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Change mem5.c so that the minimum allocation size is runtime configurable. (CVS 5320)

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FossilOrigin-Name: 4f95f4cdf77e134fab42148e10198c7b008d4ae6
This commit is contained in:
danielk1977
2008-06-27 13:27:03 +00:00
parent 6fccc35a91
commit 5099be5e85
7 changed files with 211 additions and 121 deletions
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195
src/mem5.c
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@@ -23,7 +23,7 @@
** This version of the memory allocation subsystem is included
** in the build only if SQLITE_ENABLE_MEMSYS5 is defined.
**
** $Id: mem5.c,v 1.8 2008/06/25 14:57:54 danielk1977 Exp $
** $Id: mem5.c,v 1.9 2008/06/27 13:27:04 danielk1977 Exp $
*/
#include "sqliteInt.h"
@@ -41,7 +41,6 @@
#ifndef SQLITE_POW2_LOGMIN
# define SQLITE_POW2_LOGMIN 6
#endif
#define POW2_MIN (1<<SQLITE_POW2_LOGMIN)
/*
** Log2 of the maximum size of an allocation.
@@ -61,21 +60,18 @@
** Larger allocations are an array of these structures where the
** size of the array is a power of 2.
*/
typedef struct Mem5Block Mem5Block;
struct Mem5Block {
union {
char aData[POW2_MIN];
struct {
int next; /* Index in mem5.aPool[] of next free chunk */
int prev; /* Index in mem5.aPool[] of previous free chunk */
} list;
} u;
typedef struct Mem5Link Mem5Link;
struct Mem5Link {
int next; /* Index of next free chunk */
int prev; /* Index of previous free chunk */
};
/*
** The size in blocks of an POW2_MAX allocation
** Maximum size of any allocation is ((1<<LOGMAX)*mem5.nAtom). Since
** mem5.nAtom is always at least 8, this is not really a practical
** limitation.
*/
#define SZ_MAX (1<<(NSIZE-1))
#define LOGMAX 30
/*
** Masks used for mem5.aCtrl[] elements.
@@ -122,7 +118,7 @@ static struct {
/*
** Lists of free blocks of various sizes.
*/
int aiFreelist[NSIZE];
int aiFreelist[LOGMAX+1];
/*
** Space for tracking which blocks are checked out and the size
@@ -133,10 +129,13 @@ static struct {
/*
** Memory available for allocation
*/
int nBlock;
Mem5Block *aPool;
int nAtom; /* Smallest possible allocation in bytes */
int nBlock; /* Number of nAtom sized blocks in zPool */
u8 *zPool;
} mem5;
#define MEM5LINK(idx) ((Mem5Link *)(&mem5.zPool[(idx)*mem5.nAtom]))
/*
** Unlink the chunk at mem5.aPool[i] from list it is currently
** on. It should be found on mem5.aiFreelist[iLogsize].
@@ -144,18 +143,18 @@ static struct {
static void memsys5Unlink(int i, int iLogsize){
int next, prev;
assert( i>=0 && i<mem5.nBlock );
assert( iLogsize>=0 && iLogsize<NSIZE );
assert( iLogsize>=0 && iLogsize<=LOGMAX );
assert( (mem5.aCtrl[i] & CTRL_LOGSIZE)==iLogsize );
next = mem5.aPool[i].u.list.next;
prev = mem5.aPool[i].u.list.prev;
next = MEM5LINK(i)->next;
prev = MEM5LINK(i)->prev;
if( prev<0 ){
mem5.aiFreelist[iLogsize] = next;
}else{
mem5.aPool[prev].u.list.next = next;
MEM5LINK(prev)->next = next;
}
if( next>=0 ){
mem5.aPool[next].u.list.prev = prev;
MEM5LINK(next)->prev = prev;
}
}
@@ -167,14 +166,14 @@ static void memsys5Link(int i, int iLogsize){
int x;
assert( sqlite3_mutex_held(mem5.mutex) );
assert( i>=0 && i<mem5.nBlock );
assert( iLogsize>=0 && iLogsize<NSIZE );
assert( iLogsize>=0 && iLogsize<=LOGMAX );
assert( (mem5.aCtrl[i] & CTRL_LOGSIZE)==iLogsize );
mem5.aPool[i].u.list.next = x = mem5.aiFreelist[iLogsize];
mem5.aPool[i].u.list.prev = -1;
x = MEM5LINK(i)->next = mem5.aiFreelist[iLogsize];
MEM5LINK(i)->prev = -1;
if( x>=0 ){
assert( x<mem5.nBlock );
mem5.aPool[x].u.list.prev = i;
MEM5LINK(x)->prev = i;
}
mem5.aiFreelist[iLogsize] = i;
}
@@ -202,9 +201,9 @@ static void memsys5Leave(void){
static int memsys5Size(void *p){
int iSize = 0;
if( p ){
int i = ((Mem5Block*)p) - mem5.aPool;
int i = ((u8 *)p-mem5.zPool)/mem5.nAtom;
assert( i>=0 && i<mem5.nBlock );
iSize = 1 << ((mem5.aCtrl[i]&CTRL_LOGSIZE) + SQLITE_POW2_LOGMIN);
iSize = mem5.nAtom * (1 << (mem5.aCtrl[i]&CTRL_LOGSIZE));
}
return iSize;
}
@@ -217,12 +216,12 @@ static int memsys5UnlinkFirst(int iLogsize){
int i;
int iFirst;
assert( iLogsize>=0 && iLogsize<NSIZE );
assert( iLogsize>=0 && iLogsize<=LOGMAX );
i = iFirst = mem5.aiFreelist[iLogsize];
assert( iFirst>=0 );
while( i>0 ){
if( i<iFirst ) iFirst = i;
i = mem5.aPool[i].u.list.next;
i = MEM5LINK(i)->next;
}
memsys5Unlink(iFirst, iLogsize);
return iFirst;
@@ -246,14 +245,14 @@ static void *memsys5MallocUnsafe(int nByte){
/* Round nByte up to the next valid power of two */
if( nByte>POW2_MAX ) return 0;
for(iFullSz=POW2_MIN, iLogsize=0; iFullSz<nByte; iFullSz *= 2, iLogsize++){}
for(iFullSz=mem5.nAtom, iLogsize=0; iFullSz<nByte; iFullSz *= 2, iLogsize++){}
/* Make sure mem5.aiFreelist[iLogsize] contains at least one free
** block. If not, then split a block of the next larger power of
** two in order to create a new free block of size iLogsize.
*/
for(iBin=iLogsize; mem5.aiFreelist[iBin]<0 && iBin<NSIZE; iBin++){}
if( iBin>=NSIZE ) return 0;
for(iBin=iLogsize; mem5.aiFreelist[iBin]<0 && iBin<=LOGMAX; iBin++){}
if( iBin>LOGMAX ) return 0;
i = memsys5UnlinkFirst(iBin);
while( iBin>iLogsize ){
int newSize;
@@ -275,7 +274,7 @@ static void *memsys5MallocUnsafe(int nByte){
if( mem5.maxOut<mem5.currentOut ) mem5.maxOut = mem5.currentOut;
/* Return a pointer to the allocated memory. */
return (void*)&mem5.aPool[i];
return (void*)&mem5.zPool[i*mem5.nAtom];
}
/*
@@ -283,47 +282,55 @@ static void *memsys5MallocUnsafe(int nByte){
*/
static void memsys5FreeUnsafe(void *pOld){
u32 size, iLogsize;
int i;
int iBlock;
i = ((Mem5Block*)pOld) - mem5.aPool;
assert( i>=0 && i<mem5.nBlock );
assert( (mem5.aCtrl[i] & CTRL_FREE)==0 );
iLogsize = mem5.aCtrl[i] & CTRL_LOGSIZE;
/* Set iBlock to the index of the block pointed to by pOld in
** the array of mem5.nAtom byte blocks pointed to by mem5.zPool.
*/
iBlock = ((u8 *)pOld-mem5.zPool)/mem5.nAtom;
/* Check that the pointer pOld points to a valid, non-free block. */
assert( iBlock>=0 && iBlock<mem5.nBlock );
assert( ((u8 *)pOld-mem5.zPool)%mem5.nAtom==0 );
assert( (mem5.aCtrl[iBlock] & CTRL_FREE)==0 );
iLogsize = mem5.aCtrl[iBlock] & CTRL_LOGSIZE;
size = 1<<iLogsize;
assert( i+size-1<mem5.nBlock );
mem5.aCtrl[i] |= CTRL_FREE;
mem5.aCtrl[i+size-1] |= CTRL_FREE;
assert( iBlock+size-1<mem5.nBlock );
mem5.aCtrl[iBlock] |= CTRL_FREE;
mem5.aCtrl[iBlock+size-1] |= CTRL_FREE;
assert( mem5.currentCount>0 );
assert( mem5.currentOut>=0 );
mem5.currentCount--;
mem5.currentOut -= size*POW2_MIN;
mem5.currentOut -= size*mem5.nAtom;
assert( mem5.currentOut>0 || mem5.currentCount==0 );
assert( mem5.currentCount>0 || mem5.currentOut==0 );
mem5.aCtrl[i] = CTRL_FREE | iLogsize;
while( iLogsize<NSIZE-1 ){
mem5.aCtrl[iBlock] = CTRL_FREE | iLogsize;
while( iLogsize<LOGMAX ){
int iBuddy;
if( (i>>iLogsize) & 1 ){
iBuddy = i - size;
if( (iBlock>>iLogsize) & 1 ){
iBuddy = iBlock - size;
}else{
iBuddy = i + size;
iBuddy = iBlock + size;
}
assert( iBuddy>=0 && iBuddy<mem5.nBlock );
assert( iBuddy>=0 );
if( (iBuddy+(1<<iLogsize))>mem5.nBlock ) break;
if( mem5.aCtrl[iBuddy]!=(CTRL_FREE | iLogsize) ) break;
memsys5Unlink(iBuddy, iLogsize);
iLogsize++;
if( iBuddy<i ){
if( iBuddy<iBlock ){
mem5.aCtrl[iBuddy] = CTRL_FREE | iLogsize;
mem5.aCtrl[i] = 0;
i = iBuddy;
mem5.aCtrl[iBlock] = 0;
iBlock = iBuddy;
}else{
mem5.aCtrl[i] = CTRL_FREE | iLogsize;
mem5.aCtrl[iBlock] = CTRL_FREE | iLogsize;
mem5.aCtrl[iBuddy] = 0;
}
size *= 2;
}
memsys5Link(i, iLogsize);
memsys5Link(iBlock, iLogsize);
}
/*
@@ -344,6 +351,7 @@ static void *memsys5Malloc(int nBytes){
*/
static void memsys5Free(void *pPrior){
if( pPrior==0 ){
assert(0);
return;
}
memsys5Enter();
@@ -383,14 +391,51 @@ static void *memsys5Realloc(void *pPrior, int nBytes){
*/
static int memsys5Roundup(int n){
int iFullSz;
for(iFullSz=POW2_MIN; iFullSz<n; iFullSz *= 2);
for(iFullSz=mem5.nAtom; iFullSz<n; iFullSz *= 2);
return iFullSz;
}
static int memsys5Log(int iValue){
int iLog;
for(iLog=0; (1<<iLog)<iValue; iLog++);
return iLog;
}
/*
** Initialize this module.
*/
static int memsys5Init(void *NotUsed){
int ii;
int nByte = sqlite3Config.nHeap;
u8 *zByte = (u8 *)sqlite3Config.pHeap;
int nMinLog; /* Log of minimum allocation size in bytes*/
int iOffset;
nMinLog = memsys5Log(sqlite3Config.mnReq);
mem5.nAtom = (1<<nMinLog);
while( sizeof(Mem5Link)>mem5.nAtom ){
mem5.nAtom = mem5.nAtom << 1;
}
mem5.nBlock = (nByte / (mem5.nAtom+sizeof(u8)));
mem5.zPool = zByte;
mem5.aCtrl = (u8 *)&mem5.zPool[mem5.nBlock*mem5.nAtom];
for(ii=0; ii<=LOGMAX; ii++){
mem5.aiFreelist[ii] = -1;
}
iOffset = 0;
for(ii=LOGMAX; ii>=0; ii--){
int nAlloc = (1<<ii);
if( (iOffset+nAlloc)<=mem5.nBlock ){
mem5.aCtrl[iOffset] = ii | CTRL_FREE;
memsys5Link(iOffset, ii);
iOffset += nAlloc;
}
assert((iOffset+nAlloc)>mem5.nBlock);
}
return SQLITE_OK;
}
@@ -409,6 +454,7 @@ void sqlite3Memsys5Dump(const char *zFilename){
#ifdef SQLITE_DEBUG
FILE *out;
int i, j, n;
int nMinLog;
if( zFilename==0 || zFilename[0]==0 ){
out = stdout;
@@ -421,9 +467,10 @@ void sqlite3Memsys5Dump(const char *zFilename){
}
}
memsys5Enter();
for(i=0; i<NSIZE; i++){
for(n=0, j=mem5.aiFreelist[i]; j>=0; j = mem5.aPool[j].u.list.next, n++){}
fprintf(out, "freelist items of size %d: %d\n", POW2_MIN << i, n);
nMinLog = memsys5Log(mem5.nAtom);
for(i=0; i<=LOGMAX && i+nMinLog<32; i++){
for(n=0, j=mem5.aiFreelist[i]; j>=0; j = MEM5LINK(j)->next, n++){}
fprintf(out, "freelist items of size %d: %d\n", mem5.nAtom << i, n);
}
fprintf(out, "mem5.nAlloc = %llu\n", mem5.nAlloc);
fprintf(out, "mem5.totalAlloc = %llu\n", mem5.totalAlloc);
@@ -444,16 +491,10 @@ void sqlite3Memsys5Dump(const char *zFilename){
/*
** This routine is the only routine in this file with external
** linkage.
**
** Populate the low-level memory allocation function pointers in
** sqlite3Config.m with pointers to the routines in this file. The
** arguments specify the block of memory to manage.
**
** This routine is only called by sqlite3_config(), and therefore
** is not required to be threadsafe (it is not).
** linkage. It returns a pointer to a static sqlite3_mem_methods
** struct populated with the memsys5 methods.
*/
void sqlite3MemSetMemsys5(u8 *zByte, int nByte){
const sqlite3_mem_methods *sqlite3MemGetMemsys5(void){
static const sqlite3_mem_methods memsys5Methods = {
memsys5Malloc,
memsys5Free,
@@ -464,25 +505,7 @@ void sqlite3MemSetMemsys5(u8 *zByte, int nByte){
memsys5Shutdown,
0
};
int i;
mem5.nBlock = (nByte / (sizeof(Mem5Block)+sizeof(u8)));
mem5.nBlock -= (mem5.nBlock%SZ_MAX);
mem5.aPool = (Mem5Block *)zByte;
mem5.aCtrl = (u8 *)&mem5.aPool[mem5.nBlock];
assert( sizeof(Mem5Block)==POW2_MIN );
assert( mem5.nBlock>=SZ_MAX );
assert( (mem5.nBlock%SZ_MAX)==0 );
for(i=0; i<NSIZE; i++) mem5.aiFreelist[i] = -1;
for(i=0; i<=mem5.nBlock-SZ_MAX; i += SZ_MAX){
mem5.aCtrl[i] = (NSIZE-1) | CTRL_FREE;
memsys5Link(i, NSIZE-1);
}
/* Configure the functions to call to allocate memory. */
sqlite3_config(SQLITE_CONFIG_MALLOC, &memsys5Methods);
return &memsys5Methods;
}
#endif /* SQLITE_ENABLE_MEMSYS5 */