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 C9EA2C3DA4A for ; Fri, 9 Aug 2024 16:32:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4BC0D6B00AA; Fri, 9 Aug 2024 12:32:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 445006B00AB; Fri, 9 Aug 2024 12:32:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 297566B00AE; Fri, 9 Aug 2024 12:32:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 0A97A6B00AA for ; Fri, 9 Aug 2024 12:32:54 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 182AE811C3 for ; Fri, 9 Aug 2024 16:32:53 +0000 (UTC) X-FDA: 82433251026.07.741D831 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf01.hostedemail.com (Postfix) with ESMTP id 908FB40016 for ; Fri, 9 Aug 2024 16:32:50 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=VZrPl5Iz; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf01.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 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=1723221096; 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=bK+Xr49cXd8swczor/eh9sQ26QqtTpeLaJrkqjusW/4=; b=eY4dEI3KikWXACP2haZRLb+KmnT26SYfw1igs1/AfOIndNuhbwPOHfGB2HvfVMBxVjX2g5 VHa5ucfEwvkdOriXlIMNFGqDzm5h12vDmieznSoJfQc6qapj0bXOpSlIvJXNwW9Nm/8+Nq veqmCdr+oTo1Lkx0aidgkTxxzqE6KNQ= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1723221096; a=rsa-sha256; cv=none; b=hQDMbepXAU1K5S45/TLxpm7uoA0Fy6tmUQqrUSM5nwhXAbw5jOjXn/zCz39L33Bp86hrNN 3z7ZtgXsyynebChjqBUARFsRgAz2shGFcoEtxjA+yeQ89X1Aii9IMQRMPIp6h+av7bBzrf Gng8ZYBGA43DiNvvp1TZ5cMdcdMk6Gs= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=VZrPl5Iz; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf01.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1723221169; 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=bK+Xr49cXd8swczor/eh9sQ26QqtTpeLaJrkqjusW/4=; b=VZrPl5IzAsd00vGcWUcdC4dt+0poGmKdTIQWyR2irIefqOysVsEMyHFOZY0aLUmTf6WlZc OXA/bbf6KhvB3j4sqxQvoy8Up3H8zFX/50tnavvfWP9h5AeD5mqX3KunMCaEB8KYEjLUj4 z4o/U2cYrCU9gp0ctTSdnvW9y3+oDe8= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-88-KjmYXzGIPNyokQIfhQAmFA-1; Fri, 09 Aug 2024 12:32:48 -0400 X-MC-Unique: KjmYXzGIPNyokQIfhQAmFA-1 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-428e0d30911so17133865e9.2 for ; Fri, 09 Aug 2024 09:32:48 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723221167; x=1723825967; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:from:references:cc:to:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=bK+Xr49cXd8swczor/eh9sQ26QqtTpeLaJrkqjusW/4=; b=f06yo8PbignvvBVcbOY87ydX5nOL+5jv/F1RGmQEPrWIZUorKB6m2ELW2vs/Ok0Hha ArJOmMSK6tLIbYRG1K6GmciIvamsUCXa07H2anyiB/yXsYjZzbTzTCDzji59qt8CfjRh WXHLK6g1nHnQwhlyM8RNKZ5p/UeD7O3LstzpUDxXLHHZ+pFlB2ohIY+vAlvcUdRoN5SL PJfjLZbm8D6BrGXsPO1TkDplHtHxLgLFCYh0G9FffJ1E9A4omWDKAU9Jed6gy0EsibaB JlYe5rH/cqDNDrKJk1fiSQ95vW2CzUSBQSXGI0XP7A5LfBIEMXB5+VKX/qNFJV0L/qo5 OG1Q== X-Forwarded-Encrypted: i=1; AJvYcCUAjorJXshn5tcsR0CylUKmt3nyykXyuANXkDT8Tvamx3OK982CgSJ3TPxqaWVc2Wnl2TCa9yg4cVAUf6qCCBYfIAg= X-Gm-Message-State: AOJu0Ywo3cVs0ZPCwYqo786ZmPZFMSGEQYqKN5mPRyWVS78Mkh/0NUiE hY8rUP9FW4Lot8XN5OyIbQNGqbP4m4IoX3BuL/LY8I0aKeo9xItSgqDRH0H8thDnY1VhbkmbZcU RUch3swZjv/dmw5wIGDR1rEkhqnTLfBmUaWzoICdAZbBkp7Dx X-Received: by 2002:a05:600c:5021:b0:427:9dad:e6ac with SMTP id 5b1f17b1804b1-429c3a56a5bmr15279955e9.34.1723221167468; Fri, 09 Aug 2024 09:32:47 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEDPoHMlDuTu1+qt6uPaOVEQnwg/1Il3GOa+4ekoO8nXGxI5KxFdFLdXsV2shJcGeMxkm6x4g== X-Received: by 2002:a05:600c:5021:b0:427:9dad:e6ac with SMTP id 5b1f17b1804b1-429c3a56a5bmr15279825e9.34.1723221166950; Fri, 09 Aug 2024 09:32:46 -0700 (PDT) Received: from ?IPV6:2003:d8:2f09:3f00:d228:bd67:7baa:d604? (p200300d82f093f00d228bd677baad604.dip0.t-ipconnect.de. [2003:d8:2f09:3f00:d228:bd67:7baa:d604]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-429059d040fsm125413585e9.46.2024.08.09.09.32.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 09 Aug 2024 09:32:45 -0700 (PDT) Message-ID: Date: Fri, 9 Aug 2024 18:32:44 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 07/19] mm/fork: Accept huge pfnmap entries To: Peter Xu , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Sean Christopherson , Oscar Salvador , Jason Gunthorpe , Axel Rasmussen , linux-arm-kernel@lists.infradead.org, x86@kernel.org, Will Deacon , Gavin Shan , Paolo Bonzini , Zi Yan , Andrew Morton , Catalin Marinas , Ingo Molnar , Alistair Popple , Borislav Petkov , Thomas Gleixner , kvm@vger.kernel.org, Dave Hansen , Alex Williamson , Yan Zhao References: <20240809160909.1023470-1-peterx@redhat.com> <20240809160909.1023470-8-peterx@redhat.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: <20240809160909.1023470-8-peterx@redhat.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: rspam07 X-Rspamd-Queue-Id: 908FB40016 X-Stat-Signature: 9j9sh4ft7p1n9f68rbfezcrwpy4e77em X-Rspam-User: X-HE-Tag: 1723221170-242535 X-HE-Meta: U2FsdGVkX18qxNl34Yv13nERK4jiHyS8ujAZIGiuyaTYplWumhc1HL2N/3QKtYwwazHsXIAK7UO3ANsizsQV9jxiYyQo5SyWKby5dDTOgHQOGuMt5uYWK5CiZsl9q73AAmVd3e9C01BPqFJRKfiaMhHc5gYNumred3tCci4wZhNas+fm5XMQ07dMUTHNEj20BlbwttqU5hX0aczQw40ER8O62IqsQVpdWoXXVDj2r9BmgqNm/iaw5o+lLiJttUXWhHPhvSHWb02CzY3hOG72U+y54qUr8S5czkZqtpRhpLr54k9nel1/fykFIMHSZZ6PCQ504PF/xo/JNVVfOAm8GEbwBcZAl2ixp1KPUC8V6dBxdLTchQcYozrFzh53s8b9g54AqeNTgk4uCThIikWMVA3mVGKTSCe4vTbMS8FMIcIplnkIEJtHwIMqajIugu6nhnGCqAA0jh3IN9+62UOWwnXj6v6SzUB6wvI/sXiXc7OVSZzG23GATNe6TwrsywfZv++FAREzWTBlS6hD6RxTXF0aFLu3ea8VUQK9YgcUWZa+PfTho1SLJSKxb0ayRAhpEX8hEGEiwS21JJEdod8Djp56Dax/00xkzLpCuR2Qg7WzHqRQTZhBp/Xb/hQOgc/09Xvt9x/0Qv1iE5VbOzSoVTQhZRW8oYy8Ro5ZB6Jp5MKy0S7N3mpOCvX6f3qCh2YbMQCti2JFjqPjAMoTIQ1KIvd2m1EVGSeyluEVvx9puO1g48gEtzd6IPKeOR27nznqGEWjyXyaJLaFDQSsYLgFanYdHOCuASqid161WNrP3M1tpIywWZx8nFl1VOrdZDAis+vTNX2rRj4pAN0YLgIwNzHKe3gC1c0m7wmy699iVxTuVk5YjT70cAe4IQL9O36UjcwISFVj2x0YKHW+0HTxrkeH9CLUWttEM+ZzbCUTZr+xDRxIcneCqyy4D17nsw7ofkpfQzjWbnxbeYkkJST E9R8fZov AB9PwUOFkv42lF38DY4JDYiGravTQWw+zbhQ90WN/Wi9zmNKiwXdOCK19mu/vH4qX8P5589S9P/fiG+RxQtu7bIHUm4w5hHhztgReGsLIe00tNk9gZVZLFxZfI3hwgnEW7D0CZu+bZYZwc1b+BitcXHdDhBtqqM/SZtY74JU2pERf13FTzP7hypimN1el7E/ZQ6nlOgEp+MTYWasU7cPMqxSZKjNFloF+JeOMSq734VihMdObad+lPely5cr8TxR5nflhVzb87WKaU+aBQEVRESWKGKINwNp7FcEXCmWWFQ6xJ1o8pL+ksEd5As0ZOeg6IMYwSz17szBWa+uq3bcjscpPIk338lQbota+GT5Pb73b8ursS/O9cVSNEkxWv6OFsjK6eKdPRwsVRrg= 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 09.08.24 18:08, Peter Xu wrote: > Teach the fork code to properly copy pfnmaps for pmd/pud levels. Pud is > much easier, the write bit needs to be persisted though for writable and > shared pud mappings like PFNMAP ones, otherwise a follow up write in either > parent or child process will trigger a write fault. > > Do the same for pmd level. > > Signed-off-by: Peter Xu > --- > mm/huge_memory.c | 27 ++++++++++++++++++++++++--- > 1 file changed, 24 insertions(+), 3 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 6568586b21ab..015c9468eed5 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -1375,6 +1375,22 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, > pgtable_t pgtable = NULL; > int ret = -ENOMEM; > > + pmd = pmdp_get_lockless(src_pmd); > + if (unlikely(pmd_special(pmd))) { > + dst_ptl = pmd_lock(dst_mm, dst_pmd); > + src_ptl = pmd_lockptr(src_mm, src_pmd); > + spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); > + /* > + * No need to recheck the pmd, it can't change with write > + * mmap lock held here. > + */ > + if (is_cow_mapping(src_vma->vm_flags) && pmd_write(pmd)) { > + pmdp_set_wrprotect(src_mm, addr, src_pmd); > + pmd = pmd_wrprotect(pmd); > + } > + goto set_pmd; > + } > + I strongly assume we should be using using vm_normal_page_pmd() instead of pmd_page() further below. pmd_special() should be mostly limited to GUP-fast and vm_normal_page_pmd(). Again, we should be doing this similar to how we handle PTEs. I'm a bit confused about the "unlikely(!pmd_trans_huge(pmd)" check, below: what else should we have here if it's not a migration entry but a present entry? Likely this function needs a bit of rework. -- Cheers, David / dhildenb