjmhQJkVlX/f0yVgDxT/Cu5MMk4BLHJwjOX7rpGWBsDxS O9Pm2RJL38FooJjI9OJrizHb9gZn04A= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=h2Q27Mq2; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf12.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1709025289; a=rsa-sha256; cv=none; b=DRNfbJVb6/yZ5ENtKsxOUSgVNhfQITl8GV/HL5sw3Z8Gl95+ruRshN02cknJGZ10euaB3E U8U1B29SJDbQ98PX0xVg8Ft737zbMLH6G0tYYGoWkxbAgJwI8IHJvXnhQP+ah3ZUPtBf4K tuodLs/h5+5XO1+XSLnGJP18bmJwsw0= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1709025288; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=2/gjWd2qDKmet6I9PBwA50r61BeuZ2ughk1QxC4Mh80=; b=h2Q27Mq2+2oDhNFzdZkLHT8Jd886BiLlZbjmBW4LrzTCZVADCxRzYKQOAjr7WZZsZqC1XV va/89LeMGPtLBe0RQ0eNapdqa+Yiwh0hFu0KuavEbnIHWab7BOA8aDGEEyMtKF/y1/Vxb1 zB2+DshF2H01oyV+Omz5hrpzo4AgNkA= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-417-PWU71HI0OkyBP8km1r0sNg-1; Tue, 27 Feb 2024 04:14:46 -0500 X-MC-Unique: PWU71HI0OkyBP8km1r0sNg-1 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-412a7305417so7399735e9.0 for ; Tue, 27 Feb 2024 01:14:46 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709025285; x=1709630085; h=content-transfer-encoding:in-reply-to:organization:autocrypt:from :references:cc:to:content-language:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=2/gjWd2qDKmet6I9PBwA50r61BeuZ2ughk1QxC4Mh80=; b=j4TbHZSYKYlEKPR9kfTX6N+KrusFr87e2dp24q2TuZNpGNrOXhXHtTF+igr7EwQ3Cu Aw28atVaAzuqTIFTHtRa616FwG9aHDtcU3mBS4/26h3QYjThnTyTfAjBHp0anycXZHMb qpgX/WhnYf3zR4WGuZJedZwp05rFkWvzweSJk0gQBqwC2umCWnwg7oeRwax2duvj0H0J 7130BJ9b9Hp16iZ03sD7BGP2XKvcx5BRnFktBJhZSRhGT363O99MUarBj6uVSo9SvVhb WAymuN6/JWEhaj+04jz5XNYH3PSspVrKbfUG5oIsYZvr6sbXtZPixEnF22ho65+lV8p0 ljkA== X-Forwarded-Encrypted: i=1; AJvYcCW6Tl8ofuaMT9Js/2czDVJDk056LF+2/6vuFasrSgS8E7C7yJe3HJ03ElLNr7+O6AqkcYYIu2Wpa2EwJMmQ3uMw3Tk= X-Gm-Message-State: AOJu0YyuV4YG9B5tMqIrmkD3g9SaMd2ik8+LLLBi7BYsV/QcYkEdhgj4 bM5Ac0VQ8UIiqDtzsjzCdGutA/MnCz23guO8zjEdcD/H0yLuNUVbq5dNTJwmU0LeozEuQo5sKGF BYeU61cEPEOjSNMP3iOaI+JmhaQ1SKZRJ7A+0UaBesCOOOiux X-Received: by 2002:a05:600c:1f86:b0:412:8306:a7bb with SMTP id je6-20020a05600c1f8600b004128306a7bbmr7895005wmb.12.1709025285710; Tue, 27 Feb 2024 01:14:45 -0800 (PST) X-Google-Smtp-Source: AGHT+IFnDYuhOpt+TZSeo4lVcA2J8HInWVZsVc0kUTBO9H7Gg6MmXIwJBPzdYYwZC4Hw8JgWBUma0Q== X-Received: by 2002:a05:600c:1f86:b0:412:8306:a7bb with SMTP id je6-20020a05600c1f8600b004128306a7bbmr7894980wmb.12.1709025285290; Tue, 27 Feb 2024 01:14:45 -0800 (PST) Received: from ?IPV6:2003:cb:c707:7600:5c18:5a7d:c5b7:e7a9? (p200300cbc70776005c185a7dc5b7e7a9.dip0.t-ipconnect.de. [2003:cb:c707:7600:5c18:5a7d:c5b7:e7a9]) by smtp.gmail.com with ESMTPSA id u20-20020a05600c00d400b00410b0ce91b1sm14393440wmm.25.2024.02.27.01.14.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 27 Feb 2024 01:14:44 -0800 (PST) Message-ID: Date: Tue, 27 Feb 2024 10:14:43 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: export folio_pte_batch as a couple of modules might need it To: Ryan Roberts , Barry Song <21cnbao@gmail.com>, akpm@linux-foundation.org, linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Barry Song , Lance Yang , Yin Fengwei References: <20240227024050.244567-1-21cnbao@gmail.com> <61b9dfc9-5522-44fd-89a4-140833ede8af@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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <61b9dfc9-5522-44fd-89a4-140833ede8af@arm.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 08D914000D X-Stat-Signature: pj3kr34s5qe1rgwhpzeuoxjnou56acc8 X-Rspam-User: X-HE-Tag: 1709025288-661630 X-HE-Meta: U2FsdGVkX18tCJPJHDhgOpEffhax0FMC1+35B/7Ckdj4IWktIT3g7DLqvB9Vr5ddJ83K5W9zysqQJl4h/jel/DZe88GBR/DqTgQpj78wgB6owLFgqaHnOgRbC4K0tJxcvfGdLl3L2pME2mML+aNG6oiUqNKYA1Bepo9g9sSBZ2NCUB8t76LtSwEg+2QOOLxmcrAuUpOl4DLZl6KE+ooS+4acmwwf4JA0ZNmgmjMw1HY02qosJ66wl81d0GoDb9FVXI4wZJ9ko0SMWH9yobsyN9wsGSRtVcli8CKQAXVmIzY89LQR/196cp5J7lt6V8Sqr+PdzPkTf6OA2gfl4W6XoGK9ACOeK4Un2+grEKqkbqgluncXk+zeooPGPqKM9Mtz2oUOeiYApMJs6/5DBj1nEj77+M7Sa9/yZf5aO+/7h+xz3JiCxoH+TKAiUbHRxChwR0AkK1U2Rp8zIQv6dMCwEhROH6IbakR2q6bratpa1cUiXgBJ27OS9p7Kee05K1hH5ddYse//pQo/M3Z0D6fMw4jdW6A/o3oggBnWr1IHpniSKCi/wnQnKPnCtT1ybKCvDBdW1SksBpItBaxe+Nx3Odoubhzv9qqfDJTAjE9oKoQwTdfNVqqbvMbM6kEaL7RxtYFO1Q4YvV3u+zX6Qe/UqHSdclf8MTsBXrXmdAwEInLKQUDl364EgRJ2giCuVdu+1Sg9jocIfWWAvQk4VrBszezdbBtnH/8m8fWeskLVJcdaFQAXhAnn4VTdfKbSMAbWYIhS6H8bjiR7Yt0TMQebvpbm1bKqieSwvdWUsKnvYWsvwNsLGwlE83R5DIdqoOzszd4tQgOX1tpFAnOt0bFFAot2W4wQm3q95M53N/x7D+9doytaz/ko02lwA6ulF83lbK+FJGCTKJPLSw57EzJuxVcxRto58oR1R6/Z1azzoHD5VfoE7Yl48kt655FO4KyO9ppm08qTPdBGABZQJNA NkwpWYyR sIxM32m6WVROoBFhoHZCb34T3FNhF3xDd332OBjXGdJmRFfX5TgcGgwedSPn1ZJM9Z+rCeCUS107Sb9OzU73hk1zCAUnuwlOnPnViWiZpR7dKinZ+f87xzJ6aYWTSEcxLJhLp9Dtxcaa0AOYEv2J3YwXGiiT1287GFBspr7axJ6Vzd1qSy7BHr7cQBCXE+6smg3Zs0a1NYJdSeSKc2XkrSWeMpQ== 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: On 27.02.24 10:07, Ryan Roberts wrote: > On 27/02/2024 02:40, Barry Song wrote: >> From: Barry Song >> >> madvise and some others might need folio_pte_batch to check if a range >> of PTEs are completely mapped to a large folio with contiguous physcial >> addresses. Let's export it for others to use. >> >> Cc: Lance Yang >> Cc: Ryan Roberts >> Cc: David Hildenbrand >> Cc: Yin Fengwei >> Signed-off-by: Barry Song >> --- >> -v1: >> at least two jobs madv_free and madv_pageout depend on it. To avoid >> conflicts and dependencies, after discussing with Lance, we prefer >> this one can land earlier. > > I think this will also ultimately be useful for mprotect too, though I haven't > looked at it properly yet. > Yes, I think we briefly discussed that. >> >> mm/internal.h | 13 +++++++++++++ >> mm/memory.c | 11 +---------- >> 2 files changed, 14 insertions(+), 10 deletions(-) >> >> diff --git a/mm/internal.h b/mm/internal.h >> index 13b59d384845..8e2bc304f671 100644 >> --- a/mm/internal.h >> +++ b/mm/internal.h >> @@ -83,6 +83,19 @@ static inline void *folio_raw_mapping(struct folio *folio) >> return (void *)(mapping & ~PAGE_MAPPING_FLAGS); >> } >> >> +/* Flags for folio_pte_batch(). */ >> +typedef int __bitwise fpb_t; >> + >> +/* Compare PTEs after pte_mkclean(), ignoring the dirty bit. */ >> +#define FPB_IGNORE_DIRTY ((__force fpb_t)BIT(0)) >> + >> +/* Compare PTEs after pte_clear_soft_dirty(), ignoring the soft-dirty bit. */ >> +#define FPB_IGNORE_SOFT_DIRTY ((__force fpb_t)BIT(1)) >> + >> +extern int folio_pte_batch(struct folio *folio, unsigned long addr, >> + pte_t *start_ptep, pte_t pte, int max_nr, fpb_t flags, >> + bool *any_writable); >> + >> void __acct_reclaim_writeback(pg_data_t *pgdat, struct folio *folio, >> int nr_throttled); >> static inline void acct_reclaim_writeback(struct folio *folio) >> diff --git a/mm/memory.c b/mm/memory.c >> index 1c45b6a42a1b..319b3be05e75 100644 >> --- a/mm/memory.c >> +++ b/mm/memory.c >> @@ -953,15 +953,6 @@ static __always_inline void __copy_present_ptes(struct vm_area_struct *dst_vma, >> set_ptes(dst_vma->vm_mm, addr, dst_pte, pte, nr); >> } >> >> -/* Flags for folio_pte_batch(). */ >> -typedef int __bitwise fpb_t; >> - >> -/* Compare PTEs after pte_mkclean(), ignoring the dirty bit. */ >> -#define FPB_IGNORE_DIRTY ((__force fpb_t)BIT(0)) >> - >> -/* Compare PTEs after pte_clear_soft_dirty(), ignoring the soft-dirty bit. */ >> -#define FPB_IGNORE_SOFT_DIRTY ((__force fpb_t)BIT(1)) >> - >> static inline pte_t __pte_batch_clear_ignored(pte_t pte, fpb_t flags) >> { >> if (flags & FPB_IGNORE_DIRTY) >> @@ -982,7 +973,7 @@ static inline pte_t __pte_batch_clear_ignored(pte_t pte, fpb_t flags) >> * If "any_writable" is set, it will indicate if any other PTE besides the >> * first (given) PTE is writable. >> */ > > David was talking in Lance's patch thread, about improving the docs for this > function now that its exported. Might be worth syncing on that. Here is my take: Signed-off-by: David Hildenbrand --- mm/memory.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index d0b855a1837a8..098356b8805ae 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -971,16 +971,28 @@ static inline pte_t __pte_batch_clear_ignored(pte_t pte, fpb_t flags) return pte_wrprotect(pte_mkold(pte)); } -/* +/** + * folio_pte_batch - detect a PTE batch for a large folio + * @folio: The large folio to detect a PTE batch for. + * @addr: The user virtual address the first page is mapped at. + * @start_ptep: Page table pointer for the first entry. + * @pte: Page table entry for the first page. + * @max_nr: The maximum number of table entries to consider. + * @flags: Flags to modify the PTE batch semantics. + * @any_writable: Optional pointer to indicate whether any entry except the + * first one is writable. + * * Detect a PTE batch: consecutive (present) PTEs that map consecutive - * pages of the same folio. + * pages of the same large folio. * * All PTEs inside a PTE batch have the same PTE bits set, excluding the PFN, * the accessed bit, writable bit, dirty bit (with FPB_IGNORE_DIRTY) and * soft-dirty bit (with FPB_IGNORE_SOFT_DIRTY). * - * If "any_writable" is set, it will indicate if any other PTE besides the - * first (given) PTE is writable. + * start_ptep must map any page of the folio. max_nr must be at least one and + * must be limited by the caller so scanning cannot exceed a single page table. + * + * Return: the number of table entries in the batch. */ static inline int folio_pte_batch(struct folio *folio, unsigned long addr, pte_t *start_ptep, pte_t pte, int max_nr, fpb_t flags, @@ -996,6 +1008,8 @@ static inline int folio_pte_batch(struct folio *folio, unsigned long addr, *any_writable = false; VM_WARN_ON_FOLIO(!pte_present(pte), folio); + VM_WARN_ON_FOLIO(!folio_test_large(folio) || max_nr < 1, folio); + VM_WARN_ON_FOLIO(page_folio(pfn_to_page(pte_pfn(pte))) != folio, folio); nr = pte_batch_hint(start_ptep, pte); expected_pte = __pte_batch_clear_ignored(pte_advance_pfn(pte, nr), flags); -- 2.43.2 > >> -static inline int folio_pte_batch(struct folio *folio, unsigned long addr, >> +int folio_pte_batch(struct folio *folio, unsigned long addr, > > fork() is very performance sensitive. Is there a risk we are regressing > performance by making this out-of-line? Although its in the same compilation > unit so the compiler may well inline it anyway? Easy to verify by looking at the generated asm I guess? > > Either way, perhaps we are better off making it inline in the header? That would > avoid needing to rerun David's micro-benchmarks for fork() and munmap(). That way, the compiler can most certainly better optimize it also outside of mm/memory.c -- Cheers, David / dhildenb