diff options
Diffstat (limited to 'nsprpub/pr/src/malloc/prmem.c')
| -rw-r--r-- | nsprpub/pr/src/malloc/prmem.c | 678 |
1 files changed, 678 insertions, 0 deletions
diff --git a/nsprpub/pr/src/malloc/prmem.c b/nsprpub/pr/src/malloc/prmem.c new file mode 100644 index 0000000000..08a700f7a9 --- /dev/null +++ b/nsprpub/pr/src/malloc/prmem.c @@ -0,0 +1,678 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/* +** Thread safe versions of malloc, free, realloc, calloc and cfree. +*/ + +#include "primpl.h" + +#ifdef _PR_ZONE_ALLOCATOR + +/* +** The zone allocator code must use native mutexes and cannot +** use PRLocks because PR_NewLock calls PR_Calloc, resulting +** in cyclic dependency of initialization. +*/ + +#include <string.h> + +union memBlkHdrUn; + +typedef struct MemoryZoneStr { + union memBlkHdrUn *head; /* free list */ + pthread_mutex_t lock; + size_t blockSize; /* size of blocks on this free list */ + PRUint32 locked; /* current state of lock */ + PRUint32 contention; /* counter: had to wait for lock */ + PRUint32 hits; /* allocated from free list */ + PRUint32 misses; /* had to call malloc */ + PRUint32 elements; /* on free list */ +} MemoryZone; + +typedef union memBlkHdrUn { + unsigned char filler[48]; /* fix the size of this beast */ + struct memBlkHdrStr { + union memBlkHdrUn *next; + MemoryZone *zone; + size_t blockSize; + size_t requestedSize; + PRUint32 magic; + } s; +} MemBlockHdr; + +#define MEM_ZONES 7 +#define THREAD_POOLS 11 /* prime number for modulus */ +#define ZONE_MAGIC 0x0BADC0DE + +static MemoryZone zones[MEM_ZONES][THREAD_POOLS]; + +static PRBool use_zone_allocator = PR_FALSE; + +static void pr_ZoneFree(void *ptr); + +void +_PR_DestroyZones(void) +{ + int i, j; + + if (!use_zone_allocator) { + return; + } + + for (j = 0; j < THREAD_POOLS; j++) { + for (i = 0; i < MEM_ZONES; i++) { + MemoryZone *mz = &zones[i][j]; + pthread_mutex_destroy(&mz->lock); + while (mz->head) { + MemBlockHdr *hdr = mz->head; + mz->head = hdr->s.next; /* unlink it */ + free(hdr); + mz->elements--; + } + } + } + use_zone_allocator = PR_FALSE; +} + +/* +** pr_FindSymbolInProg +** +** Find the specified data symbol in the program and return +** its address. +*/ + +#ifdef HAVE_DLL + +#if defined(USE_DLFCN) && !defined(NO_DLOPEN_NULL) + +#include <dlfcn.h> + +static void * +pr_FindSymbolInProg(const char *name) +{ + void *h; + void *sym; + + h = dlopen(0, RTLD_LAZY); + if (h == NULL) { + return NULL; + } + sym = dlsym(h, name); + (void)dlclose(h); + return sym; +} + +#elif defined(USE_HPSHL) + +#include <dl.h> + +static void * +pr_FindSymbolInProg(const char *name) +{ + shl_t h = NULL; + void *sym; + + if (shl_findsym(&h, name, TYPE_DATA, &sym) == -1) { + return NULL; + } + return sym; +} + +#elif defined(USE_MACH_DYLD) || defined(NO_DLOPEN_NULL) + +static void * +pr_FindSymbolInProg(const char *name) +{ + /* FIXME: not implemented */ + return NULL; +} + +#else + +#error "The zone allocator is not supported on this platform" + +#endif + +#else /* !defined(HAVE_DLL) */ + +static void * +pr_FindSymbolInProg(const char *name) +{ + /* can't be implemented */ + return NULL; +} + +#endif /* HAVE_DLL */ + +void +_PR_InitZones(void) +{ + int i, j; + char *envp; + PRBool *sym; + + if ((sym = (PRBool *)pr_FindSymbolInProg("nspr_use_zone_allocator")) != NULL) { + use_zone_allocator = *sym; + } else if ((envp = getenv("NSPR_USE_ZONE_ALLOCATOR")) != NULL) { + use_zone_allocator = (atoi(envp) == 1); + } + + if (!use_zone_allocator) { + return; + } + + for (j = 0; j < THREAD_POOLS; j++) { + for (i = 0; i < MEM_ZONES; i++) { + MemoryZone *mz = &zones[i][j]; + int rv = pthread_mutex_init(&mz->lock, NULL); + PR_ASSERT(0 == rv); + if (rv != 0) { + goto loser; + } + mz->blockSize = 16 << ( 2 * i); + } + } + return; + +loser: + _PR_DestroyZones(); + return; +} + +PR_IMPLEMENT(void) +PR_FPrintZoneStats(PRFileDesc *debug_out) +{ + int i, j; + + for (j = 0; j < THREAD_POOLS; j++) { + for (i = 0; i < MEM_ZONES; i++) { + MemoryZone *mz = &zones[i][j]; + MemoryZone zone = *mz; + if (zone.elements || zone.misses || zone.hits) { + PR_fprintf(debug_out, + "pool: %d, zone: %d, size: %d, free: %d, hit: %d, miss: %d, contend: %d\n", + j, i, zone.blockSize, zone.elements, + zone.hits, zone.misses, zone.contention); + } + } + } +} + +static void * +pr_ZoneMalloc(PRUint32 size) +{ + void *rv; + unsigned int zone; + size_t blockSize; + MemBlockHdr *mb, *mt; + MemoryZone *mz; + + /* Always allocate a non-zero amount of bytes */ + if (size < 1) { + size = 1; + } + for (zone = 0, blockSize = 16; zone < MEM_ZONES; ++zone, blockSize <<= 2) { + if (size <= blockSize) { + break; + } + } + if (zone < MEM_ZONES) { + pthread_t me = pthread_self(); + unsigned int pool = (PRUptrdiff)me % THREAD_POOLS; + PRUint32 wasLocked; + mz = &zones[zone][pool]; + wasLocked = mz->locked; + pthread_mutex_lock(&mz->lock); + mz->locked = 1; + if (wasLocked) { + mz->contention++; + } + if (mz->head) { + mb = mz->head; + PR_ASSERT(mb->s.magic == ZONE_MAGIC); + PR_ASSERT(mb->s.zone == mz); + PR_ASSERT(mb->s.blockSize == blockSize); + PR_ASSERT(mz->blockSize == blockSize); + + mt = (MemBlockHdr *)(((char *)(mb + 1)) + blockSize); + PR_ASSERT(mt->s.magic == ZONE_MAGIC); + PR_ASSERT(mt->s.zone == mz); + PR_ASSERT(mt->s.blockSize == blockSize); + + mz->hits++; + mz->elements--; + mz->head = mb->s.next; /* take off free list */ + mz->locked = 0; + pthread_mutex_unlock(&mz->lock); + + mt->s.next = mb->s.next = NULL; + mt->s.requestedSize = mb->s.requestedSize = size; + + rv = (void *)(mb + 1); + return rv; + } + + mz->misses++; + mz->locked = 0; + pthread_mutex_unlock(&mz->lock); + + mb = (MemBlockHdr *)malloc(blockSize + 2 * (sizeof *mb)); + if (!mb) { + PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0); + return NULL; + } + mb->s.next = NULL; + mb->s.zone = mz; + mb->s.magic = ZONE_MAGIC; + mb->s.blockSize = blockSize; + mb->s.requestedSize = size; + + mt = (MemBlockHdr *)(((char *)(mb + 1)) + blockSize); + memcpy(mt, mb, sizeof *mb); + + rv = (void *)(mb + 1); + return rv; + } + + /* size was too big. Create a block with no zone */ + blockSize = (size & 15) ? size + 16 - (size & 15) : size; + mb = (MemBlockHdr *)malloc(blockSize + 2 * (sizeof *mb)); + if (!mb) { + PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0); + return NULL; + } + mb->s.next = NULL; + mb->s.zone = NULL; + mb->s.magic = ZONE_MAGIC; + mb->s.blockSize = blockSize; + mb->s.requestedSize = size; + + mt = (MemBlockHdr *)(((char *)(mb + 1)) + blockSize); + memcpy(mt, mb, sizeof *mb); + + rv = (void *)(mb + 1); + return rv; +} + + +static void * +pr_ZoneCalloc(PRUint32 nelem, PRUint32 elsize) +{ + PRUint32 size = nelem * elsize; + void *p = pr_ZoneMalloc(size); + if (p) { + memset(p, 0, size); + } + return p; +} + +static void * +pr_ZoneRealloc(void *oldptr, PRUint32 bytes) +{ + void *rv; + MemBlockHdr *mb; + int ours; + MemBlockHdr phony; + + if (!oldptr) { + return pr_ZoneMalloc(bytes); + } + mb = (MemBlockHdr *)((char *)oldptr - (sizeof *mb)); + if (mb->s.magic != ZONE_MAGIC) { + /* Maybe this just came from ordinary malloc */ +#ifdef DEBUG + fprintf(stderr, + "Warning: reallocing memory block %p from ordinary malloc\n", + oldptr); +#endif + /* + * We are going to realloc oldptr. If realloc succeeds, the + * original value of oldptr will point to freed memory. So this + * function must not fail after a successfull realloc call. We + * must perform any operation that may fail before the realloc + * call. + */ + rv = pr_ZoneMalloc(bytes); /* this may fail */ + if (!rv) { + return rv; + } + + /* We don't know how big it is. But we can fix that. */ + oldptr = realloc(oldptr, bytes); + /* + * If realloc returns NULL, this function loses the original + * value of oldptr. This isn't a leak because the caller of + * this function still has the original value of oldptr. + */ + if (!oldptr) { + if (bytes) { + PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0); + pr_ZoneFree(rv); + return oldptr; + } + } + phony.s.requestedSize = bytes; + mb = &phony; + ours = 0; + } else { + size_t blockSize = mb->s.blockSize; + MemBlockHdr *mt = (MemBlockHdr *)(((char *)(mb + 1)) + blockSize); + + PR_ASSERT(mt->s.magic == ZONE_MAGIC); + PR_ASSERT(mt->s.zone == mb->s.zone); + PR_ASSERT(mt->s.blockSize == blockSize); + + if (bytes <= blockSize) { + /* The block is already big enough. */ + mt->s.requestedSize = mb->s.requestedSize = bytes; + return oldptr; + } + ours = 1; + rv = pr_ZoneMalloc(bytes); + if (!rv) { + return rv; + } + } + + if (oldptr && mb->s.requestedSize) { + memcpy(rv, oldptr, mb->s.requestedSize); + } + if (ours) { + pr_ZoneFree(oldptr); + } + else if (oldptr) { + free(oldptr); + } + return rv; +} + +static void +pr_ZoneFree(void *ptr) +{ + MemBlockHdr *mb, *mt; + MemoryZone *mz; + size_t blockSize; + PRUint32 wasLocked; + + if (!ptr) { + return; + } + + mb = (MemBlockHdr *)((char *)ptr - (sizeof *mb)); + + if (mb->s.magic != ZONE_MAGIC) { + /* maybe this came from ordinary malloc */ +#ifdef DEBUG + fprintf(stderr, + "Warning: freeing memory block %p from ordinary malloc\n", ptr); +#endif + free(ptr); + return; + } + + blockSize = mb->s.blockSize; + mz = mb->s.zone; + mt = (MemBlockHdr *)(((char *)(mb + 1)) + blockSize); + PR_ASSERT(mt->s.magic == ZONE_MAGIC); + PR_ASSERT(mt->s.zone == mz); + PR_ASSERT(mt->s.blockSize == blockSize); + if (!mz) { + PR_ASSERT(blockSize > 65536); + /* This block was not in any zone. Just free it. */ + free(mb); + return; + } + PR_ASSERT(mz->blockSize == blockSize); + wasLocked = mz->locked; + pthread_mutex_lock(&mz->lock); + mz->locked = 1; + if (wasLocked) { + mz->contention++; + } + mt->s.next = mb->s.next = mz->head; /* put on head of list */ + mz->head = mb; + mz->elements++; + mz->locked = 0; + pthread_mutex_unlock(&mz->lock); +} + +PR_IMPLEMENT(void *) PR_Malloc(PRUint32 size) +{ + if (!_pr_initialized) { + _PR_ImplicitInitialization(); + } + + return use_zone_allocator ? pr_ZoneMalloc(size) : malloc(size); +} + +PR_IMPLEMENT(void *) PR_Calloc(PRUint32 nelem, PRUint32 elsize) +{ + if (!_pr_initialized) { + _PR_ImplicitInitialization(); + } + + return use_zone_allocator ? + pr_ZoneCalloc(nelem, elsize) : calloc(nelem, elsize); +} + +PR_IMPLEMENT(void *) PR_Realloc(void *ptr, PRUint32 size) +{ + if (!_pr_initialized) { + _PR_ImplicitInitialization(); + } + + return use_zone_allocator ? pr_ZoneRealloc(ptr, size) : realloc(ptr, size); +} + +PR_IMPLEMENT(void) PR_Free(void *ptr) +{ + if (use_zone_allocator) { + pr_ZoneFree(ptr); + } + else { + free(ptr); + } +} + +#else /* !defined(_PR_ZONE_ALLOCATOR) */ + +/* +** The PR_Malloc, PR_Calloc, PR_Realloc, and PR_Free functions simply +** call their libc equivalents now. This may seem redundant, but it +** ensures that we are calling into the same runtime library. On +** Win32, it is possible to have multiple runtime libraries (e.g., +** objects compiled with /MD and /MDd) in the same process, and +** they maintain separate heaps, which cannot be mixed. +*/ +PR_IMPLEMENT(void *) PR_Malloc(PRUint32 size) +{ +#if defined (WIN16) + return PR_MD_malloc( (size_t) size); +#else + return malloc(size); +#endif +} + +PR_IMPLEMENT(void *) PR_Calloc(PRUint32 nelem, PRUint32 elsize) +{ +#if defined (WIN16) + return PR_MD_calloc( (size_t)nelem, (size_t)elsize ); + +#else + return calloc(nelem, elsize); +#endif +} + +PR_IMPLEMENT(void *) PR_Realloc(void *ptr, PRUint32 size) +{ +#if defined (WIN16) + return PR_MD_realloc( ptr, (size_t) size); +#else + return realloc(ptr, size); +#endif +} + +PR_IMPLEMENT(void) PR_Free(void *ptr) +{ +#if defined (WIN16) + PR_MD_free( ptr ); +#else + free(ptr); +#endif +} + +#endif /* _PR_ZONE_ALLOCATOR */ + +/* +** Complexity alert! +** +** If malloc/calloc/free (etc.) were implemented to use pr lock's then +** the entry points could block when called if some other thread had the +** lock. +** +** Most of the time this isn't a problem. However, in the case that we +** are using the thread safe malloc code after PR_Init but before +** PR_AttachThread has been called (on a native thread that nspr has yet +** to be told about) we could get royally screwed if the lock was busy +** and we tried to context switch the thread away. In this scenario +** PR_CURRENT_THREAD() == NULL +** +** To avoid this unfortunate case, we use the low level locking +** facilities for malloc protection instead of the slightly higher level +** locking. This makes malloc somewhat faster so maybe it's a good thing +** anyway. +*/ +#ifdef _PR_OVERRIDE_MALLOC + +/* Imports */ +extern void *_PR_UnlockedMalloc(size_t size); +extern void *_PR_UnlockedMemalign(size_t alignment, size_t size); +extern void _PR_UnlockedFree(void *ptr); +extern void *_PR_UnlockedRealloc(void *ptr, size_t size); +extern void *_PR_UnlockedCalloc(size_t n, size_t elsize); + +static PRBool _PR_malloc_initialised = PR_FALSE; + +#ifdef _PR_PTHREADS +static pthread_mutex_t _PR_MD_malloc_crustylock; + +#define _PR_Lock_Malloc() { \ + if(PR_TRUE == _PR_malloc_initialised) { \ + PRStatus rv; \ + rv = pthread_mutex_lock(&_PR_MD_malloc_crustylock); \ + PR_ASSERT(0 == rv); \ + } + +#define _PR_Unlock_Malloc() if(PR_TRUE == _PR_malloc_initialised) { \ + PRStatus rv; \ + rv = pthread_mutex_unlock(&_PR_MD_malloc_crustylock); \ + PR_ASSERT(0 == rv); \ + } \ + } +#else /* _PR_PTHREADS */ +static _MDLock _PR_MD_malloc_crustylock; + +#define _PR_Lock_Malloc() { \ + PRIntn _is; \ + if(PR_TRUE == _PR_malloc_initialised) { \ + if (_PR_MD_CURRENT_THREAD() && \ + !_PR_IS_NATIVE_THREAD( \ + _PR_MD_CURRENT_THREAD())) \ + _PR_INTSOFF(_is); \ + _PR_MD_LOCK(&_PR_MD_malloc_crustylock); \ + } + +#define _PR_Unlock_Malloc() if(PR_TRUE == _PR_malloc_initialised) { \ + _PR_MD_UNLOCK(&_PR_MD_malloc_crustylock); \ + if (_PR_MD_CURRENT_THREAD() && \ + !_PR_IS_NATIVE_THREAD( \ + _PR_MD_CURRENT_THREAD())) \ + _PR_INTSON(_is); \ + } \ + } +#endif /* _PR_PTHREADS */ + +PR_IMPLEMENT(PRStatus) _PR_MallocInit(void) +{ + PRStatus rv = PR_SUCCESS; + + if( PR_TRUE == _PR_malloc_initialised ) { + return PR_SUCCESS; + } + +#ifdef _PR_PTHREADS + { + int status; + pthread_mutexattr_t mattr; + + status = _PT_PTHREAD_MUTEXATTR_INIT(&mattr); + PR_ASSERT(0 == status); + status = _PT_PTHREAD_MUTEX_INIT(_PR_MD_malloc_crustylock, mattr); + PR_ASSERT(0 == status); + status = _PT_PTHREAD_MUTEXATTR_DESTROY(&mattr); + PR_ASSERT(0 == status); + } +#else /* _PR_PTHREADS */ + _MD_NEW_LOCK(&_PR_MD_malloc_crustylock); +#endif /* _PR_PTHREADS */ + + if( PR_SUCCESS == rv ) + { + _PR_malloc_initialised = PR_TRUE; + } + + return rv; +} + +void *malloc(size_t size) +{ + void *p; + _PR_Lock_Malloc(); + p = _PR_UnlockedMalloc(size); + _PR_Unlock_Malloc(); + return p; +} + +void free(void *ptr) +{ + _PR_Lock_Malloc(); + _PR_UnlockedFree(ptr); + _PR_Unlock_Malloc(); +} + +void *realloc(void *ptr, size_t size) +{ + void *p; + _PR_Lock_Malloc(); + p = _PR_UnlockedRealloc(ptr, size); + _PR_Unlock_Malloc(); + return p; +} + +void *calloc(size_t n, size_t elsize) +{ + void *p; + _PR_Lock_Malloc(); + p = _PR_UnlockedCalloc(n, elsize); + _PR_Unlock_Malloc(); + return p; +} + +void cfree(void *p) +{ + _PR_Lock_Malloc(); + _PR_UnlockedFree(p); + _PR_Unlock_Malloc(); +} + +void _PR_InitMem(void) +{ + PRStatus rv; + rv = _PR_MallocInit(); + PR_ASSERT(PR_SUCCESS == rv); +} + +#endif /* _PR_OVERRIDE_MALLOC */ |