From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id DF506606A320 for ; Tue, 27 Oct 2026 14:06:41 +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=mRvrOOSg Received: by kanga.kvack.org (Postfix) id E32896B0777; Tue, 27 Oct 2026 10:06:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DE3596B0779; Tue, 27 Oct 2026 10:06:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CF9CF6B077A; Tue, 27 Oct 2026 10:06:40 -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 AC9916B0777 for ; Tue, 27 Oct 2026 10:06:40 -0400 (EDT) Received: from smtpin22.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 4235A40A0B for ; Tue, 27 Oct 2026 14:06:40 +0000 (UTC) X-FDA: 85368581760.22.FA5D6E0 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf16.hostedemail.com (Postfix) with ESMTP id 690FF18000A for ; Tue, 27 Oct 2026 14:06:38 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=mRvrOOSg; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf16.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793109998; 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=0u2sU8fv44IdbL2rqY0zsZ1MwMIHXr4E88UCvKAQ3oM=; b=re9UKNFX0UCIQ0Wq2NrI1c+NgmIsvkvlzg/5hi1mt2TOU1ZPtV67XRC116mwHzUjgbv5Ej ddTxbOzZPjQcGqa+mQKeOoBPcQraWIpXOt4BALBwuse1r0ZLADue+SuYRQYOU/gPMF17KI UAVD1yikBatSO02WS4WnCbk+2GY43LQ= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=mRvrOOSg; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf16.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793109998; b=SVhJKuLsOI0ubHFvTYUvK0PlrHX5mkq+o7+AJ0j2KqVQheZWO1AkRuc0cEonnKwS66GiZs YeebNkYKXVgUVY8iRMwEuQkuwf9WfBQU6czWH/IMwirdz6jJINkT5uFdwbR394apdOQgv+ c440hQ0ikiztNY9Ms18CH9FoUGzVNOE= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 8E7AD43AE8; Tue, 27 Oct 2026 14:06:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 514D71F031E2; Tue, 27 Oct 2026 14:06:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793109997; bh=0u2sU8fv44IdbL2rqY0zsZ1MwMIHXr4E88UCvKAQ3oM=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=mRvrOOSgjdCxSfV4CAfO4tcpSYh41Pg239SgUcuSZUYgDaOyxgFlV9PNmIOHYL3CY vYJpvkL2efCTKqHIF1P4wYdt6XqrEXQvriF8RDuiBsDmOaO34s4R1pOzoXPqgy5EFW oqr8aS1elll1K1kIDHAob5wlCH9DQSfr3ci3chP/VixwQWTJu2mOUpEaCUBqIrW3Ws 5oBukZ1Sk3iKPkTBncIMPFXOXwlTOVC4yzKYDE1uQcvAXFGQgzTBFYMrc57XOMIjXk wMyjsU4YHDRuXRBP325OoyDoIIL6DWgVK7Wa9XeCxEOomeVBKfNeVQ9HyUQjDHkDTT ZEG0Tkbfp7qdg== Message-ID: <97aa3a39-3b39-4d8c-8e99-d58a059aca92@kernel.org> Date: Tue, 27 Oct 2026 15:06:27 +0100 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 1/4] mm/rmap: duplicate a PMD mapping as one in folio_dup_file_rmap_pmd() To: Konstantin Khorenko , Andrew Morton , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Peter Xu Cc: Alex Williamson , kvm@vger.kernel.org, =?UTF-8?Q?Lo=C3=AFc_Molinari?= , Lorenzo Stoakes , Shuah Khan , linux-kselftest@vger.kernel.org, dri-devel@lists.freedesktop.org, Madhavan Srinivasan , "Ritesh Harjani (IBM)" , linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jason Gunthorpe References: <20261021-b4-prep-vstor-149847-copy_huge_pmd-recheck-special-pmd-v4-0-66f00b7a564c@virtuozzo.com> <20261021-b4-prep-vstor-149847-copy_huge_pmd-recheck-special-pmd-v4-1-66f00b7a564c@virtuozzo.com> 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: <20261021-b4-prep-vstor-149847-copy_huge_pmd-recheck-special-pmd-v4-1-66f00b7a564c@virtuozzo.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 690FF18000A X-Stat-Signature: r6e1f3fxa8akkym4kcgsc8tpmz5fnmbp X-Rspamd-Server: rspam04 X-Spam-Status: No, score=-17.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1793109998-934011 X-HE-Meta: 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 TJuA/1/v kLEzTr5WalmZO/SJF+MOhgXy23tTqyonGPpWmswvX4A+iOUpNB8/D/AtiO2OFcsPFnGS+egMOUIlKelrBxltGf6cYiVMN1mKx+AB5hXkBwHpL0O+e9AFKWzYWhYb+X5tU+bE6BUjZ8qvgA0wxSFk/3fyVdicppLH7YqthMzaPCSeP4KS+nfsavzSD/s+bNNp3TM1+vQa+jK8LuzlVomk9vxIYXSVAS81DPvRWp51fsZHk27xVsw9pMXKM168p5QOi7vLGjhk5K+JkT4oBwk6Gn/HurSKrGidb6a3CLPEohWIkCvE0M5GHPH1uOWpyRvexa2ODT6DWwTgIACmJfQpHYcIRDYyNJIMiFEEw6hW/6kuwHIDtcopgG2HCppWjMvMXZnPjsYa/IVwV4Xvdso2vjMCCz0z51DPD3nWuuXPHJiP4XMz/vPbst++LImjko5V/oVSRj4dhy21fhrcYn+19uHC5mg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 10/21/26 22:36, Konstantin Khorenko wrote: > folio_dup_file_rmap_pmd() passes PGTABLE_LEVEL_PTE to > __folio_dup_file_rmap() for HPAGE_PMD_NR pages, so it adds HPAGE_PMD_NR > PTE mappings to the folio instead of one PMD mapping. Each unmap of the > PMD removes one PMD mapping: > > - the folio's mapcount never returns to zero, and removing the folio > from the page cache reports "Bad page cache", or hits a VM_BUG_ON > with CONFIG_DEBUG_VM; > - the first unmap already counts as the last one and drops the > PMD-mapped statistics while the other mm still maps the folio; > - the second one drives the entire mapcount below zero and drops them > again. > > The helper has no caller yet, the next patch adds the first one. Pass > PGTABLE_LEVEL_PMD, as folio_try_dup_anon_rmap_pmd() does. > > Fixes: d8ef5e311d7b ("mm/rmap: convert page_dup_file_rmap() to folio_dup_file_rmap_[pte|ptes|pmd]()") > Signed-off-by: Konstantin Khorenko > --- > include/linux/rmap.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/rmap.h b/include/linux/rmap.h > index 0b332770abeed..7562017416094 100644 > --- a/include/linux/rmap.h > +++ b/include/linux/rmap.h > @@ -558,7 +558,7 @@ static inline void folio_dup_file_rmap_pmd(struct folio *folio, > struct page *page, struct vm_area_struct *dst_vma) > { > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > - __folio_dup_file_rmap(folio, page, HPAGE_PMD_NR, dst_vma, PGTABLE_LEVEL_PTE); > + __folio_dup_file_rmap(folio, page, HPAGE_PMD_NR, dst_vma, PGTABLE_LEVEL_PMD); > #else > WARN_ON_ONCE(true); > #endif > Acked-by: David Hildenbrand (Arm) -- Cheers, David