4045 zfs write throttle & i/o scheduler performance work
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>

*** 102,117 ****
  #ifdef ZFS_DEBUG
  int arc_referenced(arc_buf_t *buf);
  #endif
  
  int arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
!     arc_done_func_t *done, void *private, int priority, int flags,
      uint32_t *arc_flags, const zbookmark_t *zb);
  zio_t *arc_write(zio_t *pio, spa_t *spa, uint64_t txg,
      blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, boolean_t l2arc_compress,
!     const zio_prop_t *zp, arc_done_func_t *ready, arc_done_func_t *done,
!     void *private, int priority, int zio_flags, const zbookmark_t *zb);
  void arc_freed(spa_t *spa, const blkptr_t *bp);
  
  void arc_set_callback(arc_buf_t *buf, arc_evict_func_t *func, void *private);
  int arc_buf_evict(arc_buf_t *buf);
  
--- 102,118 ----
  #ifdef ZFS_DEBUG
  int arc_referenced(arc_buf_t *buf);
  #endif
  
  int arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
!     arc_done_func_t *done, void *private, zio_priority_t priority, int flags,
      uint32_t *arc_flags, const zbookmark_t *zb);
  zio_t *arc_write(zio_t *pio, spa_t *spa, uint64_t txg,
      blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, boolean_t l2arc_compress,
!     const zio_prop_t *zp, arc_done_func_t *ready, arc_done_func_t *physdone,
!     arc_done_func_t *done, void *private, zio_priority_t priority,
!     int zio_flags, const zbookmark_t *zb);
  void arc_freed(spa_t *spa, const blkptr_t *bp);
  
  void arc_set_callback(arc_buf_t *buf, arc_evict_func_t *func, void *private);
  int arc_buf_evict(arc_buf_t *buf);