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      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 2009 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  * 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 */
    131