On Mon, 4 Dec 2006 11:41:42 -0800 (PST) Christoph Lameter <[EMAIL PROTECTED]> wrote:
> > That depends on how we do hot-unplug, if we do it. I continue to suspect > > that it'll be done via memory zones: effectively by resurrecting > > GFP_HIGHMEM. In which case there's little overlap with anti-frag. (btw, I > > have a suspicion that the most important application of memory hot-unplug > > will be power management: destructively turning off DIMMs). > > There are numerous other uses as well (besides DIMM and node unplug): > > 1. Faulty DIMM isolation > 2. Virtual memory managers can reduce memory without resorting to > balloons. > 3. Physical removal and exchange of memory while a system is running > (Likely necessary to complement hotplug cpu, cpus usually come > with memory). > > The multi zone approach does not work with NUMA. NUMA only supports a > single zone for memory policy control etc. Wot? memory policies are a per-vma thing? Plus NUMA of course supports more that a single zone. Perhaps you meant one zone per node. If you did, that's a pretty dumb-sounding restriction and I don't know where you got it from. > Also multiple zones carry with > it a management overhead that is unnecessary for the MOVABLE/UNMOVABLE > distinction. I suspect you'll have to live with that. I've yet to see a vaguely sane proposal to otherwise prevent unreclaimable, unmoveable kernel allocations from landing in a hot-unpluggable physical memory region. - 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/
