xref: /illumos-gate/usr/src/cmd/sendmail/db/include/lock.h (revision 7c478bd9)
1*7c478bd9Sstevel@tonic-gate /*-
2*7c478bd9Sstevel@tonic-gate  * See the file LICENSE for redistribution information.
3*7c478bd9Sstevel@tonic-gate  *
4*7c478bd9Sstevel@tonic-gate  * Copyright (c) 1996, 1997, 1998
5*7c478bd9Sstevel@tonic-gate  *	Sleepycat Software.  All rights reserved.
6*7c478bd9Sstevel@tonic-gate  *
7*7c478bd9Sstevel@tonic-gate  *	@(#)lock.h	10.17 (Sleepycat) 1/3/99
8*7c478bd9Sstevel@tonic-gate  */
10*7c478bd9Sstevel@tonic-gate typedef struct __db_lockobj	DB_LOCKOBJ;
12*7c478bd9Sstevel@tonic-gate #define DB_DEFAULT_LOCK_FILE	"__db_lock.share"
14*7c478bd9Sstevel@tonic-gate #ifndef DB_LOCK_DEFAULT_N
15*7c478bd9Sstevel@tonic-gate #define DB_LOCK_DEFAULT_N	5000	/* Default # of locks in region. */
16*7c478bd9Sstevel@tonic-gate #endif
18*7c478bd9Sstevel@tonic-gate /*
19*7c478bd9Sstevel@tonic-gate  * The locker id space is divided between the transaction manager and the lock
20*7c478bd9Sstevel@tonic-gate  * manager.  Lockid's start at 0 and go to DB_LOCK_MAXID.  Txn Id's start at
21*7c478bd9Sstevel@tonic-gate  * DB_LOCK_MAXID + 1 and go up to TXN_INVALID.
22*7c478bd9Sstevel@tonic-gate  */
23*7c478bd9Sstevel@tonic-gate #define DB_LOCK_MAXID		0x7fffffff
25*7c478bd9Sstevel@tonic-gate /* Check for region catastrophic shutdown. */
26*7c478bd9Sstevel@tonic-gate #define	LOCK_PANIC_CHECK(lt) {						\
27*7c478bd9Sstevel@tonic-gate 	if ((lt)->region->hdr.panic)					\
28*7c478bd9Sstevel@tonic-gate 		return (DB_RUNRECOVERY);				\
29*7c478bd9Sstevel@tonic-gate }
31*7c478bd9Sstevel@tonic-gate /*
32*7c478bd9Sstevel@tonic-gate  * The lock region consists of:
33*7c478bd9Sstevel@tonic-gate  *	The DB_LOCKREGION structure (sizeof(DB_LOCKREGION)).
34*7c478bd9Sstevel@tonic-gate  *	The conflict matrix of nmodes * nmodes bytes (nmodes * nmodes).
35*7c478bd9Sstevel@tonic-gate  *	The hash table for object lookup (hashsize * sizeof(DB_OBJ *)).
36*7c478bd9Sstevel@tonic-gate  *	The locks themselves (maxlocks * sizeof(struct __db_lock).
37*7c478bd9Sstevel@tonic-gate  *	The objects being locked (maxlocks * sizeof(DB_OBJ)).
38*7c478bd9Sstevel@tonic-gate  *	String space to represent the DBTs that are the objects being locked.
39*7c478bd9Sstevel@tonic-gate  */
40*7c478bd9Sstevel@tonic-gate struct __db_lockregion {
41*7c478bd9Sstevel@tonic-gate 	RLAYOUT		hdr;		/* Shared region header. */
42*7c478bd9Sstevel@tonic-gate 	u_int32_t	magic;		/* lock magic number */
43*7c478bd9Sstevel@tonic-gate 	u_int32_t	version;	/* version number */
44*7c478bd9Sstevel@tonic-gate 	u_int32_t	id;		/* unique id generator */
45*7c478bd9Sstevel@tonic-gate 	u_int32_t	need_dd;	/* flag for deadlock detector */
46*7c478bd9Sstevel@tonic-gate 	u_int32_t	detect;		/* run dd on every conflict */
47*7c478bd9Sstevel@tonic-gate 	SH_TAILQ_HEAD(lock_header) free_locks;	/* free lock header */
48*7c478bd9Sstevel@tonic-gate 	SH_TAILQ_HEAD(obj_header) free_objs;	/* free obj header */
49*7c478bd9Sstevel@tonic-gate 	u_int32_t	maxlocks;	/* maximum number of locks in table */
50*7c478bd9Sstevel@tonic-gate 	u_int32_t	table_size;	/* size of hash table */
51*7c478bd9Sstevel@tonic-gate 	u_int32_t	nmodes;		/* number of lock modes */
52*7c478bd9Sstevel@tonic-gate 	u_int32_t	numobjs;	/* number of objects */
53*7c478bd9Sstevel@tonic-gate 	u_int32_t	nlockers;	/* number of lockers */
54*7c478bd9Sstevel@tonic-gate 	size_t		increment;	/* how much to grow region */
55*7c478bd9Sstevel@tonic-gate 	size_t		hash_off;	/* offset of hash table */
56*7c478bd9Sstevel@tonic-gate 	size_t		mem_off;	/* offset of memory region */
57*7c478bd9Sstevel@tonic-gate 	size_t		mem_bytes;	/* number of bytes in memory region */
58*7c478bd9Sstevel@tonic-gate 	u_int32_t	nconflicts;	/* number of lock conflicts */
59*7c478bd9Sstevel@tonic-gate 	u_int32_t	nrequests;	/* number of lock gets */
60*7c478bd9Sstevel@tonic-gate 	u_int32_t	nreleases;	/* number of lock puts */
61*7c478bd9Sstevel@tonic-gate 	u_int32_t	ndeadlocks;	/* number of deadlocks */
62*7c478bd9Sstevel@tonic-gate };
64*7c478bd9Sstevel@tonic-gate /* Macros to lock/unlock the region. */
65*7c478bd9Sstevel@tonic-gate #define	LOCK_LOCKREGION(lt)						\
66*7c478bd9Sstevel@tonic-gate 	(void)__db_mutex_lock(&(lt)->region->hdr.lock, (lt)->reginfo.fd)
67*7c478bd9Sstevel@tonic-gate #define	UNLOCK_LOCKREGION(lt)						\
68*7c478bd9Sstevel@tonic-gate 	(void)__db_mutex_unlock(&(lt)->region->hdr.lock, (lt)->reginfo.fd)
70*7c478bd9Sstevel@tonic-gate /*
71*7c478bd9Sstevel@tonic-gate  * Since we will be keeping DBTs in shared memory, we need the equivalent
72*7c478bd9Sstevel@tonic-gate  * of a DBT that will work in shared memory.
73*7c478bd9Sstevel@tonic-gate  */
74*7c478bd9Sstevel@tonic-gate typedef struct __sh_dbt {
75*7c478bd9Sstevel@tonic-gate 	u_int32_t size;
76*7c478bd9Sstevel@tonic-gate 	ssize_t off;
77*7c478bd9Sstevel@tonic-gate } SH_DBT;
79*7c478bd9Sstevel@tonic-gate #define SH_DBT_PTR(p)	((void *)(((u_int8_t *)(p)) + (p)->off))
81*7c478bd9Sstevel@tonic-gate struct __db_lockobj {
82*7c478bd9Sstevel@tonic-gate 	SH_DBT	lockobj;		/* Identifies object locked. */
83*7c478bd9Sstevel@tonic-gate 	SH_TAILQ_ENTRY links;		/* Links for free list. */
84*7c478bd9Sstevel@tonic-gate 	union {
85*7c478bd9Sstevel@tonic-gate 		SH_TAILQ_HEAD(_wait) _waiters;	/* List of waiting locks. */
86*7c478bd9Sstevel@tonic-gate 		u_int32_t	_dd_id;		/* Deadlock detector id. */
87*7c478bd9Sstevel@tonic-gate 	} wlinks;
88*7c478bd9Sstevel@tonic-gate 	union {
89*7c478bd9Sstevel@tonic-gate 		SH_LIST_HEAD(_held) _heldby;	/* Locks held by this locker. */
90*7c478bd9Sstevel@tonic-gate 		SH_TAILQ_HEAD(_hold) _holders;	/* List of held locks. */
91*7c478bd9Sstevel@tonic-gate 	} dlinks;
92*7c478bd9Sstevel@tonic-gate #define	DB_LOCK_OBJTYPE		1
93*7c478bd9Sstevel@tonic-gate #define	DB_LOCK_LOCKER		2
94*7c478bd9Sstevel@tonic-gate 					/* Allocate room in the object to
95*7c478bd9Sstevel@tonic-gate 					 * hold typical DB lock structures
96*7c478bd9Sstevel@tonic-gate 					 * so that we do not have to
97*7c478bd9Sstevel@tonic-gate 					 * allocate them from shalloc. */
98*7c478bd9Sstevel@tonic-gate 	u_int8_t objdata[sizeof(struct __db_ilock)];
99*7c478bd9Sstevel@tonic-gate 	u_int8_t type;			/* Real object or locker id. */
100*7c478bd9Sstevel@tonic-gate };
102*7c478bd9Sstevel@tonic-gate #define dd_id	wlinks._dd_id
103*7c478bd9Sstevel@tonic-gate #define	waiters	wlinks._waiters
104*7c478bd9Sstevel@tonic-gate #define	holders	dlinks._holders
105*7c478bd9Sstevel@tonic-gate #define	heldby	dlinks._heldby
107*7c478bd9Sstevel@tonic-gate /*
108*7c478bd9Sstevel@tonic-gate  * The lock table is the per-process cookie returned from a lock_open call.
109*7c478bd9Sstevel@tonic-gate  */
110*7c478bd9Sstevel@tonic-gate struct __db_locktab {
111*7c478bd9Sstevel@tonic-gate 	DB_ENV		*dbenv;		/* Environment. */
112*7c478bd9Sstevel@tonic-gate 	REGINFO		 reginfo;	/* Region information. */
113*7c478bd9Sstevel@tonic-gate 	DB_LOCKREGION	*region;	/* Address of shared memory region. */
114*7c478bd9Sstevel@tonic-gate 	DB_HASHTAB 	*hashtab; 	/* Beginning of hash table. */
115*7c478bd9Sstevel@tonic-gate 	void		*mem;		/* Beginning of string space. */
116*7c478bd9Sstevel@tonic-gate 	u_int8_t 	*conflicts;	/* Pointer to conflict matrix. */
117*7c478bd9Sstevel@tonic-gate };
119*7c478bd9Sstevel@tonic-gate /* Test for conflicts. */
120*7c478bd9Sstevel@tonic-gate #define CONFLICTS(T, HELD, WANTED) \
121*7c478bd9Sstevel@tonic-gate 	T->conflicts[HELD * T->region->nmodes + WANTED]
123*7c478bd9Sstevel@tonic-gate /*
124*7c478bd9Sstevel@tonic-gate  * Resources in the lock region.  Used to indicate which resource
125*7c478bd9Sstevel@tonic-gate  * is running low when we need to grow the region.
126*7c478bd9Sstevel@tonic-gate  */
127*7c478bd9Sstevel@tonic-gate typedef enum {
128*7c478bd9Sstevel@tonic-gate 	DB_LOCK_MEM, DB_LOCK_OBJ, DB_LOCK_LOCK
129*7c478bd9Sstevel@tonic-gate } db_resource_t;
131*7c478bd9Sstevel@tonic-gate struct __db_lock {
132*7c478bd9Sstevel@tonic-gate 	/*
133*7c478bd9Sstevel@tonic-gate 	 * Wait on mutex to wait on lock.  You reference your own mutex with
134*7c478bd9Sstevel@tonic-gate 	 * ID 0 and others reference your mutex with ID 1.
135*7c478bd9Sstevel@tonic-gate 	 */
136*7c478bd9Sstevel@tonic-gate 	db_mutex_t	mutex;
138*7c478bd9Sstevel@tonic-gate 	u_int32_t	holder;		/* Who holds this lock. */
139*7c478bd9Sstevel@tonic-gate 	SH_TAILQ_ENTRY	links;		/* Free or holder/waiter list. */
140*7c478bd9Sstevel@tonic-gate 	SH_LIST_ENTRY	locker_links;	/* List of locks held by a locker. */
141*7c478bd9Sstevel@tonic-gate 	u_int32_t	refcount;	/* Reference count the lock. */
142*7c478bd9Sstevel@tonic-gate 	db_lockmode_t	mode;		/* What sort of lock. */
143*7c478bd9Sstevel@tonic-gate 	ssize_t		obj;		/* Relative offset of object struct. */
144*7c478bd9Sstevel@tonic-gate 	size_t		txnoff;		/* Offset of holding transaction. */
145*7c478bd9Sstevel@tonic-gate 	db_status_t	status;		/* Status of this lock. */
146*7c478bd9Sstevel@tonic-gate };
148*7c478bd9Sstevel@tonic-gate /*
149*7c478bd9Sstevel@tonic-gate  * This is a serious layering violation.  To support nested transactions, we
150*7c478bd9Sstevel@tonic-gate  * need to be able to tell that a lock is held by a transaction (as opposed to
151*7c478bd9Sstevel@tonic-gate  * some other locker) and to be able to traverse the parent/descendent chain.
152*7c478bd9Sstevel@tonic-gate  * In order to do this, each lock held by a transaction maintains a reference
153*7c478bd9Sstevel@tonic-gate  * to the shared memory transaction structure so it can be accessed during lock
154*7c478bd9Sstevel@tonic-gate  * promotion.  As the structure is in shared memory, we cannot store a pointer
155*7c478bd9Sstevel@tonic-gate  * to it, so we use the offset within the region.  As nothing lives at region
156*7c478bd9Sstevel@tonic-gate  * offset 0, we use that to indicate that there is no transaction associated
157*7c478bd9Sstevel@tonic-gate  * with the current lock.
158*7c478bd9Sstevel@tonic-gate  */
159*7c478bd9Sstevel@tonic-gate #define TXN_IS_HOLDING(L)	((L)->txnoff != 0 /* INVALID_REG_OFFSET */)
161*7c478bd9Sstevel@tonic-gate /*
162*7c478bd9Sstevel@tonic-gate  * We cannot return pointers to the user (else we cannot easily grow regions),
163*7c478bd9Sstevel@tonic-gate  * so we return offsets in the region.  These must be converted to and from
164*7c478bd9Sstevel@tonic-gate  * regular pointers.  Always use the macros below.
165*7c478bd9Sstevel@tonic-gate  */
166*7c478bd9Sstevel@tonic-gate #define OFFSET_TO_LOCK(lt, off)	\
167*7c478bd9Sstevel@tonic-gate 	((struct __db_lock *)((u_int8_t *)((lt)->region) + (off)))
168*7c478bd9Sstevel@tonic-gate #define LOCK_TO_OFFSET(lt, lock) \
169*7c478bd9Sstevel@tonic-gate 	((size_t)((u_int8_t *)(lock) - (u_int8_t *)lt->region))
170*7c478bd9Sstevel@tonic-gate #define OFFSET_TO_OBJ(lt, off)	\
171*7c478bd9Sstevel@tonic-gate 	((DB_LOCKOBJ *)((u_int8_t *)((lt)->region) + (off)))
172*7c478bd9Sstevel@tonic-gate #define OBJ_TO_OFFSET(lt, obj) \
173*7c478bd9Sstevel@tonic-gate 	((size_t)((u_int8_t *)(obj) - (u_int8_t *)lt->region))
175*7c478bd9Sstevel@tonic-gate /*
176*7c478bd9Sstevel@tonic-gate  * The lock header contains the region structure and the conflict matrix.
177*7c478bd9Sstevel@tonic-gate  * Aligned to a large boundary because we don't know what the underlying
178*7c478bd9Sstevel@tonic-gate  * type of the hash table elements are.
179*7c478bd9Sstevel@tonic-gate  */
180*7c478bd9Sstevel@tonic-gate #define LOCK_HASH_ALIGN	8
181*7c478bd9Sstevel@tonic-gate #define LOCK_HEADER_SIZE(M)	\
182*7c478bd9Sstevel@tonic-gate 	((size_t)(sizeof(DB_LOCKREGION) + ALIGN((M * M), LOCK_HASH_ALIGN)))
184*7c478bd9Sstevel@tonic-gate /*
185*7c478bd9Sstevel@tonic-gate  * For the full region, we need to add the locks, the objects, the hash table
186*7c478bd9Sstevel@tonic-gate  * and the string space (which is 16 bytes per lock).
187*7c478bd9Sstevel@tonic-gate  */
188*7c478bd9Sstevel@tonic-gate #define STRING_SIZE(N) (16 * N)
190*7c478bd9Sstevel@tonic-gate #define LOCK_REGION_SIZE(M, N, H)					\
191*7c478bd9Sstevel@tonic-gate 	(ALIGN(LOCK_HEADER_SIZE(M) +					\
192*7c478bd9Sstevel@tonic-gate 	(H) * sizeof(DB_HASHTAB), MUTEX_ALIGNMENT) +			\
193*7c478bd9Sstevel@tonic-gate 	(N) * ALIGN(sizeof(struct __db_lock), MUTEX_ALIGNMENT) +	\
194*7c478bd9Sstevel@tonic-gate 	ALIGN((N) * sizeof(DB_LOCKOBJ), sizeof(size_t)) +		\
195*7c478bd9Sstevel@tonic-gate 	ALIGN(STRING_SIZE(N), sizeof(size_t)))
197*7c478bd9Sstevel@tonic-gate #include "lock_ext.h"