%     Registration                     Hotplug Memory Redux                   
%  [2]Register/Submit Joel H Schopp (jschopp@austin.ibm.com)                  

Memory Hotplug is one of the most anticipated features  
in the Linux Kernel. The purpose of memory hotplug is   
memory replacement, dynamic workload management, or     
Capacity on Demand of Partitioned/Virtual machines. In  
this paper we discusses the history of Memory Hotplug   
and the LinuxVM including mistakes made along the way   
and technologies which have already been replaced. We   
also discuss the current state of the art in Memory     
Hotplug including user interfaces, \ident{CONFIG_SPARSEMEM},    
the no bitmap buddy allocator, free area splitting      
within zones, and memory migration on PPC64, x86-64,    
and IA64. Additionally, we give a brief discussion on   
the overlap between Memory Hotplug and other areas      
including memory defragmentation and NUMA memory        
management. Finally, we gaze into the crystal ball to   
the future of Memory Hotplug.