Re: [Xen-devel] Balloon driver and oom-killer

[Mark Williamson <mark.williamson@xxxxxxxxxxxx>]

>  I have used balloon driver in xen,and I am confused about the  meaning
> of "Improve interaction between balloon driver and page
>
> allocator to avoid memory crunch."in the roadmap,what does it mean exactly?
> does it mean to improve the performance of the balloon, or to add some
> other functionality ,or to make the guestos's memory size adapted
> automatically,or something else?

There have been some bad interactions with Linux's memory management code when 
using the balloon driver - particularly when using it aggressively to shrink 
a domain.  In this past, this has been known to cause the OOM killer to kick 
in when not strictly necessary and also has caused some issues with network 
IO when used in dom0.

The balloon driver just allocates loads of memory, and this seems to sometimes 
make Linux think that memory is running out, rather than understanding that 
the domain has been resized.  Ideally, we'd use some sort of memory hotplug 
interface to Linux to make the resizing explicit.

Cheers,
Mark

-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

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