linux-drf:/sys/devices/system/memory/memory0 # cat * 8000000000000000
cat: node0: Is a directory
cat: node1: Is a directory
cat: node2: Is a directory
cat: node3: Is a directory
0 8000000000000000
cat: power: Is a directory
1
online
cat: subsystem: Is a directory
And "echo offline > memory0/state" will cause following call trace:
kernel BUG at mm/memory_hotplug.c:885!
sh[6455]: bugcheck! 0 [1]