Re: [patch] slab: add memory hotplug support

David Rientjes
2010-03-02T21:03:13Z

On Tue, 2 Mar 2010, Christoph Lameter wrote:

>
> Not sure how this would sync with slab use during node bootstrap and
> shutdown. Kame-san?
>

All the nodelist allocation and initialization is done during
MEM_GOING_ONLINE, so there should be no use of them until that
notification cycle is done and it has graduated to MEM_ONLINE: if there
are, there're even bigger problems because zonelist haven't even been
built for that pgdat yet. I can only speculate, but since Andi's
patchset did all this during MEM_ONLINE, where the bit is already set in
node_states[N_HIGH_MEMORY] and is passable to kmalloc_node(), this is
probably why additional hacks had to be added elsewhere.

Other than that, concurrent kmem_cache_create() is protected by
cache_chain_mutex.