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>

@@ -21,11 +21,11 @@
 /*
  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 /*
- * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  */
 
 #ifndef _SYS_DMU_TX_H
 #define _SYS_DMU_TX_H
 

@@ -58,12 +58,26 @@
         uint64_t tx_lastsnap_txg;
         uint64_t tx_lasttried_txg;
         txg_handle_t tx_txgh;
         void *tx_tempreserve_cookie;
         struct dmu_tx_hold *tx_needassign_txh;
-        list_t tx_callbacks; /* list of dmu_tx_callback_t on this dmu_tx */
-        uint8_t tx_anyobj;
+
+        /* list of dmu_tx_callback_t on this dmu_tx */
+        list_t tx_callbacks;
+
+        /* placeholder for syncing context, doesn't need specific holds */
+        boolean_t tx_anyobj;
+
+        /* has this transaction already been delayed? */
+        boolean_t tx_waited;
+
+        /* time this transaction was created */
+        hrtime_t tx_start;
+
+        /* need to wait for sufficient dirty space */
+        boolean_t tx_wait_dirty;
+
         int tx_err;
 #ifdef ZFS_DEBUG
         uint64_t tx_space_towrite;
         uint64_t tx_space_tofree;
         uint64_t tx_space_tooverwrite;