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Implement new 'lightweight lock manager' that's intermediate between

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existing lock manager and spinlocks: it understands exclusive vs shared
lock but has few other fancy features.  Replace most uses of spinlocks
with lightweight locks.  All remaining uses of spinlocks have very short
lock hold times (a few dozen instructions), so tweak spinlock backoff
code to work efficiently given this assumption.  All per my proposal on
pghackers 26-Sep-01.
This commit is contained in:
Tom Lane
2001-09-29 04:02:27 +00:00
parent 818fb55ac4
commit 499abb0c0f
46 changed files with 1595 additions and 1355 deletions
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88
src/backend/storage/smgr/mm.c
View File

@@ -11,17 +11,19 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/Attic/mm.c,v 1.24 2001/06/27 23:31:39 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/Attic/mm.c,v 1.25 2001/09/29 04:02:25 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "miscadmin.h"
#ifdef STABLE_MEMORY_STORAGE
#include <math.h>
#include "storage/smgr.h"
#include "miscadmin.h"
#ifdef STABLE_MEMORY_STORAGE
/*
* MMCacheTag -- Unique triplet for blocks stored by the main memory
@@ -71,8 +73,6 @@ typedef struct MMRelHashEntry
#define MMNBUFFERS 10
#define MMNRELATIONS 2
SPINLOCK MMCacheLock;
static int *MMCurTop;
static int *MMCurRelno;
static MMCacheTag *MMBlockTags;
@@ -88,7 +88,7 @@ mminit()
bool found;
HASHCTL info;
SpinAcquire(MMCacheLock);
LWLockAcquire(MMCacheLock, LW_EXCLUSIVE);
mmsize += MAXALIGN(BLCKSZ * MMNBUFFERS);
mmsize += MAXALIGN(sizeof(*MMCurTop));
@@ -98,7 +98,7 @@ mminit()
if (mmcacheblk == (char *) NULL)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return SM_FAIL;
}
@@ -112,7 +112,7 @@ mminit()
if (MMCacheHT == (HTAB *) NULL)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return SM_FAIL;
}
@@ -126,18 +126,18 @@ mminit()
if (MMRelCacheHT == (HTAB *) NULL)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return SM_FAIL;
}
if (IsUnderPostmaster) /* was IsPostmaster bjm */
{
MemSet(mmcacheblk, 0, mmsize);
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return SM_SUCCESS;
}
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
MMCurTop = (int *) mmcacheblk;
mmcacheblk += sizeof(int);
@@ -163,11 +163,11 @@ mmcreate(Relation reln)
bool found;
MMRelTag tag;
SpinAcquire(MMCacheLock);
LWLockAcquire(MMCacheLock, LW_EXCLUSIVE);
if (*MMCurRelno == MMNRELATIONS)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return SM_FAIL;
}
@@ -184,20 +184,20 @@ mmcreate(Relation reln)
if (entry == (MMRelHashEntry *) NULL)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
elog(FATAL, "main memory storage mgr rel cache hash table corrupt");
}
if (found)
{
/* already exists */
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return SM_FAIL;
}
entry->mmrhe_nblocks = 0;
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return SM_SUCCESS;
}
@@ -211,30 +211,24 @@ int
mmunlink(RelFileNode rnode)
{
int i;
Oid reldbid;
MMHashEntry *entry;
MMRelHashEntry *rentry;
bool found;
MMRelTag rtag;
if (reln->rd_rel->relisshared)
reldbid = (Oid) 0;
else
reldbid = MyDatabaseId;
SpinAcquire(MMCacheLock);
LWLockAcquire(MMCacheLock, LW_EXCLUSIVE);
for (i = 0; i < MMNBUFFERS; i++)
{
if (MMBlockTags[i].mmct_dbid == reldbid
&& MMBlockTags[i].mmct_relid == RelationGetRelid(reln))
if (MMBlockTags[i].mmct_dbid == rnode.tblNode
&& MMBlockTags[i].mmct_relid == rnode.relNode)
{
entry = (MMHashEntry *) hash_search(MMCacheHT,
(char *) &MMBlockTags[i],
HASH_REMOVE, &found);
if (entry == (MMHashEntry *) NULL || !found)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
elog(FATAL, "mmunlink: cache hash table corrupted");
}
MMBlockTags[i].mmct_dbid = (Oid) 0;
@@ -242,21 +236,21 @@ mmunlink(RelFileNode rnode)
MMBlockTags[i].mmct_blkno = (BlockNumber) 0;
}
}
rtag.mmrt_dbid = reldbid;
rtag.mmrt_relid = RelationGetRelid(reln);
rtag.mmrt_dbid = rnode.tblNode;
rtag.mmrt_relid = rnode.relNode;
rentry = (MMRelHashEntry *) hash_search(MMRelCacheHT, (char *) &rtag,
HASH_REMOVE, &found);
if (rentry == (MMRelHashEntry *) NULL || !found)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
elog(FATAL, "mmunlink: rel cache hash table corrupted");
}
(*MMCurRelno)--;
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return 1;
}
@@ -286,7 +280,7 @@ mmextend(Relation reln, BlockNumber blocknum, char *buffer)
tag.mmct_dbid = rtag.mmrt_dbid = reldbid;
tag.mmct_relid = rtag.mmrt_relid = RelationGetRelid(reln);
SpinAcquire(MMCacheLock);
LWLockAcquire(MMCacheLock, LW_EXCLUSIVE);
if (*MMCurTop == MMNBUFFERS)
{
@@ -298,7 +292,7 @@ mmextend(Relation reln, BlockNumber blocknum, char *buffer)
}
if (i == MMNBUFFERS)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return SM_FAIL;
}
}
@@ -312,7 +306,7 @@ mmextend(Relation reln, BlockNumber blocknum, char *buffer)
HASH_FIND, &found);
if (rentry == (MMRelHashEntry *) NULL || !found)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
elog(FATAL, "mmextend: rel cache hash table corrupt");
}
@@ -322,7 +316,7 @@ mmextend(Relation reln, BlockNumber blocknum, char *buffer)
HASH_ENTER, &found);
if (entry == (MMHashEntry *) NULL || found)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
elog(FATAL, "mmextend: cache hash table corrupt");
}
@@ -338,7 +332,7 @@ mmextend(Relation reln, BlockNumber blocknum, char *buffer)
offset = (i * BLCKSZ);
memmove(&(MMBlockCache[offset]), buffer, BLCKSZ);
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return SM_SUCCESS;
}
@@ -386,20 +380,20 @@ mmread(Relation reln, BlockNumber blocknum, char *buffer)
tag.mmct_relid = RelationGetRelid(reln);
tag.mmct_blkno = blocknum;
SpinAcquire(MMCacheLock);
LWLockAcquire(MMCacheLock, LW_EXCLUSIVE);
entry = (MMHashEntry *) hash_search(MMCacheHT, (char *) &tag,
HASH_FIND, &found);
if (entry == (MMHashEntry *) NULL)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
elog(FATAL, "mmread: hash table corrupt");
}
if (!found)
{
/* reading nonexistent pages is defined to fill them with zeroes */
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
MemSet(buffer, 0, BLCKSZ);
return SM_SUCCESS;
}
@@ -407,7 +401,7 @@ mmread(Relation reln, BlockNumber blocknum, char *buffer)
offset = (entry->mmhe_bufno * BLCKSZ);
memmove(buffer, &MMBlockCache[offset], BLCKSZ);
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return SM_SUCCESS;
}
@@ -433,26 +427,26 @@ mmwrite(Relation reln, BlockNumber blocknum, char *buffer)
tag.mmct_relid = RelationGetRelid(reln);
tag.mmct_blkno = blocknum;
SpinAcquire(MMCacheLock);
LWLockAcquire(MMCacheLock, LW_EXCLUSIVE);
entry = (MMHashEntry *) hash_search(MMCacheHT, (char *) &tag,
HASH_FIND, &found);
if (entry == (MMHashEntry *) NULL)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
elog(FATAL, "mmread: hash table corrupt");
}
if (!found)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
elog(FATAL, "mmwrite: hash table missing requested page");
}
offset = (entry->mmhe_bufno * BLCKSZ);
memmove(&MMBlockCache[offset], buffer, BLCKSZ);
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return SM_SUCCESS;
}
@@ -506,14 +500,14 @@ mmnblocks(Relation reln)
rtag.mmrt_relid = RelationGetRelid(reln);
SpinAcquire(MMCacheLock);
LWLockAcquire(MMCacheLock, LW_EXCLUSIVE);
rentry = (MMRelHashEntry *) hash_search(MMRelCacheHT, (char *) &rtag,
HASH_FIND, &found);
if (rentry == (MMRelHashEntry *) NULL)
{
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
elog(FATAL, "mmnblocks: rel cache hash table corrupt");
}
@@ -522,7 +516,7 @@ mmnblocks(Relation reln)
else
nblocks = InvalidBlockNumber;
SpinRelease(MMCacheLock);
LWLockRelease(MMCacheLock);
return nblocks;
}

3
src/backend/storage/smgr/smgr.c
View File

@@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/smgr.c,v 1.52 2001/07/02 20:50:46 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/smgr/smgr.c,v 1.53 2001/09/29 04:02:25 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -19,6 +19,7 @@
#include "storage/bufmgr.h"
#include "storage/freespace.h"
#include "storage/ipc.h"
#include "storage/smgr.h"
#include "utils/memutils.h"