From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f197.google.com (mail-qk0-f197.google.com [209.85.220.197]) by kanga.kvack.org (Postfix) with ESMTP id EF6056B025E for ; Fri, 27 May 2016 04:03:43 -0400 (EDT) Received: by mail-qk0-f197.google.com with SMTP id d19so3598581qkg.3 for ; Fri, 27 May 2016 01:03:43 -0700 (PDT) Received: from mail-qk0-x242.google.com (mail-qk0-x242.google.com. [2607:f8b0:400d:c09::242]) by mx.google.com with ESMTPS id f31si8450884qkf.112.2016.05.27.01.03.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 27 May 2016 01:03:43 -0700 (PDT) Received: by mail-qk0-x242.google.com with SMTP id z80so4119033qkb.2 for ; Fri, 27 May 2016 01:03:43 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20160526142142.b16f7f3f18204faf0823ac65@linux-foundation.org> References: <1462435033-15601-1-git-send-email-oohall@gmail.com> <20160526142142.b16f7f3f18204faf0823ac65@linux-foundation.org> Date: Fri, 27 May 2016 18:03:42 +1000 Message-ID: Subject: Re: [RFC PATCH] mm/init: fix zone boundary creation From: oliver Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, Mel Gorman On Fri, May 27, 2016 at 7:21 AM, Andrew Morton wrote: > hm, this is all ten year old Mel code. > > What's the priority on this? What are the user-visible runtime > effects, how many people are affected, etc? Low priority. To get bitten by this you need to enable a zone that appears after ZONE_MOVABLE in the zone_type enum. As far as I can tell this means running a kernel with ZONE_DEVICE or ZONE_CMA enabled, so I can't see this affecting too many people. I only noticed this because I've been fiddling with ZONE_DEVICE on powerpc and 4.6 broke my test kernel. This bug, in conjunction with the changes in Taku Izumi's kernelcore=mirror patch (d91749c1dda71) and powerpc being the odd architecture which initialises max_zone_pfn[] to ~0ul instead of 0 caused all of system memory to be placed into ZONE_DEVICE at boot, followed a panic since device memory cannot be used for kernel allocations. I've already submitted a patch to fix the powerpc specific bits, but I figured this should be fixed too. oliver -- 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