16203 zfs: switch refcount tracking from lists to AVL-trees

Reviewed by: Andy Fiddaman <illumos@fiddaman.net>
Reviewed by: Bill Sommerfeld <sommerfeld@hamachi.org>
Reviewed by: Toomas Soome <tsoome@me.com>
Approved by: Dan McDonald <danmcd@mnx.io>

usr/src/cmd/mdb/common/modules/zfs/zfs.c

@@ -23,6 +23,7 @@
  * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
  * Copyright (c) 2011, 2018 by Delphix. All rights reserved.
  * Copyright 2020 Joyent, Inc.
+ * Copyright 2024 Oxide Computer Company
  */
 
 /* Portions Copyright 2010 Robert Milkowski */
@@ -3325,7 +3326,7 @@ typedef struct mdb_zfs_refcount {
 } mdb_zfs_refcount_t;
 
 typedef struct mdb_zfs_refcount_removed {
-	uint64_t rc_removed_count;
+	uint_t rc_removed_count;
 } mdb_zfs_refcount_removed_t;
 
 typedef struct mdb_zfs_refcount_tracked {
@@ -3373,18 +3374,18 @@ zfs_refcount(uintptr_t addr, uint_t flags, int argc, const mdb_arg_t *argv)
 
 	if (rct.rc_tracked && rc.rc_count > 0)
 		mdb_printf("current holds:\n");
-	off = mdb_ctf_offsetof_by_name("zfs_refcount_t", "rc_list");
+	off = mdb_ctf_offsetof_by_name("zfs_refcount_t", "rc_tree");
 	if (off == -1)
 		return (DCMD_ERR);
-	mdb_pwalk("list", reference_cb, (void*)B_FALSE, addr + off);
+	mdb_pwalk("avl", reference_cb, (void *)B_FALSE, addr + off);
 
 	if (released && rcr.rc_removed_count > 0) {
 		mdb_printf("released holds:\n");
 
 		off = mdb_ctf_offsetof_by_name("zfs_refcount_t", "rc_removed");
 		if (off == -1)
 			return (DCMD_ERR);
-		mdb_pwalk("list", reference_cb, (void*)B_TRUE, addr + off);
+		mdb_pwalk("list", reference_cb, (void *)B_TRUE, addr + off);
 	}
 
 	return (DCMD_OK);

usr/src/lib/libzpool/common/sys/zfs_context.h

@@ -293,6 +293,7 @@ extern vnode_t *rootdir;
 #endif
 
 #define	likely(x)	_zfs_expect((x) != 0, 1)
+#define	unlikely(x)	_zfs_expect((x) != 0, 0)
 
 #define	CPU_SEQID	(thr_self() & (max_ncpus - 1))