On Mon, 2007-05-14 at 12:44 -0700, Andrew Morton wrote: > On Mon, 14 May 2007 11:12:24 -0500 > Matt Mackall <[EMAIL PROTECTED]> wrote: > > > If I understand this correctly: > > > > privileged thread unprivileged greedy process > > kmem_cache_alloc(...) > > adds new slab page from lowmem pool > > do_io() > > kmem_cache_alloc(...) > > kmem_cache_alloc(...) > > kmem_cache_alloc(...) > > kmem_cache_alloc(...) > > kmem_cache_alloc(...) > > ... > > eats it all > > kmem_cache_alloc(...) -> ENOMEM > > who ate my donuts?! > > Yes, that's my understanding also. > > I can see why it's a problem in theory, but I don't think Peter has yet > revealed to us why it's a problem in practice. I got all excited when > Christoph asked "I am not sure what the point of all of this is.", but > Peter cunningly avoided answering that ;) > > What observed problem is being fixed here?
I'm moving towards swapping over networked storage. Admittedly a new feature. Like with pretty much all other swap solutions; there is the fundamental vm deadlock: freeing memory requires memory. Current block devices get around that by using mempools. This works well. However with network traffic mempools are not easily usable; the network stack uses kmalloc. By using reserve based allocation we can keep operating in a similar matter. - 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/
