cvs commit: src/sys/sys kse.h src/sys/kern kern_thread.c

[David Xu]

davidxu     2003/04/21 00:28:00 PDT

  FreeBSD src repository

  Modified files:
    sys/sys              kse.h 
    sys/kern             kern_thread.c 
  Log:
  Introduce two flags to control upcall behaviour:
  
  o KMF_NOUPCALL
          Ask kse_release to not return to userland upcall entry, but instead
          direct returns to userland by using current thread's stack and return
          address on stack. This flags is intended to be used by UTS in critical
          region to wait another UTS thread to leave critical region, by using
          kse_release with this flag to avoid spinnng and burning CPU. Also this
          flags can be used by UTS to poll completed context when there is nothing
          to do in userland and needn't restart from its entry like normal upcall.
  
  o KMF_NOCOMPLETED
          Ask kernel to not bring completed thread contexts back to userland when
          doing upcall, this flags is intend to be used with above flag when an
          upcall thread is in critical region and can not process completed contexts
          at that time.
  
  Tested by: deischen
  
  Revision  Changes    Path
  1.120     +36 -51    src/sys/kern/kern_thread.c
  1.13      +4 -0      src/sys/sys/kse.h