diff options
Diffstat (limited to 'generic/tclAlloc.c')
| -rw-r--r-- | generic/tclAlloc.c | 225 |
1 files changed, 129 insertions, 96 deletions
diff --git a/generic/tclAlloc.c b/generic/tclAlloc.c index 8c1218d..fcdd75d 100644 --- a/generic/tclAlloc.c +++ b/generic/tclAlloc.c @@ -1,10 +1,10 @@ -/* +/* * tclAlloc.c -- * - * This is a very fast storage allocator. It allocates blocks of a - * small number of different sizes, and keeps free lists of each size. - * Blocks that don't exactly fit are passed up to the next larger size. - * Blocks over a certain size are directly allocated from the system. + * This is a very fast storage allocator. It allocates blocks of a small + * number of different sizes, and keeps free lists of each size. Blocks + * that don't exactly fit are passed up to the next larger size. Blocks + * over a certain size are directly allocated from the system. * * Copyright (c) 1983 Regents of the University of California. * Copyright (c) 1996-1997 Sun Microsystems, Inc. @@ -12,10 +12,10 @@ * * Portions contributed by Chris Kingsley, Jack Jansen and Ray Johnson. * - * See the file "license.terms" for information on usage and redistribution - * of this file, and for a DISCLAIMER OF ALL WARRANTIES. + * 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 1.21 2004/10/06 12:44:52 dkf Exp $ + * RCS: @(#) $Id: tclAlloc.c,v 1.22 2005/07/19 22:45:18 dkf Exp $ */ /* @@ -35,36 +35,37 @@ #endif /* - * We should really make use of AC_CHECK_TYPE(caddr_t) - * here, but it can wait until Tcl uses config.h properly. + * We should really make use of AC_CHECK_TYPE(caddr_t) here, but it can wait + * until Tcl uses config.h properly. */ + #if defined(_MSC_VER) || defined(__MINGW32__) || defined(__BORLANDC__) typedef unsigned long caddr_t; #endif /* - * The overhead on a block is at least 8 bytes. When free, this space - * contains a pointer to the next free block, and the bottom two bits must * be zero. When in use, the first byte is set to MAGIC, and the second - * byte is the size index. The remaining bytes are for alignment. - * If range checking is enabled then a second word holds the size of the - * requested block, less 1, rounded up to a multiple of sizeof(RMAGIC). - * The order of elements is critical: ov.magic must overlay the low order - * bits of ov.next, and ov.magic can not be a valid ov.next bit pattern. + * The overhead on a block is at least 8 bytes. When free, this space contains + * a pointer to the next free block, and the bottom two bits must be zero. + * When in use, the first byte is set to MAGIC, and the second byte is the + * size index. The remaining bytes are for alignment. If range checking is + * enabled then a second word holds the size of the requested block, less 1, + * rounded up to a multiple of sizeof(RMAGIC). The order of elements is + * critical: ov.magic must overlay the low order bits of ov.next, and ov.magic + * can not be a valid ov.next bit pattern. */ union overhead { - union overhead *next; /* when free */ - unsigned char padding[8]; /* Ensure the structure is 8-byte - * aligned. */ + union overhead *next; /* when free */ + unsigned char padding[8]; /* Ensure the structure is 8-byte aligned. */ struct { - unsigned char magic0; /* magic number */ - unsigned char index; /* bucket # */ - unsigned char unused; /* unused */ - unsigned char magic1; /* other magic number */ + unsigned char magic0; /* magic number */ + unsigned char index; /* bucket # */ + unsigned char unused; /* unused */ + unsigned char magic1; /* other magic number */ #ifdef RCHECK - unsigned short rmagic; /* range magic number */ - unsigned long size; /* actual block size */ - unsigned short unused2; /* padding to 8-byte align */ + unsigned short rmagic; /* range magic number */ + unsigned long size; /* actual block size */ + unsigned short unused2; /* padding to 8-byte align */ #endif } ovu; #define overMagic0 ovu.magic0 @@ -75,8 +76,8 @@ union overhead { }; -#define MAGIC 0xef /* magic # on accounting info */ -#define RMAGIC 0x5555 /* magic # on range info */ +#define MAGIC 0xef /* magic # on accounting info */ +#define RMAGIC 0x5555 /* magic # on range info */ #ifdef RCHECK #define RSLOP sizeof (unsigned short) @@ -94,37 +95,37 @@ union overhead { (*(unsigned short *)((caddr_t)((overPtr) + 1) + (overPtr)->realBlockSize)) /* - * nextf[i] is the pointer to the next free block of size 2^(i+3). The - * smallest allocatable block is 8 bytes. The overhead information - * precedes the data area returned to the user. + * nextf[i] is the pointer to the next free block of size 2^(i+3). The + * smallest allocatable block is 8 bytes. The overhead information precedes + * the data area returned to the user. */ #define NBUCKETS 13 #define MAXMALLOC (1<<(NBUCKETS+2)) -static union overhead *nextf[NBUCKETS]; +static union overhead *nextf[NBUCKETS]; -/* - * The following structure is used to keep track of all system memory - * currently owned by Tcl. When finalizing, all this memory will - * be returned to the system. +/* + * The following structure is used to keep track of all system memory + * currently owned by Tcl. When finalizing, all this memory will be returned + * to the system. */ struct block { struct block *nextPtr; /* Linked list. */ - struct block *prevPtr; /* Linked list for big blocks, ensures 8-byte + struct block *prevPtr; /* Linked list for big blocks, ensures 8-byte * alignment for suballocated blocks. */ }; -static struct block *blockList; /* Tracks the suballocated blocks. */ -static struct block bigBlocks = { /* Big blocks aren't suballocated. */ +static struct block *blockList; /* Tracks the suballocated blocks. */ +static struct block bigBlocks={ /* Big blocks aren't suballocated. */ &bigBlocks, &bigBlocks }; /* - * The allocator is protected by a special mutex that must be - * explicitly initialized. Futhermore, because Tcl_Alloc may be - * used before anything else in Tcl, we make this module self-initializing - * after all with the allocInit variable. + * The allocator is protected by a special mutex that must be explicitly + * initialized. Futhermore, because Tcl_Alloc may be used before anything else + * in Tcl, we make this module self-initializing after all with the allocInit + * variable. */ #ifdef TCL_THREADS @@ -132,12 +133,11 @@ static Tcl_Mutex *allocMutexPtr; #endif static int allocInit = 0; - #ifdef MSTATS /* - * numMallocs[i] is the difference between the number of mallocs and frees - * for a given block size. + * numMallocs[i] is the difference between the number of mallocs and frees for + * a given block size. */ static unsigned int numMallocs[NBUCKETS+1]; @@ -145,7 +145,7 @@ static unsigned int numMallocs[NBUCKETS+1]; #endif #if defined(DEBUG) || defined(RCHECK) -#define ASSERT(p) if (!(p)) Tcl_Panic(# p) +#define ASSERT(p) if (!(p)) Tcl_Panic(# p) #define RANGE_ASSERT(p) if (!(p)) Tcl_Panic(# p) #else #define ASSERT(p) @@ -157,7 +157,6 @@ static unsigned int numMallocs[NBUCKETS+1]; */ static void MoreCore _ANSI_ARGS_((int bucket)); - /* *------------------------------------------------------------------------- @@ -191,21 +190,20 @@ TclInitAlloc() * * TclFinalizeAllocSubsystem -- * - * Release all resources being used by this subsystem, including - * aggressively freeing all memory allocated by TclpAlloc() that - * has not yet been released with TclpFree(). - * - * After this function is called, all memory allocated with - * TclpAlloc() should be considered unusable. + * Release all resources being used by this subsystem, including + * aggressively freeing all memory allocated by TclpAlloc() that has not + * yet been released with TclpFree(). + * + * After this function is called, all memory allocated with TclpAlloc() + * should be considered unusable. * * Results: * None. * * Side effects: - * This subsystem is self-initializing, since memory can be - * allocated before Tcl is formally initialized. After this call, - * this subsystem has been reset to its initial state and is - * usable again. + * This subsystem is self-initializing, since memory can be allocated + * before Tcl is formally initialized. After this call, this subsystem + * has been reset to its initial state and is usable again. * *------------------------------------------------------------------------- */ @@ -231,7 +229,7 @@ TclFinalizeAllocSubsystem() bigBlocks.nextPtr = &bigBlocks; bigBlocks.prevPtr = &bigBlocks; - for (i = 0; i < NBUCKETS; i++) { + for (i=0 ; i<NBUCKETS ; i++) { nextf[i] = NULL; #ifdef MSTATS numMallocs[i] = 0; @@ -270,18 +268,20 @@ TclpAlloc(numBytes) if (!allocInit) { /* - * We have to make the "self initializing" because Tcl_Alloc - * may be used before any other part of Tcl. E.g., see - * main() for tclsh! + * We have to make the "self initializing" because Tcl_Alloc may be + * used before any other part of Tcl. E.g., see main() for tclsh! */ + TclInitAlloc(); } Tcl_MutexLock(allocMutexPtr); + /* - * First the simple case: we simple allocate big blocks directly + * First the simple case: we simple allocate big blocks directly. */ + if (numBytes + OVERHEAD >= MAXMALLOC) { - bigBlockPtr = (struct block *) TclpSysAlloc((unsigned) + bigBlockPtr = (struct block *) TclpSysAlloc((unsigned) (sizeof(struct block) + OVERHEAD + numBytes), 0); if (bigBlockPtr == NULL) { Tcl_MutexUnlock(allocMutexPtr); @@ -298,23 +298,27 @@ TclpAlloc(numBytes) #ifdef MSTATS numMallocs[NBUCKETS]++; #endif + #ifdef RCHECK /* - * Record allocated size of block and - * bound space with magic numbers. + * Record allocated size of block and bound space with magic numbers. */ + overPtr->realBlockSize = (numBytes + RSLOP - 1) & ~(RSLOP - 1); overPtr->rangeCheckMagic = RMAGIC; BLOCK_END(overPtr) = RMAGIC; #endif + Tcl_MutexUnlock(allocMutexPtr); return (void *)(overPtr+1); } + /* - * Convert amount of memory requested into closest block size - * stored in hash buckets which satisfies request. - * Account for space used per block for accounting. + * Convert amount of memory requested into closest block size stored in + * hash buckets which satisfies request. Account for space used per block + * for accounting. */ + #ifndef RCHECK amount = 8; /* size of first bucket */ bucket = 0; @@ -322,45 +326,52 @@ TclpAlloc(numBytes) amount = 16; /* size of first bucket */ bucket = 1; #endif + while (numBytes + OVERHEAD > amount) { amount <<= 1; if (amount == 0) { Tcl_MutexUnlock(allocMutexPtr); - return (NULL); + return NULL; } bucket++; } ASSERT(bucket < NBUCKETS); /* - * If nothing in hash bucket right now, - * request more memory from the system. + * If nothing in hash bucket right now, request more memory from the + * system. */ + if ((overPtr = nextf[bucket]) == NULL) { MoreCore(bucket); if ((overPtr = nextf[bucket]) == NULL) { Tcl_MutexUnlock(allocMutexPtr); - return (NULL); + return NULL; } } + /* * Remove from linked list */ + nextf[bucket] = overPtr->next; overPtr->overMagic0 = overPtr->overMagic1 = MAGIC; overPtr->bucketIndex = (unsigned char) bucket; + #ifdef MSTATS numMallocs[bucket]++; #endif + #ifdef RCHECK /* - * Record allocated size of block and - * bound space with magic numbers. + * Record allocated size of block and bound space with magic numbers. */ + overPtr->realBlockSize = (numBytes + RSLOP - 1) & ~(RSLOP - 1); overPtr->rangeCheckMagic = RMAGIC; BLOCK_END(overPtr) = RMAGIC; #endif + Tcl_MutexUnlock(allocMutexPtr); return ((char *)(overPtr + 1)); } @@ -394,9 +405,10 @@ MoreCore(bucket) struct block *blockPtr; /* - * sbrk_size <= 0 only for big, FLUFFY, requests (about - * 2^30 bytes on a VAX, I think) or for a negative arg. + * sbrk_size <= 0 only for big, FLUFFY, requests (about 2^30 bytes on a + * VAX, I think) or for a negative arg. */ + size = 1 << (bucket + 3); ASSERT(size > 0); @@ -404,7 +416,7 @@ MoreCore(bucket) numBlocks = amount / size; ASSERT(numBlocks*size == amount); - blockPtr = (struct block *) TclpSysAlloc((unsigned) + blockPtr = (struct block *) TclpSysAlloc((unsigned) (sizeof(struct block) + amount), 1); /* no more room! */ if (blockPtr == NULL) { @@ -414,11 +426,11 @@ MoreCore(bucket) blockList = blockPtr; overPtr = (union overhead *) (blockPtr + 1); - + /* - * Add new memory allocated to that on - * free list for this hash bucket. + * Add new memory allocated to that on free list for this hash bucket. */ + nextf[bucket] = overPtr; while (--numBlocks > 0) { overPtr->next = (union overhead *)((caddr_t)overPtr + size); @@ -446,7 +458,7 @@ MoreCore(bucket) void TclpFree(oldPtr) char *oldPtr; /* Pointer to memory to free. */ -{ +{ register long size; register union overhead *overPtr; struct block *bigBlockPtr; @@ -472,19 +484,23 @@ TclpFree(oldPtr) #ifdef MSTATS numMallocs[NBUCKETS]--; #endif + bigBlockPtr = (struct block *) overPtr - 1; bigBlockPtr->prevPtr->nextPtr = bigBlockPtr->nextPtr; bigBlockPtr->nextPtr->prevPtr = bigBlockPtr->prevPtr; TclpSysFree(bigBlockPtr); + Tcl_MutexUnlock(allocMutexPtr); return; } ASSERT(size < NBUCKETS); overPtr->next = nextf[size]; /* also clobbers overMagic */ nextf[size] = overPtr; + #ifdef MSTATS numMallocs[size]--; #endif + Tcl_MutexUnlock(allocMutexPtr); } @@ -508,7 +524,7 @@ char * TclpRealloc(oldPtr, numBytes) char *oldPtr; /* Pointer to alloced block. */ unsigned int numBytes; /* New size of memory. */ -{ +{ int i; union overhead *overPtr; struct block *bigBlockPtr; @@ -516,7 +532,7 @@ TclpRealloc(oldPtr, numBytes) unsigned long maxSize; if (oldPtr == NULL) { - return (TclpAlloc(numBytes)); + return TclpAlloc(numBytes); } Tcl_MutexLock(allocMutexPtr); @@ -543,7 +559,7 @@ TclpRealloc(oldPtr, numBytes) bigBlockPtr = (struct block *) overPtr - 1; prevPtr = bigBlockPtr->prevPtr; nextPtr = bigBlockPtr->nextPtr; - bigBlockPtr = (struct block *) TclpSysRealloc(bigBlockPtr, + bigBlockPtr = (struct block *) TclpSysRealloc(bigBlockPtr, sizeof(struct block) + OVERHEAD + numBytes); if (bigBlockPtr == NULL) { Tcl_MutexUnlock(allocMutexPtr); @@ -552,8 +568,8 @@ TclpRealloc(oldPtr, numBytes) if (prevPtr->nextPtr != bigBlockPtr) { /* - * If the block has moved, splice the new block into the list where - * the old block used to be. + * If the block has moved, splice the new block into the list + * where the old block used to be. */ prevPtr->nextPtr = bigBlockPtr; @@ -561,9 +577,11 @@ TclpRealloc(oldPtr, numBytes) } overPtr = (union overhead *) (bigBlockPtr + 1); + #ifdef MSTATS numMallocs[NBUCKETS]++; #endif + #ifdef RCHECK /* * Record allocated size of block and update magic number bounds. @@ -572,6 +590,7 @@ TclpRealloc(oldPtr, numBytes) overPtr->realBlockSize = (numBytes + RSLOP - 1) & ~(RSLOP - 1); BLOCK_END(overPtr) = RMAGIC; #endif + Tcl_MutexUnlock(allocMutexPtr); return (char *)(overPtr+1); } @@ -600,14 +619,16 @@ TclpRealloc(oldPtr, numBytes) TclpFree(oldPtr); return newPtr; } - + /* * Ok, we don't have to copy, it fits as-is */ + #ifdef RCHECK overPtr->realBlockSize = (numBytes + RSLOP - 1) & ~(RSLOP - 1); BLOCK_END(overPtr) = RMAGIC; #endif + Tcl_MutexUnlock(allocMutexPtr); return(oldPtr); } @@ -617,9 +638,9 @@ TclpRealloc(oldPtr, numBytes) * * mstats -- * - * Prints two lines of numbers, one showing the length of the - * free list for each size category, the second showing the - * number of mallocs - frees for each size category. + * Prints two lines of numbers, one showing the length of the free list + * for each size category, the second showing the number of mallocs - + * frees for each size category. * * Results: * None. @@ -633,13 +654,14 @@ TclpRealloc(oldPtr, numBytes) #ifdef MSTATS void mstats(s) - char *s; /* Where to write info. */ + char *s; /* Where to write info. */ { register int i, j; register union overhead *overPtr; int totalFree = 0, totalUsed = 0; Tcl_MutexLock(allocMutexPtr); + fprintf(stderr, "Memory allocation statistics %s\nTclpFree:\t", s); for (i = 0; i < NBUCKETS; i++) { for (j=0, overPtr=nextf[i]; overPtr; overPtr=overPtr->next, j++) { @@ -647,15 +669,18 @@ mstats(s) } totalFree += j * (1 << (i + 3)); } + fprintf(stderr, "\nused:\t"); for (i = 0; i < NBUCKETS; i++) { fprintf(stderr, " %d", numMallocs[i]); totalUsed += numMallocs[i] * (1 << (i + 3)); } + fprintf(stderr, "\n\tTotal small in use: %d, total free: %d\n", totalUsed, totalFree); - fprintf(stderr, "\n\tNumber of big (>%d) blocks in use: %d\n", + fprintf(stderr, "\n\tNumber of big (>%d) blocks in use: %d\n", MAXMALLOC, numMallocs[NBUCKETS]); + Tcl_MutexUnlock(allocMutexPtr); } #endif @@ -704,7 +729,7 @@ TclpAlloc(numBytes) void TclpFree(oldPtr) char *oldPtr; /* Pointer to memory to free. */ -{ +{ free(oldPtr); return; } @@ -729,9 +754,17 @@ char * TclpRealloc(oldPtr, numBytes) char *oldPtr; /* Pointer to alloced block. */ unsigned int numBytes; /* New size of memory. */ -{ +{ return (char*) realloc(oldPtr, numBytes); } #endif /* !USE_TCLALLOC */ #endif /* !TCL_THREADS */ + +/* + * Local Variables: + * mode: c + * c-basic-offset: 4 + * fill-column: 78 + * End: + */ |