K 10
svn:author
V 3
avg
K 8
svn:date
V 27
2011-05-09T07:14:16.567988Z
K 7
svn:log
V 1251
re-implement smp rendezvous code

- create one rendezvous (outgoing) mailbox per each cpu where a cpu would
  place its rendezvous request directed to other cpus
- create a cpu mask for each cpu where other cpus can set a bit to indicate
  that they send a rendezvous request to the cpu in question
- send an ipi only for a first rv request, piggyback subsequent
  requests if a target cpu is still processing previous incoming requests
- many-to-many rv requests can be sent now, there is no locking, the only
  limitation is that a cpu can have only a single outgoing request at
  a time
- to avoid deadlocks, when a cpu waits for its requested to be completed
  by target cpus, it also checks for and processes incoming requests
- to avoid deadlock with cpu stopping logic, cpus also check for stop
  requests while waiting
- there can be only one cpu asking other cpus to stop; this is implemented
  via a handrolled spin mutex analogue; similar to the above, to avoid
  deadlocks a cpu spinning for this lock also checks for an incoming stop
  request
- implement tlb shootdowns via smp rendezvous mechanism, no special ipis
  are needed now, amd64 only (see if the code can be further simplified)
- thus the smp_ipi_mtx is not needed any longer

END