(2012/12/30 15:02), Wen Congyang wrote: > At 12/28/2012 08:28 AM, Kamezawa Hiroyuki Wrote: >> (2012/12/27 21:16), Wen Congyang wrote: >>> At 12/26/2012 11:55 AM, Kamezawa Hiroyuki Wrote: >>>> (2012/12/24 21:09), Tang Chen wrote: >>>>> From: Wen Congyang <wency@xxxxxxxxxxxxxx> >>>>> >>>>> 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 <wency@xxxxxxxxxxxxxx> >>>> >>>> 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>