Xen project Mailing List

On Mon, Mar 28, 2016 at 3:42 AM, Zhang, Chunyu <zhangcy@xxxxxxxxxxxxxx> wrote:

>
>
>On Fri, Mar 25, 2016 at 11:08 AM, Zhang, Chunyu <zhangcy@xxxxxxxxxxxxxx> wrote:
>
>Populate on Demand + balloon , see :
>
>https://blog.xenproject.org/2014/02/14/ballooning-rebooting-and-the-feature-youve-never-heard-of/
>
>
>So, if I understand, support for memory hotplug is present but is not compiled by default, is it?
pv or hvm ?

It's HVM

Also, I don't run neither XCP nor XenServer.

Instead, I have a Fedora 21 server where I installed Xen 4.4 (which is the version of Xen shipped with Fedora 21)

Cheers

if hvm, i think yes ...
http://wiki.xen.org/wiki/Archive/XCP_FAQ_Dynamic_Memory_Control
http://wiki.xensource.com/wiki/Xen_Windows_GplPv

>
>I say this because the kernel 3.10 already contains the hotplug patch proposed by Daniel Kiper (https://lkml.org/lkml/2011/3/28/108).
>See ./drivers/xen/balloon.c in the linux kernel source (lines between the CONFIG_XEN_BALLOON_MEMORY_HOTPLUG macro).
>
>Cheers,
>
>S.
>
>>Hello,
>>
>>I'm using Xen 4.4.3 under Fedora 21 (kernel 4.1.13 x86_64).
>>
>>All my virtual machines run CentOS 7 (kernel 3.10 x86_64) as HVM and start with overcommitted memory:
>> builder="hvm"
>> maxmem=8192
>> memory=6144
>>
>>I would like to know what techniques Xen uses to change the memory allocation of a virtual machine, when I run commands like these:
>>
>>Memory decrease:
>>$ xl mem-set foo 4096m
>>
>>Memory increase:
>>
>>$ xl mem-set foo 7168m
>>
>>On the Web, I found different posts talking about techniques like memory ballooning and memory hotplug.
>>But I don't understand what techniques my version of Xen actually uses, since some posts are very outdated and other seems related to unstable versions of Xen.
>>
>>How can I find it out?
>>
>>
>>Thank you very much for your help.
>>
>>
>>Best,
>>
>>S.
>
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Re: [Xen-users] Memory allocation with Xen