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More efficient implementation of a lookaside allocator that supports mini (in this case, harcoded to 128B) slots.

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FossilOrigin-Name: b02fdc09c838f355d9efce57f817d6a86153153b4a1f2b763914f4aaa34cb76e
This commit is contained in:
numist
2019-12-12 02:50:07 +00:00
parent 3ecc05bc3f
commit 115d663c05
6 changed files with 86 additions and 15 deletions
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36
src/malloc.c
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@@ -332,6 +332,13 @@ int sqlite3MallocSize(void *p){
assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
return sqlite3GlobalConfig.m.xSize(p);
}
static int lookasideMallocSize(sqlite3 *db, void *p){
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
return p<db->lookaside.pMiddle ? db->lookaside.szTrue : 128;
#else
return db->lookaside.szTrue;
#endif
}
int sqlite3DbMallocSize(sqlite3 *db, void *p){
assert( p!=0 );
if( db==0 || !isLookaside(db,p) ){
@@ -347,7 +354,7 @@ int sqlite3DbMallocSize(sqlite3 *db, void *p){
return sqlite3GlobalConfig.m.xSize(p);
}else{
assert( sqlite3_mutex_held(db->mutex) );
return db->lookaside.szTrue;
return lookasideMallocSize(db, p);
}
}
sqlite3_uint64 sqlite3_msize(void *p){
@@ -397,6 +404,17 @@ void sqlite3DbFreeNN(sqlite3 *db, void *p){
}
if( isLookaside(db, p) ){
LookasideSlot *pBuf = (LookasideSlot*)p;
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
if( p>=db->lookaside.pMiddle ){
# ifdef SQLITE_DEBUG
/* Trash all content in the buffer being freed */
memset(p, 0xaa, 128);
# endif
pBuf->pNext = db->lookaside.pMiniFree;
db->lookaside.pMiniFree = pBuf;
return;
}
#endif
#ifdef SQLITE_DEBUG
/* Trash all content in the buffer being freed */
memset(p, 0xaa, db->lookaside.szTrue);
@@ -564,6 +582,18 @@ void *sqlite3DbMallocRawNN(sqlite3 *db, u64 n){
return db->mallocFailed ? 0 : dbMallocRawFinish(db, n);
}
db->lookaside.anStat[1]++;
# ifndef SQLITE_OMIT_MINI_LOOKASIDE
}else if( n<=128 ){
if( (pBuf = db->lookaside.pMiniFree)!=0 ){
db->lookaside.pMiniFree = pBuf->pNext;
db->lookaside.anStat[0]++;
return (void*)pBuf;
}else if( (pBuf = db->lookaside.pMiniInit)!=0 ){
db->lookaside.pMiniInit = pBuf->pNext;
db->lookaside.anStat[0]++;
return (void*)pBuf;
}
# endif
}else if( (pBuf = db->lookaside.pFree)!=0 ){
db->lookaside.pFree = pBuf->pNext;
db->lookaside.anStat[0]++;
@@ -597,7 +627,7 @@ void *sqlite3DbRealloc(sqlite3 *db, void *p, u64 n){
assert( db!=0 );
if( p==0 ) return sqlite3DbMallocRawNN(db, n);
assert( sqlite3_mutex_held(db->mutex) );
if( isLookaside(db,p) && n<=db->lookaside.szTrue ) return p;
if( isLookaside(db,p) && n<lookasideMallocSize(db, p) ) return p;
return dbReallocFinish(db, p, n);
}
static SQLITE_NOINLINE void *dbReallocFinish(sqlite3 *db, void *p, u64 n){
@@ -608,7 +638,7 @@ static SQLITE_NOINLINE void *dbReallocFinish(sqlite3 *db, void *p, u64 n){
if( isLookaside(db, p) ){
pNew = sqlite3DbMallocRawNN(db, n);
if( pNew ){
memcpy(pNew, p, db->lookaside.szTrue);
memcpy(pNew, p, lookasideMallocSize(db, p));
sqlite3DbFree(db, p);
}
}else{