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.
   */
  
  #ifdef _KERNEL
--- 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.
   */
  
  #ifdef _KERNEL
*** 162,167 ****
--- 162,170 ----
              "org.illumos:lz4_compress", "lz4_compress",
              "LZ4 compression algorithm support.", B_FALSE, B_FALSE, NULL);
          zfeature_register(SPA_FEATURE_MULTI_VDEV_CRASH_DUMP,
              "com.joyent:multi_vdev_crash_dump", "multi_vdev_crash_dump",
              "Crash dumps to multiple vdev pools.", B_FALSE, B_FALSE, NULL);
+         zfeature_register(SPA_FEATURE_SPACEMAP_HISTOGRAM,
+             "com.delphix:spacemap_histogram", "spacemap_histogram",
+             "Spacemaps maintain space histograms.", B_TRUE, B_FALSE, NULL);
  }