From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f43.google.com (mail-wm0-f43.google.com [74.125.82.43]) by kanga.kvack.org (Postfix) with ESMTP id 8B82E6B0256 for ; Mon, 7 Mar 2016 04:53:37 -0500 (EST) Received: by mail-wm0-f43.google.com with SMTP id l68so63454130wml.1 for ; Mon, 07 Mar 2016 01:53:37 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id wd3si18125530wjc.88.2016.03.07.01.53.36 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 07 Mar 2016 01:53:36 -0800 (PST) Subject: Re: [PATCH] mm: ZONE_DEVICE depends on SPARSEMEM_VMEMMAP References: <20160305004214.12356.32017.stgit@dwillia2-desk3.jf.intel.com> From: Vlastimil Babka Message-ID: <56DD4F9F.303@suse.cz> Date: Mon, 7 Mar 2016 10:53:35 +0100 MIME-Version: 1.0 In-Reply-To: <20160305004214.12356.32017.stgit@dwillia2-desk3.jf.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dan Williams , akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org On 03/05/2016 01:42 AM, Dan Williams wrote: > The primary use case for devm_memremap_pages() is to allocate an > memmap array from persistent memory. That capabilty requires > vmem_altmap which requires SPARSEMEM_VMEMMAP. Some if the ifdefs around to_vmem_altmap() could now be simplified, but that can also be done later... > Also, without SPARSEMEM_VMEMMAP the addition of ZONE_DEVICE expands > ZONES_WIDTH and triggers the: > > "Unfortunate NUMA and NUMA Balancing config, growing page-frame for > last_cpupid." > > ...warning in mm/memory.c. SPARSEMEM_VMEMMAP=n && ZONE_DEVICE=y is not > a configuration we should worry about supporting. > > Reported-by: Vlastimil Babka > Signed-off-by: Dan Williams Acked-by: Vlastimil Babka > --- > mm/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/Kconfig b/mm/Kconfig > index 664fa2416909..b95322ba542b 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -654,6 +654,7 @@ config ZONE_DEVICE > bool "Device memory (pmem, etc...) hotplug support" if EXPERT > depends on MEMORY_HOTPLUG > depends on MEMORY_HOTREMOVE > + depends on SPARSEMEM_VMEMMAP > depends on X86_64 #arch_add_memory() comprehends device memory > > help > -- 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