zfs/lib/libzpool/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 2008 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 #pragma ident   "%Z%%M% %I%     %E% SMI"
  30
  31 #include <sys/spa.h>
  32 #include <sys/zfs_context.h>
  33
  34 #ifdef  __cplusplus
  35 extern "C" {
  36 #endif
  37
  38 #define TXG_CONCURRENT_STATES   3       /* open, quiescing, syncing     */
  39 #define TXG_SIZE                4               /* next power of 2      */
  40 #define TXG_MASK                (TXG_SIZE - 1)  /* mask for size        */
  41 #define TXG_INITIAL             TXG_SIZE        /* initial txg          */
  42 #define TXG_IDX                 (txg & TXG_MASK)
  43
  44 #define TXG_WAIT                1ULL
  45 #define TXG_NOWAIT              2ULL
  46
  47 typedef struct tx_cpu tx_cpu_t;
  48
  49 typedef struct txg_handle {
  50         tx_cpu_t        *th_cpu;
  51         uint64_t        th_txg;
  52 } txg_handle_t;
  53
  54 typedef struct txg_node {
  55         struct txg_node *tn_next[TXG_SIZE];
  56         uint8_t         tn_member[TXG_SIZE];
  57 } txg_node_t;
  58
  59 typedef struct txg_list {
  60         kmutex_t        tl_lock;
  61         size_t          tl_offset;
  62         txg_node_t      *tl_head[TXG_SIZE];
  63 } txg_list_t;
  64
  65 struct dsl_pool;
  66
  67 extern void txg_init(struct dsl_pool *dp, uint64_t txg);
  68 extern void txg_fini(struct dsl_pool *dp);
  69 extern void txg_sync_start(struct dsl_pool *dp);
  70 extern void txg_sync_stop(struct dsl_pool *dp);
  71 extern uint64_t txg_hold_open(struct dsl_pool *dp, txg_handle_t *txghp);
  72 extern void txg_rele_to_quiesce(txg_handle_t *txghp);
  73 extern void txg_rele_to_sync(txg_handle_t *txghp);
  74 extern void txg_suspend(struct dsl_pool *dp);
  75 extern void txg_resume(struct dsl_pool *dp);
  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  * Per-txg object lists.
 112  */
 113
 114 #define TXG_CLEAN(txg)  ((txg) - 1)
 115
 116 extern void txg_list_create(txg_list_t *tl, size_t offset);
 117 extern void txg_list_destroy(txg_list_t *tl);
 118 extern int txg_list_empty(txg_list_t *tl, uint64_t txg);
 119 extern int txg_list_add(txg_list_t *tl, void *p, uint64_t txg);
 120 extern void *txg_list_remove(txg_list_t *tl, uint64_t txg);
 121 extern void *txg_list_remove_this(txg_list_t *tl, void *p, uint64_t txg);
 122 extern int txg_list_member(txg_list_t *tl, void *p, uint64_t txg);
 123 extern void *txg_list_head(txg_list_t *tl, uint64_t txg);
 124 extern void *txg_list_next(txg_list_t *tl, void *p, uint64_t txg);
 125
 126 #ifdef  __cplusplus
 127 }
 128 #endif
 129
 130 #endif  /* _SYS_TXG_H */