Re: [Qemu-devel] [PATCH 4/4] Reallocate dma buffers in read/write path if needed

[Paul Brook]

On Saturday 04 October 2008, Ryan Harper wrote:
> In all, it seems silly to worry about this sort of thing since the
> entire process could be contained with process ulimits if this is really
> a concern.  Are we any more concerned that by splitting the requests
> into many smaller requests that we're wasting cpu, pegging the
> processor to 100% in some cases?

Using small requests may be a bit inefficient, but it still works and allows 
the guest to make progress.

Allocating very large quantities of memory is very likely to kill the VM one 
way or another. This is not acceptable, especially when the guest hasn't even 
done anything wrong. There are legitimate circumstances where the size of the 
outstanding IO requests may be comparable to the guest ram size.

Paul