Matt Ahrens' review comments, round 3.

1) Removed the first-fit allocator.
2) Moved the autotrim metaslab scheduling logic into vdev_auto_trim.
2a) As a consequence of #2, metaslab_trimset_t was rendered superfluous. New
   trimsets are simple range_tree_t's.
3) Made ms_trimming_ts remove extents it is working on from ms_tree and then
   add them back in.
3a) As a consequence of #3, undone all the direct changes to the allocators and
   removed metaslab_check_trim_conflict and range_tree_find_gap.

Porting Notes:
* Removed WITH_*_ALLOCATOR macros and aligned remaining allocations
  with OpenZFS.  Unused wariables warnings resolved with the gcc
  __attribute__ ((unused__ keyword.
* Added missing calls for ms_condensing_cv.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Requires-builders: none

include/sys/metaslab.h

@@ -57,7 +57,7 @@ void metaslab_sync(metaslab_t *, uint64_t);
 void metaslab_sync_done(metaslab_t *, uint64_t);
 void metaslab_sync_reassess(metaslab_group_t *);
 uint64_t metaslab_block_maxsize(metaslab_t *);
-void metaslab_auto_trim(metaslab_t *, uint64_t, boolean_t);
+void metaslab_auto_trim(metaslab_t *, boolean_t);
 uint64_t metaslab_trim_mem_used(metaslab_t *);
 
 /*

include/sys/metaslab_impl.h

@@ -279,11 +279,6 @@ struct metaslab_group {
 	kcondvar_t		mg_ms_initialize_cv;
 };
 
-typedef struct {
-	uint64_t	ts_birth;	/* TXG at which this trimset starts */
-	range_tree_t	*ts_tree;	/* tree of extents in the trimset */
-} metaslab_trimset_t;
-
 /*
  * This value defines the number of elements in the ms_lbas array. The value
  * of 64 was chosen as it covers all power of 2 buckets up to UINT64_MAX.
@@ -358,10 +353,10 @@ struct metaslab {
 	range_tree_t	*ms_allocating[TXG_SIZE];
 	range_tree_t	*ms_allocatable;
 
-	metaslab_trimset_t *ms_cur_ts;	/* currently prepared trims */
-	metaslab_trimset_t *ms_prev_ts;	/* previous (aging) trims */
+	range_tree_t	*ms_cur_ts;		/* currently prepared trims */
+	range_tree_t	*ms_prev_ts;		/* previous (aging) trims */
 	kcondvar_t	ms_trim_cv;
-	metaslab_trimset_t *ms_trimming_ts;
+	range_tree_t	*ms_trimming_ts;	/* in flight trims */
 
 	/*
 	 * The following range trees are accessed only from syncing context.

include/sys/range_tree.h

@@ -95,7 +95,6 @@ void range_tree_resize_segment(range_tree_t *rt, range_seg_t *rs,
     uint64_t newstart, uint64_t newsize);
 boolean_t range_tree_contains_part(range_tree_t *rt, uint64_t start,
     uint64_t size);
-uint64_t range_tree_find_gap(range_tree_t *rt, uint64_t start, uint64_t size);
 uint64_t range_tree_space(range_tree_t *rt);
 boolean_t range_tree_is_empty(range_tree_t *rt);
 void range_tree_verify(range_tree_t *rt, uint64_t start, uint64_t size);