1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or https://opensource.org/licenses/CDDL-1.0.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright (c) 2013, Delphix. All rights reserved.
24  * Copyright (c) 2013, Saso Kiselkov. All rights reserved.
25  * Copyright (c) 2013, Nexenta Systems, Inc.  All rights reserved.
26  * Copyright (c) 2020, George Amanakis. All rights reserved.
27  */
28 
29 #ifndef _SYS_ARC_IMPL_H
30 #define	_SYS_ARC_IMPL_H
31 
32 #include <sys/arc.h>
33 #include <sys/multilist.h>
34 #include <sys/zio_crypt.h>
35 #include <sys/zthr.h>
36 #include <sys/aggsum.h>
37 #include <sys/wmsum.h>
38 
39 #ifdef __cplusplus
40 extern "C" {
41 #endif
42 
43 /*
44  * Note that buffers can be in one of 6 states:
45  *	ARC_anon	- anonymous (discussed below)
46  *	ARC_mru		- recently used, currently cached
47  *	ARC_mru_ghost	- recently used, no longer in cache
48  *	ARC_mfu		- frequently used, currently cached
49  *	ARC_mfu_ghost	- frequently used, no longer in cache
50  *	ARC_uncached	- uncacheable prefetch, to be evicted
51  *	ARC_l2c_only	- exists in L2ARC but not other states
52  * When there are no active references to the buffer, they are
53  * are linked onto a list in one of these arc states.  These are
54  * the only buffers that can be evicted or deleted.  Within each
55  * state there are multiple lists, one for meta-data and one for
56  * non-meta-data.  Meta-data (indirect blocks, blocks of dnodes,
57  * etc.) is tracked separately so that it can be managed more
58  * explicitly: favored over data, limited explicitly.
59  *
60  * Anonymous buffers are buffers that are not associated with
61  * a DVA.  These are buffers that hold dirty block copies
62  * before they are written to stable storage.  By definition,
63  * they are "ref'd" and are considered part of arc_mru
64  * that cannot be freed.  Generally, they will acquire a DVA
65  * as they are written and migrate onto the arc_mru list.
66  *
67  * The ARC_l2c_only state is for buffers that are in the second
68  * level ARC but no longer in any of the ARC_m* lists.  The second
69  * level ARC itself may also contain buffers that are in any of
70  * the ARC_m* states - meaning that a buffer can exist in two
71  * places.  The reason for the ARC_l2c_only state is to keep the
72  * buffer header in the hash table, so that reads that hit the
73  * second level ARC benefit from these fast lookups.
74  */
75 
76 typedef struct arc_state {
77 	/*
78 	 * list of evictable buffers
79 	 */
80 	multilist_t arcs_list[ARC_BUFC_NUMTYPES];
81 	/*
82 	 * supports the "dbufs" kstat
83 	 */
84 	arc_state_type_t arcs_state;
85 	/*
86 	 * total amount of data in this state.
87 	 */
88 	zfs_refcount_t arcs_size[ARC_BUFC_NUMTYPES] ____cacheline_aligned;
89 	/*
90 	 * total amount of evictable data in this state
91 	 */
92 	zfs_refcount_t arcs_esize[ARC_BUFC_NUMTYPES];
93 	/*
94 	 * amount of hit bytes for this state (counted only for ghost states)
95 	 */
96 	wmsum_t arcs_hits[ARC_BUFC_NUMTYPES];
97 } arc_state_t;
98 
99 typedef struct arc_callback arc_callback_t;
100 
101 struct arc_callback {
102 	void			*acb_private;
103 	arc_read_done_func_t	*acb_done;
104 	arc_buf_t		*acb_buf;
105 	boolean_t		acb_encrypted;
106 	boolean_t		acb_compressed;
107 	boolean_t		acb_noauth;
108 	boolean_t		acb_nobuf;
109 	boolean_t		acb_wait;
110 	int			acb_wait_error;
111 	kmutex_t		acb_wait_lock;
112 	kcondvar_t		acb_wait_cv;
113 	zbookmark_phys_t	acb_zb;
114 	zio_t			*acb_zio_dummy;
115 	zio_t			*acb_zio_head;
116 	arc_callback_t		*acb_prev;
117 	arc_callback_t		*acb_next;
118 };
119 
120 typedef struct arc_write_callback arc_write_callback_t;
121 
122 struct arc_write_callback {
123 	void			*awcb_private;
124 	arc_write_done_func_t	*awcb_ready;
125 	arc_write_done_func_t	*awcb_children_ready;
126 	arc_write_done_func_t	*awcb_done;
127 	arc_buf_t		*awcb_buf;
128 };
129 
130 /*
131  * ARC buffers are separated into multiple structs as a memory saving measure:
132  *   - Common fields struct, always defined, and embedded within it:
133  *       - L2-only fields, always allocated but undefined when not in L2ARC
134  *       - L1-only fields, only allocated when in L1ARC
135  *
136  *           Buffer in L1                     Buffer only in L2
137  *    +------------------------+          +------------------------+
138  *    | arc_buf_hdr_t          |          | arc_buf_hdr_t          |
139  *    |                        |          |                        |
140  *    |                        |          |                        |
141  *    |                        |          |                        |
142  *    +------------------------+          +------------------------+
143  *    | l2arc_buf_hdr_t        |          | l2arc_buf_hdr_t        |
144  *    | (undefined if L1-only) |          |                        |
145  *    +------------------------+          +------------------------+
146  *    | l1arc_buf_hdr_t        |
147  *    |                        |
148  *    |                        |
149  *    |                        |
150  *    |                        |
151  *    +------------------------+
152  *
153  * Because it's possible for the L2ARC to become extremely large, we can wind
154  * up eating a lot of memory in L2ARC buffer headers, so the size of a header
155  * is minimized by only allocating the fields necessary for an L1-cached buffer
156  * when a header is actually in the L1 cache. The sub-headers (l1arc_buf_hdr and
157  * l2arc_buf_hdr) are embedded rather than allocated separately to save a couple
158  * words in pointers. arc_hdr_realloc() is used to switch a header between
159  * these two allocation states.
160  */
161 typedef struct l1arc_buf_hdr {
162 	/* protected by arc state mutex */
163 	arc_state_t		*b_state;
164 	multilist_node_t	b_arc_node;
165 
166 	/* protected by hash lock */
167 	clock_t			b_arc_access;
168 	uint32_t		b_mru_hits;
169 	uint32_t		b_mru_ghost_hits;
170 	uint32_t		b_mfu_hits;
171 	uint32_t		b_mfu_ghost_hits;
172 	uint8_t			b_byteswap;
173 	arc_buf_t		*b_buf;
174 
175 	/* self protecting */
176 	zfs_refcount_t		b_refcnt;
177 
178 	arc_callback_t		*b_acb;
179 	abd_t			*b_pabd;
180 
181 #ifdef ZFS_DEBUG
182 	zio_cksum_t		*b_freeze_cksum;
183 	kmutex_t		b_freeze_lock;
184 #endif
185 } l1arc_buf_hdr_t;
186 
187 typedef enum l2arc_dev_hdr_flags_t {
188 	L2ARC_DEV_HDR_EVICT_FIRST = (1 << 0)	/* mirror of l2ad_first */
189 } l2arc_dev_hdr_flags_t;
190 
191 /*
192  * Pointer used in persistent L2ARC (for pointing to log blocks).
193  */
194 typedef struct l2arc_log_blkptr {
195 	/*
196 	 * Offset of log block within the device, in bytes
197 	 */
198 	uint64_t	lbp_daddr;
199 	/*
200 	 * Aligned payload size (in bytes) of the log block
201 	 */
202 	uint64_t	lbp_payload_asize;
203 	/*
204 	 * Offset in bytes of the first buffer in the payload
205 	 */
206 	uint64_t	lbp_payload_start;
207 	/*
208 	 * lbp_prop has the following format:
209 	 *	* logical size (in bytes)
210 	 *	* aligned (after compression) size (in bytes)
211 	 *	* compression algorithm (we always LZ4-compress l2arc logs)
212 	 *	* checksum algorithm (used for lbp_cksum)
213 	 */
214 	uint64_t	lbp_prop;
215 	zio_cksum_t	lbp_cksum;	/* checksum of log */
216 } l2arc_log_blkptr_t;
217 
218 /*
219  * The persistent L2ARC device header.
220  * Byte order of magic determines whether 64-bit bswap of fields is necessary.
221  */
222 typedef struct l2arc_dev_hdr_phys {
223 	uint64_t	dh_magic;	/* L2ARC_DEV_HDR_MAGIC */
224 	uint64_t	dh_version;	/* Persistent L2ARC version */
225 
226 	/*
227 	 * Global L2ARC device state and metadata.
228 	 */
229 	uint64_t	dh_spa_guid;
230 	uint64_t	dh_vdev_guid;
231 	uint64_t	dh_log_entries;		/* mirror of l2ad_log_entries */
232 	uint64_t	dh_evict;		/* evicted offset in bytes */
233 	uint64_t	dh_flags;		/* l2arc_dev_hdr_flags_t */
234 	/*
235 	 * Used in zdb.c for determining if a log block is valid, in the same
236 	 * way that l2arc_rebuild() does.
237 	 */
238 	uint64_t	dh_start;		/* mirror of l2ad_start */
239 	uint64_t	dh_end;			/* mirror of l2ad_end */
240 	/*
241 	 * Start of log block chain. [0] -> newest log, [1] -> one older (used
242 	 * for initiating prefetch).
243 	 */
244 	l2arc_log_blkptr_t	dh_start_lbps[2];
245 	/*
246 	 * Aligned size of all log blocks as accounted by vdev_space_update().
247 	 */
248 	uint64_t	dh_lb_asize;		/* mirror of l2ad_lb_asize */
249 	uint64_t	dh_lb_count;		/* mirror of l2ad_lb_count */
250 	/*
251 	 * Mirrors of vdev_trim_action_time and vdev_trim_state, used to
252 	 * display when the cache device was fully trimmed for the last
253 	 * time.
254 	 */
255 	uint64_t		dh_trim_action_time;
256 	uint64_t		dh_trim_state;
257 	const uint64_t		dh_pad[30];	/* pad to 512 bytes */
258 	zio_eck_t		dh_tail;
259 } l2arc_dev_hdr_phys_t;
260 _Static_assert(sizeof (l2arc_dev_hdr_phys_t) == SPA_MINBLOCKSIZE,
261 	"l2arc_dev_hdr_phys_t wrong size");
262 
263 /*
264  * A single ARC buffer header entry in a l2arc_log_blk_phys_t.
265  */
266 typedef struct l2arc_log_ent_phys {
267 	dva_t			le_dva;		/* dva of buffer */
268 	uint64_t		le_birth;	/* birth txg of buffer */
269 	/*
270 	 * le_prop has the following format:
271 	 *	* logical size (in bytes)
272 	 *	* physical (compressed) size (in bytes)
273 	 *	* compression algorithm
274 	 *	* object type (used to restore arc_buf_contents_t)
275 	 *	* protected status (used for encryption)
276 	 *	* prefetch status (used in l2arc_read_done())
277 	 */
278 	uint64_t		le_prop;
279 	uint64_t		le_daddr;	/* buf location on l2dev */
280 	uint64_t		le_complevel;
281 	/*
282 	 * We pad the size of each entry to a power of 2 so that the size of
283 	 * l2arc_log_blk_phys_t is power-of-2 aligned with SPA_MINBLOCKSHIFT,
284 	 * because of the L2ARC_SET_*SIZE macros.
285 	 */
286 	const uint64_t		le_pad[2];	/* pad to 64 bytes	 */
287 } l2arc_log_ent_phys_t;
288 
289 #define	L2ARC_LOG_BLK_MAX_ENTRIES	(1022)
290 
291 /*
292  * A log block of up to 1022 ARC buffer log entries, chained into the
293  * persistent L2ARC metadata linked list. Byte order of magic determines
294  * whether 64-bit bswap of fields is necessary.
295  */
296 typedef struct l2arc_log_blk_phys {
297 	uint64_t		lb_magic;	/* L2ARC_LOG_BLK_MAGIC */
298 	/*
299 	 * There are 2 chains (headed by dh_start_lbps[2]), and this field
300 	 * points back to the previous block in this chain. We alternate
301 	 * which chain we append to, so they are time-wise and offset-wise
302 	 * interleaved, but that is an optimization rather than for
303 	 * correctness.
304 	 */
305 	l2arc_log_blkptr_t	lb_prev_lbp;	/* pointer to prev log block */
306 	/*
307 	 * Pad header section to 128 bytes
308 	 */
309 	uint64_t		lb_pad[7];
310 	/* Payload */
311 	l2arc_log_ent_phys_t	lb_entries[L2ARC_LOG_BLK_MAX_ENTRIES];
312 } l2arc_log_blk_phys_t;				/* 64K total */
313 
314 /*
315  * The size of l2arc_log_blk_phys_t has to be power-of-2 aligned with
316  * SPA_MINBLOCKSHIFT because of L2BLK_SET_*SIZE macros.
317  */
318 _Static_assert(IS_P2ALIGNED(sizeof (l2arc_log_blk_phys_t),
319     1ULL << SPA_MINBLOCKSHIFT), "l2arc_log_blk_phys_t misaligned");
320 _Static_assert(sizeof (l2arc_log_blk_phys_t) >= SPA_MINBLOCKSIZE,
321 	"l2arc_log_blk_phys_t too small");
322 _Static_assert(sizeof (l2arc_log_blk_phys_t) <= SPA_MAXBLOCKSIZE,
323 	"l2arc_log_blk_phys_t too big");
324 
325 /*
326  * These structures hold in-flight abd buffers for log blocks as they're being
327  * written to the L2ARC device.
328  */
329 typedef struct l2arc_lb_abd_buf {
330 	abd_t		*abd;
331 	list_node_t	node;
332 } l2arc_lb_abd_buf_t;
333 
334 /*
335  * These structures hold pointers to log blocks present on the L2ARC device.
336  */
337 typedef struct l2arc_lb_ptr_buf {
338 	l2arc_log_blkptr_t	*lb_ptr;
339 	list_node_t		node;
340 } l2arc_lb_ptr_buf_t;
341 
342 /* Macros for setting fields in le_prop and lbp_prop */
343 #define	L2BLK_GET_LSIZE(field)	\
344 	BF64_GET_SB((field), 0, SPA_LSIZEBITS, SPA_MINBLOCKSHIFT, 1)
345 #define	L2BLK_SET_LSIZE(field, x)	\
346 	BF64_SET_SB((field), 0, SPA_LSIZEBITS, SPA_MINBLOCKSHIFT, 1, x)
347 #define	L2BLK_GET_PSIZE(field)	\
348 	BF64_GET_SB((field), 16, SPA_PSIZEBITS, SPA_MINBLOCKSHIFT, 1)
349 #define	L2BLK_SET_PSIZE(field, x)	\
350 	BF64_SET_SB((field), 16, SPA_PSIZEBITS, SPA_MINBLOCKSHIFT, 1, x)
351 #define	L2BLK_GET_COMPRESS(field)	\
352 	BF64_GET((field), 32, SPA_COMPRESSBITS)
353 #define	L2BLK_SET_COMPRESS(field, x)	\
354 	BF64_SET((field), 32, SPA_COMPRESSBITS, x)
355 #define	L2BLK_GET_PREFETCH(field)	BF64_GET((field), 39, 1)
356 #define	L2BLK_SET_PREFETCH(field, x)	BF64_SET((field), 39, 1, x)
357 #define	L2BLK_GET_CHECKSUM(field)	BF64_GET((field), 40, 8)
358 #define	L2BLK_SET_CHECKSUM(field, x)	BF64_SET((field), 40, 8, x)
359 /* +/- 1 here are to keep compatibility after ARC_BUFC_INVALID removal. */
360 #define	L2BLK_GET_TYPE(field)		(BF64_GET((field), 48, 8) - 1)
361 #define	L2BLK_SET_TYPE(field, x)	BF64_SET((field), 48, 8, (x) + 1)
362 #define	L2BLK_GET_PROTECTED(field)	BF64_GET((field), 56, 1)
363 #define	L2BLK_SET_PROTECTED(field, x)	BF64_SET((field), 56, 1, x)
364 #define	L2BLK_GET_STATE(field)		BF64_GET((field), 57, 4)
365 #define	L2BLK_SET_STATE(field, x)	BF64_SET((field), 57, 4, x)
366 
367 #define	PTR_SWAP(x, y)		\
368 	do {			\
369 		void *tmp = (x);\
370 		x = y;		\
371 		y = tmp;	\
372 	} while (0)
373 
374 #define	L2ARC_DEV_HDR_MAGIC	0x5a46534341434845LLU	/* ASCII: "ZFSCACHE" */
375 #define	L2ARC_LOG_BLK_MAGIC	0x4c4f47424c4b4844LLU	/* ASCII: "LOGBLKHD" */
376 
377 /*
378  * L2ARC Internals
379  */
380 typedef struct l2arc_dev {
381 	vdev_t			*l2ad_vdev;	/* vdev */
382 	spa_t			*l2ad_spa;	/* spa */
383 	uint64_t		l2ad_hand;	/* next write location */
384 	uint64_t		l2ad_start;	/* first addr on device */
385 	uint64_t		l2ad_end;	/* last addr on device */
386 	boolean_t		l2ad_first;	/* first sweep through */
387 	boolean_t		l2ad_writing;	/* currently writing */
388 	kmutex_t		l2ad_mtx;	/* lock for buffer list */
389 	list_t			l2ad_buflist;	/* buffer list */
390 	list_node_t		l2ad_node;	/* device list node */
391 	zfs_refcount_t		l2ad_alloc;	/* allocated bytes */
392 	/*
393 	 * Persistence-related stuff
394 	 */
395 	l2arc_dev_hdr_phys_t	*l2ad_dev_hdr;	/* persistent device header */
396 	uint64_t		l2ad_dev_hdr_asize; /* aligned hdr size */
397 	l2arc_log_blk_phys_t	l2ad_log_blk;	/* currently open log block */
398 	int			l2ad_log_ent_idx; /* index into cur log blk */
399 	/* Number of bytes in current log block's payload */
400 	uint64_t		l2ad_log_blk_payload_asize;
401 	/*
402 	 * Offset (in bytes) of the first buffer in current log block's
403 	 * payload.
404 	 */
405 	uint64_t		l2ad_log_blk_payload_start;
406 	/* Flag indicating whether a rebuild is scheduled or is going on */
407 	boolean_t		l2ad_rebuild;
408 	boolean_t		l2ad_rebuild_cancel;
409 	boolean_t		l2ad_rebuild_began;
410 	uint64_t		l2ad_log_entries;   /* entries per log blk  */
411 	uint64_t		l2ad_evict;	 /* evicted offset in bytes */
412 	/* List of pointers to log blocks present in the L2ARC device */
413 	list_t			l2ad_lbptr_list;
414 	/*
415 	 * Aligned size of all log blocks as accounted by vdev_space_update().
416 	 */
417 	zfs_refcount_t		l2ad_lb_asize;
418 	/*
419 	 * Number of log blocks present on the device.
420 	 */
421 	zfs_refcount_t		l2ad_lb_count;
422 	boolean_t		l2ad_trim_all; /* TRIM whole device */
423 } l2arc_dev_t;
424 
425 /*
426  * Encrypted blocks will need to be stored encrypted on the L2ARC
427  * disk as they appear in the main pool. In order for this to work we
428  * need to pass around the encryption parameters so they can be used
429  * to write data to the L2ARC. This struct is only defined in the
430  * arc_buf_hdr_t if the L1 header is defined and has the ARC_FLAG_ENCRYPTED
431  * flag set.
432  */
433 typedef struct arc_buf_hdr_crypt {
434 	abd_t			*b_rabd;	/* raw encrypted data */
435 
436 	/* dsobj for looking up encryption key for l2arc encryption */
437 	uint64_t		b_dsobj;
438 
439 	dmu_object_type_t	b_ot;		/* object type */
440 
441 	/* encryption parameters */
442 	uint8_t			b_salt[ZIO_DATA_SALT_LEN];
443 	uint8_t			b_iv[ZIO_DATA_IV_LEN];
444 
445 	/*
446 	 * Technically this could be removed since we will always be able to
447 	 * get the mac from the bp when we need it. However, it is inconvenient
448 	 * for callers of arc code to have to pass a bp in all the time. This
449 	 * also allows us to assert that L2ARC data is properly encrypted to
450 	 * match the data in the main storage pool.
451 	 */
452 	uint8_t			b_mac[ZIO_DATA_MAC_LEN];
453 } arc_buf_hdr_crypt_t;
454 
455 typedef struct l2arc_buf_hdr {
456 	/* protected by arc_buf_hdr mutex */
457 	l2arc_dev_t		*b_dev;		/* L2ARC device */
458 	uint64_t		b_daddr;	/* disk address, offset byte */
459 	uint32_t		b_hits;
460 	arc_state_type_t	b_arcs_state;
461 	list_node_t		b_l2node;
462 } l2arc_buf_hdr_t;
463 
464 typedef struct l2arc_write_callback {
465 	l2arc_dev_t	*l2wcb_dev;		/* device info */
466 	arc_buf_hdr_t	*l2wcb_head;		/* head of write buflist */
467 	/* in-flight list of log blocks */
468 	list_t		l2wcb_abd_list;
469 } l2arc_write_callback_t;
470 
471 struct arc_buf_hdr {
472 	/* protected by hash lock */
473 	dva_t			b_dva;
474 	uint64_t		b_birth;
475 
476 	arc_buf_contents_t	b_type;
477 	uint8_t			b_complevel;
478 	uint8_t			b_reserved1; /* used for 4 byte alignment */
479 	uint16_t		b_reserved2; /* used for 4 byte alignment */
480 	arc_buf_hdr_t		*b_hash_next;
481 	arc_flags_t		b_flags;
482 
483 	/*
484 	 * This field stores the size of the data buffer after
485 	 * compression, and is set in the arc's zio completion handlers.
486 	 * It is in units of SPA_MINBLOCKSIZE (e.g. 1 == 512 bytes).
487 	 *
488 	 * While the block pointers can store up to 32MB in their psize
489 	 * field, we can only store up to 32MB minus 512B. This is due
490 	 * to the bp using a bias of 1, whereas we use a bias of 0 (i.e.
491 	 * a field of zeros represents 512B in the bp). We can't use a
492 	 * bias of 1 since we need to reserve a psize of zero, here, to
493 	 * represent holes and embedded blocks.
494 	 *
495 	 * This isn't a problem in practice, since the maximum size of a
496 	 * buffer is limited to 16MB, so we never need to store 32MB in
497 	 * this field. Even in the upstream illumos code base, the
498 	 * maximum size of a buffer is limited to 16MB.
499 	 */
500 	uint16_t		b_psize;
501 
502 	/*
503 	 * This field stores the size of the data buffer before
504 	 * compression, and cannot change once set. It is in units
505 	 * of SPA_MINBLOCKSIZE (e.g. 2 == 1024 bytes)
506 	 */
507 	uint16_t		b_lsize;	/* immutable */
508 	uint64_t		b_spa;		/* immutable */
509 
510 	/* L2ARC fields. Undefined when not in L2ARC. */
511 	l2arc_buf_hdr_t		b_l2hdr;
512 	/* L1ARC fields. Undefined when in l2arc_only state */
513 	l1arc_buf_hdr_t		b_l1hdr;
514 	/*
515 	 * Encryption parameters. Defined only when ARC_FLAG_ENCRYPTED
516 	 * is set and the L1 header exists.
517 	 */
518 	arc_buf_hdr_crypt_t b_crypt_hdr;
519 };
520 
521 typedef struct arc_stats {
522 	/* Number of requests that were satisfied without I/O. */
523 	kstat_named_t arcstat_hits;
524 	/* Number of requests for which I/O was already running. */
525 	kstat_named_t arcstat_iohits;
526 	/* Number of requests for which I/O has to be issued. */
527 	kstat_named_t arcstat_misses;
528 	/* Same three, but specifically for demand data. */
529 	kstat_named_t arcstat_demand_data_hits;
530 	kstat_named_t arcstat_demand_data_iohits;
531 	kstat_named_t arcstat_demand_data_misses;
532 	/* Same three, but specifically for demand metadata. */
533 	kstat_named_t arcstat_demand_metadata_hits;
534 	kstat_named_t arcstat_demand_metadata_iohits;
535 	kstat_named_t arcstat_demand_metadata_misses;
536 	/* Same three, but specifically for prefetch data. */
537 	kstat_named_t arcstat_prefetch_data_hits;
538 	kstat_named_t arcstat_prefetch_data_iohits;
539 	kstat_named_t arcstat_prefetch_data_misses;
540 	/* Same three, but specifically for prefetch metadata. */
541 	kstat_named_t arcstat_prefetch_metadata_hits;
542 	kstat_named_t arcstat_prefetch_metadata_iohits;
543 	kstat_named_t arcstat_prefetch_metadata_misses;
544 	kstat_named_t arcstat_mru_hits;
545 	kstat_named_t arcstat_mru_ghost_hits;
546 	kstat_named_t arcstat_mfu_hits;
547 	kstat_named_t arcstat_mfu_ghost_hits;
548 	kstat_named_t arcstat_uncached_hits;
549 	kstat_named_t arcstat_deleted;
550 	/*
551 	 * Number of buffers that could not be evicted because the hash lock
552 	 * was held by another thread.  The lock may not necessarily be held
553 	 * by something using the same buffer, since hash locks are shared
554 	 * by multiple buffers.
555 	 */
556 	kstat_named_t arcstat_mutex_miss;
557 	/*
558 	 * Number of buffers skipped when updating the access state due to the
559 	 * header having already been released after acquiring the hash lock.
560 	 */
561 	kstat_named_t arcstat_access_skip;
562 	/*
563 	 * Number of buffers skipped because they have I/O in progress, are
564 	 * indirect prefetch buffers that have not lived long enough, or are
565 	 * not from the spa we're trying to evict from.
566 	 */
567 	kstat_named_t arcstat_evict_skip;
568 	/*
569 	 * Number of times arc_evict_state() was unable to evict enough
570 	 * buffers to reach its target amount.
571 	 */
572 	kstat_named_t arcstat_evict_not_enough;
573 	kstat_named_t arcstat_evict_l2_cached;
574 	kstat_named_t arcstat_evict_l2_eligible;
575 	kstat_named_t arcstat_evict_l2_eligible_mfu;
576 	kstat_named_t arcstat_evict_l2_eligible_mru;
577 	kstat_named_t arcstat_evict_l2_ineligible;
578 	kstat_named_t arcstat_evict_l2_skip;
579 	kstat_named_t arcstat_hash_elements;
580 	kstat_named_t arcstat_hash_elements_max;
581 	kstat_named_t arcstat_hash_collisions;
582 	kstat_named_t arcstat_hash_chains;
583 	kstat_named_t arcstat_hash_chain_max;
584 	kstat_named_t arcstat_meta;
585 	kstat_named_t arcstat_pd;
586 	kstat_named_t arcstat_pm;
587 	kstat_named_t arcstat_c;
588 	kstat_named_t arcstat_c_min;
589 	kstat_named_t arcstat_c_max;
590 	kstat_named_t arcstat_size;
591 	/*
592 	 * Number of compressed bytes stored in the arc_buf_hdr_t's b_pabd.
593 	 * Note that the compressed bytes may match the uncompressed bytes
594 	 * if the block is either not compressed or compressed arc is disabled.
595 	 */
596 	kstat_named_t arcstat_compressed_size;
597 	/*
598 	 * Uncompressed size of the data stored in b_pabd. If compressed
599 	 * arc is disabled then this value will be identical to the stat
600 	 * above.
601 	 */
602 	kstat_named_t arcstat_uncompressed_size;
603 	/*
604 	 * Number of bytes stored in all the arc_buf_t's. This is classified
605 	 * as "overhead" since this data is typically short-lived and will
606 	 * be evicted from the arc when it becomes unreferenced unless the
607 	 * zfs_keep_uncompressed_metadata or zfs_keep_uncompressed_level
608 	 * values have been set (see comment in dbuf.c for more information).
609 	 */
610 	kstat_named_t arcstat_overhead_size;
611 	/*
612 	 * Number of bytes consumed by internal ARC structures necessary
613 	 * for tracking purposes; these structures are not actually
614 	 * backed by ARC buffers. This includes arc_buf_hdr_t structures
615 	 * (allocated via arc_buf_hdr_t_full and arc_buf_hdr_t_l2only
616 	 * caches), and arc_buf_t structures (allocated via arc_buf_t
617 	 * cache).
618 	 */
619 	kstat_named_t arcstat_hdr_size;
620 	/*
621 	 * Number of bytes consumed by ARC buffers of type equal to
622 	 * ARC_BUFC_DATA. This is generally consumed by buffers backing
623 	 * on disk user data (e.g. plain file contents).
624 	 */
625 	kstat_named_t arcstat_data_size;
626 	/*
627 	 * Number of bytes consumed by ARC buffers of type equal to
628 	 * ARC_BUFC_METADATA. This is generally consumed by buffers
629 	 * backing on disk data that is used for internal ZFS
630 	 * structures (e.g. ZAP, dnode, indirect blocks, etc).
631 	 */
632 	kstat_named_t arcstat_metadata_size;
633 	/*
634 	 * Number of bytes consumed by dmu_buf_impl_t objects.
635 	 */
636 	kstat_named_t arcstat_dbuf_size;
637 	/*
638 	 * Number of bytes consumed by dnode_t objects.
639 	 */
640 	kstat_named_t arcstat_dnode_size;
641 	/*
642 	 * Number of bytes consumed by bonus buffers.
643 	 */
644 	kstat_named_t arcstat_bonus_size;
645 #if defined(COMPAT_FREEBSD11)
646 	/*
647 	 * Sum of the previous three counters, provided for compatibility.
648 	 */
649 	kstat_named_t arcstat_other_size;
650 #endif
651 
652 	/*
653 	 * Total number of bytes consumed by ARC buffers residing in the
654 	 * arc_anon state. This includes *all* buffers in the arc_anon
655 	 * state; e.g. data, metadata, evictable, and unevictable buffers
656 	 * are all included in this value.
657 	 */
658 	kstat_named_t arcstat_anon_size;
659 	kstat_named_t arcstat_anon_data;
660 	kstat_named_t arcstat_anon_metadata;
661 	/*
662 	 * Number of bytes consumed by ARC buffers that meet the
663 	 * following criteria: backing buffers of type ARC_BUFC_DATA,
664 	 * residing in the arc_anon state, and are eligible for eviction
665 	 * (e.g. have no outstanding holds on the buffer).
666 	 */
667 	kstat_named_t arcstat_anon_evictable_data;
668 	/*
669 	 * Number of bytes consumed by ARC buffers that meet the
670 	 * following criteria: backing buffers of type ARC_BUFC_METADATA,
671 	 * residing in the arc_anon state, and are eligible for eviction
672 	 * (e.g. have no outstanding holds on the buffer).
673 	 */
674 	kstat_named_t arcstat_anon_evictable_metadata;
675 	/*
676 	 * Total number of bytes consumed by ARC buffers residing in the
677 	 * arc_mru state. This includes *all* buffers in the arc_mru
678 	 * state; e.g. data, metadata, evictable, and unevictable buffers
679 	 * are all included in this value.
680 	 */
681 	kstat_named_t arcstat_mru_size;
682 	kstat_named_t arcstat_mru_data;
683 	kstat_named_t arcstat_mru_metadata;
684 	/*
685 	 * Number of bytes consumed by ARC buffers that meet the
686 	 * following criteria: backing buffers of type ARC_BUFC_DATA,
687 	 * residing in the arc_mru state, and are eligible for eviction
688 	 * (e.g. have no outstanding holds on the buffer).
689 	 */
690 	kstat_named_t arcstat_mru_evictable_data;
691 	/*
692 	 * Number of bytes consumed by ARC buffers that meet the
693 	 * following criteria: backing buffers of type ARC_BUFC_METADATA,
694 	 * residing in the arc_mru state, and are eligible for eviction
695 	 * (e.g. have no outstanding holds on the buffer).
696 	 */
697 	kstat_named_t arcstat_mru_evictable_metadata;
698 	/*
699 	 * Total number of bytes that *would have been* consumed by ARC
700 	 * buffers in the arc_mru_ghost state. The key thing to note
701 	 * here, is the fact that this size doesn't actually indicate
702 	 * RAM consumption. The ghost lists only consist of headers and
703 	 * don't actually have ARC buffers linked off of these headers.
704 	 * Thus, *if* the headers had associated ARC buffers, these
705 	 * buffers *would have* consumed this number of bytes.
706 	 */
707 	kstat_named_t arcstat_mru_ghost_size;
708 	kstat_named_t arcstat_mru_ghost_data;
709 	kstat_named_t arcstat_mru_ghost_metadata;
710 	/*
711 	 * Number of bytes that *would have been* consumed by ARC
712 	 * buffers that are eligible for eviction, of type
713 	 * ARC_BUFC_DATA, and linked off the arc_mru_ghost state.
714 	 */
715 	kstat_named_t arcstat_mru_ghost_evictable_data;
716 	/*
717 	 * Number of bytes that *would have been* consumed by ARC
718 	 * buffers that are eligible for eviction, of type
719 	 * ARC_BUFC_METADATA, and linked off the arc_mru_ghost state.
720 	 */
721 	kstat_named_t arcstat_mru_ghost_evictable_metadata;
722 	/*
723 	 * Total number of bytes consumed by ARC buffers residing in the
724 	 * arc_mfu state. This includes *all* buffers in the arc_mfu
725 	 * state; e.g. data, metadata, evictable, and unevictable buffers
726 	 * are all included in this value.
727 	 */
728 	kstat_named_t arcstat_mfu_size;
729 	kstat_named_t arcstat_mfu_data;
730 	kstat_named_t arcstat_mfu_metadata;
731 	/*
732 	 * Number of bytes consumed by ARC buffers that are eligible for
733 	 * eviction, of type ARC_BUFC_DATA, and reside in the arc_mfu
734 	 * state.
735 	 */
736 	kstat_named_t arcstat_mfu_evictable_data;
737 	/*
738 	 * Number of bytes consumed by ARC buffers that are eligible for
739 	 * eviction, of type ARC_BUFC_METADATA, and reside in the
740 	 * arc_mfu state.
741 	 */
742 	kstat_named_t arcstat_mfu_evictable_metadata;
743 	/*
744 	 * Total number of bytes that *would have been* consumed by ARC
745 	 * buffers in the arc_mfu_ghost state. See the comment above
746 	 * arcstat_mru_ghost_size for more details.
747 	 */
748 	kstat_named_t arcstat_mfu_ghost_size;
749 	kstat_named_t arcstat_mfu_ghost_data;
750 	kstat_named_t arcstat_mfu_ghost_metadata;
751 	/*
752 	 * Number of bytes that *would have been* consumed by ARC
753 	 * buffers that are eligible for eviction, of type
754 	 * ARC_BUFC_DATA, and linked off the arc_mfu_ghost state.
755 	 */
756 	kstat_named_t arcstat_mfu_ghost_evictable_data;
757 	/*
758 	 * Number of bytes that *would have been* consumed by ARC
759 	 * buffers that are eligible for eviction, of type
760 	 * ARC_BUFC_METADATA, and linked off the arc_mru_ghost state.
761 	 */
762 	kstat_named_t arcstat_mfu_ghost_evictable_metadata;
763 	/*
764 	 * Total number of bytes that are going to be evicted from ARC due to
765 	 * ARC_FLAG_UNCACHED being set.
766 	 */
767 	kstat_named_t arcstat_uncached_size;
768 	kstat_named_t arcstat_uncached_data;
769 	kstat_named_t arcstat_uncached_metadata;
770 	/*
771 	 * Number of data bytes that are going to be evicted from ARC due to
772 	 * ARC_FLAG_UNCACHED being set.
773 	 */
774 	kstat_named_t arcstat_uncached_evictable_data;
775 	/*
776 	 * Number of metadata bytes that that are going to be evicted from ARC
777 	 * due to ARC_FLAG_UNCACHED being set.
778 	 */
779 	kstat_named_t arcstat_uncached_evictable_metadata;
780 	kstat_named_t arcstat_l2_hits;
781 	kstat_named_t arcstat_l2_misses;
782 	/*
783 	 * Allocated size (in bytes) of L2ARC cached buffers by ARC state.
784 	 */
785 	kstat_named_t arcstat_l2_prefetch_asize;
786 	kstat_named_t arcstat_l2_mru_asize;
787 	kstat_named_t arcstat_l2_mfu_asize;
788 	/*
789 	 * Allocated size (in bytes) of L2ARC cached buffers by buffer content
790 	 * type.
791 	 */
792 	kstat_named_t arcstat_l2_bufc_data_asize;
793 	kstat_named_t arcstat_l2_bufc_metadata_asize;
794 	kstat_named_t arcstat_l2_feeds;
795 	kstat_named_t arcstat_l2_rw_clash;
796 	kstat_named_t arcstat_l2_read_bytes;
797 	kstat_named_t arcstat_l2_write_bytes;
798 	kstat_named_t arcstat_l2_writes_sent;
799 	kstat_named_t arcstat_l2_writes_done;
800 	kstat_named_t arcstat_l2_writes_error;
801 	kstat_named_t arcstat_l2_writes_lock_retry;
802 	kstat_named_t arcstat_l2_evict_lock_retry;
803 	kstat_named_t arcstat_l2_evict_reading;
804 	kstat_named_t arcstat_l2_evict_l1cached;
805 	kstat_named_t arcstat_l2_free_on_write;
806 	kstat_named_t arcstat_l2_abort_lowmem;
807 	kstat_named_t arcstat_l2_cksum_bad;
808 	kstat_named_t arcstat_l2_io_error;
809 	kstat_named_t arcstat_l2_lsize;
810 	kstat_named_t arcstat_l2_psize;
811 	kstat_named_t arcstat_l2_hdr_size;
812 	/*
813 	 * Number of L2ARC log blocks written. These are used for restoring the
814 	 * L2ARC. Updated during writing of L2ARC log blocks.
815 	 */
816 	kstat_named_t arcstat_l2_log_blk_writes;
817 	/*
818 	 * Moving average of the aligned size of the L2ARC log blocks, in
819 	 * bytes. Updated during L2ARC rebuild and during writing of L2ARC
820 	 * log blocks.
821 	 */
822 	kstat_named_t arcstat_l2_log_blk_avg_asize;
823 	/* Aligned size of L2ARC log blocks on L2ARC devices. */
824 	kstat_named_t arcstat_l2_log_blk_asize;
825 	/* Number of L2ARC log blocks present on L2ARC devices. */
826 	kstat_named_t arcstat_l2_log_blk_count;
827 	/*
828 	 * Moving average of the aligned size of L2ARC restored data, in bytes,
829 	 * to the aligned size of their metadata in L2ARC, in bytes.
830 	 * Updated during L2ARC rebuild and during writing of L2ARC log blocks.
831 	 */
832 	kstat_named_t arcstat_l2_data_to_meta_ratio;
833 	/*
834 	 * Number of times the L2ARC rebuild was successful for an L2ARC device.
835 	 */
836 	kstat_named_t arcstat_l2_rebuild_success;
837 	/*
838 	 * Number of times the L2ARC rebuild failed because the device header
839 	 * was in an unsupported format or corrupted.
840 	 */
841 	kstat_named_t arcstat_l2_rebuild_abort_unsupported;
842 	/*
843 	 * Number of times the L2ARC rebuild failed because of IO errors
844 	 * while reading a log block.
845 	 */
846 	kstat_named_t arcstat_l2_rebuild_abort_io_errors;
847 	/*
848 	 * Number of times the L2ARC rebuild failed because of IO errors when
849 	 * reading the device header.
850 	 */
851 	kstat_named_t arcstat_l2_rebuild_abort_dh_errors;
852 	/*
853 	 * Number of L2ARC log blocks which failed to be restored due to
854 	 * checksum errors.
855 	 */
856 	kstat_named_t arcstat_l2_rebuild_abort_cksum_lb_errors;
857 	/*
858 	 * Number of times the L2ARC rebuild was aborted due to low system
859 	 * memory.
860 	 */
861 	kstat_named_t arcstat_l2_rebuild_abort_lowmem;
862 	/* Logical size of L2ARC restored data, in bytes. */
863 	kstat_named_t arcstat_l2_rebuild_size;
864 	/* Aligned size of L2ARC restored data, in bytes. */
865 	kstat_named_t arcstat_l2_rebuild_asize;
866 	/*
867 	 * Number of L2ARC log entries (buffers) that were successfully
868 	 * restored in ARC.
869 	 */
870 	kstat_named_t arcstat_l2_rebuild_bufs;
871 	/*
872 	 * Number of L2ARC log entries (buffers) already cached in ARC. These
873 	 * were not restored again.
874 	 */
875 	kstat_named_t arcstat_l2_rebuild_bufs_precached;
876 	/*
877 	 * Number of L2ARC log blocks that were restored successfully. Each
878 	 * log block may hold up to L2ARC_LOG_BLK_MAX_ENTRIES buffers.
879 	 */
880 	kstat_named_t arcstat_l2_rebuild_log_blks;
881 	kstat_named_t arcstat_memory_throttle_count;
882 	kstat_named_t arcstat_memory_direct_count;
883 	kstat_named_t arcstat_memory_indirect_count;
884 	kstat_named_t arcstat_memory_all_bytes;
885 	kstat_named_t arcstat_memory_free_bytes;
886 	kstat_named_t arcstat_memory_available_bytes;
887 	kstat_named_t arcstat_no_grow;
888 	kstat_named_t arcstat_tempreserve;
889 	kstat_named_t arcstat_loaned_bytes;
890 	kstat_named_t arcstat_prune;
891 	kstat_named_t arcstat_meta_used;
892 	kstat_named_t arcstat_dnode_limit;
893 	kstat_named_t arcstat_async_upgrade_sync;
894 	/* Number of predictive prefetch requests. */
895 	kstat_named_t arcstat_predictive_prefetch;
896 	/* Number of requests for which predictive prefetch has completed. */
897 	kstat_named_t arcstat_demand_hit_predictive_prefetch;
898 	/* Number of requests for which predictive prefetch was running. */
899 	kstat_named_t arcstat_demand_iohit_predictive_prefetch;
900 	/* Number of prescient prefetch requests. */
901 	kstat_named_t arcstat_prescient_prefetch;
902 	/* Number of requests for which prescient prefetch has completed. */
903 	kstat_named_t arcstat_demand_hit_prescient_prefetch;
904 	/* Number of requests for which prescient prefetch was running. */
905 	kstat_named_t arcstat_demand_iohit_prescient_prefetch;
906 	kstat_named_t arcstat_need_free;
907 	kstat_named_t arcstat_sys_free;
908 	kstat_named_t arcstat_raw_size;
909 	kstat_named_t arcstat_cached_only_in_progress;
910 	kstat_named_t arcstat_abd_chunk_waste_size;
911 } arc_stats_t;
912 
913 typedef struct arc_sums {
914 	wmsum_t arcstat_hits;
915 	wmsum_t arcstat_iohits;
916 	wmsum_t arcstat_misses;
917 	wmsum_t arcstat_demand_data_hits;
918 	wmsum_t arcstat_demand_data_iohits;
919 	wmsum_t arcstat_demand_data_misses;
920 	wmsum_t arcstat_demand_metadata_hits;
921 	wmsum_t arcstat_demand_metadata_iohits;
922 	wmsum_t arcstat_demand_metadata_misses;
923 	wmsum_t arcstat_prefetch_data_hits;
924 	wmsum_t arcstat_prefetch_data_iohits;
925 	wmsum_t arcstat_prefetch_data_misses;
926 	wmsum_t arcstat_prefetch_metadata_hits;
927 	wmsum_t arcstat_prefetch_metadata_iohits;
928 	wmsum_t arcstat_prefetch_metadata_misses;
929 	wmsum_t arcstat_mru_hits;
930 	wmsum_t arcstat_mru_ghost_hits;
931 	wmsum_t arcstat_mfu_hits;
932 	wmsum_t arcstat_mfu_ghost_hits;
933 	wmsum_t arcstat_uncached_hits;
934 	wmsum_t arcstat_deleted;
935 	wmsum_t arcstat_mutex_miss;
936 	wmsum_t arcstat_access_skip;
937 	wmsum_t arcstat_evict_skip;
938 	wmsum_t arcstat_evict_not_enough;
939 	wmsum_t arcstat_evict_l2_cached;
940 	wmsum_t arcstat_evict_l2_eligible;
941 	wmsum_t arcstat_evict_l2_eligible_mfu;
942 	wmsum_t arcstat_evict_l2_eligible_mru;
943 	wmsum_t arcstat_evict_l2_ineligible;
944 	wmsum_t arcstat_evict_l2_skip;
945 	wmsum_t arcstat_hash_collisions;
946 	wmsum_t arcstat_hash_chains;
947 	aggsum_t arcstat_size;
948 	wmsum_t arcstat_compressed_size;
949 	wmsum_t arcstat_uncompressed_size;
950 	wmsum_t arcstat_overhead_size;
951 	wmsum_t arcstat_hdr_size;
952 	wmsum_t arcstat_data_size;
953 	wmsum_t arcstat_metadata_size;
954 	wmsum_t arcstat_dbuf_size;
955 	wmsum_t arcstat_dnode_size;
956 	wmsum_t arcstat_bonus_size;
957 	wmsum_t arcstat_l2_hits;
958 	wmsum_t arcstat_l2_misses;
959 	wmsum_t arcstat_l2_prefetch_asize;
960 	wmsum_t arcstat_l2_mru_asize;
961 	wmsum_t arcstat_l2_mfu_asize;
962 	wmsum_t arcstat_l2_bufc_data_asize;
963 	wmsum_t arcstat_l2_bufc_metadata_asize;
964 	wmsum_t arcstat_l2_feeds;
965 	wmsum_t arcstat_l2_rw_clash;
966 	wmsum_t arcstat_l2_read_bytes;
967 	wmsum_t arcstat_l2_write_bytes;
968 	wmsum_t arcstat_l2_writes_sent;
969 	wmsum_t arcstat_l2_writes_done;
970 	wmsum_t arcstat_l2_writes_error;
971 	wmsum_t arcstat_l2_writes_lock_retry;
972 	wmsum_t arcstat_l2_evict_lock_retry;
973 	wmsum_t arcstat_l2_evict_reading;
974 	wmsum_t arcstat_l2_evict_l1cached;
975 	wmsum_t arcstat_l2_free_on_write;
976 	wmsum_t arcstat_l2_abort_lowmem;
977 	wmsum_t arcstat_l2_cksum_bad;
978 	wmsum_t arcstat_l2_io_error;
979 	wmsum_t arcstat_l2_lsize;
980 	wmsum_t arcstat_l2_psize;
981 	aggsum_t arcstat_l2_hdr_size;
982 	wmsum_t arcstat_l2_log_blk_writes;
983 	wmsum_t arcstat_l2_log_blk_asize;
984 	wmsum_t arcstat_l2_log_blk_count;
985 	wmsum_t arcstat_l2_rebuild_success;
986 	wmsum_t arcstat_l2_rebuild_abort_unsupported;
987 	wmsum_t arcstat_l2_rebuild_abort_io_errors;
988 	wmsum_t arcstat_l2_rebuild_abort_dh_errors;
989 	wmsum_t arcstat_l2_rebuild_abort_cksum_lb_errors;
990 	wmsum_t arcstat_l2_rebuild_abort_lowmem;
991 	wmsum_t arcstat_l2_rebuild_size;
992 	wmsum_t arcstat_l2_rebuild_asize;
993 	wmsum_t arcstat_l2_rebuild_bufs;
994 	wmsum_t arcstat_l2_rebuild_bufs_precached;
995 	wmsum_t arcstat_l2_rebuild_log_blks;
996 	wmsum_t arcstat_memory_throttle_count;
997 	wmsum_t arcstat_memory_direct_count;
998 	wmsum_t arcstat_memory_indirect_count;
999 	wmsum_t arcstat_prune;
1000 	wmsum_t arcstat_meta_used;
1001 	wmsum_t arcstat_async_upgrade_sync;
1002 	wmsum_t arcstat_predictive_prefetch;
1003 	wmsum_t arcstat_demand_hit_predictive_prefetch;
1004 	wmsum_t arcstat_demand_iohit_predictive_prefetch;
1005 	wmsum_t arcstat_prescient_prefetch;
1006 	wmsum_t arcstat_demand_hit_prescient_prefetch;
1007 	wmsum_t arcstat_demand_iohit_prescient_prefetch;
1008 	wmsum_t arcstat_raw_size;
1009 	wmsum_t arcstat_cached_only_in_progress;
1010 	wmsum_t arcstat_abd_chunk_waste_size;
1011 } arc_sums_t;
1012 
1013 typedef struct arc_evict_waiter {
1014 	list_node_t aew_node;
1015 	kcondvar_t aew_cv;
1016 	uint64_t aew_count;
1017 } arc_evict_waiter_t;
1018 
1019 #define	ARCSTAT(stat)	(arc_stats.stat.value.ui64)
1020 
1021 #define	ARCSTAT_INCR(stat, val) \
1022 	wmsum_add(&arc_sums.stat, (val))
1023 
1024 #define	ARCSTAT_BUMP(stat)	ARCSTAT_INCR(stat, 1)
1025 #define	ARCSTAT_BUMPDOWN(stat)	ARCSTAT_INCR(stat, -1)
1026 
1027 #define	arc_no_grow	ARCSTAT(arcstat_no_grow) /* do not grow cache size */
1028 #define	arc_meta	ARCSTAT(arcstat_meta)	/* target frac of metadata */
1029 #define	arc_pd		ARCSTAT(arcstat_pd)	/* target frac of data MRU */
1030 #define	arc_pm		ARCSTAT(arcstat_pm)	/* target frac of meta MRU */
1031 #define	arc_c		ARCSTAT(arcstat_c)	/* target size of cache */
1032 #define	arc_c_min	ARCSTAT(arcstat_c_min)	/* min target cache size */
1033 #define	arc_c_max	ARCSTAT(arcstat_c_max)	/* max target cache size */
1034 #define	arc_sys_free	ARCSTAT(arcstat_sys_free) /* target system free bytes */
1035 
1036 #define	arc_anon	(&ARC_anon)
1037 #define	arc_mru		(&ARC_mru)
1038 #define	arc_mru_ghost	(&ARC_mru_ghost)
1039 #define	arc_mfu		(&ARC_mfu)
1040 #define	arc_mfu_ghost	(&ARC_mfu_ghost)
1041 #define	arc_l2c_only	(&ARC_l2c_only)
1042 #define	arc_uncached	(&ARC_uncached)
1043 
1044 extern taskq_t *arc_prune_taskq;
1045 extern arc_stats_t arc_stats;
1046 extern arc_sums_t arc_sums;
1047 extern hrtime_t arc_growtime;
1048 extern boolean_t arc_warm;
1049 extern uint_t arc_grow_retry;
1050 extern uint_t arc_no_grow_shift;
1051 extern uint_t arc_shrink_shift;
1052 extern kmutex_t arc_prune_mtx;
1053 extern list_t arc_prune_list;
1054 extern arc_state_t	ARC_mfu;
1055 extern arc_state_t	ARC_mru;
1056 extern uint_t zfs_arc_pc_percent;
1057 extern uint_t arc_lotsfree_percent;
1058 extern uint64_t zfs_arc_min;
1059 extern uint64_t zfs_arc_max;
1060 
1061 extern uint64_t arc_reduce_target_size(uint64_t to_free);
1062 extern boolean_t arc_reclaim_needed(void);
1063 extern void arc_kmem_reap_soon(void);
1064 extern void arc_wait_for_eviction(uint64_t, boolean_t, boolean_t);
1065 
1066 extern void arc_lowmem_init(void);
1067 extern void arc_lowmem_fini(void);
1068 extern int arc_memory_throttle(spa_t *spa, uint64_t reserve, uint64_t txg);
1069 extern uint64_t arc_free_memory(void);
1070 extern int64_t arc_available_memory(void);
1071 extern void arc_tuning_update(boolean_t);
1072 extern void arc_register_hotplug(void);
1073 extern void arc_unregister_hotplug(void);
1074 
1075 extern int param_set_arc_u64(ZFS_MODULE_PARAM_ARGS);
1076 extern int param_set_arc_int(ZFS_MODULE_PARAM_ARGS);
1077 extern int param_set_arc_min(ZFS_MODULE_PARAM_ARGS);
1078 extern int param_set_arc_max(ZFS_MODULE_PARAM_ARGS);
1079 
1080 /* used in zdb.c */
1081 boolean_t l2arc_log_blkptr_valid(l2arc_dev_t *dev,
1082     const l2arc_log_blkptr_t *lbp);
1083 
1084 /* used in vdev_trim.c */
1085 void l2arc_dev_hdr_update(l2arc_dev_t *dev);
1086 l2arc_dev_t *l2arc_vdev_get(vdev_t *vd);
1087 
1088 #ifdef __cplusplus
1089 }
1090 #endif
1091 
1092 #endif /* _SYS_ARC_IMPL_H */
1093