On 02/21/2013 02:47 PM, Cody P Schafer wrote: > Yes, this is late. Sorry. > > I'd like to discuss the following topic: I'd be interested in discussing this as well (no code at the moment, but I at the least I could contribute experiences on how the HP-UX memory management system handles this if invited). Thanks, Don Morris > > -- > > Presently, NUMA layout is determined at boot time and never changes again. > This setup works for real hardware, but virtual machines are more dynamic: > they could be migrated between different hosts, and have to share the physical > memory space with other VMs which are also being moved around or shut down > while other new VMs are started up. As a result, the physical backing memory > that a VM had when it started up changes at runtime. > > Problems to be overcome: > > - How should userspace be notified? Do we need new interfaces so > applications can query memory to see if it was affected? > > - Can we make the NUMA layout initialization generic? This also > implies that all initialization of struct zone/struct > page/NODE_DATA() would be made (somewhat) generic. > > - Some one-time allocations now will know they are on a non-optimal > node. > > - hotpluged per node data is (in general) not being allocated optimally) > > - NODE_DATA() for hotpluged nodes is allocated off-node (except for > ia64). > > - SLUB's kmem_cache_node is always allocated off-node for > hotpluged nodes. > > [Not a new problem, but one that needs solving]. > > Some more generic NUMA layout/mm init things: > > - boot-time and hotplug NUMA init don't share enough code. > > - architectures do not share mm init code > > - NUMA layout (from init) is kept (if it is kept at all) in only arch > specific ways. Memblock _happens_ to contain this info, while also > also tracking allocations, and every arch but powerpc discards it as > __init/__initdata) > > A WIP patchset addressing initial reconfiguration of the page allocator: > https://github.com/jmesmon/linux/tree/dnuma/v25 > > -- > Cody P Schafer > > -- > 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> > . > -- 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>