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? Thanks Wen Congyang > > > 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>