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 E5A9540928A for ; Fri, 10 Jul 2026 12:22:10 +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=1783686132; cv=none; b=XxKoTP1Khx7H9PodsIe604KOs+IewNcPO86wse1I3OxlsDbuwadsVmxk5lEiQ/gmIb8CijjO5PIrtMJXJ94ngLXC2vZMs28cjX4oZ9yschHYPHgHG5WW+82LH9L1me5UguU4Xohuum43iLHBJtNSmCYMKRuqHL0apsp94bouyCo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783686132; c=relaxed/simple; bh=FoDKzhBNB0u+NxuIiqczQ+1eOwIoH2uz/0VdwZ32ZDA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=d7O9ImPMxn3N3i1zlfKPCbN8gn/rPpyMwfE1517E9v/LEe0gE/ZL8nOjLMlV1HK2ZJmqWulShuuFNzS1CS8qWpuzyv4sYwvWxOc2KmivUB2ZQkZ5mkSZmC/plW17bhTyrBu4R1s0AuMa825YDV6HdPenzEAMBQZ7kGBqEI9a4ms= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SDXK/0wx; 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="SDXK/0wx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0DAE1F0155A; Fri, 10 Jul 2026 12:22:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783686130; bh=fDgjRBlYu1xxBnZ1IMeHj51O6m+GeaRvDabt0r9az68=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=SDXK/0wxM+vVK5Aq9AxQaVGqL3/lAKIHy1sJwPtT4QLKGiyAwSKhXKd1G9DrHgsas ve4xSKX2z1MWh9cMllqIqSzkrxvJLiPfr34a5Zu9v0ERWAMykx6UVg6eDHjivhqESK NmGg9NMzLOVemntDlyZHzhB6warnBuU0ZHNV3ruxdMudK2Q2MGFxf6060nUEAFY1zB DbwRHu6rgoHVw3DWF2XoJ0X7jS+QnF16R7uZwjvzhUaWC7ENs0qyKmS6UL/XrSgLXX j8UfhpgN4jmgZeUuVMkQIFyfonnp/Hi0Oh1c8xJkhH+GTtP8IpnQ+U8tlQWkCj4ItL vqEeSka/ysxiQ== Message-ID: <87b94730-7543-487e-8f3e-c13251a00a21@kernel.org> Date: Fri, 10 Jul 2026 14:22:05 +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 v2 1/5] mm/rmap: convert page -> folio for hwpoison checks To: Dev Jain , akpm@linux-foundation.org, ljs@kernel.org, muchun.song@linux.dev, osalvador@suse.de Cc: riel@surriel.com, liam@infradead.org, vbabka@kernel.org, harry@kernel.org, jannh@google.com, lance.yang@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com References: <20260710055915.638659-1-dev.jain@arm.com> <20260710055915.638659-2-dev.jain@arm.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: <20260710055915.638659-2-dev.jain@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/10/26 07:59, Dev Jain wrote: > try_to_unmap() receives hugetlb folios only from the hwpoison path. > hugetlb_update_hwpoison() sets the hugetlb folio's head-page > hwpoison bit, and page_vma_mapped_walk() reports the hugetlb mapping at > the head PFN, so the previous PageHWPoison(subpage) check happened to > work for hugetlb. > > For non-hugetlb folios, unmap_poisoned_folio() currently rejects large > folios before calling try_to_unmap(). Hence it is always the case that > if try_to_unmap_one() handles an hwpoisoned folio, then the head page is > marked with the poison bit. > > Therefore, convert the poisoned subpage checks to folio_test_hwpoison(). > > No functional change intended, except that, while at it, > convert VM_BUG_* to VM_WARN_*. > > Acked-by: David Hildenbrand (Arm) > Signed-off-by: Dev Jain > --- > mm/rmap.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/mm/rmap.c b/mm/rmap.c > index 9939400e77c79..dbb077f8443e3 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -2122,10 +2122,11 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, > bool anon = folio_test_anon(folio); > > /* > - * The try_to_unmap() is only passed a hugetlb page > - * in the case where the hugetlb page is poisoned. > + * The try_to_unmap() is only passed a hugetlb folio > + * in the case where the hugetlb folio contains a > + * poisoned page. > */ > - VM_BUG_ON_PAGE(!PageHWPoison(subpage), subpage); > + VM_WARN_ON_FOLIO(!folio_test_hwpoison(folio), folio); > /* > * huge_pmd_unshare may unmap an entire PMD page. > * There is no way of knowing exactly which PMDs may > @@ -2204,7 +2205,11 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, > /* Update high watermark before we lower rss */ > update_hiwater_rss(mm); > > - if (PageHWPoison(subpage) && (flags & TTU_HWPOISON)) { > + /* > + * With TTU_HWPOISON, we only expect small folios or hugetlb > + * folios here for now. > + */ Is this comment helpful given that you change that in patch #2, where you forget to update the comment? :) -- Cheers, David