From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 3EF4D3203B6; Wed, 5 Nov 2025 19:06:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762369616; cv=none; b=HuQEjqY8Pnea9gFTkz9LT0ce/KRYgThJdaWBkzNkgShy0Tnb98i5W28yxsO/IPCC3ZrWYQwXJiK6LwYsyIL2HhvGjaaSJLDbyfwmXdmgy5jLeDYrAwJAttmWVEWtEQyQYV5moCYYl8Z1PSznF+HF0SdkKRB9easPZLjXp+lxRkQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762369616; c=relaxed/simple; bh=r1RUQ5w8cqf5Ixyk9+1OWb64pQySNdzgjfAjsvNRiJU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=FlwWRp5UV7OxbHF3hRKd1ndf5QqsvcP52HKi4Psn52krWv9XFTwyK+n+LLurvAJLrdbCJyDphb2bU//mvlJL5C76ab4xeN2Y76HiqyjUEwgODJP3kUc5QIofSJiZKZ6pjrRtLxBgnBwdQ8y+P+mH46ja9HQ7xCmXWca0eoFBgek= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=IBWlsteG; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="IBWlsteG" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=uNlLN91IPUmzKBqToljugUBHU3xTh3YeZQvGikTGxf8=; b=IBWlsteGV5BqKNpBp269P8rt+Z 0VKCpMHLJcEcVC5ca9y4mzUMBegTviTXPimmvvPBDSDtP77WZVHbwThO2KmT1T+XeAvGKLAHF0PRS 80OeZej4TWRoq+EBL9TfPVoHaT5QOWeDqbMqMYIPbHtgQcNFN/L4z1JJbVyFD/pSjiTrFgovznnIc XkeQQXR5rl4/W2+7Z7UKzeQs8t3TjbaEvjtqAn49fXOGK2vvpbhXLkByLlSORalsuHmw82rYhXDs8 Uheq42GmULctQ5UcWDeMNW3yFM55Ral+on9Ve62bU57pkBQ0EU+4PaIXi/iqPUMHvyrIi9YQne70n F2cEH7Kw==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vGipf-0000000EnwZ-1iQX; Wed, 05 Nov 2025 19:06:11 +0000 Date: Wed, 5 Nov 2025 19:06:11 +0000 From: Matthew Wilcox To: Lorenzo Stoakes Cc: Andrew Morton , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , David Hildenbrand , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Sven Schnelle , Peter Xu , Alexander Viro , Christian Brauner , Jan Kara , Arnd Bergmann , Zi Yan , Baolin Wang , "Liam R . Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Muchun Song , Oscar Salvador , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Axel Rasmussen , Yuanchu Xie , Wei Xu , Kemeng Shi , Kairui Song , Nhat Pham , Baoquan He , Chris Li , SeongJae Park , Jason Gunthorpe , Leon Romanovsky , Xu Xin , Chengming Zhou , Jann Horn , Miaohe Lin , Naoya Horiguchi , Pedro Falcato , Pasha Tatashin , Rik van Riel , Harry Yoo , Hugh Dickins , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, damon@lists.linux.dev Subject: Re: [PATCH 02/16] mm: introduce leaf entry type and use to simplify leaf entry logic Message-ID: References: <2c75a316f1b91a502fad718de9b1bb151aafe717.1762171281.git.lorenzo.stoakes@oracle.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2c75a316f1b91a502fad718de9b1bb151aafe717.1762171281.git.lorenzo.stoakes@oracle.com> On Mon, Nov 03, 2025 at 12:31:43PM +0000, Lorenzo Stoakes wrote: > The kernel maintains leaf page table entries which contain either: > > - Nothing ('none' entries) > - Present entries (that is stuff the hardware can navigate without fault) > - Everything else that will cause a fault which the kernel handles The problem is that we're already using 'pmd leaf entries' to mean "this is a pointer to a PMD entry rather than a table of PTEs". So I think we need a new name. A boring name would be 'swent' (software entry). An acronym would be SWE. In the XArray I distinguish between pointer entries and value entries -- would calling them value entries work here? Or we could call them something entirely different. Say 'twig'. Or 'cask'.