zfs/sys/arc.h

/*
 * 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) 2012, 2016 by Delphix. All rights reserved.
 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
 */

#ifndef _SYS_ARC_H
#define _SYS_ARC_H

#include <sys/zfs_context.h>

#ifdef  __cplusplus
extern "C" {
#endif

#include <sys/zio.h>
#include <sys/dmu.h>
#include <sys/spa.h>

/*
 * Used by arc_flush() to inform arc_evict_state() that it should evict
 * all available buffers from the arc state being passed in.
 */
#define ARC_EVICT_ALL   -1ULL

#define HDR_SET_LSIZE(hdr, x) do { \
    ASSERT(IS_P2ALIGNED(x, 1U << SPA_MINBLOCKSHIFT)); \
    (hdr)->b_lsize = ((x) >> SPA_MINBLOCKSHIFT); \
_NOTE(CONSTCOND) } while (0)

#define HDR_SET_PSIZE(hdr, x) do { \
    ASSERT(IS_P2ALIGNED((x), 1U << SPA_MINBLOCKSHIFT)); \
    (hdr)->b_psize = ((x) >> SPA_MINBLOCKSHIFT); \
_NOTE(CONSTCOND) } while (0)

#define HDR_GET_LSIZE(hdr)  ((hdr)->b_lsize << SPA_MINBLOCKSHIFT)
#define HDR_GET_PSIZE(hdr)  ((hdr)->b_psize << SPA_MINBLOCKSHIFT)

typedef struct arc_buf_hdr arc_buf_hdr_t;
typedef struct arc_buf arc_buf_t;
typedef void arc_done_func_t(zio_t *zio, arc_buf_t *buf, void *private);

/* generic arc_done_func_t's which you can use */
arc_done_func_t arc_bcopy_func;
arc_done_func_t arc_getbuf_func;

extern int zfs_arc_num_sublists_per_state;

typedef enum arc_flags
{
    /*
     * Public flags that can be passed into the ARC by external consumers.
     */
    ARC_FLAG_WAIT           = 1 << 0,   /* perform sync I/O */
    ARC_FLAG_NOWAIT         = 1 << 1,   /* perform async I/O */
    ARC_FLAG_PREFETCH       = 1 << 2,   /* I/O is a prefetch */
    ARC_FLAG_CACHED         = 1 << 3,   /* I/O was in cache */
    ARC_FLAG_L2CACHE        = 1 << 4,   /* cache in L2ARC */
    ARC_FLAG_PREDICTIVE_PREFETCH    = 1 << 5,   /* I/O from zfetch */

    /*
     * Private ARC flags.  These flags are private ARC only flags that
     * will show up in b_flags in the arc_hdr_buf_t. These flags should
     * only be set by ARC code.
     */
    ARC_FLAG_IN_HASH_TABLE      = 1 << 6,   /* buffer is hashed */
    ARC_FLAG_IO_IN_PROGRESS     = 1 << 7,   /* I/O in progress */
    ARC_FLAG_IO_ERROR       = 1 << 8,   /* I/O failed for buf */
    ARC_FLAG_INDIRECT       = 1 << 9,   /* indirect block */
    /* Indicates that block was read with ASYNC priority. */
    ARC_FLAG_PRIO_ASYNC_READ    = 1 << 10,
    ARC_FLAG_L2_WRITING     = 1 << 11,  /* write in progress */
    ARC_FLAG_L2_EVICTED     = 1 << 12,  /* evicted during I/O */
    ARC_FLAG_L2_WRITE_HEAD      = 1 << 13,  /* head of write list */
    /* indicates that the buffer contains metadata (otherwise, data) */
    ARC_FLAG_BUFC_METADATA      = 1 << 14,

    /* Flags specifying whether optional hdr struct fields are defined */
    ARC_FLAG_HAS_L1HDR      = 1 << 15,
    ARC_FLAG_HAS_L2HDR      = 1 << 16,

    /*
     * Indicates the arc_buf_hdr_t's b_pdata matches the on-disk data.
     * This allows the l2arc to use the blkptr's checksum to verify
     * the data without having to store the checksum in the hdr.
     */
    ARC_FLAG_COMPRESSED_ARC     = 1 << 17,
    ARC_FLAG_SHARED_DATA        = 1 << 18,

    /*
     * The arc buffer's compression mode is stored in the top 7 bits of the
     * flags field, so these dummy flags are included so that MDB can
     * interpret the enum properly.
     */
    ARC_FLAG_COMPRESS_0     = 1 << 24,
    ARC_FLAG_COMPRESS_1     = 1 << 25,
    ARC_FLAG_COMPRESS_2     = 1 << 26,
    ARC_FLAG_COMPRESS_3     = 1 << 27,
    ARC_FLAG_COMPRESS_4     = 1 << 28,
    ARC_FLAG_COMPRESS_5     = 1 << 29,
    ARC_FLAG_COMPRESS_6     = 1 << 30

} arc_flags_t;

typedef enum arc_buf_flags {
    ARC_BUF_FLAG_SHARED     = 1 << 0,
    ARC_BUF_FLAG_COMPRESSED     = 1 << 1
} arc_buf_flags_t;

struct arc_buf {
    arc_buf_hdr_t       *b_hdr;
    arc_buf_t       *b_next;
    kmutex_t        b_evict_lock;
    void            *b_data;
    arc_buf_flags_t     b_flags;
};

typedef enum arc_buf_contents {
    ARC_BUFC_INVALID,           /* invalid type */
    ARC_BUFC_DATA,              /* buffer contains data */
    ARC_BUFC_METADATA,          /* buffer contains metadata */
    ARC_BUFC_NUMTYPES
} arc_buf_contents_t;

/*
 * The following breakdows of arc_size exist for kstat only.
 */
typedef enum arc_space_type {
    ARC_SPACE_DATA,
    ARC_SPACE_META,
    ARC_SPACE_HDRS,
    ARC_SPACE_L2HDRS,
    ARC_SPACE_OTHER,
    ARC_SPACE_NUMTYPES
} arc_space_type_t;

void arc_space_consume(uint64_t space, arc_space_type_t type);
void arc_space_return(uint64_t space, arc_space_type_t type);
boolean_t arc_is_metadata(arc_buf_t *buf);
enum zio_compress arc_get_compression(arc_buf_t *buf);
int arc_decompress(arc_buf_t *buf);
arc_buf_t *arc_alloc_buf(spa_t *spa, void *tag, arc_buf_contents_t type,
    int32_t size);
arc_buf_t *arc_alloc_compressed_buf(spa_t *spa, void *tag,
    uint64_t psize, uint64_t lsize, enum zio_compress compression_type);
arc_buf_t *arc_loan_buf(spa_t *spa, boolean_t is_metadata, int size);
arc_buf_t *arc_loan_compressed_buf(spa_t *spa, uint64_t psize, uint64_t lsize,
    enum zio_compress compression_type);
void arc_return_buf(arc_buf_t *buf, void *tag);
void arc_loan_inuse_buf(arc_buf_t *buf, void *tag);
void arc_buf_destroy(arc_buf_t *buf, void *tag);
int arc_buf_size(arc_buf_t *buf);
int arc_buf_lsize(arc_buf_t *buf);
void arc_release(arc_buf_t *buf, void *tag);
int arc_released(arc_buf_t *buf);
void arc_buf_freeze(arc_buf_t *buf);
void arc_buf_thaw(arc_buf_t *buf);
#ifdef ZFS_DEBUG
int arc_referenced(arc_buf_t *buf);
#endif

int arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
    arc_done_func_t *done, void *private, zio_priority_t priority, int flags,
    arc_flags_t *arc_flags, const zbookmark_phys_t *zb);
zio_t *arc_write(zio_t *pio, spa_t *spa, uint64_t txg,
    blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, const zio_prop_t *zp,
    arc_done_func_t *ready, arc_done_func_t *child_ready,
    arc_done_func_t *physdone, arc_done_func_t *done,
    void *private, zio_priority_t priority, int zio_flags,
    const zbookmark_phys_t *zb);
void arc_freed(spa_t *spa, const blkptr_t *bp);

void arc_flush(spa_t *spa, boolean_t retry);
void arc_tempreserve_clear(uint64_t reserve);
int arc_tempreserve_space(uint64_t reserve, uint64_t txg);

uint64_t arc_max_bytes(void);
void arc_init(void);
void arc_fini(void);

/*
 * Level 2 ARC
 */

void l2arc_add_vdev(spa_t *spa, vdev_t *vd);
void l2arc_remove_vdev(vdev_t *vd);
boolean_t l2arc_vdev_present(vdev_t *vd);
void l2arc_init(void);
void l2arc_fini(void);
void l2arc_start(void);
void l2arc_stop(void);

#ifndef _KERNEL
extern boolean_t arc_watch;
extern int arc_procfd;
#endif

#ifdef  __cplusplus
}
#endif

#endif /* _SYS_ARC_H */