On Tue, 2 Oct 2007 00:43:24 -0700 Andrew Morton <[EMAIL PROTECTED]> wrote:
> On Tue, 2 Oct 2007 16:36:24 +0900 KAMEZAWA Hiroyuki <[EMAIL PROTECTED]> > > > Don't think so. A node is a lump of circuitry which can have zero or more > > > CPUs, IO and memory. > > > > > > It may initially have been conceived as a memory-only concept in the Linux > > > kernel, but that doesn't fully map onto reality (does it?) > > > > > > There was a real-world need for this, I think from the Fujitsu guys. That > > > should be spelled out in the changelog but isn't. > > > > Yes, Fujitsu and HP guys really need this memory-less-node support. > > > > For what reason, please? > For fujitsu, problem is called "empty" node. When ACPI's SRAT table includes "possible nodes", ia64 bootstrap(acpi_numa_init) creates nodes, which includes no memory, no cpu. I tried to remove empty-node in past, but that was denied. It was because we can hot-add cpu to the empty node. (node-hotplug triggered by cpu is not implemented now. and it will be ugly.) For HP, (Lee can comment on this later), they have memory-less-node. As far as I hear, HP's machine can have following configration. (example) Node0: CPU0 memory AAA MB Node1: CPU1 memory AAA MB Node2: CPU2 memory AAA MB Node3: CPU3 memory AAA MB Node4: Memory XXX GB AAA is very small value (below 16MB) and will be omitted by ia64 bootstrap. After boot, only Node 4 has valid memory (but have no cpu.) Maybe this is memory-interleave by firmware config. Thanks, -Kame - 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/
