On Mon, Jun 12, 2017 at 08:45:02AM +0200, Michal Hocko wrote: >On Mon 12-06-17 12:28:32, Wei Yang wrote: >> On Thu, Jun 08, 2017 at 02:23:18PM +0200, Michal Hocko wrote: >> >From: Michal Hocko <mhocko@xxxxxxxx> >> > >> >movable_node kernel parameter allows to make hotplugable NUMA >> >nodes to put all the hotplugable memory into movable zone which >> >allows more or less reliable memory hotremove. At least this >> >is the case for the NUMA nodes present during the boot (see >> >find_zone_movable_pfns_for_nodes). >> > >> >> When movable_node is enabled, we would have overlapped zones, right? > >It won't based on this patch. See movable_pfn_range > Ok, I went through the code and here maybe a question not that close related to this patch. I did some experiment with qemu+kvm and see this. Guest config: 8G RAM, 2 nodes with 4G on each Guest kernel: 4.11 Guest kernel command: kernelcore=1G The log message in kernel is: [ 0.000000] Zone ranges: [ 0.000000] DMA [mem 0x0000000000001000-0x0000000000ffffff] [ 0.000000] DMA32 [mem 0x0000000001000000-0x00000000ffffffff] [ 0.000000] Normal [mem 0x0000000100000000-0x000000023fffffff] [ 0.000000] Movable zone start for each node [ 0.000000] Node 0: 0x0000000100000000 [ 0.000000] Node 1: 0x0000000140000000 We see on node 2, ZONE_NORMAL overlap with ZONE_MOVABLE. [0x0000000140000000 - 0x000000023fffffff] belongs to both ZONE. My confusion is: After we enable ZONE_MOVABLE, no matter whether it is enabled by "movable_node" or "kernelcore", we would face this kind of overlap? Finally, the pages in the overlapped range be belongs to which ZONE? -- Wei Yang Help you, Help me
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