(2012/12/30 15:02), Wen Congyang wrote:

At 12/28/2012 08:28 AM, Kamezawa Hiroyuki Wrote:

quoted

(2012/12/27 21:16), Wen Congyang wrote:

quoted

At 12/26/2012 11:55 AM, Kamezawa Hiroyuki Wrote:

quoted

(2012/12/24 21:09), Tang Chen wrote:

quoted

From: Wen Congyang <redacted>

We call hotadd_new_pgdat() to allocate memory to store node_data. So we
should free it when removing a node.

Signed-off-by: Wen Congyang <redacted>

I'm sorry but is it safe to remove pgdat ? All zone cache and zonelists are
properly cleared/rebuilded in synchronous way ? and No threads are visinting
zone in vmscan.c ?

We have rebuilt zonelists when a zone has no memory after offlining some pages.

How do you guarantee that the address of pgdat/zone is not on stack of any kernel
threads or other kernel objects without reference counting or other syncing method ?

No way to guarentee this. But, the kernel should not use the address of pgdat/zone when
it is offlined.

Hmm, what about this: reuse the memory when the node is onlined again?

That's the only way which we can go now. Please don't free it.

Thanks,
-Kame