What: I want to add another member to mca_mpool_base_registration_t for mpools that need to keep track of extra context data.
Why: I plan to add a new mpool to support Cray's udreg registration cache. This new mpool will allow us to turn off the memory hooks on Cray systems. Unfortunately, in order to get the symantics right I need to keep track of the udreg context for the base registration. Originally, I subclassed the base registration and put the context in there but it makes switching mpools more awkward than it already is. I want to move this pointer down to the base registration as void *mpool_context for both trunk and 1.7.4 (the target for the new mpool). When: This is a small change and shouldn't have much impact on the code base but I would like some feedback on this change before committing it. Timeout set for next Tuesday around noon. -Nathan Hjelm HPC-5, LANL
