| /* $RCSfile$$Revision$$Date$ |
| * |
| * $Log$ |
| * Revision 1.2 2004/04/05 16:26:28 lattner |
| * Disable the custom allocator that is really buggy |
| * |
| * Revision 1.1 2004/02/17 22:21:16 criswell |
| * Initial commit of the perl Malloc Benchmark. I've cheated a little by |
| * generating the yacc output files and committing them directly, but it was |
| * easier than disabling the Bison Voodoo that gets executed by default. |
| * |
| * Revision 4.0.1.1 91/04/11 17:48:31 lwall |
| * patch1: Configure now figures out malloc ptr type |
| * |
| * Revision 4.0 91/03/20 01:28:52 lwall |
| * 4.0 baseline. |
| * |
| */ |
| |
| #if 0 |
| static char sccsid[] = "@(#)malloc.c 4.3 (Berkeley) 9/16/83"; |
| |
| #ifdef DEBUGGING |
| #define RCHECK |
| #endif |
| /* |
| * malloc.c (Caltech) 2/21/82 |
| * Chris Kingsley, kingsley@cit-20. |
| * |
| * 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. In this |
| * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long. |
| * This is designed for use in a program that uses vast quantities of memory, |
| * but bombs when it runs out. |
| */ |
| |
| #include "EXTERN.h" |
| #include "perl.h" |
| |
| static findbucket(), morecore(); |
| |
| /* I don't much care whether these are defined in sys/types.h--LAW */ |
| |
| #define u_char unsigned char |
| #define u_int unsigned int |
| #define u_short unsigned short |
| |
| /* |
| * The overhead on a block is at least 4 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 and the size of the block fits |
| * in two bytes, then the top two bytes hold the size of the requested block |
| * plus the range checking words, and the header word MINUS ONE. |
| */ |
| union overhead { |
| union overhead *ov_next; /* when free */ |
| #if ALIGNBYTES > 4 |
| double strut; /* alignment problems */ |
| #endif |
| struct { |
| u_char ovu_magic; /* magic number */ |
| u_char ovu_index; /* bucket # */ |
| #ifdef RCHECK |
| u_short ovu_size; /* actual block size */ |
| u_int ovu_rmagic; /* range magic number */ |
| #endif |
| } ovu; |
| #define ov_magic ovu.ovu_magic |
| #define ov_index ovu.ovu_index |
| #define ov_size ovu.ovu_size |
| #define ov_rmagic ovu.ovu_rmagic |
| }; |
| |
| #define MAGIC 0xff /* magic # on accounting info */ |
| #define OLDMAGIC 0x7f /* same after a free() */ |
| #define RMAGIC 0x55555555 /* magic # on range info */ |
| #ifdef RCHECK |
| #define RSLOP sizeof (u_int) |
| #else |
| #define RSLOP 0 |
| #endif |
| |
| /* |
| * 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 30 |
| static union overhead *nextf[NBUCKETS]; |
| extern char *sbrk(); |
| |
| #ifdef MSTATS |
| /* |
| * nmalloc[i] is the difference between the number of mallocs and frees |
| * for a given block size. |
| */ |
| static u_int nmalloc[NBUCKETS]; |
| #include <stdio.h> |
| #endif |
| |
| #ifdef debug |
| #define ASSERT(p) if (!(p)) botch("p"); else |
| static |
| botch(s) |
| char *s; |
| { |
| |
| printf("assertion botched: %s\n", s); |
| abort(); |
| } |
| #else |
| #define ASSERT(p) |
| #endif |
| |
| MALLOCPTRTYPE * |
| malloc(nbytes) |
| register unsigned nbytes; |
| { |
| register union overhead *p; |
| register int bucket = 0; |
| register unsigned shiftr; |
| |
| /* |
| * Convert amount of memory requested into |
| * closest block size stored in hash buckets |
| * which satisfies request. Account for |
| * space used per block for accounting. |
| */ |
| nbytes += sizeof (union overhead) + RSLOP; |
| nbytes = (nbytes + 3) &~ 3; |
| shiftr = (nbytes - 1) >> 2; |
| /* apart from this loop, this is O(1) */ |
| while (shiftr >>= 1) |
| bucket++; |
| printf("NB: %d %d\n", nbytes, bucket); |
| /* |
| * If nothing in hash bucket right now, |
| * request more memory from the system. |
| */ |
| if (nextf[bucket] == NULL) |
| morecore(bucket); |
| if ((p = (union overhead *)nextf[bucket]) == NULL) |
| return (NULL); |
| /* remove from linked list */ |
| #ifdef RCHECK |
| if (*((int*)p) & (sizeof(union overhead) - 1)) |
| #ifndef I286 |
| fprintf(stderr,"Corrupt malloc ptr 0x%x at 0x%x\n",*((int*)p),p); |
| #else |
| fprintf(stderr,"Corrupt malloc ptr 0x%lx at 0x%lx\n",*((int*)p),p); |
| #endif |
| #endif |
| nextf[bucket] = p->ov_next; |
| p->ov_magic = MAGIC; |
| p->ov_index= bucket; |
| #ifdef MSTATS |
| nmalloc[bucket]++; |
| #endif |
| #ifdef RCHECK |
| /* |
| * Record allocated size of block and |
| * bound space with magic numbers. |
| */ |
| if (nbytes <= 0x10000) |
| p->ov_size = nbytes - 1; |
| p->ov_rmagic = RMAGIC; |
| *((u_int *)((caddr_t)p + nbytes - RSLOP)) = RMAGIC; |
| #endif |
| return ((char *)(p + 1)); |
| } |
| |
| /* |
| * Allocate more memory to the indicated bucket. |
| */ |
| static |
| morecore(bucket) |
| register int bucket; |
| { |
| register union overhead *op; |
| register int rnu; /* 2^rnu bytes will be requested */ |
| register int nblks; /* become nblks blocks of the desired size */ |
| register int siz; |
| |
| if (nextf[bucket]) |
| return; |
| /* |
| * Insure memory is allocated |
| * on a page boundary. Should |
| * make getpageize call? |
| */ |
| op = (union overhead *)sbrk(0); |
| #ifndef I286 |
| if ((int)op & 0x3ff) |
| (void)sbrk(1024 - ((int)op & 0x3ff)); |
| #else |
| /* The sbrk(0) call on the I286 always returns the next segment */ |
| #endif |
| |
| #ifndef I286 |
| /* take 2k unless the block is bigger than that */ |
| rnu = (bucket <= 8) ? 11 : bucket + 3; |
| #else |
| /* take 16k unless the block is bigger than that |
| (80286s like large segments!) */ |
| rnu = (bucket <= 11) ? 14 : bucket + 3; |
| #endif |
| nblks = 1 << (rnu - (bucket + 3)); /* how many blocks to get */ |
| if (rnu < bucket) |
| rnu = bucket; |
| op = (union overhead *)sbrk(1 << rnu); |
| /* no more room! */ |
| if ((int)op == -1) |
| return; |
| /* |
| * Round up to minimum allocation size boundary |
| * and deduct from block count to reflect. |
| */ |
| #ifndef I286 |
| if ((int)op & 7) { |
| op = (union overhead *)(((int)op + 8) &~ 7); |
| nblks--; |
| } |
| #else |
| /* Again, this should always be ok on an 80286 */ |
| #endif |
| /* |
| * Add new memory allocated to that on |
| * free list for this hash bucket. |
| */ |
| nextf[bucket] = op; |
| siz = 1 << (bucket + 3); |
| while (--nblks > 0) { |
| op->ov_next = (union overhead *)((caddr_t)op + siz); |
| op = (union overhead *)((caddr_t)op + siz); |
| } |
| } |
| |
| int |
| free(tcp) |
| void *tcp; |
| { |
| char * cp = tcp; |
| register int size; |
| register union overhead *op; |
| |
| #ifdef IGNOREFREE |
| return; |
| #else |
| if (cp == NULL) |
| return; |
| op = (union overhead *)((caddr_t)cp - sizeof (union overhead)); |
| #ifdef debug |
| ASSERT(op->ov_magic == MAGIC); /* make sure it was in use */ |
| #else |
| if (op->ov_magic != MAGIC) { |
| warn("%s free() ignored", |
| op->ov_magic == OLDMAGIC ? "Duplicate" : "Bad"); |
| return; /* sanity */ |
| } |
| op->ov_magic = OLDMAGIC; |
| #endif |
| #ifdef RCHECK |
| ASSERT(op->ov_rmagic == RMAGIC); |
| if (op->ov_index <= 13) |
| ASSERT(*(u_int *)((caddr_t)op + op->ov_size + 1 - RSLOP) == RMAGIC); |
| #endif |
| ASSERT(op->ov_index < NBUCKETS); |
| size = op->ov_index; |
| op->ov_next = nextf[size]; |
| nextf[size] = op; |
| #ifdef MSTATS |
| nmalloc[size]--; |
| #endif |
| #endif |
| } |
| |
| /* |
| * When a program attempts "storage compaction" as mentioned in the |
| * old malloc man page, it realloc's an already freed block. Usually |
| * this is the last block it freed; occasionally it might be farther |
| * back. We have to search all the free lists for the block in order |
| * to determine its bucket: 1st we make one pass thru the lists |
| * checking only the first block in each; if that fails we search |
| * ``reall_srchlen'' blocks in each list for a match (the variable |
| * is extern so the caller can modify it). If that fails we just copy |
| * however many bytes was given to realloc() and hope it's not huge. |
| */ |
| int reall_srchlen = 4; /* 4 should be plenty, -1 =>'s whole list */ |
| |
| MALLOCPTRTYPE * |
| realloc(tcp, nbytes) |
| void *tcp; |
| unsigned nbytes; |
| { |
| char * cp = tcp; |
| register u_int onb; |
| union overhead *op; |
| char *res; |
| register int i; |
| int was_alloced = 0; |
| |
| if (cp == NULL) |
| return (malloc(nbytes)); |
| op = (union overhead *)((caddr_t)cp - sizeof (union overhead)); |
| if (op->ov_magic == MAGIC) { |
| was_alloced++; |
| i = op->ov_index; |
| } else { |
| /* |
| * Already free, doing "compaction". |
| * |
| * Search for the old block of memory on the |
| * free list. First, check the most common |
| * case (last element free'd), then (this failing) |
| * the last ``reall_srchlen'' items free'd. |
| * If all lookups fail, then assume the size of |
| * the memory block being realloc'd is the |
| * smallest possible. |
| */ |
| if ((i = findbucket(op, 1)) < 0 && |
| (i = findbucket(op, reall_srchlen)) < 0) |
| i = 0; |
| } |
| onb = (1 << (i + 3)) - sizeof (*op) - RSLOP; |
| /* avoid the copy if same size block */ |
| if (was_alloced && |
| nbytes <= onb && nbytes > (onb >> 1) - sizeof(*op) - RSLOP) { |
| #ifdef RCHECK |
| /* |
| * Record new allocated size of block and |
| * bound space with magic numbers. |
| */ |
| if (op->ov_index <= 13) { |
| /* |
| * Convert amount of memory requested into |
| * closest block size stored in hash buckets |
| * which satisfies request. Account for |
| * space used per block for accounting. |
| */ |
| nbytes += sizeof (union overhead) + RSLOP; |
| nbytes = (nbytes + 3) &~ 3; |
| op->ov_size = nbytes - 1; |
| *((u_int *)((caddr_t)op + nbytes - RSLOP)) = RMAGIC; |
| } |
| #endif |
| return(cp); |
| } |
| if ((res = malloc(nbytes)) == NULL) |
| return (NULL); |
| if (cp != res) /* common optimization */ |
| (void)bcopy(cp, res, (int)((nbytes < onb) ? nbytes : onb)); |
| if (was_alloced) |
| free(cp); |
| return (res); |
| } |
| |
| /* |
| * Search ``srchlen'' elements of each free list for a block whose |
| * header starts at ``freep''. If srchlen is -1 search the whole list. |
| * Return bucket number, or -1 if not found. |
| */ |
| static |
| findbucket(freep, srchlen) |
| union overhead *freep; |
| int srchlen; |
| { |
| register union overhead *p; |
| register int i, j; |
| |
| for (i = 0; i < NBUCKETS; i++) { |
| j = 0; |
| for (p = nextf[i]; p && j != srchlen; p = p->ov_next) { |
| if (p == freep) |
| return (i); |
| j++; |
| } |
| } |
| return (-1); |
| } |
| |
| #ifdef MSTATS |
| /* |
| * mstats - print out statistics about malloc |
| * |
| * 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. |
| */ |
| mstats(s) |
| char *s; |
| { |
| register int i, j; |
| register union overhead *p; |
| int totfree = 0, |
| totused = 0; |
| |
| fprintf(stderr, "Memory allocation statistics %s\nfree:\t", s); |
| for (i = 0; i < NBUCKETS; i++) { |
| for (j = 0, p = nextf[i]; p; p = p->ov_next, j++) |
| ; |
| fprintf(stderr, " %d", j); |
| totfree += j * (1 << (i + 3)); |
| } |
| fprintf(stderr, "\nused:\t"); |
| for (i = 0; i < NBUCKETS; i++) { |
| fprintf(stderr, " %d", nmalloc[i]); |
| totused += nmalloc[i] * (1 << (i + 3)); |
| } |
| fprintf(stderr, "\n\tTotal in use: %d, total free: %d\n", |
| totused, totfree); |
| } |
| #endif |
| #endif /* lint */ |
