Hi, I am trying to hotplug/offline sections of memory on a Power machine. I boot the kernel with kernelcore=1G commandline parameter. I see that except for 512MB, the rest of the memory is movable. When trying to do hot-remove, I notice that I am unable to remove the very last section of memory, one with the highest physical address. It is always marked as non-movable. With some debugging I found that that section has reserved pages. On instrumenting the memblock_reserve() and reserve_bootmem() routines, I can see that many of the memory areas are reserved for kernel and initrd by the memblock reserve() itself. reserve_bootmem then looks at the pages already reserved and marks them reserved. However, for the very last section, I see that bootmem reserves it but I am unable to find a corresponding reservation by the memblock code. memblock_reserve: start 0 size 3519 reserve_bootmem 0 dbf000 nid=0 memblock_reserve: start 12096 size 15372 reserve_bootmem 2f40000 ccc000 nid=0 memblock_reserve: start 15628 size 15650 reserve_bootmem 3d0c000 16000 nid=0 ... ... memblock_reserve: start 1982455 size 1982464 reserve_bootmem 1e3ff7c00 8400 nid=0 reserve_bootmem 3d7f64000 3f000 nid=1 reserve_bootmem 3d7fa3c00 48400 nid=1 reserve_bootmem 3d7feeda8 11258 nid=1 .. Is it a known behavior on Power ? If yes, for what purpose is the memory in the higher address reserved for ? I have seen that even if the system has multiple nodes, only the very last section of the last node is not removable. -- Regards, Ankita Garg (ankita@xxxxxxxxxx) Linux Technology Center IBM India Systems & Technology Labs, Bangalore, India -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>