From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Chulmin Kim" Subject: FW: maximum memory size allocated by _xmalloc Date: Thu, 12 Jul 2012 18:24:26 +0900 Message-ID: <003501cd6010$224d58d0$66e80a70$@core.kaist.ac.kr> References: <008601cd5f45$6eff7530$4cfe5f90$@core.kaist.ac.kr> <4FFD4C06.7090403@citrix.com> <001301cd5fc1$818953c0$849bfb40$@core.kaist.ac.kr> <4FFE93DE.5020608@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: ko List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org > On 12/07/12 01:01, Chulmin Kim wrote: > >> On 11/07/12 10:13, Chulmin Kim wrote: > >>> Hi all, > >>> > >>> I'm currently inserting my own code to adjust the several existing > >>> memory ballooning works. > >>> > >>> To accomplish it, I manage some kind of statistics in Xen memory area. > >>> > >>> Using _xmalloc, I've allocated certain size of memory chunk for > >>> the data structure. ( I varied it from 10kb to 24 MB.) > >>> > >>> When the size is equal to 24 MB, xen won't boot anymore. (stuck > >>> during the xmalloc, according to my debugging. _xmalloc returns > >>> NULL.) There was no problem when the size is below 12MB. > >>> > >>> Is there any limitation such as max memory size for _xmalloc? > >>> > >>> I suspected xen heap size, but, it is no longer adjustable. Right? > >>> > >>> I hope somebody can give me a clue. Thanks. > >> _xmalloc will first try to use the size pools for allocation, and > >> failing > > that, try to > >> allocate full pages. > >> > >> As it is returning NULL, this probably means you no longer have > >> 24MB of > > free > >> contiguous RAM to allocate. > >> > >> ~Andrew > >> > > Thanks for the reply, Andrew. > > > > I have to check the contiguity. > > > > If it is the cause of the problem, then, how can I detour this problem? > > > > Other xen part calling xmalloc_array does not handle this problem as > > far as I know. (only consider it as an error) > > > > Should I split the data structure into two or more chunks? > > Personally, I would think that 24M is a stupidly large amount to be > trying to allocate with xmalloc and friends. > > If you are using that much memory, it might be worth using > alloc_xenheap_pages() and working with full pages instead. > > Why do you need so much space for memory statistics? > > ~Andrew OK. I will try alloc_xenheap_pages(). I am following up a research work (Dynamic Memory Balncing ~~), and it maintains a table which has an entry per page in the machine. My machine has large memory (different from that in the research work), so it needs that amount of memory. Thanks! > > -- > Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer > T: +44 (0)1223 225 900, http://www.citrix.com