Convert the lock manager to use the new dynahash.c support for partitioned

hash tables, instead of the previous kluge involving multiple hash tables.
This partially undoes my patch of last December.

2 files changed, 31 insertions, 16 deletions

diff --git a/src/include/storage/lock.h b/src/include/storage/lock.h
index d471293b702..7a2651cd28f 100644
--- a/src/include/storage/lock.h
+++ b/src/include/storage/lock.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.95 2006/07/23 03:07:58 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.96 2006/07/23 23:08:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -266,7 +266,9 @@ typedef struct LOCK
  *
  * PROCLOCKTAG is the key information needed to look up a PROCLOCK item in the
  * proclock hashtable.	A PROCLOCKTAG value uniquely identifies the combination
- * of a lockable object and a holder/waiter for that object.
+ * of a lockable object and a holder/waiter for that object.  (We can use
+ * pointers here because the PROCLOCKTAG need only be unique for the lifespan
+ * of the PROCLOCK, and it will never outlive the lock or the proc.)
  *
  * Internally to a backend, it is possible for the same lock to be held
  * for different purposes: the backend tracks transaction locks separately
@@ -292,8 +294,9 @@ typedef struct LOCK
  */
 typedef struct PROCLOCKTAG
 {
-	SHMEM_OFFSET lock;			/* link to per-lockable-object information */
-	SHMEM_OFFSET proc;			/* link to PGPROC of owning backend */
+	/* NB: we assume this struct contains no padding! */
+	LOCK	   *myLock;			/* link to per-lockable-object information */
+	PGPROC	   *myProc;			/* link to PGPROC of owning backend */
 } PROCLOCKTAG;
 
 typedef struct PROCLOCK
@@ -309,7 +312,7 @@ typedef struct PROCLOCK
 } PROCLOCK;
 
 #define PROCLOCK_LOCKMETHOD(proclock) \
-	LOCK_LOCKMETHOD(*((LOCK *) MAKE_PTR((proclock).tag.lock)))
+	LOCK_LOCKMETHOD(*((proclock).tag.myLock))
 
 /*
  * Each backend also maintains a local hash table with information about each
@@ -347,7 +350,7 @@ typedef struct LOCALLOCK
 	LOCK	   *lock;			/* associated LOCK object in shared mem */
 	PROCLOCK   *proclock;		/* associated PROCLOCK object in shmem */
 	bool		isTempObject;	/* true if lock is on a temporary object */
-	int			partition;		/* ID of partition containing this lock */
+	uint32		hashcode;		/* copy of LOCKTAG's hash value */
 	int			nLocks;			/* total number of times lock is held */
 	int			numLockOwners;	/* # of relevant ResourceOwners */
 	int			maxLockOwners;	/* allocated size of array */
@@ -360,15 +363,14 @@ typedef struct LOCALLOCK
 /*
  * This struct holds information passed from lmgr internals to the lock
  * listing user-level functions (lockfuncs.c).	For each PROCLOCK in the
- * system, the SHMEM_OFFSET, PROCLOCK itself, and associated PGPROC and
- * LOCK objects are stored.  (Note there will often be multiple copies
- * of the same PGPROC or LOCK.)  We do not store the SHMEM_OFFSET of the
- * PGPROC or LOCK separately, since they're in the PROCLOCK's tag fields.
+ * system, copies of the PROCLOCK object and associated PGPROC and
+ * LOCK objects are stored.  Note there will often be multiple copies
+ * of the same PGPROC or LOCK --- to detect whether two are the same,
+ * compare the PROCLOCK tag fields.
  */
-typedef struct
+typedef struct LockData
 {
 	int			nelements;		/* The length of each of the arrays */
-	SHMEM_OFFSET *proclockaddrs;
 	PROCLOCK   *proclocks;
 	PGPROC	   *procs;
 	LOCK	   *locks;
@@ -385,11 +387,23 @@ typedef enum
 
 
 /*
+ * The lockmgr's shared hash tables are partitioned to reduce contention.
+ * To determine which partition a given locktag belongs to, compute the tag's
+ * hash code with LockTagHashCode(), then apply one of these macros.
+ * NB: NUM_LOCK_PARTITIONS must be a power of 2!
+ */
+#define LockHashPartition(hashcode) \
+	((hashcode) % NUM_LOCK_PARTITIONS)
+#define LockHashPartitionLock(hashcode) \
+	((LWLockId) (FirstLockMgrLock + LockHashPartition(hashcode)))
+
+
+/*
  * function prototypes
  */
 extern void InitLocks(void);
 extern LockMethod GetLocksMethodTable(const LOCK *lock);
-extern int	LockTagToPartition(const LOCKTAG *locktag);
+extern uint32 LockTagHashCode(const LOCKTAG *locktag);
 extern LockAcquireResult LockAcquire(const LOCKTAG *locktag,
 			bool isTempObject,
 			LOCKMODE lockmode,
@@ -407,7 +421,7 @@ extern int LockCheckConflicts(LockMethod lockMethodTable,
 				   LOCK *lock, PROCLOCK *proclock, PGPROC *proc);
 extern void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode);
 extern void GrantAwaitedLock(void);
-extern void RemoveFromWaitQueue(PGPROC *proc, int partition);
+extern void RemoveFromWaitQueue(PGPROC *proc, uint32 hashcode);
 extern Size LockShmemSize(void);
 extern bool DeadLockCheck(PGPROC *proc);
 extern void DeadLockReport(void);
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h
index 2810326597e..ce779932430 100644
--- a/src/include/storage/lwlock.h
+++ b/src/include/storage/lwlock.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/storage/lwlock.h,v 1.29 2006/07/23 03:07:58 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/storage/lwlock.h,v 1.30 2006/07/23 23:08:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -24,7 +24,8 @@
 #define NUM_BUFFER_PARTITIONS  16
 
 /* Number of partitions the shared lock tables are divided into */
-#define NUM_LOCK_PARTITIONS  16
+#define LOG2_NUM_LOCK_PARTITIONS  4
+#define NUM_LOCK_PARTITIONS  (1 << LOG2_NUM_LOCK_PARTITIONS)
 
 /*
  * We have a number of predefined LWLocks, plus a bunch of LWLocks that are