4101 metaslab_debug should allow for fine-grained control
4102 space_maps should store more information about themselves
4103 space map object blocksize should be increased
4104 ::spa_space no longer works
4105 removing a mirrored log device results in a leaked object
4106 asynchronously load metaslab
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Sebastien Roy <seb@delphix.com>

*** 18,28 ****
   *
   * CDDL HEADER END
   */
  
  /*
!  * Copyright (c) 2012 by Delphix. All rights reserved.
   * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
   * Copyright (c) 2013, Joyent, Inc. All rights reserved.
   */
  
  #ifndef _ZFEATURE_COMMON_H
--- 18,28 ----
   *
   * CDDL HEADER END
   */
  
  /*
!  * Copyright (c) 2013 by Delphix. All rights reserved.
   * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
   * Copyright (c) 2013, Joyent, Inc. All rights reserved.
   */
  
  #ifndef _ZFEATURE_COMMON_H
*** 54,63 ****
--- 54,64 ----
  enum spa_feature {
          SPA_FEATURE_ASYNC_DESTROY,
          SPA_FEATURE_EMPTY_BPOBJ,
          SPA_FEATURE_LZ4_COMPRESS,
          SPA_FEATURE_MULTI_VDEV_CRASH_DUMP,
+         SPA_FEATURE_SPACEMAP_HISTOGRAM,
          SPA_FEATURES
  } spa_feature_t;
  
  extern zfeature_info_t spa_feature_table[SPA_FEATURES];