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OpenFPGA/libs/EXTERNAL/tcl8.6.12/generic/tclThreadAlloc.c

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adding Tcl interface to vpr
2022-06-07 11:15:20 -05:00
/*
* tclThreadAlloc.c --
*
* This is a very fast storage allocator for used with threads (designed
* avoid lock contention). The basic strategy is to allocate memory in
* fixed size blocks from block caches.
*
* The Initial Developer of the Original Code is America Online, Inc.
* Portions created by AOL are Copyright (C) 1999 America Online, Inc.
*
* See the file "license.terms" for information on usage and redistribution of
* this file, and for a DISCLAIMER OF ALL WARRANTIES.
*/
#include "tclInt.h"
#if defined(TCL_THREADS) && defined(USE_THREAD_ALLOC)
/*
* If range checking is enabled, an additional byte will be allocated to store
* the magic number at the end of the requested memory.
*/
#ifndef RCHECK
#ifdef NDEBUG
#define RCHECK 0
#else
#define RCHECK 1
#endif
#endif
/*
* The following define the number of Tcl_Obj's to allocate/move at a time and
* the high water mark to prune a per-thread cache. On a 32 bit system,
* sizeof(Tcl_Obj) = 24 so 800 * 24 = ~16k.
*/
#define NOBJALLOC 800
/* Actual definition moved to tclInt.h */
#define NOBJHIGH ALLOC_NOBJHIGH
/*
* The following union stores accounting information for each block including
* two small magic numbers and a bucket number when in use or a next pointer
* when free. The original requested size (not including the Block overhead)
* is also maintained.
*/
typedef union Block {
struct {
union {
union Block *next; /* Next in free list. */
struct {
unsigned char magic1; /* First magic number. */
unsigned char bucket; /* Bucket block allocated from. */
unsigned char unused; /* Padding. */
unsigned char magic2; /* Second magic number. */
} s;
} u;
size_t reqSize; /* Requested allocation size. */
} b;
unsigned char padding[TCL_ALLOCALIGN];
} Block;
#define nextBlock b.u.next
#define sourceBucket b.u.s.bucket
#define magicNum1 b.u.s.magic1
#define magicNum2 b.u.s.magic2
#define MAGIC 0xEF
#define blockReqSize b.reqSize
/*
* The following defines the minimum and and maximum block sizes and the number
* of buckets in the bucket cache.
*/
#define MINALLOC ((sizeof(Block) + 8 + (TCL_ALLOCALIGN-1)) & ~(TCL_ALLOCALIGN-1))
#define NBUCKETS (11 - (MINALLOC >> 5))
#define MAXALLOC (MINALLOC << (NBUCKETS - 1))
/*
* The following structure defines a bucket of blocks with various accounting
* and statistics information.
*/
typedef struct Bucket {
Block *firstPtr; /* First block available */
Block *lastPtr; /* End of block list */
long numFree; /* Number of blocks available */
/* All fields below for accounting only */
long numRemoves; /* Number of removes from bucket */
long numInserts; /* Number of inserts into bucket */
long numWaits; /* Number of waits to acquire a lock */
long numLocks; /* Number of locks acquired */
long totalAssigned; /* Total space assigned to bucket */
} Bucket;
/*
* The following structure defines a cache of buckets and objs, of which there
* will be (at most) one per thread. Any changes need to be reflected in the
* struct AllocCache defined in tclInt.h, possibly also in the initialisation
* code in Tcl_CreateInterp().
*/
typedef struct Cache {
struct Cache *nextPtr; /* Linked list of cache entries */
Tcl_ThreadId owner; /* Which thread's cache is this? */
Tcl_Obj *firstObjPtr; /* List of free objects for thread */
int numObjects; /* Number of objects for thread */
Tcl_Obj *lastPtr; /* Last object in this cache */
int totalAssigned; /* Total space assigned to thread */
Bucket buckets[NBUCKETS]; /* The buckets for this thread */
} Cache;
/*
* The following array specifies various per-bucket limits and locks. The
* values are statically initialized to avoid calculating them repeatedly.
*/
static struct {
size_t blockSize; /* Bucket blocksize. */
int maxBlocks; /* Max blocks before move to share. */
int numMove; /* Num blocks to move to share. */
Tcl_Mutex *lockPtr; /* Share bucket lock. */
} bucketInfo[NBUCKETS];
/*
* Static functions defined in this file.
*/
static Cache * GetCache(void);
static void LockBucket(Cache *cachePtr, int bucket);
static void UnlockBucket(Cache *cachePtr, int bucket);
static void PutBlocks(Cache *cachePtr, int bucket, int numMove);
static int GetBlocks(Cache *cachePtr, int bucket);
static Block * Ptr2Block(char *ptr);
static char * Block2Ptr(Block *blockPtr, int bucket, unsigned int reqSize);
static void MoveObjs(Cache *fromPtr, Cache *toPtr, int numMove);
static void PutObjs(Cache *fromPtr, int numMove);
/*
* Local variables defined in this file and initialized at startup.
*/
static Tcl_Mutex *listLockPtr;
static Tcl_Mutex *objLockPtr;
static Cache sharedCache;
static Cache *sharedPtr = &sharedCache;
static Cache *firstCachePtr = &sharedCache;
#if defined(HAVE_FAST_TSD)
static __thread Cache *tcachePtr;
# define GETCACHE(cachePtr) \
do { \
if (!tcachePtr) { \
tcachePtr = GetCache(); \
} \
(cachePtr) = tcachePtr; \
} while (0)
#else
# define GETCACHE(cachePtr) \
do { \
(cachePtr) = TclpGetAllocCache(); \
if ((cachePtr) == NULL) { \
(cachePtr) = GetCache(); \
} \
} while (0)
#endif
/*
*----------------------------------------------------------------------
*
* GetCache ---
*
* Gets per-thread memory cache, allocating it if necessary.
*
* Results:
* Pointer to cache.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
static Cache *
GetCache(void)
{
Cache *cachePtr;
/*
* Check for first-time initialization.
*/
if (listLockPtr == NULL) {
Tcl_Mutex *initLockPtr;
unsigned int i;
initLockPtr = Tcl_GetAllocMutex();
Tcl_MutexLock(initLockPtr);
if (listLockPtr == NULL) {
listLockPtr = TclpNewAllocMutex();
objLockPtr = TclpNewAllocMutex();
for (i = 0; i < NBUCKETS; ++i) {
bucketInfo[i].blockSize = MINALLOC << i;
bucketInfo[i].maxBlocks = 1 << (NBUCKETS - 1 - i);
bucketInfo[i].numMove = i < NBUCKETS - 1 ?
1 << (NBUCKETS - 2 - i) : 1;
bucketInfo[i].lockPtr = TclpNewAllocMutex();
}
}
Tcl_MutexUnlock(initLockPtr);
}
/*
* Get this thread's cache, allocating if necessary.
*/
cachePtr = TclpGetAllocCache();
if (cachePtr == NULL) {
cachePtr = TclpSysAlloc(sizeof(Cache), 0);
if (cachePtr == NULL) {
Tcl_Panic("alloc: could not allocate new cache");
}
memset(cachePtr, 0, sizeof(Cache));
Tcl_MutexLock(listLockPtr);
cachePtr->nextPtr = firstCachePtr;
firstCachePtr = cachePtr;
Tcl_MutexUnlock(listLockPtr);
cachePtr->owner = Tcl_GetCurrentThread();
TclpSetAllocCache(cachePtr);
}
return cachePtr;
}
/*
*----------------------------------------------------------------------
*
* TclFreeAllocCache --
*
* Flush and delete a cache, removing from list of caches.
*
* Results:
* None.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
void
TclFreeAllocCache(
void *arg)
{
Cache *cachePtr = arg;
Cache **nextPtrPtr;
unsigned int bucket;
/*
* Flush blocks.
*/
for (bucket = 0; bucket < NBUCKETS; ++bucket) {
if (cachePtr->buckets[bucket].numFree > 0) {
PutBlocks(cachePtr, bucket, cachePtr->buckets[bucket].numFree);
}
}
/*
* Flush objs.
*/
if (cachePtr->numObjects > 0) {
PutObjs(cachePtr, cachePtr->numObjects);
}
/*
* Remove from pool list.
*/
Tcl_MutexLock(listLockPtr);
nextPtrPtr = &firstCachePtr;
while (*nextPtrPtr != cachePtr) {
nextPtrPtr = &(*nextPtrPtr)->nextPtr;
}
*nextPtrPtr = cachePtr->nextPtr;
cachePtr->nextPtr = NULL;
Tcl_MutexUnlock(listLockPtr);
TclpSysFree(cachePtr);
}
/*
*----------------------------------------------------------------------
*
* TclpAlloc --
*
* Allocate memory.
*
* Results:
* Pointer to memory just beyond Block pointer.
*
* Side effects:
* May allocate more blocks for a bucket.
*
*----------------------------------------------------------------------
*/
char *
TclpAlloc(
unsigned int reqSize)
{
Cache *cachePtr;
Block *blockPtr;
int bucket;
size_t size;
#ifndef __LP64__
if (sizeof(int) >= sizeof(size_t)) {
/* An unsigned int overflow can also be a size_t overflow */
const size_t zero = 0;
const size_t max = ~zero;
if (((size_t) reqSize) > max - sizeof(Block) - RCHECK) {
/* Requested allocation exceeds memory */
return NULL;
}
}
#endif
GETCACHE(cachePtr);
/*
* Increment the requested size to include room for the Block structure.
* Call TclpSysAlloc() directly if the required amount is greater than the
* largest block, otherwise pop the smallest block large enough,
* allocating more blocks if necessary.
*/
blockPtr = NULL;
size = reqSize + sizeof(Block);
#if RCHECK
size++;
#endif
if (size > MAXALLOC) {
bucket = NBUCKETS;
blockPtr = TclpSysAlloc(size, 0);
if (blockPtr != NULL) {
cachePtr->totalAssigned += reqSize;
}
} else {
bucket = 0;
while (bucketInfo[bucket].blockSize < size) {
bucket++;
}
if (cachePtr->buckets[bucket].numFree || GetBlocks(cachePtr, bucket)) {
blockPtr = cachePtr->buckets[bucket].firstPtr;
cachePtr->buckets[bucket].firstPtr = blockPtr->nextBlock;
cachePtr->buckets[bucket].numFree--;
cachePtr->buckets[bucket].numRemoves++;
cachePtr->buckets[bucket].totalAssigned += reqSize;
}
}
if (blockPtr == NULL) {
return NULL;
}
return Block2Ptr(blockPtr, bucket, reqSize);
}
/*
*----------------------------------------------------------------------
*
* TclpFree --
*
* Return blocks to the thread block cache.
*
* Results:
* None.
*
* Side effects:
* May move blocks to shared cache.
*
*----------------------------------------------------------------------
*/
void
TclpFree(
char *ptr)
{
Cache *cachePtr;
Block *blockPtr;
int bucket;
if (ptr == NULL) {
return;
}
GETCACHE(cachePtr);
/*
* Get the block back from the user pointer and call system free directly
* for large blocks. Otherwise, push the block back on the bucket and move
* blocks to the shared cache if there are now too many free.
*/
blockPtr = Ptr2Block(ptr);
bucket = blockPtr->sourceBucket;
if (bucket == NBUCKETS) {
cachePtr->totalAssigned -= blockPtr->blockReqSize;
TclpSysFree(blockPtr);
return;
}
cachePtr->buckets[bucket].totalAssigned -= blockPtr->blockReqSize;
blockPtr->nextBlock = cachePtr->buckets[bucket].firstPtr;
cachePtr->buckets[bucket].firstPtr = blockPtr;
if (cachePtr->buckets[bucket].numFree == 0) {
cachePtr->buckets[bucket].lastPtr = blockPtr;
}
cachePtr->buckets[bucket].numFree++;
cachePtr->buckets[bucket].numInserts++;
if (cachePtr != sharedPtr &&
cachePtr->buckets[bucket].numFree > bucketInfo[bucket].maxBlocks) {
PutBlocks(cachePtr, bucket, bucketInfo[bucket].numMove);
}
}
/*
*----------------------------------------------------------------------
*
* TclpRealloc --
*
* Re-allocate memory to a larger or smaller size.
*
* Results:
* Pointer to memory just beyond Block pointer.
*
* Side effects:
* Previous memory, if any, may be freed.
*
*----------------------------------------------------------------------
*/
char *
TclpRealloc(
char *ptr,
unsigned int reqSize)
{
Cache *cachePtr;
Block *blockPtr;
void *newPtr;
size_t size, min;
int bucket;
if (ptr == NULL) {
return TclpAlloc(reqSize);
}
#ifndef __LP64__
if (sizeof(int) >= sizeof(size_t)) {
/* An unsigned int overflow can also be a size_t overflow */
const size_t zero = 0;
const size_t max = ~zero;
if (((size_t) reqSize) > max - sizeof(Block) - RCHECK) {
/* Requested allocation exceeds memory */
return NULL;
}
}
#endif
GETCACHE(cachePtr);
/*
* If the block is not a system block and fits in place, simply return the
* existing pointer. Otherwise, if the block is a system block and the new
* size would also require a system block, call TclpSysRealloc() directly.
*/
blockPtr = Ptr2Block(ptr);
size = reqSize + sizeof(Block);
#if RCHECK
size++;
#endif
bucket = blockPtr->sourceBucket;
if (bucket != NBUCKETS) {
if (bucket > 0) {
min = bucketInfo[bucket-1].blockSize;
} else {
min = 0;
}
if (size > min && size <= bucketInfo[bucket].blockSize) {
cachePtr->buckets[bucket].totalAssigned -= blockPtr->blockReqSize;
cachePtr->buckets[bucket].totalAssigned += reqSize;
return Block2Ptr(blockPtr, bucket, reqSize);
}
} else if (size > MAXALLOC) {
cachePtr->totalAssigned -= blockPtr->blockReqSize;
cachePtr->totalAssigned += reqSize;
blockPtr = TclpSysRealloc(blockPtr, size);
if (blockPtr == NULL) {
return NULL;
}
return Block2Ptr(blockPtr, NBUCKETS, reqSize);
}
/*
* Finally, perform an expensive malloc/copy/free.
*/
newPtr = TclpAlloc(reqSize);
if (newPtr != NULL) {
if (reqSize > blockPtr->blockReqSize) {
reqSize = blockPtr->blockReqSize;
}
memcpy(newPtr, ptr, reqSize);
TclpFree(ptr);
}
return newPtr;
}
/*
*----------------------------------------------------------------------
*
* TclThreadAllocObj --
*
* Allocate a Tcl_Obj from the per-thread cache.
*
* Results:
* Pointer to uninitialized Tcl_Obj.
*
* Side effects:
* May move Tcl_Obj's from shared cached or allocate new Tcl_Obj's if
* list is empty.
*
* Note:
* If this code is updated, the changes need to be reflected in the macro
* TclAllocObjStorageEx() defined in tclInt.h
*
*----------------------------------------------------------------------
*/
Tcl_Obj *
TclThreadAllocObj(void)
{
Cache *cachePtr;
Tcl_Obj *objPtr;
GETCACHE(cachePtr);
/*
* Get this thread's obj list structure and move or allocate new objs if
* necessary.
*/
if (cachePtr->numObjects == 0) {
int numMove;
Tcl_MutexLock(objLockPtr);
numMove = sharedPtr->numObjects;
if (numMove > 0) {
if (numMove > NOBJALLOC) {
numMove = NOBJALLOC;
}
MoveObjs(sharedPtr, cachePtr, numMove);
}
Tcl_MutexUnlock(objLockPtr);
if (cachePtr->numObjects == 0) {
Tcl_Obj *newObjsPtr;
cachePtr->numObjects = numMove = NOBJALLOC;
newObjsPtr = TclpSysAlloc(sizeof(Tcl_Obj) * numMove, 0);
if (newObjsPtr == NULL) {
Tcl_Panic("alloc: could not allocate %d new objects", numMove);
}
cachePtr->lastPtr = newObjsPtr + numMove - 1;
objPtr = cachePtr->firstObjPtr; /* NULL */
while (--numMove >= 0) {
newObjsPtr[numMove].internalRep.twoPtrValue.ptr1 = objPtr;
objPtr = newObjsPtr + numMove;
}
cachePtr->firstObjPtr = newObjsPtr;
}
}
/*
* Pop the first object.
*/
objPtr = cachePtr->firstObjPtr;
cachePtr->firstObjPtr = objPtr->internalRep.twoPtrValue.ptr1;
cachePtr->numObjects--;
return objPtr;
}
/*
*----------------------------------------------------------------------
*
* TclThreadFreeObj --
*
* Return a free Tcl_Obj to the per-thread cache.
*
* Results:
* None.
*
* Side effects:
* May move free Tcl_Obj's to shared list upon hitting high water mark.
*
* Note:
* If this code is updated, the changes need to be reflected in the macro
* TclAllocObjStorageEx() defined in tclInt.h
*
*----------------------------------------------------------------------
*/
void
TclThreadFreeObj(
Tcl_Obj *objPtr)
{
Cache *cachePtr;
GETCACHE(cachePtr);
/*
* Get this thread's list and push on the free Tcl_Obj.
*/
objPtr->internalRep.twoPtrValue.ptr1 = cachePtr->firstObjPtr;
cachePtr->firstObjPtr = objPtr;
if (cachePtr->numObjects == 0) {
cachePtr->lastPtr = objPtr;
}
cachePtr->numObjects++;
/*
* If the number of free objects has exceeded the high water mark, move
* some blocks to the shared list.
*/
if (cachePtr->numObjects > NOBJHIGH) {
PutObjs(cachePtr, NOBJALLOC);
}
}
/*
*----------------------------------------------------------------------
*
* Tcl_GetMemoryInfo --
*
* Return a list-of-lists of memory stats.
*
* Results:
* None.
*
* Side effects:
* List appended to given dstring.
*
*----------------------------------------------------------------------
*/
void
Tcl_GetMemoryInfo(
Tcl_DString *dsPtr)
{
Cache *cachePtr;
char buf[200];
unsigned int n;
Tcl_MutexLock(listLockPtr);
cachePtr = firstCachePtr;
while (cachePtr != NULL) {
Tcl_DStringStartSublist(dsPtr);
if (cachePtr == sharedPtr) {
Tcl_DStringAppendElement(dsPtr, "shared");
} else {
sprintf(buf, "thread%p", cachePtr->owner);
Tcl_DStringAppendElement(dsPtr, buf);
}
for (n = 0; n < NBUCKETS; ++n) {
sprintf(buf, "%lu %ld %ld %ld %ld %ld %ld",
(unsigned long) bucketInfo[n].blockSize,
cachePtr->buckets[n].numFree,
cachePtr->buckets[n].numRemoves,
cachePtr->buckets[n].numInserts,
cachePtr->buckets[n].totalAssigned,
cachePtr->buckets[n].numLocks,
cachePtr->buckets[n].numWaits);
Tcl_DStringAppendElement(dsPtr, buf);
}
Tcl_DStringEndSublist(dsPtr);
cachePtr = cachePtr->nextPtr;
}
Tcl_MutexUnlock(listLockPtr);
}
/*
*----------------------------------------------------------------------
*
* MoveObjs --
*
* Move Tcl_Obj's between caches.
*
* Results:
* None.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
static void
MoveObjs(
Cache *fromPtr,
Cache *toPtr,
int numMove)
{
Tcl_Obj *objPtr = fromPtr->firstObjPtr;
Tcl_Obj *fromFirstObjPtr = objPtr;
toPtr->numObjects += numMove;
fromPtr->numObjects -= numMove;
/*
* Find the last object to be moved; set the next one (the first one not
* to be moved) as the first object in the 'from' cache.
*/
while (--numMove) {
objPtr = objPtr->internalRep.twoPtrValue.ptr1;
}
fromPtr->firstObjPtr = objPtr->internalRep.twoPtrValue.ptr1;
/*
* Move all objects as a block - they are already linked to each other, we
* just have to update the first and last.
*/
toPtr->lastPtr = objPtr;
objPtr->internalRep.twoPtrValue.ptr1 = toPtr->firstObjPtr; /* NULL */
toPtr->firstObjPtr = fromFirstObjPtr;
}
/*
*----------------------------------------------------------------------
*
* PutObjs --
*
* Move Tcl_Obj's from thread cache to shared cache.
*
* Results:
* None.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
static void
PutObjs(
Cache *fromPtr,
int numMove)
{
int keep = fromPtr->numObjects - numMove;
Tcl_Obj *firstPtr, *lastPtr = NULL;
fromPtr->numObjects = keep;
firstPtr = fromPtr->firstObjPtr;
if (keep == 0) {
fromPtr->firstObjPtr = NULL;
} else {
do {
lastPtr = firstPtr;
firstPtr = firstPtr->internalRep.twoPtrValue.ptr1;
} while (--keep > 0);
lastPtr->internalRep.twoPtrValue.ptr1 = NULL;
}
/*
* Move all objects as a block - they are already linked to each other, we
* just have to update the first and last.
*/
Tcl_MutexLock(objLockPtr);
fromPtr->lastPtr->internalRep.twoPtrValue.ptr1 = sharedPtr->firstObjPtr;
sharedPtr->firstObjPtr = firstPtr;
if (sharedPtr->numObjects == 0) {
sharedPtr->lastPtr = fromPtr->lastPtr;
}
sharedPtr->numObjects += numMove;
Tcl_MutexUnlock(objLockPtr);
fromPtr->lastPtr = lastPtr;
}
/*
*----------------------------------------------------------------------
*
* Block2Ptr, Ptr2Block --
*
* Convert between internal blocks and user pointers.
*
* Results:
* User pointer or internal block.
*
* Side effects:
* Invalid blocks will abort the server.
*
*----------------------------------------------------------------------
*/
static char *
Block2Ptr(
Block *blockPtr,
int bucket,
unsigned int reqSize)
{
void *ptr;
blockPtr->magicNum1 = blockPtr->magicNum2 = MAGIC;
blockPtr->sourceBucket = bucket;
blockPtr->blockReqSize = reqSize;
ptr = ((void *) (blockPtr + 1));
#if RCHECK
((unsigned char *)(ptr))[reqSize] = MAGIC;
#endif
return (char *) ptr;
}
static Block *
Ptr2Block(
char *ptr)
{
Block *blockPtr;
blockPtr = (((Block *) ptr) - 1);
if (blockPtr->magicNum1 != MAGIC || blockPtr->magicNum2 != MAGIC) {
Tcl_Panic("alloc: invalid block: %p: %x %x",
blockPtr, blockPtr->magicNum1, blockPtr->magicNum2);
}
#if RCHECK
if (((unsigned char *) ptr)[blockPtr->blockReqSize] != MAGIC) {
Tcl_Panic("alloc: invalid block: %p: %x %x %x",
blockPtr, blockPtr->magicNum1, blockPtr->magicNum2,
((unsigned char *) ptr)[blockPtr->blockReqSize]);
}
#endif
return blockPtr;
}
/*
*----------------------------------------------------------------------
*
* LockBucket, UnlockBucket --
*
* Set/unset the lock to access a bucket in the shared cache.
*
* Results:
* None.
*
* Side effects:
* Lock activity and contention are monitored globally and on a per-cache
* basis.
*
*----------------------------------------------------------------------
*/
static void
LockBucket(
Cache *cachePtr,
int bucket)
{
Tcl_MutexLock(bucketInfo[bucket].lockPtr);
cachePtr->buckets[bucket].numLocks++;
sharedPtr->buckets[bucket].numLocks++;
}
static void
UnlockBucket(
Cache *cachePtr,
int bucket)
{
Tcl_MutexUnlock(bucketInfo[bucket].lockPtr);
}
/*
*----------------------------------------------------------------------
*
* PutBlocks --
*
* Return unused blocks to the shared cache.
*
* Results:
* None.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
static void
PutBlocks(
Cache *cachePtr,
int bucket,
int numMove)
{
/*
* We have numFree. Want to shed numMove. So compute how many
* Blocks to keep.
*/
int keep = cachePtr->buckets[bucket].numFree - numMove;
Block *lastPtr = NULL, *firstPtr;
cachePtr->buckets[bucket].numFree = keep;
firstPtr = cachePtr->buckets[bucket].firstPtr;
if (keep == 0) {
cachePtr->buckets[bucket].firstPtr = NULL;
} else {
do {
lastPtr = firstPtr;
firstPtr = firstPtr->nextBlock;
} while (--keep > 0);
lastPtr->nextBlock = NULL;
}
/*
* Aquire the lock and place the list of blocks at the front of the shared
* cache bucket.
*/
LockBucket(cachePtr, bucket);
cachePtr->buckets[bucket].lastPtr->nextBlock
= sharedPtr->buckets[bucket].firstPtr;
sharedPtr->buckets[bucket].firstPtr = firstPtr;
if (sharedPtr->buckets[bucket].numFree == 0) {
sharedPtr->buckets[bucket].lastPtr
= cachePtr->buckets[bucket].lastPtr;
}
sharedPtr->buckets[bucket].numFree += numMove;
UnlockBucket(cachePtr, bucket);
cachePtr->buckets[bucket].lastPtr = lastPtr;
}
/*
*----------------------------------------------------------------------
*
* GetBlocks --
*
* Get more blocks for a bucket.
*
* Results:
* 1 if blocks where allocated, 0 otherwise.
*
* Side effects:
* Cache may be filled with available blocks.
*
*----------------------------------------------------------------------
*/
static int
GetBlocks(
Cache *cachePtr,
int bucket)
{
Block *blockPtr;
int n;
/*
* First, atttempt to move blocks from the shared cache. Note the
* potentially dirty read of numFree before acquiring the lock which is a
* slight performance enhancement. The value is verified after the lock is
* actually acquired.
*/
if (cachePtr != sharedPtr && sharedPtr->buckets[bucket].numFree > 0) {
LockBucket(cachePtr, bucket);
if (sharedPtr->buckets[bucket].numFree > 0) {
/*
* Either move the entire list or walk the list to find the last
* block to move.
*/
n = bucketInfo[bucket].numMove;
if (n >= sharedPtr->buckets[bucket].numFree) {
cachePtr->buckets[bucket].firstPtr =
sharedPtr->buckets[bucket].firstPtr;
cachePtr->buckets[bucket].lastPtr =
sharedPtr->buckets[bucket].lastPtr;
cachePtr->buckets[bucket].numFree =
sharedPtr->buckets[bucket].numFree;
sharedPtr->buckets[bucket].firstPtr = NULL;
sharedPtr->buckets[bucket].numFree = 0;
} else {
blockPtr = sharedPtr->buckets[bucket].firstPtr;
cachePtr->buckets[bucket].firstPtr = blockPtr;
sharedPtr->buckets[bucket].numFree -= n;
cachePtr->buckets[bucket].numFree = n;
while (--n > 0) {
blockPtr = blockPtr->nextBlock;
}
sharedPtr->buckets[bucket].firstPtr = blockPtr->nextBlock;
cachePtr->buckets[bucket].lastPtr = blockPtr;
blockPtr->nextBlock = NULL;
}
}
UnlockBucket(cachePtr, bucket);
}
if (cachePtr->buckets[bucket].numFree == 0) {
size_t size;
/*
* If no blocks could be moved from shared, first look for a larger
* block in this cache to split up.
*/
blockPtr = NULL;
n = NBUCKETS;
size = 0; /* lint */
while (--n > bucket) {
if (cachePtr->buckets[n].numFree > 0) {
size = bucketInfo[n].blockSize;
blockPtr = cachePtr->buckets[n].firstPtr;
cachePtr->buckets[n].firstPtr = blockPtr->nextBlock;
cachePtr->buckets[n].numFree--;
break;
}
}
/*
* Otherwise, allocate a big new block directly.
*/
if (blockPtr == NULL) {
size = MAXALLOC;
blockPtr = TclpSysAlloc(size, 0);
if (blockPtr == NULL) {
return 0;
}
}
/*
* Split the larger block into smaller blocks for this bucket.
*/
n = size / bucketInfo[bucket].blockSize;
cachePtr->buckets[bucket].numFree = n;
cachePtr->buckets[bucket].firstPtr = blockPtr;
while (--n > 0) {
blockPtr->nextBlock = (Block *)
((char *) blockPtr + bucketInfo[bucket].blockSize);
blockPtr = blockPtr->nextBlock;
}
cachePtr->buckets[bucket].lastPtr = blockPtr;
blockPtr->nextBlock = NULL;
}
return 1;
}
/*
*----------------------------------------------------------------------
*
* TclFinalizeThreadAlloc --
*
* This procedure is used to destroy all private resources used in this
* file.
*
* Results:
* None.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
void
TclFinalizeThreadAlloc(void)
{
unsigned int i;
for (i = 0; i < NBUCKETS; ++i) {
TclpFreeAllocMutex(bucketInfo[i].lockPtr);
bucketInfo[i].lockPtr = NULL;
}
TclpFreeAllocMutex(objLockPtr);
objLockPtr = NULL;
TclpFreeAllocMutex(listLockPtr);
listLockPtr = NULL;
TclpFreeAllocCache(NULL);
}
/*
*----------------------------------------------------------------------
*
* TclFinalizeThreadAllocThread --
*
* This procedure is used to destroy single thread private resources
* defined in this file. Called either during Tcl_FinalizeThread() or
* Tcl_Finalize().
*
* Results:
* None.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
void
TclFinalizeThreadAllocThread(void)
{
Cache *cachePtr = TclpGetAllocCache();
if (cachePtr != NULL) {
TclpFreeAllocCache(cachePtr);
}
}
#else /* !(TCL_THREADS && USE_THREAD_ALLOC) */
/*
*----------------------------------------------------------------------
*
* Tcl_GetMemoryInfo --
*
* Return a list-of-lists of memory stats.
*
* Results:
* None.
*
* Side effects:
* List appended to given dstring.
*
*----------------------------------------------------------------------
*/
void
Tcl_GetMemoryInfo(
Tcl_DString *dsPtr)
{
Tcl_Panic("Tcl_GetMemoryInfo called when threaded memory allocator not in use");
}
/*
*----------------------------------------------------------------------
*
* TclFinalizeThreadAlloc --
*
* This procedure is used to destroy all private resources used in this
* file.
*
* Results:
* None.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
void
TclFinalizeThreadAlloc(void)
{
Tcl_Panic("TclFinalizeThreadAlloc called when threaded memory allocator not in use");
}
#endif /* TCL_THREADS && USE_THREAD_ALLOC */
/*
* Local Variables:
* mode: c
* c-basic-offset: 4
* fill-column: 78
* End:
*/