Implement the "lookaside" memory allocation cache. Use of this cache makes
the speed1.test script run about 15% faster. Added new interfaces to
control the cache. (CVS 5488)
FossilOrigin-Name: e48f9697e9fea339e150ddc32940760027dd07d9
diff --git a/src/malloc.c b/src/malloc.c
index 86ba2be..f90e627 100644
--- a/src/malloc.c
+++ b/src/malloc.c
@@ -12,7 +12,7 @@
**
** Memory allocation functions used throughout sqlite.
**
-** $Id: malloc.c,v 1.29 2008/07/18 18:56:17 drh Exp $
+** $Id: malloc.c,v 1.30 2008/07/28 19:34:53 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
@@ -454,12 +454,26 @@
}
/*
+** TRUE if p is a lookaside memory allocation from db
+*/
+static int isLookaside(sqlite3 *db, void *p){
+ return db && p && p>=db->lookaside.pStart && p<db->lookaside.pEnd;
+}
+
+/*
** Return the size of a memory allocation previously obtained from
** sqlite3Malloc() or sqlite3_malloc().
*/
int sqlite3MallocSize(void *p){
return sqlite3Config.m.xSize(p);
}
+int sqlite3DbMallocSize(sqlite3 *db, void *p){
+ if( isLookaside(db, p) ){
+ return db->lookaside.sz;
+ }else{
+ return sqlite3Config.m.xSize(p);
+ }
+}
/*
** Free memory previously obtained from sqlite3Malloc().
@@ -477,6 +491,21 @@
}
/*
+** Free memory that might be associated with a particular database
+** connection.
+*/
+void sqlite3DbFree(sqlite3 *db, void *p){
+ if( isLookaside(db, p) ){
+ LookasideSlot *pBuf = (LookasideSlot*)p;
+ pBuf->pNext = db->lookaside.pFree;
+ db->lookaside.pFree = pBuf;
+ db->lookaside.nOut--;
+ }else{
+ sqlite3_free(p);
+ }
+}
+
+/*
** Change the size of an existing memory allocation
*/
void *sqlite3Realloc(void *pOld, int nBytes){
@@ -558,26 +587,53 @@
** the mallocFailed flag in the connection pointer.
*/
void *sqlite3DbMallocRaw(sqlite3 *db, int n){
- void *p = 0;
- if( !db || db->mallocFailed==0 ){
- p = sqlite3Malloc(n);
- if( !p && db ){
- db->mallocFailed = 1;
+ void *p;
+ if( db ){
+ LookasideSlot *pBuf;
+ if( db->mallocFailed ){
+ return 0;
}
+ if( db->lookaside.bEnabled && n<=db->lookaside.sz
+ && (pBuf = db->lookaside.pFree)!=0 ){
+ db->lookaside.pFree = pBuf->pNext;
+ db->lookaside.nOut++;
+ if( db->lookaside.nOut>db->lookaside.mxOut ){
+ db->lookaside.mxOut = db->lookaside.nOut;
+ }
+ return (void*)pBuf;
+ }
+ }
+ p = sqlite3Malloc(n);
+ if( !p && db ){
+ db->mallocFailed = 1;
}
return p;
}
/*
** Resize the block of memory pointed to by p to n bytes. If the
-** resize fails, set the mallocFailed flag inthe connection object.
+** resize fails, set the mallocFailed flag in the connection object.
*/
void *sqlite3DbRealloc(sqlite3 *db, void *p, int n){
void *pNew = 0;
if( db->mallocFailed==0 ){
- pNew = sqlite3_realloc(p, n);
- if( !pNew ){
- db->mallocFailed = 1;
+ if( p==0 ){
+ return sqlite3DbMallocRaw(db, n);
+ }
+ if( isLookaside(db, p) ){
+ if( n<=db->lookaside.sz ){
+ return p;
+ }
+ pNew = sqlite3DbMallocRaw(db, n);
+ if( pNew ){
+ memcpy(pNew, p, db->lookaside.sz);
+ sqlite3DbFree(db, p);
+ }
+ }else{
+ pNew = sqlite3_realloc(p, n);
+ if( !pNew ){
+ db->mallocFailed = 1;
+ }
}
}
return pNew;
@@ -591,7 +647,7 @@
void *pNew;
pNew = sqlite3DbRealloc(db, p, n);
if( !pNew ){
- sqlite3_free(p);
+ sqlite3DbFree(db, p);
}
return pNew;
}
@@ -603,37 +659,30 @@
** called via macros that record the current file and line number in the
** ThreadData structure.
*/
-char *sqlite3StrDup(const char *z){
+char *sqlite3DbStrDup(sqlite3 *db, const char *z){
char *zNew;
- int n;
- if( z==0 ) return 0;
+ size_t n;
+ if( z==0 ){
+ return 0;
+ }
n = strlen(z)+1;
- zNew = sqlite3Malloc(n);
- if( zNew ) memcpy(zNew, z, n);
- return zNew;
-}
-char *sqlite3StrNDup(const char *z, int n){
- char *zNew;
- if( z==0 ) return 0;
- zNew = sqlite3Malloc(n+1);
+ assert( (n&0x7fffffff)==n );
+ zNew = sqlite3DbMallocRaw(db, (int)n);
if( zNew ){
memcpy(zNew, z, n);
- zNew[n] = 0;
- }
- return zNew;
-}
-
-char *sqlite3DbStrDup(sqlite3 *db, const char *z){
- char *zNew = sqlite3StrDup(z);
- if( z && !zNew ){
- db->mallocFailed = 1;
}
return zNew;
}
char *sqlite3DbStrNDup(sqlite3 *db, const char *z, int n){
- char *zNew = sqlite3StrNDup(z, n);
- if( z && !zNew ){
- db->mallocFailed = 1;
+ char *zNew;
+ if( z==0 ){
+ return 0;
+ }
+ assert( (n&0x7fffffff)==n );
+ zNew = sqlite3DbMallocRaw(db, n+1);
+ if( zNew ){
+ memcpy(zNew, z, n);
+ zNew[n] = 0;
}
return zNew;
}
@@ -650,7 +699,7 @@
va_start(ap, zFormat);
z = sqlite3VMPrintf(db, zFormat, ap);
va_end(ap);
- sqlite3_free(*pz);
+ sqlite3DbFree(db, *pz);
*pz = z;
}