+++ /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 acquire 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
- */
- refcount_t arcs_esize[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;
- boolean_t acb_compressed;
- 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_children_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;
- zio_cksum_t *b_freeze_cksum;
-
- arc_buf_t *b_buf;
- uint32_t b_bufcnt;
- /* for waiting on writes to complete */
- kcondvar_t b_cv;
- uint8_t b_byteswap;
-
-
- /* 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;
- abd_t *b_pabd;
-} 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 */
- uint32_t b_hits;
-
- 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;
-
- arc_buf_contents_t b_type;
- arc_buf_hdr_t *b_hash_next;
- arc_flags_t b_flags;
-
- /*
- * This field stores the size of the data buffer after
- * compression, and is set in the arc's zio completion handlers.
- * It is in units of SPA_MINBLOCKSIZE (e.g. 1 == 512 bytes).
- *
- * While the block pointers can store up to 32MB in their psize
- * field, we can only store up to 32MB minus 512B. This is due
- * to the bp using a bias of 1, whereas we use a bias of 0 (i.e.
- * a field of zeros represents 512B in the bp). We can't use a
- * bias of 1 since we need to reserve a psize of zero, here, to
- * represent holes and embedded blocks.
- *
- * This isn't a problem in practice, since the maximum size of a
- * buffer is limited to 16MB, so we never need to store 32MB in
- * this field. Even in the upstream illumos code base, the
- * maximum size of a buffer is limited to 16MB.
- */
- uint16_t b_psize;
-
- /*
- * This field stores the size of the data buffer before
- * compression, and cannot change once set. It is in units
- * of SPA_MINBLOCKSIZE (e.g. 2 == 1024 bytes)
- */
- uint16_t b_lsize; /* immutable */
- uint64_t b_spa; /* immutable */
-
- /* 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 */
projects / mirror_ubuntu-bionic-kernel.git / blobdiff