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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996-2003
* Sleepycat Software. All rights reserved.
*
* $Id: lock.h,v 11.47 2003/04/16 18:23:27 ubell Exp $
*/
#ifndef _DB_LOCK_H_
#define _DB_LOCK_H_
#define DB_LOCK_DEFAULT_N 1000 /* Default # of locks in region. */
/*
* The locker id space is divided between the transaction manager and the lock
* manager. Lock IDs start at 1 and go to DB_LOCK_MAXID. Txn IDs start at
* DB_LOCK_MAXID + 1 and go up to TXN_MAXIMUM.
*/
#define DB_LOCK_INVALIDID 0
#define DB_LOCK_MAXID 0x7fffffff
/*
* Out of band value for a lock. Locks contain an offset into a lock region,
* so we use an invalid region offset to indicate an invalid or unset lock.
*/
#define LOCK_INVALID INVALID_ROFF
#define LOCK_ISSET(lock) ((lock).off != LOCK_INVALID)
#define LOCK_INIT(lock) ((lock).off = LOCK_INVALID)
/*
* Macro to identify a write lock for the purpose of counting locks
* for the NUMWRITES option to deadlock detection.
*/
#define IS_WRITELOCK(m) \
((m) == DB_LOCK_WRITE || (m) == DB_LOCK_WWRITE || \
(m) == DB_LOCK_IWRITE || (m) == DB_LOCK_IWR)
/*
* Lock timers.
*/
typedef struct {
u_int32_t tv_sec; /* Seconds. */
u_int32_t tv_usec; /* Microseconds. */
} db_timeval_t;
#define LOCK_TIME_ISVALID(time) ((time)->tv_sec != 0)
#define LOCK_SET_TIME_INVALID(time) ((time)->tv_sec = 0)
#define LOCK_TIME_ISMAX(time) ((time)->tv_sec == UINT32_T_MAX)
#define LOCK_SET_TIME_MAX(time) ((time)->tv_sec = UINT32_T_MAX)
#define LOCK_TIME_EQUAL(t1, t2) \
((t1)->tv_sec == (t2)->tv_sec && (t1)->tv_usec == (t2)->tv_usec)
#define LOCK_TIME_GREATER(t1, t2) \
((t1)->tv_sec > (t2)->tv_sec || \
((t1)->tv_sec == (t2)->tv_sec && (t1)->tv_usec > (t2)->tv_usec))
/*
* DB_LOCKREGION --
* The lock shared region.
*/
typedef struct __db_lockregion {
u_int32_t need_dd; /* flag for deadlock detector */
u_int32_t detect; /* run dd on every conflict */
db_timeval_t next_timeout; /* next time to expire a lock */
/* free lock header */
SH_TAILQ_HEAD(__flock) free_locks;
/* free obj header */
SH_TAILQ_HEAD(__fobj) free_objs;
/* free locker header */
SH_TAILQ_HEAD(__flocker) free_lockers;
SH_TAILQ_HEAD(__dobj) dd_objs; /* objects with waiters */
SH_TAILQ_HEAD(__lkrs) lockers; /* list of lockers */
db_timeout_t lk_timeout; /* timeout for locks. */
db_timeout_t tx_timeout; /* timeout for txns. */
u_int32_t locker_t_size; /* size of locker hash table */
u_int32_t object_t_size; /* size of object hash table */
roff_t conf_off; /* offset of conflicts array */
roff_t obj_off; /* offset of object hash table */
roff_t osynch_off; /* offset of the object mutex table */
roff_t locker_off; /* offset of locker hash table */
roff_t lsynch_off; /* offset of the locker mutex table */
DB_LOCK_STAT stat; /* stats about locking. */
#ifdef HAVE_MUTEX_SYSTEM_RESOURCES
roff_t maint_off; /* offset of region maintenance info */
#endif
} DB_LOCKREGION;
/*
* Since we will store DBTs in shared memory, we need the equivalent of a
* DBT that will work in shared memory.
*/
typedef struct __sh_dbt {
u_int32_t size; /* Byte length. */
ssize_t off; /* Region offset. */
} SH_DBT;
#define SH_DBT_PTR(p) ((void *)(((u_int8_t *)(p)) + (p)->off))
/*
* Object structures; these live in the object hash table.
*/
typedef struct __db_lockobj {
SH_DBT lockobj; /* Identifies object locked. */
SH_TAILQ_ENTRY links; /* Links for free list or hash list. */
SH_TAILQ_ENTRY dd_links; /* Links for dd list. */
SH_TAILQ_HEAD(__waitl) waiters; /* List of waiting locks. */
SH_TAILQ_HEAD(__holdl) holders; /* List of held locks. */
/* Declare room in the object to hold
* typical DB lock structures so that
* we do not have to allocate them from
* shalloc at run-time. */
u_int8_t objdata[sizeof(struct __db_ilock)];
} DB_LOCKOBJ;
/*
* Locker structures; these live in the locker hash table.
*/
typedef struct __db_locker {
u_int32_t id; /* Locker id. */
u_int32_t dd_id; /* Deadlock detector id. */
u_int32_t nlocks; /* Number of locks held. */
u_int32_t nwrites; /* Number of write locks held. */
size_t master_locker; /* Locker of master transaction. */
size_t parent_locker; /* Parent of this child. */
SH_LIST_HEAD(_child) child_locker; /* List of descendant txns;
only used in a "master"
txn. */
SH_LIST_ENTRY child_link; /* Links transactions in the family;
elements of the child_locker
list. */
SH_TAILQ_ENTRY links; /* Links for free and hash list. */
SH_TAILQ_ENTRY ulinks; /* Links in-use list. */
SH_LIST_HEAD(_held) heldby; /* Locks held by this locker. */
db_timeval_t lk_expire; /* When current lock expires. */
db_timeval_t tx_expire; /* When this txn expires. */
db_timeout_t lk_timeout; /* How long do we let locks live. */
#define DB_LOCKER_DELETED 0x0001
#define DB_LOCKER_DIRTY 0x0002
#define DB_LOCKER_INABORT 0x0004
#define DB_LOCKER_TIMEOUT 0x0008
u_int32_t flags;
} DB_LOCKER;
/*
* DB_LOCKTAB --
* The primary library lock data structure (i.e., the one referenced
* by the environment, as opposed to the internal one laid out in the region.)
*/
typedef struct __db_locktab {
DB_ENV *dbenv; /* Environment. */
REGINFO reginfo; /* Region information. */
u_int8_t *conflicts; /* Pointer to conflict matrix. */
DB_HASHTAB *obj_tab; /* Beginning of object hash table. */
DB_HASHTAB *locker_tab; /* Beginning of locker hash table. */
} DB_LOCKTAB;
/* Test for conflicts. */
#define CONFLICTS(T, R, HELD, WANTED) \
(T)->conflicts[(HELD) * (R)->stat.st_nmodes + (WANTED)]
#define OBJ_LINKS_VALID(L) ((L)->links.stqe_prev != -1)
struct __db_lock {
/*
* Wait on mutex to wait on lock. You reference your own mutex with
* ID 0 and others reference your mutex with ID 1.
*/
DB_MUTEX mutex;
u_int32_t holder; /* Who holds this lock. */
u_int32_t gen; /* Generation count. */
SH_TAILQ_ENTRY links; /* Free or holder/waiter list. */
SH_LIST_ENTRY locker_links; /* List of locks held by a locker. */
u_int32_t refcount; /* Reference count the lock. */
db_lockmode_t mode; /* What sort of lock. */
ssize_t obj; /* Relative offset of object struct. */
db_status_t status; /* Status of this lock. */
};
/*
* Flag values for __lock_put_internal:
* DB_LOCK_DOALL: Unlock all references in this lock (instead of only 1).
* DB_LOCK_FREE: Free the lock (used in checklocker).
* DB_LOCK_NOPROMOTE: Don't bother running promotion when releasing locks
* (used by __lock_put_internal).
* DB_LOCK_UNLINK: Remove from the locker links (used in checklocker).
* Make sure that these do not conflict with the interface flags because
* we pass some of those around (i.e., DB_LOCK_REMOVE).
*/
#define DB_LOCK_DOALL 0x010000
#define DB_LOCK_FREE 0x020000
#define DB_LOCK_NOPROMOTE 0x040000
#define DB_LOCK_UNLINK 0x080000
#define DB_LOCK_NOWAITERS 0x100000
/*
* Macros to get/release different types of mutexes.
*/
#define OBJECT_LOCK(lt, reg, obj, ndx) \
ndx = __lock_ohash(obj) % (reg)->object_t_size
#define SHOBJECT_LOCK(lt, reg, shobj, ndx) \
ndx = __lock_lhash(shobj) % (reg)->object_t_size
#define LOCKER_LOCK(lt, reg, locker, ndx) \
ndx = __lock_locker_hash(locker) % (reg)->locker_t_size;
#define LOCKREGION(dbenv, lt) R_LOCK((dbenv), &(lt)->reginfo)
#define UNLOCKREGION(dbenv, lt) R_UNLOCK((dbenv), &(lt)->reginfo)
#include "dbinc_auto/lock_ext.h"
#endif /* !_DB_LOCK_H_ */
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