From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yasunori Goto Date: Wed, 04 Apr 2007 05:58:13 +0000 Subject: Re: question about memory-hotplug Message-Id: <20070404141923.01FD.Y-GOTO@jp.fujitsu.com> List-Id: References: <4611BF4D.6020002@ncic.ac.cn> In-Reply-To: <4611BF4D.6020002@ncic.ac.cn> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: linux-hotplug@vger.kernel.org Hello. > hi > I try to understand the memory_hotplug.c ,but I am confused about=20 > the mechanism in it > Does the mem_map is allocated when setup for all the memory page both=20 > the existing and the hotplug , or does the mem_map is allocated=20 > dynamically when a chip of memory is hotpluged ? > if mem_map is allocated dynamically,does the mem_map is maintained in=20 > the list or how to deal with it ? > and if mem_map is allocated dynamically,does system need new node and=20 > new zone structure to manage the dynamically-allocated memmap ,or not ? Basically, memory hotplug code depends on sparsemem. So, I'll recommend that you should see mm/sparse.c too. In sparsemem code, mem_map is allocated dynamically, and=20 its pointed by mem_section[] array. (However, x86-64 code has original code. IIRC, its memmap was allcated=20 statically....) > if system need new node and new zone structure to manage the=20 > dynamically-allocated memmap,does system have to be a NUMA-surpport one=20 > or not? Pgdat and zone can be allocated dynamically for NUMA system, but memmap is not pointed by them if sparsemem is on. Thanks for your concern. :-) --- Yasunori Goto=20 ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=3Djoin.php&p=3Dsourceforge&CID=DEVD= EV _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel