From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lin Feng Date: Fri, 18 Jan 2013 07:58:27 +0000 Subject: Re: [PATCH v3 1/2] memory-hotplug: introduce CONFIG_HAVE_BOOTMEM_INFO_NODE and revert register_page_ Message-Id: <50F900A3.4060903@cn.fujitsu.com> List-Id: 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> <50F7D456.9000904@cn.fujitsu.com> <20130117130509.GE20538@dhcp22.suse.cz> In-Reply-To: <20130117130509.GE20538@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 01/17/2013 09:05 PM, Michal Hocko wrote: > On Thu 17-01-13 18:37:10, Lin Feng wrote: > [...] >>> > > 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. > OK, then I suggest moving it under CONFIG_MEMORY_HOTREMOVE guards rather > than CONFIG_MEMORY_HOTPLUG. I can't agree more ;-) I also find that page_isolation.c selected by MEMORY_ISOLATION under MEMORY_HOTPLUG is also such case, I fix it by the way. thanks, linfeng >