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Diffstat (limited to 'db/include/lock.h')
| -rw-r--r-- | db/include/lock.h | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/db/include/lock.h b/db/include/lock.h new file mode 100644 index 000000000..e4a01ddf9 --- /dev/null +++ b/db/include/lock.h @@ -0,0 +1,190 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 1996, 1997, 1998, 1999, 2000 + * Sleepycat Software. All rights reserved. + * + * $Id: lock.h,v 11.20 2000/12/12 17:43:56 bostic Exp $ + */ + +#define DB_LOCK_DEFAULT_N 1000 /* Default # of locks in region. */ + +/* + * 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 + +/* + * The locker id space is divided between the transaction manager and the lock + * manager. Lock IDs start at 0 and go to DB_LOCK_MAXID. Txn IDs start at + * DB_LOCK_MAXID + 1 and go up to TXN_INVALID. + */ +#define DB_LOCK_MAXID 0x7fffffff + +/* + * DB_LOCKREGION -- + * The lock shared region. + */ +typedef struct __db_lockregion { + u_int32_t id; /* unique id generator */ + u_int32_t need_dd; /* flag for deadlock detector */ + u_int32_t detect; /* run dd on every conflict */ + /* 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 */ + u_int32_t maxlocks; /* maximum number of locks in table */ + u_int32_t maxlockers; /* maximum number of lockers in table */ + u_int32_t maxobjects; /* maximum number of objects in table */ + u_int32_t locker_t_size; /* size of locker hash table */ + u_int32_t object_t_size; /* size of object hash table */ + u_int32_t nmodes; /* number of lock modes */ + u_int32_t nlocks; /* current number of locks */ + u_int32_t maxnlocks; /* maximum number of locks so far*/ + u_int32_t nlockers; /* current number of lockers */ + u_int32_t maxnlockers; /* maximum number of lockers so far */ + u_int32_t nobjects; /* current number of objects */ + u_int32_t maxnobjects; /* maximum number of objects so far */ + 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 */ + u_int32_t nconflicts; /* number of lock conflicts */ + u_int32_t nrequests; /* number of lock gets */ + u_int32_t nreleases; /* number of lock puts */ + u_int32_t nnowaits; /* number of lock requests that would + have waited without nowait */ + u_int32_t ndeadlocks; /* number of deadlocks */ +#ifdef 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(__wait) waiters; /* List of waiting locks. */ + SH_TAILQ_HEAD(__hold) 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. */ + 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 list. */ + SH_LIST_HEAD(_held) heldby; /* Locks held by this locker. */ + +#define DB_LOCKER_DELETED 0x0001 + u_int32_t flags; +} DB_LOCKER; + +/* + * Lockers can be freed if they are not part of a transaction family. + * Members of a family either point at the master transaction or are + * the master transaction and have children lockers. + */ +#define LOCKER_FREEABLE(lp) \ + ((lp)->master_locker == TXN_INVALID_ID && \ + SH_LIST_FIRST(&(lp)->child_locker, __db_locker) == NULL) + +/* + * 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)->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. + */ + 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_IGNOREDEL: Remove from the locker hash table even if already + deleted (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). + */ +#define DB_LOCK_DOALL 0x001 +#define DB_LOCK_FREE 0x002 +#define DB_LOCK_IGNOREDEL 0x004 +#define DB_LOCK_NOPROMOTE 0x008 +#define DB_LOCK_UNLINK 0x010 +#define DB_LOCK_NOWAITERS 0x020 + +/* + * 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 "lock_ext.h" |