Top wait latch free

This morning, our production system is brought down to its knees. Kernel was running 70% and the load at times was hit into 40s and 70s from OS top statistics. It pretty much kick everyone out of the session, and even I can't login to the database to do system query and try to find things. Ten minutes later when the system back to normal, I ran AWR report. The top wait shows latch free.

             Snap Id      Snap Time      Sessions Curs/Sess
            --------- ------------------- -------- ---------
Begin Snap:     31016 30-Jul-12 10:00:28     2,614      17.0
  End Snap:     31017 30-Jul-12 11:03:12     1,941      21.5
   Elapsed:               62.72 (mins)
   DB Time:            1,101.42 (mins)

Cache Sizes
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