Re: The performance and behaviour of the anti-fragmentation relatedpatches

[Paul Mackerras]

Linus Torvalds writes:

> The point being that in the guests, hotunplug is almost useless (for 
> bigger ranges), and we're much better off just telling the virtualization 
> hosts on a per-page level whether we care about a page or not, than to 
> worry about fragmentation.

We don't have that luxury on IBM System p machines, where the
hypervisor manages memory in much larger units than a page.  Typically
the size of memory block that the hypervisor uses to manage memory is
16MB or more -- which makes sense from the point of view that if the
hypervisor had to manage individual pages, it would end up adding a
lot more overhead than it does.

Paul.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/