From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f53.google.com (mail-wm0-f53.google.com [74.125.82.53]) by kanga.kvack.org (Postfix) with ESMTP id B10226B0005 for ; Thu, 10 Mar 2016 04:56:05 -0500 (EST) Received: by mail-wm0-f53.google.com with SMTP id l68so21160263wml.0 for ; Thu, 10 Mar 2016 01:56:05 -0800 (PST) Received: from mail-wm0-x243.google.com (mail-wm0-x243.google.com. [2a00:1450:400c:c09::243]) by mx.google.com with ESMTPS id i1si3634675wmd.89.2016.03.10.01.56.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 10 Mar 2016 01:56:04 -0800 (PST) Received: by mail-wm0-x243.google.com with SMTP id n205so2815546wmf.2 for ; Thu, 10 Mar 2016 01:56:04 -0800 (PST) Date: Thu, 10 Mar 2016 10:56:01 +0100 From: Ingo Molnar Subject: Re: [PATCH 03/11] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Message-ID: <20160310095601.GA9677@gmail.com> References: <1442903021-3893-1-git-send-email-mingo@kernel.org> <1442903021-3893-4-git-send-email-mingo@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Andy Lutomirski Cc: "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Andrew Morton , Denys Vlasenko , Brian Gerst , Peter Zijlstra , Borislav Petkov , "H. Peter Anvin" , Linus Torvalds , Oleg Nesterov , Waiman Long , Thomas Gleixner * Andy Lutomirski wrote: > On Fri, Feb 12, 2016 at 11:04 AM, Andy Lutomirski wrote: > > On Mon, Sep 21, 2015 at 11:23 PM, Ingo Molnar wrote: > >> So when memory hotplug removes a piece of physical memory from pagetable > >> mappings, it also frees the underlying PGD entry. > >> > >> This complicates PGD management, so don't do this. We can keep the > >> PGD mapped and the PUD table all clear - it's only a single 4K page > >> per 512 GB of memory hotplugged. > > > > Ressurecting an ancient thread: I want this particular change to make > > it (much) easier to make vmapped stacks work correctly. Could it be > > applied by itself? > > > > It's incomplete. pageattr.c has another instance of the same thing. > I'll see if I can make it work, but I may end up doing something a > little different. If so then mind picking up (and fixing ;-) tip:WIP.x86/mm in its entirety? It's well tested so shouldn't have too many easy to hit bugs. Feel free to rebase and restructure it, it's a WIP tree. I keep getting distracted with other things but I'd hate if this got dropped on the floor. Thanks, Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org