From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx203.postini.com [74.125.245.203]) by kanga.kvack.org (Postfix) with SMTP id C9F306B005D for ; Thu, 17 Jan 2013 06:10:59 -0500 (EST) Message-ID: <50F7D456.9000904@cn.fujitsu.com> Date: Thu, 17 Jan 2013 18:37:10 +0800 From: Lin Feng MIME-Version: 1.0 Subject: Re: [PATCH v3 1/2] memory-hotplug: introduce CONFIG_HAVE_BOOTMEM_INFO_NODE and revert register_page_bootmem_info_node() when platform not support References: <1358324059-9608-1-git-send-email-linfeng@cn.fujitsu.com> <1358324059-9608-2-git-send-email-linfeng@cn.fujitsu.com> <20130116141436.GE343@dhcp22.suse.cz> In-Reply-To: <20130116141436.GE343@dhcp22.suse.cz> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: akpm@linux-foundation.org, linux-mm@kvack.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, jbeulich@suse.com, dhowells@redhat.com, wency@cn.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, paul.gortmaker@windriver.com, laijs@cn.fujitsu.com, kamezawa.hiroyu@jp.fujitsu.com, mel@csn.ul.ie, minchan@kernel.org, aquini@redhat.com, jiang.liu@huawei.com, tony.luck@intel.com, fenghua.yu@intel.com, benh@kernel.crashing.org, paulus@samba.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, davem@davemloft.net, michael@ellerman.id.au, gerald.schaefer@de.ibm.com, gregkh@linuxfoundation.org, x86@kernel.org, linux390@de.ibm.com, linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, tangchen@cn.fujitsu.com Hi Michal, On 01/16/2013 10:14 PM, Michal Hocko wrote: > On Wed 16-01-13 16:14:18, Lin Feng wrote: > [...] >> diff --git a/mm/Kconfig b/mm/Kconfig >> index 278e3ab..f8c5799 100644 >> --- a/mm/Kconfig >> +++ b/mm/Kconfig >> @@ -162,10 +162,18 @@ config MOVABLE_NODE >> Say Y here if you want to hotplug a whole node. >> Say N here if you want kernel to use memory on all nodes evenly. >> >> +# >> +# Only be set on architectures that have completely implemented memory hotplug >> +# feature. If you are not sure, don't touch it. >> +# >> +config HAVE_BOOTMEM_INFO_NODE >> + def_bool n >> + >> # eventually, we can have this option just 'select SPARSEMEM' >> config MEMORY_HOTPLUG >> bool "Allow for memory hot-add" >> select MEMORY_ISOLATION >> + select HAVE_BOOTMEM_INFO_NODE if X86_64 >> depends on SPARSEMEM || X86_64_ACPI_NUMA >> depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG >> depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390) > > I am still not sure I understand the relation to MEMORY_HOTREMOVE. > Is register_page_bootmem_info_node required/helpful even if > !CONFIG_MEMORY_HOTREMOVE? >>From old kenrel's view register_page_bootmem_info_node() is defined in CONFIG_MEMORY_HOTPLUG_SPARSE, it registers some info for memory hotplug/remove. If we don't use MEMORY_HOTPLUG feature, this function is empty, we don't need the info at all. So this info is not required/helpful if !CONFIG_MEMORY_HOTREMOVE. > > Also, now that I am thinking about that more, maybe it would > be cleaner to put the select into arch/x86/Kconfig and do it > same as ARCH_ENABLE_MEMORY_{HOTPLUG,HOTREMOVE} (and name it > ARCH_HAVE_BOOTMEM_INFO_NODE). > Maybe put it in mm/Kconfig is a better choice, because if one day someone implements the register_page_bootmem_info_node() for other archs they will get some clues here, that's it has been implemented on x86_64. But I'm not so sure... thanks, linfeng -- 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