[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] A tale of three memory allocators
This should be a good meaty developers discussion, full of opinions. I'm far from an expert in this area and hereby solicit help. Once upon a time there was the Xen simplified memory allocator, written by Keir. When Dan (the ia64 man) looked at this allocator for Xen/ia64, he was very displeased. "Ia64 has a much more complex physical memory architecture than x86," he said. "For example, physical memory space is often not contiguous, and what about the cool NUMA stuff that is in Linux 2.6?" So Dan took the Linux memory allocation code, hacked on it mightily, adding numerous ugly ifdefs and used the result in place of Keir's code for Xen/ia64. The result works, but is truly an abomination. Some time later, Rusty looked at Keir's code and too was displeased. He rewrote it to be much cleaner and more simplified, much to Keir's delight. And this code was placed in common, still to be ignored by Xen/ia64. Now Arun gazed upon the ugly Xen/ia64 memory allocator full of ifdefs and was much dismayed. He preferred Rusty's code and, even better, sharing more code with Xen/x86, so he busily generated a patch for Xen/ia64 to use the common code. Said patch is still pending because coincidentally Greg is currently looking at porting Xen/ia64 to one of those newfangled ia64 NUMA machines. "I would like to turn on CONFIG_NUMA. CONFIG_DISCONTIGMEM, and CONFIG_VIRTUAL_MEM_MAP," said Greg. What should Dan (the ia64 man) do??? How complex is too complex? How ugly is too ugly? This concludes (for now) the tale of three memory allocators... (please respond/discuss :-) ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_ide95&alloc_id396&op=click _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/xen-devel
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