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diff --git a/include/sys/multilist.h b/include/sys/multilist.h
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+/*
+ * CDDL HEADER START
+ *
+ * This file and its contents are supplied under the terms of the
+ * Common Development and Distribution License ("CDDL"), version 1.0.
+ * You may only use this file in accordance with the terms of version
+ * 1.0 of the CDDL.
+ *
+ * A full copy of the text of the CDDL should have accompanied this
+ * source. A copy of the CDDL is also available via the Internet at
+ * http://www.illumos.org/license/CDDL.
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2013, 2017 by Delphix. All rights reserved.
+ */
+
+#ifndef _SYS_MULTILIST_H
+#define _SYS_MULTILIST_H
+
+#include <sys/zfs_context.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef list_node_t multilist_node_t;
+typedef struct multilist multilist_t;
+typedef struct multilist_sublist multilist_sublist_t;
+typedef unsigned int multilist_sublist_index_func_t(multilist_t *, void *);
+
+struct multilist_sublist {
+ /*
+ * The mutex used internally to implement thread safe insertions
+ * and removals to this individual sublist. It can also be locked
+ * by a consumer using multilist_sublist_{lock,unlock}, which is
+ * useful if a consumer needs to traverse the list in a thread
+ * safe manner.
+ */
+ kmutex_t mls_lock;
+ /*
+ * The actual list object containing all objects in this sublist.
+ */
+ list_t mls_list;
+ /*
+ * Pad to cache line, in an effort to try and prevent cache line
+ * contention.
+ */
+} ____cacheline_aligned;
+
+struct multilist {
+ /*
+ * This is used to get to the multilist_node_t structure given
+ * the void *object contained on the list.
+ */
+ size_t ml_offset;
+ /*
+ * The number of sublists used internally by this multilist.
+ */
+ uint64_t ml_num_sublists;
+ /*
+ * The array of pointers to the actual sublists.
+ */
+ multilist_sublist_t *ml_sublists;
+ /*
+ * Pointer to function which determines the sublist to use
+ * when inserting and removing objects from this multilist.
+ * Please see the comment above multilist_create for details.
+ */
+ multilist_sublist_index_func_t *ml_index_func;
+};
+
+void multilist_destroy(multilist_t *);
+multilist_t *multilist_create(size_t, size_t, multilist_sublist_index_func_t *);
+
+void multilist_insert(multilist_t *, void *);
+void multilist_remove(multilist_t *, void *);
+int multilist_is_empty(multilist_t *);
+
+unsigned int multilist_get_num_sublists(multilist_t *);
+unsigned int multilist_get_random_index(multilist_t *);
+
+multilist_sublist_t *multilist_sublist_lock(multilist_t *, unsigned int);
+multilist_sublist_t *multilist_sublist_lock_obj(multilist_t *, void *);
+void multilist_sublist_unlock(multilist_sublist_t *);
+
+void multilist_sublist_insert_head(multilist_sublist_t *, void *);
+void multilist_sublist_insert_tail(multilist_sublist_t *, void *);
+void multilist_sublist_move_forward(multilist_sublist_t *mls, void *obj);
+void multilist_sublist_remove(multilist_sublist_t *, void *);
+int multilist_sublist_is_empty(multilist_sublist_t *);
+int multilist_sublist_is_empty_idx(multilist_t *, unsigned int);
+
+void *multilist_sublist_head(multilist_sublist_t *);
+void *multilist_sublist_tail(multilist_sublist_t *);
+void *multilist_sublist_next(multilist_sublist_t *, void *);
+void *multilist_sublist_prev(multilist_sublist_t *, void *);
+
+void multilist_link_init(multilist_node_t *);
+int multilist_link_active(multilist_node_t *);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _SYS_MULTILIST_H */