--- /dev/null
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
+ * Copyright 2013 Nexenta Systems, Inc. All rights reserved.
+ */
+
+#ifndef _SYS_ARC_IMPL_H
+#define _SYS_ARC_IMPL_H
+
+#include <sys/arc.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Note that buffers can be in one of 6 states:
+ * ARC_anon - anonymous (discussed below)
+ * ARC_mru - recently used, currently cached
+ * ARC_mru_ghost - recentely used, no longer in cache
+ * ARC_mfu - frequently used, currently cached
+ * ARC_mfu_ghost - frequently used, no longer in cache
+ * ARC_l2c_only - exists in L2ARC but not other states
+ * When there are no active references to the buffer, they are
+ * are linked onto a list in one of these arc states. These are
+ * the only buffers that can be evicted or deleted. Within each
+ * state there are multiple lists, one for meta-data and one for
+ * non-meta-data. Meta-data (indirect blocks, blocks of dnodes,
+ * etc.) is tracked separately so that it can be managed more
+ * explicitly: favored over data, limited explicitly.
+ *
+ * Anonymous buffers are buffers that are not associated with
+ * a DVA. These are buffers that hold dirty block copies
+ * before they are written to stable storage. By definition,
+ * they are "ref'd" and are considered part of arc_mru
+ * that cannot be freed. Generally, they will aquire a DVA
+ * as they are written and migrate onto the arc_mru list.
+ *
+ * The ARC_l2c_only state is for buffers that are in the second
+ * level ARC but no longer in any of the ARC_m* lists. The second
+ * level ARC itself may also contain buffers that are in any of
+ * the ARC_m* states - meaning that a buffer can exist in two
+ * places. The reason for the ARC_l2c_only state is to keep the
+ * buffer header in the hash table, so that reads that hit the
+ * second level ARC benefit from these fast lookups.
+ */
+
+typedef struct arc_state {
+ /*
+ * list of evictable buffers
+ */
+ multilist_t arcs_list[ARC_BUFC_NUMTYPES];
+ /*
+ * total amount of evictable data in this state
+ */
+ uint64_t arcs_lsize[ARC_BUFC_NUMTYPES];
+ /*
+ * total amount of data in this state; this includes: evictable,
+ * non-evictable, ARC_BUFC_DATA, and ARC_BUFC_METADATA.
+ */
+ refcount_t arcs_size;
+ /*
+ * supports the "dbufs" kstat
+ */
+ arc_state_type_t arcs_state;
+} arc_state_t;
+
+typedef struct arc_callback arc_callback_t;
+
+struct arc_callback {
+ void *acb_private;
+ arc_done_func_t *acb_done;
+ arc_buf_t *acb_buf;
+ zio_t *acb_zio_dummy;
+ arc_callback_t *acb_next;
+};
+
+typedef struct arc_write_callback arc_write_callback_t;
+
+struct arc_write_callback {
+ void *awcb_private;
+ arc_done_func_t *awcb_ready;
+ arc_done_func_t *awcb_physdone;
+ arc_done_func_t *awcb_done;
+ arc_buf_t *awcb_buf;
+};
+
+/*
+ * ARC buffers are separated into multiple structs as a memory saving measure:
+ * - Common fields struct, always defined, and embedded within it:
+ * - L2-only fields, always allocated but undefined when not in L2ARC
+ * - L1-only fields, only allocated when in L1ARC
+ *
+ * Buffer in L1 Buffer only in L2
+ * +------------------------+ +------------------------+
+ * | arc_buf_hdr_t | | arc_buf_hdr_t |
+ * | | | |
+ * | | | |
+ * | | | |
+ * +------------------------+ +------------------------+
+ * | l2arc_buf_hdr_t | | l2arc_buf_hdr_t |
+ * | (undefined if L1-only) | | |
+ * +------------------------+ +------------------------+
+ * | l1arc_buf_hdr_t |
+ * | |
+ * | |
+ * | |
+ * | |
+ * +------------------------+
+ *
+ * Because it's possible for the L2ARC to become extremely large, we can wind
+ * up eating a lot of memory in L2ARC buffer headers, so the size of a header
+ * is minimized by only allocating the fields necessary for an L1-cached buffer
+ * when a header is actually in the L1 cache. The sub-headers (l1arc_buf_hdr and
+ * l2arc_buf_hdr) are embedded rather than allocated separately to save a couple
+ * words in pointers. arc_hdr_realloc() is used to switch a header between
+ * these two allocation states.
+ */
+typedef struct l1arc_buf_hdr {
+ kmutex_t b_freeze_lock;
+
+ arc_buf_t *b_buf;
+ uint32_t b_datacnt;
+ /* for waiting on writes to complete */
+ kcondvar_t b_cv;
+
+
+ /* protected by arc state mutex */
+ arc_state_t *b_state;
+ multilist_node_t b_arc_node;
+
+ /* updated atomically */
+ clock_t b_arc_access;
+ uint32_t b_mru_hits;
+ uint32_t b_mru_ghost_hits;
+ uint32_t b_mfu_hits;
+ uint32_t b_mfu_ghost_hits;
+ uint32_t b_l2_hits;
+
+ /* self protecting */
+ refcount_t b_refcnt;
+
+ arc_callback_t *b_acb;
+ /* temporary buffer holder for in-flight compressed data */
+ void *b_tmp_cdata;
+} l1arc_buf_hdr_t;
+
+typedef struct l2arc_dev {
+ vdev_t *l2ad_vdev; /* vdev */
+ spa_t *l2ad_spa; /* spa */
+ uint64_t l2ad_hand; /* next write location */
+ uint64_t l2ad_start; /* first addr on device */
+ uint64_t l2ad_end; /* last addr on device */
+ boolean_t l2ad_first; /* first sweep through */
+ boolean_t l2ad_writing; /* currently writing */
+ kmutex_t l2ad_mtx; /* lock for buffer list */
+ list_t l2ad_buflist; /* buffer list */
+ list_node_t l2ad_node; /* device list node */
+ refcount_t l2ad_alloc; /* allocated bytes */
+} l2arc_dev_t;
+
+typedef struct l2arc_buf_hdr {
+ /* protected by arc_buf_hdr mutex */
+ l2arc_dev_t *b_dev; /* L2ARC device */
+ uint64_t b_daddr; /* disk address, offset byte */
+ /* real alloc'd buffer size depending on b_compress applied */
+ uint32_t b_hits;
+ int32_t b_asize;
+ uint8_t b_compress;
+
+ list_node_t b_l2node;
+} l2arc_buf_hdr_t;
+
+typedef struct l2arc_write_callback {
+ l2arc_dev_t *l2wcb_dev; /* device info */
+ arc_buf_hdr_t *l2wcb_head; /* head of write buflist */
+} l2arc_write_callback_t;
+
+struct arc_buf_hdr {
+ /* protected by hash lock */
+ dva_t b_dva;
+ uint64_t b_birth;
+ /*
+ * Even though this checksum is only set/verified when a buffer is in
+ * the L1 cache, it needs to be in the set of common fields because it
+ * must be preserved from the time before a buffer is written out to
+ * L2ARC until after it is read back in.
+ */
+ zio_cksum_t *b_freeze_cksum;
+
+ arc_buf_hdr_t *b_hash_next;
+ arc_flags_t b_flags;
+
+ /* immutable */
+ int32_t b_size;
+ uint64_t b_spa;
+
+ /* L2ARC fields. Undefined when not in L2ARC. */
+ l2arc_buf_hdr_t b_l2hdr;
+ /* L1ARC fields. Undefined when in l2arc_only state */
+ l1arc_buf_hdr_t b_l1hdr;
+};
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _SYS_ARC_IMPL_H */
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