On Fri, 12 Jan 2007, Nick Piggin wrote: > > Yeah *smallish* higher order allocations are fine, and we use them all the > time for things like stacks or networking. > > But Aubrey (who somehow got removed from the cc list) wants to do order 9 > allocations from userspace in his nommu environment. I'm just trying to be > realistic when I say that this isn't going to be robust and a userspace > solution is needed.
I do agree that order-9 allocations simply is unlikely to work without some pre-allocation notion or some serious work at active de-fragmentation (and the page cache is likely to be the _least_ of the problems people will hit - slab and other kernel allocations are likely to be much much harder to handle, since you can't free them in quite as directed a manner). But for smallish-order (eg perhaps 3-4 possibly even more if you are careful in other places), the page cache limiter may well be a "good enough" solution in practice, especially if other allocations can be controlled by strict usage patterns (which is not realistic in a general- purpose kind of situation, but might be realistic in embedded). Linus - 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/