1fa9e4066Sahrens /* 2fa9e4066Sahrens * CDDL HEADER START 3fa9e4066Sahrens * 4fa9e4066Sahrens * The contents of this file are subject to the terms of the 51ab7f2deSmaybee * Common Development and Distribution License (the "License"). 61ab7f2deSmaybee * You may not use this file except in compliance with the License. 7fa9e4066Sahrens * 8fa9e4066Sahrens * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9fa9e4066Sahrens * or http://www.opensolaris.org/os/licensing. 10fa9e4066Sahrens * See the License for the specific language governing permissions 11fa9e4066Sahrens * and limitations under the License. 12fa9e4066Sahrens * 13fa9e4066Sahrens * When distributing Covered Code, include this CDDL HEADER in each 14fa9e4066Sahrens * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15fa9e4066Sahrens * If applicable, add the following below this CDDL HEADER, with the 16fa9e4066Sahrens * fields enclosed by brackets "[]" replaced with your own identifying 17fa9e4066Sahrens * information: Portions Copyright [yyyy] [name of copyright owner] 18fa9e4066Sahrens * 19fa9e4066Sahrens * CDDL HEADER END 20fa9e4066Sahrens */ 2169962b56SMatthew Ahrens 22fa9e4066Sahrens /* 23d20e665cSRicardo M. Correia * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 24fa9e4066Sahrens * Use is subject to license terms. 25fa9e4066Sahrens */ 26fa9e4066Sahrens 270689f76cSAdam Leventhal /* 28*fa41d87dSSerapheim Dimitropoulos * Copyright (c) 2013, 2017 by Delphix. All rights reserved. 290689f76cSAdam Leventhal */ 300689f76cSAdam Leventhal 31fa9e4066Sahrens #ifndef _SYS_TXG_IMPL_H 32fa9e4066Sahrens #define _SYS_TXG_IMPL_H 33fa9e4066Sahrens 34fa9e4066Sahrens #include <sys/spa.h> 35fa9e4066Sahrens #include <sys/txg.h> 36fa9e4066Sahrens 37fa9e4066Sahrens #ifdef __cplusplus 38fa9e4066Sahrens extern "C" { 39fa9e4066Sahrens #endif 40fa9e4066Sahrens 414a923759SGeorge Wilson /* 424a923759SGeorge Wilson * The tx_cpu structure is a per-cpu structure that is used to track 434a923759SGeorge Wilson * the number of active transaction holds (tc_count). As transactions 444a923759SGeorge Wilson * are assigned into a transaction group the appropriate tc_count is 454a923759SGeorge Wilson * incremented to indicate that there are pending changes that have yet 464a923759SGeorge Wilson * to quiesce. Consumers evenutally call txg_rele_to_sync() to decrement 474a923759SGeorge Wilson * the tc_count. A transaction group is not considered quiesced until all 484a923759SGeorge Wilson * tx_cpu structures have reached a tc_count of zero. 494a923759SGeorge Wilson * 504a923759SGeorge Wilson * This structure is a per-cpu structure by design. Updates to this structure 514a923759SGeorge Wilson * are frequent and concurrent. Having a single structure would result in 524a923759SGeorge Wilson * heavy lock contention so a per-cpu design was implemented. With the fanned 534a923759SGeorge Wilson * out mutex design, consumers only need to lock the mutex associated with 544a923759SGeorge Wilson * thread's cpu. 554a923759SGeorge Wilson * 564a923759SGeorge Wilson * The tx_cpu contains two locks, the tc_lock and tc_open_lock. 574a923759SGeorge Wilson * The tc_lock is used to protect all members of the tx_cpu structure with 584a923759SGeorge Wilson * the exception of the tc_open_lock. This lock should only be held for a 594a923759SGeorge Wilson * short period of time, typically when updating the value of tc_count. 604a923759SGeorge Wilson * 614a923759SGeorge Wilson * The tc_open_lock protects the tx_open_txg member of the tx_state structure. 624a923759SGeorge Wilson * This lock is used to ensure that transactions are only assigned into 634a923759SGeorge Wilson * the current open transaction group. In order to move the current open 644a923759SGeorge Wilson * transaction group to the quiesce phase, the txg_quiesce thread must 654a923759SGeorge Wilson * grab all tc_open_locks, increment the tx_open_txg, and drop the locks. 664a923759SGeorge Wilson * The tc_open_lock is held until the transaction is assigned into the 674a923759SGeorge Wilson * transaction group. Typically, this is a short operation but if throttling 684a923759SGeorge Wilson * is occuring it may be held for longer periods of time. 694a923759SGeorge Wilson */ 70fa9e4066Sahrens struct tx_cpu { 714a923759SGeorge Wilson kmutex_t tc_open_lock; /* protects tx_open_txg */ 724a923759SGeorge Wilson kmutex_t tc_lock; /* protects the rest of this struct */ 73fa9e4066Sahrens kcondvar_t tc_cv[TXG_SIZE]; 740689f76cSAdam Leventhal uint64_t tc_count[TXG_SIZE]; /* tx hold count on each txg */ 75d20e665cSRicardo M. Correia list_t tc_callbacks[TXG_SIZE]; /* commit cb list */ 764a923759SGeorge Wilson char tc_pad[8]; /* pad to fill 3 cache lines */ 77fa9e4066Sahrens }; 78fa9e4066Sahrens 794a923759SGeorge Wilson /* 804a923759SGeorge Wilson * The tx_state structure maintains the state information about the different 814a923759SGeorge Wilson * stages of the pool's transcation groups. A per pool tx_state structure 824a923759SGeorge Wilson * is used to track this information. The tx_state structure also points to 834a923759SGeorge Wilson * an array of tx_cpu structures (described above). Although the tx_sync_lock 844a923759SGeorge Wilson * is used to protect the members of this structure, it is not used to 854a923759SGeorge Wilson * protect the tx_open_txg. Instead a special lock in the tx_cpu structure 864a923759SGeorge Wilson * is used. Readers of tx_open_txg must grab the per-cpu tc_open_lock. 874a923759SGeorge Wilson * Any thread wishing to update tx_open_txg must grab the tc_open_lock on 884a923759SGeorge Wilson * every cpu (see txg_quiesce()). 894a923759SGeorge Wilson */ 90fa9e4066Sahrens typedef struct tx_state { 910689f76cSAdam Leventhal tx_cpu_t *tx_cpu; /* protects access to tx_open_txg */ 920689f76cSAdam Leventhal kmutex_t tx_sync_lock; /* protects the rest of this struct */ 9369962b56SMatthew Ahrens 94fa9e4066Sahrens uint64_t tx_open_txg; /* currently open txg id */ 95*fa41d87dSSerapheim Dimitropoulos uint64_t tx_quiescing_txg; /* currently quiescing txg id */ 96fa9e4066Sahrens uint64_t tx_quiesced_txg; /* quiesced txg waiting for sync */ 97fa9e4066Sahrens uint64_t tx_syncing_txg; /* currently syncing txg id */ 98fa9e4066Sahrens uint64_t tx_synced_txg; /* last synced txg id */ 99fa9e4066Sahrens 10069962b56SMatthew Ahrens hrtime_t tx_open_time; /* start time of tx_open_txg */ 10169962b56SMatthew Ahrens 102fa9e4066Sahrens uint64_t tx_sync_txg_waiting; /* txg we're waiting to sync */ 103fa9e4066Sahrens uint64_t tx_quiesce_txg_waiting; /* txg we're waiting to open */ 104fa9e4066Sahrens 105fa9e4066Sahrens kcondvar_t tx_sync_more_cv; 106fa9e4066Sahrens kcondvar_t tx_sync_done_cv; 107fa9e4066Sahrens kcondvar_t tx_quiesce_more_cv; 108fa9e4066Sahrens kcondvar_t tx_quiesce_done_cv; 1091ab7f2deSmaybee kcondvar_t tx_timeout_cv; 110fa9e4066Sahrens kcondvar_t tx_exit_cv; /* wait for all threads to exit */ 111fa9e4066Sahrens 112fa9e4066Sahrens uint8_t tx_threads; /* number of threads */ 113fa9e4066Sahrens uint8_t tx_exiting; /* set when we're exiting */ 114fa9e4066Sahrens 115fa9e4066Sahrens kthread_t *tx_sync_thread; 116fa9e4066Sahrens kthread_t *tx_quiesce_thread; 117d20e665cSRicardo M. Correia 118d20e665cSRicardo M. Correia taskq_t *tx_commit_cb_taskq; /* commit callback taskq */ 119fa9e4066Sahrens } tx_state_t; 120fa9e4066Sahrens 121fa9e4066Sahrens #ifdef __cplusplus 122fa9e4066Sahrens } 123fa9e4066Sahrens #endif 124fa9e4066Sahrens 125fa9e4066Sahrens #endif /* _SYS_TXG_IMPL_H */ 126