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 1124E46AF27; Thu, 6 Aug 2026 11:35:37 +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=1786016141; cv=none; b=QEusgwmaQhv6437cye9WT91Sl6A+3rwYuyieSW+0J+YVFEOdGXDz5DZn3/Ox/QlMF4kUFzHa+ysE0Nujv+0bkC89UmvWgrC275Cv2EjWUrTEF87xFROsCKWGLhdT2wmZmloETGN5Q1zudzddf0sMnfrtQQeG6uuqBx7iHctXWIo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786016141; c=relaxed/simple; bh=4moVM7TQhgOEnxVOW8ZNheGwST9mR6QX6NpMP15Z5WY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CXyxpgH0K39Ty5uYh+dXf/jUSVyEEHijeqYVa5pFhV2kiO/VMSl7vxSYRWFSl3DbNuNYn9+ameSBrNpFUBYzkdxEmZlS5+8noUcv/zD06b1/rMZ3ZVk2MFUUdg1x5/oHnHeEQJa53aawOPFukL8lk9fWPMieS6CWopFyyQVOlfc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D+6XGZ/h; 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="D+6XGZ/h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 03C2F1F000E9; Thu, 6 Aug 2026 11:35:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786016136; bh=o+F0RzuVtNz+eojtGhM+HYo6D1XEZrIxjfPHKREvRLU=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=D+6XGZ/hqaszvFrMxClhmjIejkkpunmP+HkRtEn60r2qHNOn4GxTSTJYAf8YvKHR1 vK977umQqmd7c8GlZ0HK/6iH3wE3LmJTmMT6Uj/bwQBP2DiR13DZa1DbGbpUAqWnIg QQ6UG9rweFFW91srrvAHYUb50WMc3T+Nk37Xum6iSVtJgUzhsVphsgerdZLAJ2ny77 P2iEmLyn9VfaMo5XS3Te6PZLeWZP2PGQ8idcqQNRVKPrbUFMuybFPzH+cpsWn5pdy+ ALHhFRgeg4Hf1uO+g/hpk+vE+vNFx8h8kvGmxYGdAnNyLZJr/1FmC/cMAYZsg7D0C8 /E6VIrHqwRr8Q== Message-ID: <919b804b-6f1d-417e-9c0c-d06f50d765d8@kernel.org> Date: Thu, 6 Aug 2026 13:35:30 +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] mm/madvise: avoid skipping pages after splitting large folios To: "Lorenzo Stoakes (ARM)" , Yunhui Cui Cc: akpm@linux-foundation.org, liam@infradead.org, vbabka@kernel.org, jannh@google.com, 00moses.alexander00@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20260806055501.56761-1-cuiyunhui@bytedance.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit > > Let's at least split out the folio check into a helper to make things > clearer: > > static bool poison_splits_folio(const struct folio *folio) > { > /* Hugetlb is, as always, a world unto itself. */ > if (folio_test_hugetlb(folio)) > return false; > /* Soft-offline errors out, hwpoison traverse DAX intact. */ > if (folio_is_zone_device(folio)) > return false; > return true; > } > > Then for your patch: > > - size = PAGE_SIZE; > - if (folio_test_hugetlb(folio) || folio_is_zone_device(folio)) > - size = folio_size(folio); > + size = poison_splits_folio(folio) ? PAGE_SIZE : folio_size(folio); > > I tried writing something that was neater and nicer but AI kept pointing > out how it was totally broken and I really really hate this code (not your > fault :). No, I don't think any such special casing on folios is the right way to handle it. -- Cheers, David