But if you don't require a lot of higher order allocations anyway, then guest fragmentation caused by ballooning doesn't seem like much problem.
If you only need to allocate 1 page size and smaller allocations then no it's not a problem. As soon as you go above that it will be. You don't need to go all the way up to MAX_ORDER size to see an impact, it's just increasingly more severe as you get away from 1 page and towards MAX_ORDER.
If you need higher order allocations, then ballooning is bad because of fragmentation, so you need memory unplug, so you need higher order allocations. Goto 1.
Yes, it's a closed loop. But hotplug isn't the only one that needs higher order allocations. In fact it's pretty far down the list. I look at it like this, a lot of users need high order allocations for better performance and things like on-demand hugepages. As a bonus you get memory hot-remove.
Balooning probably does skew memory management stats and watermarks, but that's just because it is implemented as a module. A couple of hooks should be enough to allow things to be adjusted?
That is a good idea independent of the current discussion. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
