zfs_arc_num_sublists_per_state should be common to all multilists

The global tunable zfs_arc_num_sublists_per_state is used by the ARC and
the dbuf cache, and other users are planned. We should change this
tunable to be common to all multilists.  This tuning may be overridden
on a per-multilist basis.

Reviewed-by: Pavel Zakharov <[email protected]>
Reviewed-by: Dan Kimmel <[email protected]>
Reviewed-by: Tony Hutter <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Matthew Ahrens <[email protected]>
Closes #5764 

1 files changed, 11 insertions, 25 deletions

diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 1495b0891..9fac5a6c4 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -21,7 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
- * Copyright (c) 2011, 2016 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2017 by Delphix. All rights reserved.
  * Copyright (c) 2014 by Saso Kiselkov. All rights reserved.
  * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
  */
@@ -307,13 +307,6 @@ static kcondvar_t	arc_reclaim_waiters_cv;
  */
 int zfs_arc_evict_batch_limit = 10;
 
-/*
- * The number of sublists used for each of the arc state lists. If this
- * is not set to a suitable value by the user, it will be configured to
- * the number of CPUs on the system in arc_init().
- */
-int zfs_arc_num_sublists_per_state = 0;
-
 /* number of seconds before growing cache again */
 static int		arc_grow_retry = 5;
 
@@ -6285,43 +6278,43 @@ arc_state_init(void)
 	multilist_create(&arc_mru->arcs_list[ARC_BUFC_METADATA],
 	    sizeof (arc_buf_hdr_t),
 	    offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
-	    zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
+	    arc_state_multilist_index_func);
 	multilist_create(&arc_mru->arcs_list[ARC_BUFC_DATA],
 	    sizeof (arc_buf_hdr_t),
 	    offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
-	    zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
+	    arc_state_multilist_index_func);
 	multilist_create(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA],
 	    sizeof (arc_buf_hdr_t),
 	    offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
-	    zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
+	    arc_state_multilist_index_func);
 	multilist_create(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA],
 	    sizeof (arc_buf_hdr_t),
 	    offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
-	    zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
+	    arc_state_multilist_index_func);
 	multilist_create(&arc_mfu->arcs_list[ARC_BUFC_METADATA],
 	    sizeof (arc_buf_hdr_t),
 	    offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
-	    zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
+	    arc_state_multilist_index_func);
 	multilist_create(&arc_mfu->arcs_list[ARC_BUFC_DATA],
 	    sizeof (arc_buf_hdr_t),
 	    offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
-	    zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
+	    arc_state_multilist_index_func);
 	multilist_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA],
 	    sizeof (arc_buf_hdr_t),
 	    offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
-	    zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
+	    arc_state_multilist_index_func);
 	multilist_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA],
 	    sizeof (arc_buf_hdr_t),
 	    offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
-	    zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
+	    arc_state_multilist_index_func);
 	multilist_create(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA],
 	    sizeof (arc_buf_hdr_t),
 	    offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
-	    zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
+	    arc_state_multilist_index_func);
 	multilist_create(&arc_l2c_only->arcs_list[ARC_BUFC_DATA],
 	    sizeof (arc_buf_hdr_t),
 	    offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node),
-	    zfs_arc_num_sublists_per_state, arc_state_multilist_index_func);
+	    arc_state_multilist_index_func);
 
 	refcount_create(&arc_anon->arcs_esize[ARC_BUFC_METADATA]);
 	refcount_create(&arc_anon->arcs_esize[ARC_BUFC_DATA]);
@@ -6452,9 +6445,6 @@ arc_init(void)
 	/* Apply user specified tunings */
 	arc_tuning_update();
 
-	if (zfs_arc_num_sublists_per_state < 1)
-		zfs_arc_num_sublists_per_state = MAX(boot_ncpus, 1);
-
 	/* if kmem_flags are set, lets try to use less memory */
 	if (kmem_debugging())
 		arc_c = arc_c / 2;
@@ -7745,10 +7735,6 @@ MODULE_PARM_DESC(zfs_compressed_arc_enabled, "Disable compressed arc buffers");
 module_param(zfs_arc_min_prefetch_lifespan, int, 0644);
 MODULE_PARM_DESC(zfs_arc_min_prefetch_lifespan, "Min life of prefetch block");
 
-module_param(zfs_arc_num_sublists_per_state, int, 0644);
-MODULE_PARM_DESC(zfs_arc_num_sublists_per_state,
-	"Number of sublists used in each of the ARC state lists");
-
 module_param(l2arc_write_max, ulong, 0644);
 MODULE_PARM_DESC(l2arc_write_max, "Max write bytes per interval");