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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 488ECCAC582 for ; Fri, 12 Sep 2025 07:32:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 967398E0007; Fri, 12 Sep 2025 03:32:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 93F478E0001; Fri, 12 Sep 2025 03:32:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 82E448E0007; Fri, 12 Sep 2025 03:32:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 6EAD38E0001 for ; Fri, 12 Sep 2025 03:32:31 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id E74551606C2 for ; Fri, 12 Sep 2025 07:32:30 +0000 (UTC) X-FDA: 83879780460.19.7824943 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf04.hostedemail.com (Postfix) with ESMTP id A8A3240003 for ; Fri, 12 Sep 2025 07:32:28 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=AOaei1ID; spf=pass (imf04.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1757662348; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to: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=95M+ctN1eGHsC7Fsc60NySfMXccvZmx8uQ8XIqmO9d0=; b=T7aTY/cANIs//KhutKNdsw3e8lWD7A3kTS5mDGLBS0k0hyfPUBrLFKBa4Yq5xqgd8gG8+V VWOe4TcLqy+gmivUj+C7UjaA/evoHtbA7RGnFtXQZFpH/4xXOjle1u1odBaXRN8qL86d+L ZuFPl4vmRJEFhG4Am4IpkusEIY94V8s= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1757662348; a=rsa-sha256; cv=none; b=UqJfn/eRar6rHywUljWWRgUas/VlbbpBveBTFEkZ8DKEu2elyGfKvjSgRxCyTBqTG5Brt9 6guAbnfOFYYTPzyQa/92ezciwLZMqKzhZaDReD9LB3pdWnnHlXuBteCbHhAGkEcGq1Hrnn yFwhoF62V2fcZuPxt/YNsj2xiUgD78k= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=AOaei1ID; spf=pass (imf04.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1757662348; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to: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=95M+ctN1eGHsC7Fsc60NySfMXccvZmx8uQ8XIqmO9d0=; b=AOaei1IDI2OOOb3KhArugtYerJfdNJwM4+IfJyJk5qbd5ANE335Lv37PTDSOAuiRZhNUJw igaeg+RBQ8r5uUHbwsfg33Me4H2uh66Iw3pF9Hjhe+OzBfCgoaIqyJmmLx18ZxVSOhs3rE hG4dla0p24zxaIo3/KU8vgsvg6V//pU= Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-628-mx2AgCULNiyDEakBeSB5Gg-1; Fri, 12 Sep 2025 03:32:26 -0400 X-MC-Unique: mx2AgCULNiyDEakBeSB5Gg-1 X-Mimecast-MFC-AGG-ID: mx2AgCULNiyDEakBeSB5Gg_1757662345 Received: by mail-wm1-f72.google.com with SMTP id 5b1f17b1804b1-45decfa5b26so8851135e9.3 for ; Fri, 12 Sep 2025 00:32:26 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757662345; x=1758267145; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :from:references:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=95M+ctN1eGHsC7Fsc60NySfMXccvZmx8uQ8XIqmO9d0=; b=ift5Np49QCRLkzcy2Ua7fw0CZ199SFez+9UUHDkFk95c/p4U7GDGAHG7Wd0tLOpNQz ZEygP9How4Fd9xaJuT0bXJ5l2KTLPiQq/83E+vUGVDRBYpgIuP2M/Mpc4PB+UinpWTK1 D/A22Cdc8c9EdqKNDkUNkOwj8h9QW4UmaAEXTEE+uQOt/oBveeupNibIhtHYwXUbffF3 zDuLdx/TKI7YK1Wc0K97BlR0Fe+zh7w+rTfi1KXAa+IMcoh6+Q4iiYHtKkNGlGqb70QA ozi57TZ7TZrpUHDsFpTK1IEStZty0Tdiztq8VpKMV5Wijt7Ly6nvINLnNQ84sUy5DpWN IWwQ== X-Forwarded-Encrypted: i=1; AJvYcCVDQ1dgrySLbqmjy8H9a/z45QHvFXZ+AtZTfj5tiz85Lmrq+RczVoNBy1yjOCVN7p6vRzLFq6FPOg==@kvack.org X-Gm-Message-State: AOJu0YwYKPEbdDWFjSuDslJ7/7x5hWwWmEkbMPzKCn3vx2gkcNoQkUWK PGQgiRi6g8a9U5JWuw/nveBMQNqL6o/3gcbRs105n8YrKkmj/yvQ0fxwrqTC/gNy6MuJ+L4Y3MQ 9hPq2n1HxGUE0rbMol8fb5p9TX1rMB2oSbYhvaoNjR/R02KMbmDtv X-Gm-Gg: ASbGncslp9t5/Cyv3hn1S/NRjABVn7WpOd4L/26Blyg2jct/Ay47uxNJ49GJciqKOTs jbicaZGaGaox9Ncf6VORqz1Ax9nLua1Y2I9EFH+65Ow7glr6GYnFhGDFk9cRMVLyOETHHeB9jXx +fDucAxEGwzy+/Q0zUttaWl8LxWLxVdLFGJtdW/QvCX3Y+aBKIrssHBrhpB3PEmeEj2Ew91fxr1 ZdUoHluco5AZ11tf5uXEGzE4hePe0wQbat/YI27givahUTwXw5OFOdGpyrVDfo5BsGrif1AnruE bHw/9nJExmv2DmXGCiOo05BfkE6E2HqqPqvH1wAERtJBc9cIqfPDPPwIFFiPA5H5XsBek0ubYf0 LWMpmIZPyilsHgIOp9XawdHoASWF20bDrqLeF50Zr4QqqfAwULm2kfI03u/E0o9xYNsg= X-Received: by 2002:a05:600c:3b23:b0:45d:d2d2:f095 with SMTP id 5b1f17b1804b1-45f211f708emr17024155e9.19.1757662345333; Fri, 12 Sep 2025 00:32:25 -0700 (PDT) X-Google-Smtp-Source: AGHT+IE291A72hUcioW8Th7oBQOwDU40VMWQG7GX58xF3iUOfk0bITXHhgpL+U49NQSEOwl8XHibag== X-Received: by 2002:a05:600c:3b23:b0:45d:d2d2:f095 with SMTP id 5b1f17b1804b1-45f211f708emr17023855e9.19.1757662344930; Fri, 12 Sep 2025 00:32:24 -0700 (PDT) Received: from ?IPV6:2003:d8:2f20:da00:b70a:d502:3b51:1f2d? (p200300d82f20da00b70ad5023b511f2d.dip0.t-ipconnect.de. [2003:d8:2f20:da00:b70a:d502:3b51:1f2d]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3e760776bb8sm5665006f8f.3.2025.09.12.00.32.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 12 Sep 2025 00:32:24 -0700 (PDT) Message-ID: Date: Fri, 12 Sep 2025 09:32:23 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] mm/hugetlb: fix copy_hugetlb_page_range() to use ->pt_share_count To: jane.chu@oracle.com, harry.yoo@oracle.com, osalvador@suse.de, liushixin2@huawei.com, muchun.song@linux.dev, akpm@linux-foundation.org, jannh@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20250910192730.635688-1-jane.chu@oracle.com> <16fd43b6-930a-4a33-980d-c493f88747b2@oracle.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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+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: <16fd43b6-930a-4a33-980d-c493f88747b2@oracle.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: ZQOw2VR3xrtBA6jLLgQbCL8r9UArfqLSCg8ivllb2pg_1757662345 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Stat-Signature: im998barnoae1a8ahso8yqzhhyq6ecdr X-Rspam-User: X-Rspamd-Queue-Id: A8A3240003 X-Rspamd-Server: rspam10 X-HE-Tag: 1757662348-515500 X-HE-Meta: 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 8MVZXEO0 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 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 11.09.25 21:58, jane.chu@oracle.com wrote: > > > On 9/11/2025 1:17 AM, David Hildenbrand wrote: > [..] >>> >>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >>> index 753f99b4c718..8ca5b4f7805f 100644 >>> --- a/mm/hugetlb.c >>> +++ b/mm/hugetlb.c >>> @@ -5594,18 +5594,13 @@ int copy_hugetlb_page_range(struct mm_struct >>> *dst, struct mm_struct *src, >>>               break; >>>           } >>> -        /* >>> -         * If the pagetables are shared don't copy or take references. >>> -         * >>> -         * dst_pte == src_pte is the common case of src/dest sharing. >>> -         * However, src could have 'unshared' and dst shares with >>> -         * another vma. So page_count of ptep page is checked instead >>> -         * to reliably determine whether pte is shared. >>> -         */ >> >> I think you ignored my question to v1 regarding the change of comment. >> > > Sorry David, didn't mean disrespect, I missed your earlier comments. No worries. Replied there about possibly simplifying the comment further. BTW, I think the code would be even clearer if we would have ptdesc_pmd_is_shared() that is simply a wrapper around the ptdesc_pmd_pts_count() check. -- Cheers David / dhildenb