include/sys/arc.h

   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 http://www.opensolaris.org/os/licensing.
  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) 2012, 2016 by Delphix. All rights reserved.
  24  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
  25  */
  26
  27 #ifndef _SYS_ARC_H
  28 #define _SYS_ARC_H
  29
  30 #include <sys/zfs_context.h>
  31
  32 #ifdef  __cplusplus
  33 extern "C" {
  34 #endif
  35
  36 #include <sys/zio.h>
  37 #include <sys/dmu.h>
  38 #include <sys/spa.h>
  39 #include <sys/refcount.h>
  40
  41 /*
  42  * Used by arc_flush() to inform arc_evict_state() that it should evict
  43  * all available buffers from the arc state being passed in.
  44  */
  45 #define ARC_EVICT_ALL   -1ULL
  46
  47 #define HDR_SET_LSIZE(hdr, x) do { \
  48         ASSERT(IS_P2ALIGNED(x, 1U << SPA_MINBLOCKSHIFT)); \
  49         (hdr)->b_lsize = ((x) >> SPA_MINBLOCKSHIFT); \
  50 _NOTE(CONSTCOND) } while (0)
  51
  52 #define HDR_SET_PSIZE(hdr, x) do { \
  53         ASSERT(IS_P2ALIGNED((x), 1U << SPA_MINBLOCKSHIFT)); \
  54         (hdr)->b_psize = ((x) >> SPA_MINBLOCKSHIFT); \
  55 _NOTE(CONSTCOND) } while (0)
  56
  57 #define HDR_GET_LSIZE(hdr)      ((hdr)->b_lsize << SPA_MINBLOCKSHIFT)
  58 #define HDR_GET_PSIZE(hdr)      ((hdr)->b_psize << SPA_MINBLOCKSHIFT)
  59
  60 typedef struct arc_buf_hdr arc_buf_hdr_t;
  61 typedef struct arc_buf arc_buf_t;
  62 typedef struct arc_prune arc_prune_t;
  63 typedef void arc_done_func_t(zio_t *zio, arc_buf_t *buf, void *private);
  64 typedef void arc_prune_func_t(int64_t bytes, void *private);
  65
  66 /* Shared module parameters */
  67 extern int zfs_arc_average_blocksize;
  68
  69 /* generic arc_done_func_t's which you can use */
  70 arc_done_func_t arc_bcopy_func;
  71 arc_done_func_t arc_getbuf_func;
  72
  73 extern int zfs_arc_num_sublists_per_state;
  74
  75 /* generic arc_prune_func_t wrapper for callbacks */
  76 struct arc_prune {
  77         arc_prune_func_t        *p_pfunc;
  78         void                    *p_private;
  79         uint64_t                p_adjust;
  80         list_node_t             p_node;
  81         refcount_t              p_refcnt;
  82 };
  83
  84 typedef enum arc_strategy {
  85         ARC_STRATEGY_META_ONLY          = 0, /* Evict only meta data buffers */
  86         ARC_STRATEGY_META_BALANCED      = 1, /* Evict data buffers if needed */
  87 } arc_strategy_t;
  88
  89 typedef enum arc_flags
  90 {
  91         /*
  92          * Public flags that can be passed into the ARC by external consumers.
  93          */
  94         ARC_FLAG_WAIT                   = 1 << 0,       /* perform sync I/O */
  95         ARC_FLAG_NOWAIT                 = 1 << 1,       /* perform async I/O */
  96         ARC_FLAG_PREFETCH               = 1 << 2,       /* I/O is a prefetch */
  97         ARC_FLAG_CACHED                 = 1 << 3,       /* I/O was in cache */
  98         ARC_FLAG_L2CACHE                = 1 << 4,       /* cache in L2ARC */
  99         ARC_FLAG_PREDICTIVE_PREFETCH    = 1 << 5,       /* I/O from zfetch */
 100
 101         /*
 102          * Private ARC flags.  These flags are private ARC only flags that
 103          * will show up in b_flags in the arc_hdr_buf_t. These flags should
 104          * only be set by ARC code.
 105          */
 106         ARC_FLAG_IN_HASH_TABLE          = 1 << 6,       /* buffer is hashed */
 107         ARC_FLAG_IO_IN_PROGRESS         = 1 << 7,       /* I/O in progress */
 108         ARC_FLAG_IO_ERROR               = 1 << 8,       /* I/O failed for buf */
 109         ARC_FLAG_INDIRECT               = 1 << 9,       /* indirect block */
 110         /* Indicates that block was read with ASYNC priority. */
 111         ARC_FLAG_PRIO_ASYNC_READ        = 1 << 10,
 112         ARC_FLAG_L2_WRITING             = 1 << 11,      /* write in progress */
 113         ARC_FLAG_L2_EVICTED             = 1 << 12,      /* evicted during I/O */
 114         ARC_FLAG_L2_WRITE_HEAD          = 1 << 13,      /* head of write list */
 115         /* indicates that the buffer contains metadata (otherwise, data) */
 116         ARC_FLAG_BUFC_METADATA          = 1 << 14,
 117
 118         /* Flags specifying whether optional hdr struct fields are defined */
 119         ARC_FLAG_HAS_L1HDR              = 1 << 15,
 120         ARC_FLAG_HAS_L2HDR              = 1 << 16,
 121
 122         /*
 123          * Indicates the arc_buf_hdr_t's b_pdata matches the on-disk data.
 124          * This allows the l2arc to use the blkptr's checksum to verify
 125          * the data without having to store the checksum in the hdr.
 126          */
 127         ARC_FLAG_COMPRESSED_ARC         = 1 << 17,
 128         ARC_FLAG_SHARED_DATA            = 1 << 18,
 129
 130         /*
 131          * The arc buffer's compression mode is stored in the top 7 bits of the
 132          * flags field, so these dummy flags are included so that MDB can
 133          * interpret the enum properly.
 134          */
 135         ARC_FLAG_COMPRESS_0             = 1 << 24,
 136         ARC_FLAG_COMPRESS_1             = 1 << 25,
 137         ARC_FLAG_COMPRESS_2             = 1 << 26,
 138         ARC_FLAG_COMPRESS_3             = 1 << 27,
 139         ARC_FLAG_COMPRESS_4             = 1 << 28,
 140         ARC_FLAG_COMPRESS_5             = 1 << 29,
 141         ARC_FLAG_COMPRESS_6             = 1 << 30
 142
 143 } arc_flags_t;
 144
 145 typedef enum arc_buf_flags {
 146         ARC_BUF_FLAG_SHARED             = 1 << 0,
 147         ARC_BUF_FLAG_COMPRESSED         = 1 << 1
 148 } arc_buf_flags_t;
 149
 150 struct arc_buf {
 151         arc_buf_hdr_t           *b_hdr;
 152         arc_buf_t               *b_next;
 153         kmutex_t                b_evict_lock;
 154         void                    *b_data;
 155         arc_buf_flags_t         b_flags;
 156 };
 157
 158 typedef enum arc_buf_contents {
 159         ARC_BUFC_INVALID,                       /* invalid type */
 160         ARC_BUFC_DATA,                          /* buffer contains data */
 161         ARC_BUFC_METADATA,                      /* buffer contains metadata */
 162         ARC_BUFC_NUMTYPES
 163 } arc_buf_contents_t;
 164
 165 /*
 166  * The following breakdows of arc_size exist for kstat only.
 167  */
 168 typedef enum arc_space_type {
 169         ARC_SPACE_DATA,
 170         ARC_SPACE_META,
 171         ARC_SPACE_HDRS,
 172         ARC_SPACE_L2HDRS,
 173         ARC_SPACE_DBUF,
 174         ARC_SPACE_DNODE,
 175         ARC_SPACE_BONUS,
 176         ARC_SPACE_NUMTYPES
 177 } arc_space_type_t;
 178
 179 typedef enum arc_state_type {
 180         ARC_STATE_ANON,
 181         ARC_STATE_MRU,
 182         ARC_STATE_MRU_GHOST,
 183         ARC_STATE_MFU,
 184         ARC_STATE_MFU_GHOST,
 185         ARC_STATE_L2C_ONLY,
 186         ARC_STATE_NUMTYPES
 187 } arc_state_type_t;
 188
 189 typedef struct arc_buf_info {
 190         arc_state_type_t        abi_state_type;
 191         arc_buf_contents_t      abi_state_contents;
 192         uint32_t                abi_flags;
 193         uint32_t                abi_bufcnt;
 194         uint64_t                abi_size;
 195         uint64_t                abi_spa;
 196         uint64_t                abi_access;
 197         uint32_t                abi_mru_hits;
 198         uint32_t                abi_mru_ghost_hits;
 199         uint32_t                abi_mfu_hits;
 200         uint32_t                abi_mfu_ghost_hits;
 201         uint32_t                abi_l2arc_hits;
 202         uint32_t                abi_holds;
 203         uint64_t                abi_l2arc_dattr;
 204         uint64_t                abi_l2arc_asize;
 205         enum zio_compress       abi_l2arc_compress;
 206 } arc_buf_info_t;
 207
 208 void arc_space_consume(uint64_t space, arc_space_type_t type);
 209 void arc_space_return(uint64_t space, arc_space_type_t type);
 210 boolean_t arc_is_metadata(arc_buf_t *buf);
 211 enum zio_compress arc_get_compression(arc_buf_t *buf);
 212 int arc_decompress(arc_buf_t *buf);
 213 arc_buf_t *arc_alloc_buf(spa_t *spa, void *tag, arc_buf_contents_t type,
 214     int32_t size);
 215 arc_buf_t *arc_alloc_compressed_buf(spa_t *spa, void *tag,
 216     uint64_t psize, uint64_t lsize, enum zio_compress compression_type);
 217 arc_buf_t *arc_loan_buf(spa_t *spa, boolean_t is_metadata, int size);
 218 arc_buf_t *arc_loan_compressed_buf(spa_t *spa, uint64_t psize, uint64_t lsize,
 219     enum zio_compress compression_type);
 220 void arc_return_buf(arc_buf_t *buf, void *tag);
 221 void arc_loan_inuse_buf(arc_buf_t *buf, void *tag);
 222 void arc_buf_destroy(arc_buf_t *buf, void *tag);
 223 void arc_buf_info(arc_buf_t *buf, arc_buf_info_t *abi, int state_index);
 224 uint64_t arc_buf_size(arc_buf_t *buf);
 225 uint64_t arc_buf_lsize(arc_buf_t *buf);
 226 void arc_release(arc_buf_t *buf, void *tag);
 227 int arc_released(arc_buf_t *buf);
 228 void arc_buf_sigsegv(int sig, siginfo_t *si, void *unused);
 229 void arc_buf_freeze(arc_buf_t *buf);
 230 void arc_buf_thaw(arc_buf_t *buf);
 231 #ifdef ZFS_DEBUG
 232 int arc_referenced(arc_buf_t *buf);
 233 #endif
 234
 235 int arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
 236     arc_done_func_t *done, void *private, zio_priority_t priority, int flags,
 237     arc_flags_t *arc_flags, const zbookmark_phys_t *zb);
 238 zio_t *arc_write(zio_t *pio, spa_t *spa, uint64_t txg,
 239     blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, const zio_prop_t *zp,
 240     arc_done_func_t *ready, arc_done_func_t *child_ready,
 241     arc_done_func_t *physdone, arc_done_func_t *done,
 242     void *private, zio_priority_t priority, int zio_flags,
 243     const zbookmark_phys_t *zb);
 244
 245 arc_prune_t *arc_add_prune_callback(arc_prune_func_t *func, void *private);
 246 void arc_remove_prune_callback(arc_prune_t *p);
 247 void arc_freed(spa_t *spa, const blkptr_t *bp);
 248
 249 void arc_flush(spa_t *spa, boolean_t retry);
 250 void arc_tempreserve_clear(uint64_t reserve);
 251 int arc_tempreserve_space(uint64_t reserve, uint64_t txg);
 252
 253 uint64_t arc_max_bytes(void);
 254 void arc_init(void);
 255 void arc_fini(void);
 256
 257 /*
 258  * Level 2 ARC
 259  */
 260
 261 void l2arc_add_vdev(spa_t *spa, vdev_t *vd);
 262 void l2arc_remove_vdev(vdev_t *vd);
 263 boolean_t l2arc_vdev_present(vdev_t *vd);
 264 void l2arc_init(void);
 265 void l2arc_fini(void);
 266 void l2arc_start(void);
 267 void l2arc_stop(void);
 268
 269 #ifndef _KERNEL
 270 extern boolean_t arc_watch;
 271 #endif
 272
 273 #ifdef  __cplusplus
 274 }
 275 #endif
 276
 277 #endif /* _SYS_ARC_H */