[ruby-cvs:78310] 8e743fad4e (master): Count pinned slots using only bitmap

John Hawthorn	2019-11-22 04:05:48 +0900 (Fri, 22 Nov 2019)

  New Revision: 8e743fad4e

  https://github.com/ruby/ruby/commit/8e743fad4e

  Log:
    Count pinned slots using only bitmap
    
    This is significantly faster than checking BUILTIN_TYPEs because we
    access significantly less memory. We also use popcount to count entire
    words at a time.
    
    The only functional difference from the previous implementation is that
    T_ZOMBIE objects will no longer be counted. However those are temporary
    objects which should be small in number, and this method has always been
    an estimate.

  Modified files:
    gc.c