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authorhobbs <hobbs>2002-02-27 07:08:28 (GMT)
committerhobbs <hobbs>2002-02-27 07:08:28 (GMT)
commitf0869bb4b6ea0271b6f244b0adea210bb1332cae (patch)
treedf02d27d4196ab5b02cd38c173f712e099731cb5 /generic/tclAlloc.c
parentb8243a4158d130a28312c6e3f5475855f48ed2dc (diff)
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reversed accidental commit of unfinished sources
Diffstat (limited to 'generic/tclAlloc.c')
-rw-r--r--generic/tclAlloc.c948
1 files changed, 2 insertions, 946 deletions
diff --git a/generic/tclAlloc.c b/generic/tclAlloc.c
index 6452ec5..099da71 100644
--- a/generic/tclAlloc.c
+++ b/generic/tclAlloc.c
@@ -15,957 +15,13 @@
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
- * RCS: @(#) $Id: tclAlloc.c,v 1.14 2002/02/27 06:39:26 hobbs Exp $
+ * RCS: @(#) $Id: tclAlloc.c,v 1.15 2002/02/27 07:08:28 hobbs Exp $
*/
#include "tclInt.h"
#include "tclPort.h"
-#if defined(TCL_THREADS) && !defined(MAC_TCL) && !defined(WIN32)
-
-/*
- * tclAlloc.c --
- *
- * Special purpose allocator for threaded Tcl.
- *
- * Fast cache memory allocator designed to avoid lock
- * contention. The basic strategy is to allocate memory in
- * fixed size blocks from block caches.
- */
-
-#include "tclInt.h"
-#include <pthread.h>
-#include <errno.h>
-
-/*
- * 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
-#define NOBJHIGH 1200
-
-/*
- * The following defines the number of buckets in the bucket
- * cache and those block sizes from (1<<4) to (1<<(3+NBUCKETS))
- */
-
-#define NBUCKETS 11
-#define MAXALLOC 16284
-
-/*
- * 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 struct Block {
- union {
- struct 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. */
- } b_s;
- } b_u;
- size_t b_reqsize; /* Requested allocation size. */
-} Block;
-#define b_next b_u.next
-#define b_bucket b_u.b_s.bucket
-#define b_magic1 b_u.b_s.magic1
-#define b_magic2 b_u.b_s.magic2
-#define MAGIC 0xef
-
-/*
- * The following structure defines a bucket of blocks with
- * various accouting and statistics information.
- */
-
-typedef struct Bucket {
- Block *firstPtr;
- int nfree;
- int nget;
- int nput;
- int nwait;
- int nlock;
- int nrequest;
-} Bucket;
-
-/*
- * The following structure defines a cache of buckets and objs.
- */
-
-typedef struct Cache {
- struct Cache *nextPtr;
- pthread_t owner;
- int busy;
- Tcl_Obj *firstObjPtr;
- int nobjs;
- int nsysalloc;
- Bucket buckets[NBUCKETS];
-} Cache;
-
-/*
- * The following array specifies various per-bucket
- * limits and locks. The values are statically initialized
- * to avoid calculating them repeatedly.
- */
-
-struct binfo {
- size_t blocksize; /* Bucket blocksize. */
- int maxblocks; /* Max blocks before move to share. */
- int nmove; /* Num blocks to move to share. */
- pthread_mutex_t lock; /* Share bucket lock. */
-} binfo[NBUCKETS] = {
- { 16, 1024, 512, PTHREAD_MUTEX_INITIALIZER},
- { 32, 512, 256, PTHREAD_MUTEX_INITIALIZER},
- { 64, 256, 128, PTHREAD_MUTEX_INITIALIZER},
- { 128, 128, 64, PTHREAD_MUTEX_INITIALIZER},
- { 256, 64, 32, PTHREAD_MUTEX_INITIALIZER},
- { 512, 32, 16, PTHREAD_MUTEX_INITIALIZER},
- { 1024, 16, 8, PTHREAD_MUTEX_INITIALIZER},
- { 2048, 8, 4, PTHREAD_MUTEX_INITIALIZER},
- { 4096, 4, 2, PTHREAD_MUTEX_INITIALIZER},
- { 8192, 2, 1, PTHREAD_MUTEX_INITIALIZER},
- {16284, 1, 1, PTHREAD_MUTEX_INITIALIZER},
-};
-
-/*
- * Static functions defined in this file.
- */
-
-static void LockBucket(Cache *cachePtr, int bucket);
-static void UnlockBucket(Cache *cachePtr, int bucket);
-static void PutBlocks(Cache *cachePtr, int bucket, int nmove);
-static int GetBlocks(Cache *cachePtr, int bucket);
-static Block *Ptr2Block(char *ptr);
-static char *Block2Ptr(Block *blockPtr, int bucket, unsigned int reqsize);
-static void FreeCache(void *arg);
-static void MoveObjs(Cache *fromPtr, Cache *toPtr, int nmove);
-
-/*
- * Local variables defined in this file and initialized at
- * startup.
- */
-
-static int initialized = 0;
-static pthread_mutex_t listlock = PTHREAD_MUTEX_INITIALIZER;
-static pthread_mutex_t objlock = PTHREAD_MUTEX_INITIALIZER;
-static pthread_once_t once = PTHREAD_ONCE_INIT;
-static pthread_key_t key;
-static Cache sharedCache;
-static Cache *sharedPtr = &sharedCache;
-static Cache *firstCachePtr = &sharedCache;
-
-
-/*
- *----------------------------------------------------------------------
- *
- * GetCache ---
- *
- * Gets per-thread memory cache, allocating it if necessary.
- *
- * Results:
- * Pointer to cache.
- *
- * Side effects:
- * None.
- *
- *----------------------------------------------------------------------
- */
-
-static void
-Init(void)
-{
- int err;
-
- err = pthread_key_create(&key, FreeCache);
- if (err != 0) {
- panic("alloc: pthread_key_create: %s", strerror(err));
- }
- initialized = 1;
-}
-
-static Cache *
-GetCache(void)
-{
- Cache *cachePtr;
- int err;
-
- /*
- * Check for first-time initialization.
- */
-
- if (!initialized) {
- pthread_once(&once, Init);
- }
-
- /*
- * Get this thread's cache, allocating if necessary.
- */
-
- cachePtr = pthread_getspecific(key);
- if (cachePtr == NULL) {
- cachePtr = calloc(1, sizeof(Cache));
- if (cachePtr == NULL) {
- panic("alloc: could not allocate new cache");
- }
- pthread_mutex_lock(&listlock);
- cachePtr->nextPtr = firstCachePtr;
- firstCachePtr = cachePtr;
- pthread_mutex_unlock(&listlock);
- cachePtr->owner = pthread_self();
- err = pthread_setspecific(key, cachePtr);
- if (err != 0) {
- panic("alloc: pthread_setspecific: %s", strerror(err));
- }
- }
- cachePtr->busy = 1;
- return cachePtr;
-}
-
-
-/*
- *----------------------------------------------------------------------
- *
- * FreeCache --
- *
- * Flush and delete a cache, removing from all-caches list.
- *
- * Results:
- * None.
- *
- * Side effects:
- * None.
- *
- *----------------------------------------------------------------------
- */
-
-static void
-FreeCache(void *arg)
-{
- Cache *cachePtr = arg;
- Cache **nextPtrPtr;
- register int bucket;
- int err;
-
- /*
- * Reset the cache and continue to finalize the thread until
- * it appears idle.
- */
-
- if (cachePtr->busy) {
- err = pthread_setspecific(key, cachePtr);
- if (err != 0) {
- panic("alloc: pthread_setspecific: %s", strerror(err));
- }
- Tcl_FinalizeThread();
- cachePtr->busy = 0;
- return;
- }
-
- /*
- * Flush blocks.
- */
-
- for (bucket = 0; bucket < NBUCKETS; ++bucket) {
- if (cachePtr->buckets[bucket].nfree > 0) {
- PutBlocks(cachePtr, bucket, cachePtr->buckets[bucket].nfree);
- }
- }
-
- /*
- * Flush objs.
- */
-
- if (cachePtr->nobjs > 0) {
- pthread_mutex_lock(&objlock);
- MoveObjs(cachePtr, sharedPtr, cachePtr->nobjs);
- pthread_mutex_unlock(&objlock);
- }
-
- /*
- * Remove from pool list.
- */
-
- pthread_mutex_lock(&listlock);
- nextPtrPtr = &firstCachePtr;
- while (*nextPtrPtr != cachePtr) {
- nextPtrPtr = &(*nextPtrPtr)->nextPtr;
- }
- *nextPtrPtr = cachePtr->nextPtr;
- cachePtr->nextPtr = NULL;
- pthread_mutex_unlock(&listlock);
-
- free(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 = GetCache();
- Block *blockPtr;
- register int bucket;
- size_t size;
-
- /*
- * Increment the requested size to include room for
- * the Block structure. Call malloc() 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 = malloc(size);
- if (blockPtr != NULL) {
- cachePtr->nsysalloc += reqsize;
- }
- } else {
- bucket = 0;
- while (binfo[bucket].blocksize < size) {
- ++bucket;
- }
- if (cachePtr->buckets[bucket].nfree || GetBlocks(cachePtr, bucket)) {
- blockPtr = cachePtr->buckets[bucket].firstPtr;
- cachePtr->buckets[bucket].firstPtr = blockPtr->b_next;
- --cachePtr->buckets[bucket].nfree;
- ++cachePtr->buckets[bucket].nget;
- cachePtr->buckets[bucket].nrequest += 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 = GetCache();
- Block *blockPtr;
- int bucket;
-
- if (ptr == NULL) {
- return;
- }
-
- /*
- * 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->b_bucket;
- if (bucket == NBUCKETS) {
- cachePtr->nsysalloc -= blockPtr->b_reqsize;
- free(blockPtr);
- } else {
- cachePtr->buckets[bucket].nrequest -= blockPtr->b_reqsize;
- blockPtr->b_next = cachePtr->buckets[bucket].firstPtr;
- cachePtr->buckets[bucket].firstPtr = blockPtr;
- ++cachePtr->buckets[bucket].nfree;
- ++cachePtr->buckets[bucket].nput;
- if (cachePtr != sharedPtr &&
- cachePtr->buckets[bucket].nfree > binfo[bucket].maxblocks) {
- PutBlocks(cachePtr, bucket, binfo[bucket].nmove);
- }
- }
-}
-
-
-/*
- *----------------------------------------------------------------------
- *
- * 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 = GetCache();
- Block *blockPtr;
- void *new;
- size_t size, min;
- int bucket;
-
- if (ptr == NULL) {
- return (TclpAlloc(reqsize));
- }
-
- /*
- * 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 realloc() directly.
- */
-
- blockPtr = Ptr2Block(ptr);
- size = reqsize + sizeof(Block);
-#if RCHECK
- ++size;
-#endif
- bucket = blockPtr->b_bucket;
- if (bucket != NBUCKETS) {
- if (bucket > 0) {
- min = binfo[bucket-1].blocksize;
- } else {
- min = 0;
- }
- if (size > min && size <= binfo[bucket].blocksize) {
- cachePtr->buckets[bucket].nrequest -= blockPtr->b_reqsize;
- cachePtr->buckets[bucket].nrequest += reqsize;
- return Block2Ptr(blockPtr, bucket, reqsize);
- }
- } else if (size > MAXALLOC) {
- cachePtr->nsysalloc -= blockPtr->b_reqsize;
- cachePtr->nsysalloc += reqsize;
- blockPtr = realloc(blockPtr, size);
- if (blockPtr == NULL) {
- return NULL;
- }
- return Block2Ptr(blockPtr, NBUCKETS, reqsize);
- }
-
- /*
- * Finally, perform an expensive malloc/copy/free.
- */
-
- new = TclpAlloc(reqsize);
- if (new != NULL) {
- if (reqsize > blockPtr->b_reqsize) {
- reqsize = blockPtr->b_reqsize;
- }
- memcpy(new, ptr, reqsize);
- TclpFree(ptr);
- }
- return new;
-}
-
-
-/*
- *----------------------------------------------------------------------
- *
- * 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.
- *
- *----------------------------------------------------------------------
- */
-
-Tcl_Obj *
-TclThreadAllocObj(void)
-{
- register Cache *cachePtr = GetCache();
- register int nmove;
- register Tcl_Obj *objPtr;
- Tcl_Obj *newObjsPtr;
-
- /*
- * Get this thread's obj list structure and move
- * or allocate new objs if necessary.
- */
-
- if (cachePtr->nobjs == 0) {
- pthread_mutex_lock(&objlock);
- nmove = sharedPtr->nobjs;
- if (nmove > 0) {
- if (nmove > NOBJALLOC) {
- nmove = NOBJALLOC;
- }
- MoveObjs(sharedPtr, cachePtr, nmove);
- }
- pthread_mutex_unlock(&objlock);
- if (cachePtr->nobjs == 0) {
- cachePtr->nobjs = nmove = NOBJALLOC;
- newObjsPtr = malloc(sizeof(Tcl_Obj) * nmove);
- if (newObjsPtr == NULL) {
- panic("alloc: could not allocate %d new objects", nmove);
- }
- while (--nmove >= 0) {
- objPtr = &newObjsPtr[nmove];
- objPtr->internalRep.otherValuePtr = cachePtr->firstObjPtr;
- cachePtr->firstObjPtr = objPtr;
- }
- }
- }
-
- /*
- * Pop the first object.
- */
-
- objPtr = cachePtr->firstObjPtr;
- cachePtr->firstObjPtr = objPtr->internalRep.otherValuePtr;
- --cachePtr->nobjs;
- 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.
- *
- *----------------------------------------------------------------------
- */
-
-void
-TclThreadFreeObj(Tcl_Obj *objPtr)
-{
- Cache *cachePtr = GetCache();
-
- /*
- * Get this thread's list and push on the free Tcl_Obj.
- */
-
- objPtr->internalRep.otherValuePtr = cachePtr->firstObjPtr;
- cachePtr->firstObjPtr = objPtr;
-
- /*
- * If the number of free objects has exceeded the high
- * water mark, move some blocks to the shared list.
- */
-
- ++cachePtr->nobjs;
- if (cachePtr->nobjs > NOBJHIGH) {
- pthread_mutex_lock(&objlock);
- MoveObjs(cachePtr, sharedPtr, NOBJALLOC);
- pthread_mutex_unlock(&objlock);
- }
-}
-
-
-/*
- *----------------------------------------------------------------------
- *
- * 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];
- int n;
-
- pthread_mutex_lock(&listlock);
- cachePtr = firstCachePtr;
- while (cachePtr != NULL) {
- Tcl_DStringStartSublist(dsPtr);
- if (cachePtr == sharedPtr) {
- Tcl_DStringAppendElement(dsPtr, "shared");
- } else {
- sprintf(buf, "thread%d", (int) cachePtr->owner);
- Tcl_DStringAppendElement(dsPtr, buf);
- }
- for (n = 0; n < NBUCKETS; ++n) {
- sprintf(buf, "%d %d %d %d %d %d %d",
- binfo[n].blocksize,
- cachePtr->buckets[n].nfree,
- cachePtr->buckets[n].nget,
- cachePtr->buckets[n].nput,
- cachePtr->buckets[n].nrequest,
- cachePtr->buckets[n].nlock,
- cachePtr->buckets[n].nwait);
- Tcl_DStringAppendElement(dsPtr, buf);
- }
- Tcl_DStringEndSublist(dsPtr);
- cachePtr = cachePtr->nextPtr;
- }
- pthread_mutex_unlock(&listlock);
-}
-
-
-/*
- *----------------------------------------------------------------------
- *
- * MoveObjs --
- *
- * Move Tcl_Obj's between caches.
- *
- * Results:
- * None.
- *
- * Side effects:
- * None.
- *
- *----------------------------------------------------------------------
- */
-
-static void
-MoveObjs(Cache *fromPtr, Cache *toPtr, int nmove)
-{
- register Tcl_Obj *objPtr;
-
- toPtr->nobjs += nmove;
- fromPtr->nobjs -= nmove;
- while (--nmove >= 0) {
- objPtr = fromPtr->firstObjPtr;
- fromPtr->firstObjPtr = objPtr->internalRep.otherValuePtr;
- objPtr->internalRep.otherValuePtr = toPtr->firstObjPtr;
- toPtr->firstObjPtr = objPtr;
- }
-}
-
-
-/*
- *----------------------------------------------------------------------
- *
- * 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)
-{
- register void *ptr;
-
- blockPtr->b_magic1 = blockPtr->b_magic2 = MAGIC;
- blockPtr->b_bucket = bucket;
- blockPtr->b_reqsize = reqsize;
- ptr = ((void *) (blockPtr + 1));
-#if RCHECK
- ((unsigned char *)(ptr))[reqsize] = MAGIC;
-#endif
- return (char *) ptr;
-}
-
-static Block *
-Ptr2Block(char *ptr)
-{
- register Block *blockPtr;
-
- blockPtr = (((Block *) ptr) - 1);
- if (blockPtr->b_magic1 != MAGIC
-#if RCHECK
- || ((unsigned char *) ptr)[blockPtr->b_reqsize] != MAGIC
-#endif
- || blockPtr->b_magic2 != MAGIC) {
- panic("alloc: invalid block: %p: %x %x %x\n",
- blockPtr, blockPtr->b_magic1, blockPtr->b_magic2,
- ((unsigned char *) ptr)[blockPtr->b_reqsize]);
- }
- 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)
-{
- int err;
-
- err = pthread_mutex_trylock(&binfo[bucket].lock);
- if (err == EBUSY) {
- err = pthread_mutex_lock(&binfo[bucket].lock);
- if (err != 0) {
- panic("alloc: pthread_mutex_lock: %s", strerror(err));
- }
- ++cachePtr->buckets[bucket].nwait;
- ++sharedPtr->buckets[bucket].nwait;
- } else if (err != 0) {
- panic("alloc: pthread_mutex_trylock: %s", strerror(err));
- }
- ++cachePtr->buckets[bucket].nlock;
- ++sharedPtr->buckets[bucket].nlock;
-}
-
-
-static void
-UnlockBucket(Cache *cachePtr, int bucket)
-{
- int err;
-
- err = pthread_mutex_unlock(&binfo[bucket].lock);
- if (err != 0) {
- panic("alloc: pthread_mutex_unlock: %s", strerror(err));
- }
-}
-
-
-/*
- *----------------------------------------------------------------------
- *
- * PutBlocks --
- *
- * Return unused blocks to the shared cache.
- *
- * Results:
- * None.
- *
- * Side effects:
- * None.
- *
- *----------------------------------------------------------------------
- */
-
-static void
-PutBlocks(Cache *cachePtr, int bucket, int nmove)
-{
- register Block *lastPtr, *firstPtr;
- register int n = nmove;
-
- /*
- * Before acquiring the lock, walk the block list to find
- * the last block to be moved.
- */
-
- firstPtr = lastPtr = cachePtr->buckets[bucket].firstPtr;
- while (--n > 0) {
- lastPtr = lastPtr->b_next;
- }
- cachePtr->buckets[bucket].firstPtr = lastPtr->b_next;
- cachePtr->buckets[bucket].nfree -= nmove;
-
- /*
- * Aquire the lock and place the list of blocks at the front
- * of the shared cache bucket.
- */
-
- LockBucket(cachePtr, bucket);
- lastPtr->b_next = sharedPtr->buckets[bucket].firstPtr;
- sharedPtr->buckets[bucket].firstPtr = firstPtr;
- sharedPtr->buckets[bucket].nfree += nmove;
- UnlockBucket(cachePtr, bucket);
-}
-
-
-/*
- *----------------------------------------------------------------------
- *
- * 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)
-{
- register Block *blockPtr;
- register int n;
- register size_t size;
-
- /*
- * First, atttempt to move blocks from the shared cache. Note
- * the potentially dirty read of nfree 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].nfree > 0) {
- LockBucket(cachePtr, bucket);
- if (sharedPtr->buckets[bucket].nfree > 0) {
-
- /*
- * Either move the entire list or walk the list to find
- * the last block to move.
- */
-
- n = binfo[bucket].nmove;
- if (n >= sharedPtr->buckets[bucket].nfree) {
- cachePtr->buckets[bucket].firstPtr = sharedPtr->buckets[bucket].firstPtr;
- cachePtr->buckets[bucket].nfree = sharedPtr->buckets[bucket].nfree;
- sharedPtr->buckets[bucket].firstPtr = NULL;
- sharedPtr->buckets[bucket].nfree = 0;
- } else {
- blockPtr = sharedPtr->buckets[bucket].firstPtr;
- cachePtr->buckets[bucket].firstPtr = blockPtr;
- sharedPtr->buckets[bucket].nfree -= n;
- cachePtr->buckets[bucket].nfree = n;
- while (--n > 0) {
- blockPtr = blockPtr->b_next;
- }
- sharedPtr->buckets[bucket].firstPtr = blockPtr->b_next;
- blockPtr->b_next = NULL;
- }
- }
- UnlockBucket(cachePtr, bucket);
- }
-
- if (cachePtr->buckets[bucket].nfree == 0) {
-
- /*
- * If no blocks could be moved from shared, first look for a
- * larger block in this cache to split up.
- */
-
- size = 0; /* lint */
- blockPtr = NULL;
- n = NBUCKETS;
- while (--n > bucket) {
- if (cachePtr->buckets[n].nfree > 0) {
- size = binfo[n].blocksize;
- blockPtr = cachePtr->buckets[n].firstPtr;
- cachePtr->buckets[n].firstPtr = blockPtr->b_next;
- --cachePtr->buckets[n].nfree;
- break;
- }
- }
-
- /*
- * Otherwise, allocate a big new block directly.
- */
-
- if (blockPtr == NULL) {
- size = MAXALLOC;
- blockPtr = malloc(size);
- if (blockPtr == NULL) {
- return 0;
- }
- }
-
- /*
- * Split the larger block into smaller blocks for this bucket.
- */
-
- n = size / binfo[bucket].blocksize;
- cachePtr->buckets[bucket].nfree = n;
- cachePtr->buckets[bucket].firstPtr = blockPtr;
- while (--n > 0) {
- blockPtr->b_next = (Block *)
- ((char *) blockPtr + binfo[bucket].blocksize);
- blockPtr = blockPtr->b_next;
- }
- blockPtr->b_next = NULL;
- }
- return 1;
-}
-
-/*
- * END TCL_THREADS MEMORY ALLOCATOR
- */
-
-#elif USE_TCLALLOC
+#if USE_TCLALLOC
#ifdef TCL_DEBUG
# define DEBUG