[Xen-users] Re: Memory resizing

[Jiri Denemark <jirka@xxxxxxxxxxx>]

Thanks for explaining how the balloon driver actually works.

> What's really going on here, is that you create a domain with 7800MB, and
> then the balloon driver tells the kernel that it's allocated (7800-160)MBs.
> The kernel really doesn't know that the balloon driver gave that memory back
> to Xen--it just thinks it's a greedy kernel module.
So the kernel still has 7800MB of memory, (7800-160)MBs eaten up by balloon
driver and 160MBs available to userspace, right? In that case, it seems it's
rather an issue of VM subsystem in Linux.

It's strange the kernel is not willing to swap out a process and kills it even
if there is enough free swap space. But I guess that's somehow connected with
those (7800-160)MBs "held" by ballon driver which kernel cannot swap out.
Anyway it would be nice if the kernel could behave in exactly the same way
regardless of whether a domain is started with limited memory or its memory is
ballooned down.

I wonder if playing with altering kernel's swappiness would help in that... I
tried to make 8GB swap but that didn't help much.

Jirka

-- 
The reason computer chips are so small is computers don't eat much.

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users