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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C9683C44501 for ; Thu, 16 Jul 2026 09:49:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=DULupypI0kQO6VR/9Hnm6xvd1I56RK/sZSlBe1w/CWE=; b=I68zyTSBcy6JP1latbAlZniIqJ lWAwyKxR1vmYjk4iqRhCXRAYiUaUIDznEUyo5YaRAAPofE3BTwO2TF/DZc6h4ifgtfTrkub7iyYEs GNugIE7J5BkBZ8oy2yr30dO6As0V2dyz6n4a0VrgLUoc7C+pBTpweeTFY/Ql+t2OQtaVZr1vyGIWN QTu83vm8SEt5AG0sia1G4knVE+evq2QepJuhUFgimJ3COGS8HUsMIC+WuBS+B+cL7VsHN3SpYm//3 fS9ST1n+5DGQdRJqLK0Of3lB9kzQT2EsH25B9F2kcaZ9htjh0PSvx6Y49BISrPGb/ryhjpbmCXUtM EO3mifBg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wkIj0-0000000GvUa-0TCz; Thu, 16 Jul 2026 09:49:50 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wkIiw-0000000GvTk-1tdf; Thu, 16 Jul 2026 09:49:47 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A60E11477; Thu, 16 Jul 2026 02:49:40 -0700 (PDT) Received: from [10.57.83.230] (unknown [10.57.83.230]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 28D693F905; Thu, 16 Jul 2026 02:49:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1784195384; bh=DULupypI0kQO6VR/9Hnm6xvd1I56RK/sZSlBe1w/CWE=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=s0WjY92k6FXXGsVb/uHJpLBIVOYUjUI8eS0BHss4CJRfj+QIoU4lVy2lHkTcCkoLf HXbioh4bhVzyH7KrUz8UAnwAXsoSNPBoK+CXb0kGziyOHBz0wHOsqFAI5ri0j0KaxN AXVBsuWhv1zZICmG2yvm8TKcS7aYUdVdoYT9nYUs= Message-ID: Date: Thu, 16 Jul 2026 11:49:31 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 14/22] mm: set page table page type when allocated To: Vishal Moola Cc: linux-mm@kvack.org, Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Pasha Tatashin , Russell King , Catalin Marinas , Will Deacon , Ryan Roberts , linux-arm-kernel@lists.infradead.org, Huacai Chen , loongarch@lists.linux.dev, "James E.J. Bottomley" , Helge Deller , linux-parisc@vger.kernel.org, Madhavan Srinivasan , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Gerald Schaefer , linux-s390@vger.kernel.org, "David S. Miller" , Andreas Larsson , sparclinux@vger.kernel.org, Richard Weinberger , Anton Ivanov , Johannes Berg , linux-um@lists.infradead.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Ning Sun , x86@kernel.org, tboot-devel@lists.sourceforge.net, Ard Biesheuvel , Ilias Apalodimas , linux-efi@vger.kernel.org, Alistair Popple , "Matthew Wilcox (Oracle)" , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org References: <20260714-remove_pgtable_cdtor-v1-0-44be8a7685d7@arm.com> <20260714-remove_pgtable_cdtor-v1-14-44be8a7685d7@arm.com> From: Kevin Brodsky Content-Language: en-GB In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260716_024946_590096_76480DFE X-CRM114-Status: GOOD ( 16.61 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org On 14/07/2026 17:16, Vishal Moola wrote: > On Tue, Jul 14, 2026 at 03:04:03PM +0100, Kevin Brodsky wrote: >> As a step towards removing pagetable ctor/dtor calls for kernel >> mm's, move the page type updates from the ctor/dtor to >> pagetable_{alloc,free}. > Thanks for doing this patchset. Thanks for suggesting it :) It's turning out to be quite a bit more involved than I expected though! (There are multiple cases where we call the ctor/dtor without using pagetable_{alloc,free}, see my reply to the cover letter.) > We should switch over from __folio_set_pgtable() to __SetPagePgtable() > in this patch. Ptdescs and folios should be treated as distinctly > independent of each other. I sure remember the previous discussion, but my reading of your comments [1] is that we cannot really change this as long as pagetable_alloc() can be called with order > 0, right? Multiple archs still rely on that. > Eventually, we want to replace the memcg accounting as well, but > there's no existing API for that right now. Lets leave that as is for > now; this patchset is big enough already ;) Yep, looks like there was an attempt to improve this but it had to be reverted [2]. - Kevin [1] https://lore.kernel.org/all/aha321ndGSdReBJR@fedora/ [2] https://lore.kernel.org/all/20260225002434.2953895-1-axelrasmussen@google.com/