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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 02E0EC3DA7F for ; Wed, 7 Aug 2024 21:17:49 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=0TFKINsp; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4WfNLN4nkMz3d9s for ; Thu, 8 Aug 2024 07:17:48 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=0TFKINsp; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux-foundation.org (client-ip=139.178.84.217; helo=dfw.source.kernel.org; envelope-from=akpm@linux-foundation.org; receiver=lists.ozlabs.org) Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4WfNKc74LFz3cnv for ; Thu, 8 Aug 2024 07:17:08 +1000 (AEST) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 7F13161361; Wed, 7 Aug 2024 21:17:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 43CC7C32781; Wed, 7 Aug 2024 21:17:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1723065425; bh=+gUpbSegd1rP99qLghMnsgBErS9zrHF45NWkbO3C0pc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=0TFKINspgpAlLabxd/er+hxRd2vgR0Zs5pOwaZjJoMxyXSkODwI2oFe2cXYsgU71q Run8TO4CZCIZS1bbMHvyICsWBdEqyNihC5Nqewyg+REZ3YSGiX6Jk1u9Z9eJt6Ocsv Ud42JWI0sqQqmHgCa6cvnF/vmd5PDgkW2tmTDDQA= Date: Wed, 7 Aug 2024 14:17:03 -0700 From: Andrew Morton To: Peter Xu Subject: Re: [PATCH v4 0/7] mm/mprotect: Fix dax puds Message-Id: <20240807141703.d641001ee14177ccf80a31d8@linux-foundation.org> In-Reply-To: <20240807194812.819412-1-peterx@redhat.com> References: <20240807194812.819412-1-peterx@redhat.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: James Houghton , David Hildenbrand , Dave Hansen , linux-mm@kvack.org, Christophe Leroy , Thomas Gleixner , Dave Jiang , x86@kernel.org, Hugh Dickins , Matthew Wilcox , Ingo Molnar , Huang Ying , Rik van Riel , Nicholas Piggin , Borislav Petkov , "Kirill A . Shutemov" , Dan Williams , Vlastimil Babka , Oscar Salvador , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, "Aneesh Kumar K . V" , Rick P Edgecombe , Mel Gorman Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, 7 Aug 2024 15:48:04 -0400 Peter Xu wrote: > > Dax supports pud pages for a while, but mprotect on puds was missing since > the start. This series tries to fix that by providing pud handling in > mprotect(). The goal is to add more types of pud mappings like hugetlb or > pfnmaps. This series paves way for it by fixing known pud entries. > > Considering nobody reported this until when I looked at those other types > of pud mappings, I am thinking maybe it doesn't need to be a fix for stable > and this may not need to be backported. I would guess whoever cares about > mprotect() won't care 1G dax puds yet, vice versa. I hope fixing that in > new kernels would be fine, but I'm open to suggestions. Yes, I'm not sure this is a "fix" at all. We're implementing something which previously wasn't there. Perhaps the entire series should be called "mm: implement mprotect() for DAX PUDs"?