Fix bug 466: race condition destected by helgrind in manage_caching_sizes. After all, the solution based on threadprivate is not that costly.
Fix bug 466: race condition destected by helgrind in manage_caching_sizes.
After all, the solution based on threadprivate is not that costly.

pthulhu/eigen,cjntaylor/eigen,cjntaylor/eigen,pthulhu/eigen,cjntaylor/eigen,pthulhu/eigen,cjntaylor/eigen,pthulhu/eigen,pthulhu/eigen