11909 THREAD_KPRI_RELEASE does nothing of the sort
Reviewed by: Bryan Cantrill <bryan@joyent.com>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>

*** 201,211 ****
          ushort_t        t_oldspl;       /* spl level before dispatcher locked */
          volatile char   t_pre_sys;      /* pre-syscall work needed */
          lock_t          t_lock_flush;   /* for lock_mutex_flush() impl */
          struct _disp    *t_disp_queue;  /* run queue for chosen CPU */
          clock_t         t_disp_time;    /* last time this thread was running */
-         uint_t          t_kpri_req;     /* kernel priority required */
  
          /*
           * Post-syscall / post-trap flags.
           *      No lock is required to set these.
           *      These must be cleared only by the thread itself.
--- 201,210 ----
*** 606,629 ****
  #endif  /* _KERNEL */
  
  #define THREAD_NAME_MAX 32      /* includes terminating NUL */
  
  /*
-  * Macros to indicate that the thread holds resources that could be critical
-  * to other kernel threads, so this thread needs to have kernel priority
-  * if it blocks or is preempted.  Note that this is not necessary if the
-  * resource is a mutex or a writer lock because of priority inheritance.
-  *
-  * The only way one thread may legally manipulate another thread's t_kpri_req
-  * is to hold the target thread's thread lock while that thread is asleep.
-  * (The rwlock code does this to implement direct handoff to waiting readers.)
-  */
- #define THREAD_KPRI_REQUEST()   (curthread->t_kpri_req++)
- #define THREAD_KPRI_RELEASE()   (curthread->t_kpri_req--)
- #define THREAD_KPRI_RELEASE_N(n) (curthread->t_kpri_req -= (n))
- 
- /*
   * Macro to change a thread's priority.
   */
  #define THREAD_CHANGE_PRI(t, pri) {                                     \
          pri_t __new_pri = (pri);                                        \
          DTRACE_SCHED2(change__pri, kthread_t *, (t), pri_t, __new_pri); \
--- 605,614 ----