include/sys/txg.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 2010 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #ifndef _SYS_TXG_H
  27 #define _SYS_TXG_H
  28
  29 #include <sys/spa.h>
  30 #include <sys/zfs_context.h>
  31
  32 #ifdef  __cplusplus
  33 extern "C" {
  34 #endif
  35
  36 #define TXG_CONCURRENT_STATES   3       /* open, quiescing, syncing     */
  37 #define TXG_SIZE                4               /* next power of 2      */
  38 #define TXG_MASK                (TXG_SIZE - 1)  /* mask for size        */
  39 #define TXG_INITIAL             TXG_SIZE        /* initial txg          */
  40 #define TXG_IDX                 (txg & TXG_MASK)
  41
  42 /* Number of txgs worth of frees we defer adding to in-core spacemaps */
  43 #define TXG_DEFER_SIZE          2
  44
  45 #define TXG_WAIT                1ULL
  46 #define TXG_NOWAIT              2ULL
  47
  48 typedef struct tx_cpu tx_cpu_t;
  49
  50 typedef struct txg_handle {
  51         tx_cpu_t        *th_cpu;
  52         uint64_t        th_txg;
  53 } txg_handle_t;
  54
  55 typedef struct txg_node {
  56         struct txg_node *tn_next[TXG_SIZE];
  57         uint8_t         tn_member[TXG_SIZE];
  58 } txg_node_t;
  59
  60 typedef struct txg_list {
  61         kmutex_t        tl_lock;
  62         size_t          tl_offset;
  63         txg_node_t      *tl_head[TXG_SIZE];
  64 } txg_list_t;
  65
  66 struct dsl_pool;
  67
  68 extern void txg_init(struct dsl_pool *dp, uint64_t txg);
  69 extern void txg_fini(struct dsl_pool *dp);
  70 extern void txg_sync_start(struct dsl_pool *dp);
  71 extern void txg_sync_stop(struct dsl_pool *dp);
  72 extern uint64_t txg_hold_open(struct dsl_pool *dp, txg_handle_t *txghp);
  73 extern void txg_rele_to_quiesce(txg_handle_t *txghp);
  74 extern void txg_rele_to_sync(txg_handle_t *txghp);
  75 extern void txg_register_callbacks(txg_handle_t *txghp, list_t *tx_callbacks);
  76
  77 /*
  78  * Delay the caller by the specified number of ticks or until
  79  * the txg closes (whichever comes first).  This is intended
  80  * to be used to throttle writers when the system nears its
  81  * capacity.
  82  */
  83 extern void txg_delay(struct dsl_pool *dp, uint64_t txg, int ticks);
  84
  85 /*
  86  * Wait until the given transaction group has finished syncing.
  87  * Try to make this happen as soon as possible (eg. kick off any
  88  * necessary syncs immediately).  If txg==0, wait for the currently open
  89  * txg to finish syncing.
  90  */
  91 extern void txg_wait_synced(struct dsl_pool *dp, uint64_t txg);
  92
  93 /*
  94  * Wait until the given transaction group, or one after it, is
  95  * the open transaction group.  Try to make this happen as soon
  96  * as possible (eg. kick off any necessary syncs immediately).
  97  * If txg == 0, wait for the next open txg.
  98  */
  99 extern void txg_wait_open(struct dsl_pool *dp, uint64_t txg);
 100
 101 /*
 102  * Returns TRUE if we are "backed up" waiting for the syncing
 103  * transaction to complete; otherwise returns FALSE.
 104  */
 105 extern boolean_t txg_stalled(struct dsl_pool *dp);
 106
 107 /* returns TRUE if someone is waiting for the next txg to sync */
 108 extern boolean_t txg_sync_waiting(struct dsl_pool *dp);
 109
 110 /*
 111  * Wait for pending commit callbacks of already-synced transactions to finish
 112  * processing.
 113  */
 114 extern void txg_wait_callbacks(struct dsl_pool *dp);
 115
 116 /*
 117  * Per-txg object lists.
 118  */
 119
 120 #define TXG_CLEAN(txg)  ((txg) - 1)
 121
 122 extern void txg_list_create(txg_list_t *tl, size_t offset);
 123 extern void txg_list_destroy(txg_list_t *tl);
 124 extern int txg_list_empty(txg_list_t *tl, uint64_t txg);
 125 extern int txg_list_add(txg_list_t *tl, void *p, uint64_t txg);
 126 extern int txg_list_add_tail(txg_list_t *tl, void *p, uint64_t txg);
 127 extern void *txg_list_remove(txg_list_t *tl, uint64_t txg);
 128 extern void *txg_list_remove_this(txg_list_t *tl, void *p, uint64_t txg);
 129 extern int txg_list_member(txg_list_t *tl, void *p, uint64_t txg);
 130 extern void *txg_list_head(txg_list_t *tl, uint64_t txg);
 131 extern void *txg_list_next(txg_list_t *tl, void *p, uint64_t txg);
 132
 133 #ifdef  __cplusplus
 134 }
 135 #endif
 136
 137 #endif  /* _SYS_TXG_H */