the context is not actually stolen, as it would be for i386. Instead of
deactivating a user vmspace immediately when switching out, and recycling
its tlb context, wait until the next context switch to a different user
vmspace. In this way we can switch from a user process to any number of
kernel threads and back to the same user process again, without losing any
of its mappings in the tlb that would not already be knocked by the automatic
replacement algorithm. This is not expected to have a measurable performance
improvement on the machines we currently run on, but it sounds cool and makes
the sparc64 port SMPng buzz word compliant.
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