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>

*** 21,30 ****
--- 21,34 ----
  /*
   * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
+ /*
+  * Copyright (c) 2013 by Delphix. All rights reserved.
+  */
+ 
  #include <sys/zfs_context.h>
  #include <sys/dnode.h>
  #include <sys/dmu_objset.h>
  #include <sys/dmu_zfetch.h>
  #include <sys/dmu.h>
*** 285,295 ****
          uint64_t        i;
  
          fetchsz = dmu_zfetch_fetchsz(dn, blkid, nblks);
  
          for (i = 0; i < fetchsz; i++) {
!                 dbuf_prefetch(dn, blkid + i);
          }
  
          return (fetchsz);
  }
  
--- 289,299 ----
          uint64_t        i;
  
          fetchsz = dmu_zfetch_fetchsz(dn, blkid, nblks);
  
          for (i = 0; i < fetchsz; i++) {
!                 dbuf_prefetch(dn, blkid + i, ZIO_PRIORITY_ASYNC_READ);
          }
  
          return (fetchsz);
  }