You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
489 lines
13 KiB
489 lines
13 KiB
![]()
5 years ago
|
/* $NetBSD: malloc.c,v 1.8 1997/04/07 03:12:14 christos Exp $ */
|
||
|
|
||
|
/*
|
||
|
* Copyright (c) 1983 Regents of the University of California.
|
||
|
* All rights reserved.
|
||
|
*
|
||
|
* Redistribution and use in source and binary forms, with or without
|
||
|
* modification, are permitted provided that the following conditions
|
||
|
* are met:
|
||
|
* 1. Redistributions of source code must retain the above copyright
|
||
|
* notice, this list of conditions and the following disclaimer.
|
||
|
* 2. Redistributions in binary form must reproduce the above copyright
|
||
|
* notice, this list of conditions and the following disclaimer in the
|
||
|
* documentation and/or other materials provided with the distribution.
|
||
|
* 3. All advertising materials mentioning features or use of this software
|
||
|
* must display the following acknowledgement:
|
||
|
* This product includes software developed by the University of
|
||
|
* California, Berkeley and its contributors.
|
||
|
* 4. Neither the name of the University nor the names of its contributors
|
||
|
* may be used to endorse or promote products derived from this software
|
||
|
* without specific prior written permission.
|
||
|
*
|
||
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
||
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
||
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
||
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
||
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
||
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
||
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
||
|
* SUCH DAMAGE.
|
||
|
*/
|
||
|
|
||
|
#if defined(LIBC_SCCS) && !defined(lint)
|
||
|
#if 0
|
||
|
static char *sccsid = "from: @(#)malloc.c 5.11 (Berkeley) 2/23/91";
|
||
|
#else
|
||
|
static char *rcsid = "$NetBSD: malloc.c,v 1.8 1997/04/07 03:12:14 christos Exp $";
|
||
|
#endif
|
||
|
#endif /* LIBC_SCCS and not lint */
|
||
|
|
||
|
/*
|
||
|
* 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-10) bytes long.
|
||
|
* This is designed for use in a virtual memory environment.
|
||
|
*/
|
||
|
|
||
|
#include <sys/types.h>
|
||
|
#include <stdlib.h>
|
||
|
#include <string.h>
|
||
|
#include "platform/swap/swap.h"
|
||
|
/* #define MSTATS 1 */
|
||
|
|
||
|
#ifndef _WIN32
|
||
|
#include <unistd.h>
|
||
|
#define NULL 0
|
||
|
#else
|
||
|
|
||
|
#define u_char unsigned char
|
||
|
#define u_long unsigned long
|
||
|
#define getpagesize() 4096
|
||
|
#define caddr_t size_t
|
||
|
#define bcopy(a,b,c) memcpy(b,a,c)
|
||
|
|
||
|
#endif
|
||
|
|
||
|
|
||
|
static void morecore(int);
|
||
|
/*
|
||
|
* 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 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 *ov_next; /* when free */
|
||
|
struct {
|
||
|
u_char ovu_magic; /* magic number */
|
||
|
u_char ovu_index; /* bucket # */
|
||
|
#ifdef RCHECK
|
||
|
u_short ovu_rmagic; /* range magic number */
|
||
|
u_long ovu_size; /* actual block size */
|
||
|
#endif
|
||
|
} ovu;
|
||
|
#define ov_magic ovu.ovu_magic
|
||
|
#define ov_index ovu.ovu_index
|
||
|
#define ov_rmagic ovu.ovu_rmagic
|
||
|
#define ov_size ovu.ovu_size
|
||
|
};
|
||
|
|
||
|
static int findbucket( union overhead *freep,
|
||
|
int srchlen);
|
||
|
#define MAGIC 0xef /* magic # on accounting info */
|
||
|
#define RMAGIC 0x5555 /* magic # on range info */
|
||
|
|
||
|
#ifdef RCHECK
|
||
|
#define RSLOP sizeof (u_short)
|
||
|
#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(); */
|
||
|
|
||
|
static int pagesz; /* page size */
|
||
|
static int pagebucket; /* page size bucket */
|
||
|
|
||
|
#ifdef MSTATS
|
||
|
/*
|
||
|
* nmalloc[i] is the difference between the number of mallocs and frees
|
||
|
* for a given block size.
|
||
|
*/
|
||
|
static unsigned int nmalloc[NBUCKETS];
|
||
|
#include <stdio.h>
|
||
|
#endif
|
||
|
|
||
|
#if defined(DEBUG) || defined(RCHECK)
|
||
|
#define ASSERT(p) if (!(p)) botch(__STRING(p))
|
||
|
#include /* <stdio.h> */
|
||
|
static
|
||
|
botch(s)
|
||
|
char *s;
|
||
|
{
|
||
|
fprintf(stderr, "\r\nassertion botched: %s\r\n", s);
|
||
|
(void) fflush(stderr); /* just in case user buffered it */
|
||
|
abort();
|
||
|
}
|
||
|
#else
|
||
|
#define ASSERT(p)
|
||
|
#endif
|
||
|
|
||
|
#include <stdio.h>
|
||
|
|
||
|
/* */
|
||
|
/* malloc */
|
||
|
/* malloc */
|
||
|
void * SWAP_Malloc( size_t nbytes )
|
||
|
{
|
||
|
register union overhead *op;
|
||
|
register int bucket;
|
||
|
register long n;
|
||
|
register unsigned amt;
|
||
|
|
||
|
/*
|
||
|
* First time malloc is called, setup page size and
|
||
|
* align break pointer so all data will be page aligned.
|
||
|
*/
|
||
|
if (pagesz == 0) {
|
||
|
pagesz = n = getpagesize();
|
||
|
op = (union overhead *)SWAP_Sbrk( 0 );
|
||
|
n = n - sizeof (*op) - ((long)op & (n - 1));
|
||
|
if (n < 0)
|
||
|
n += pagesz;
|
||
|
if (n) {
|
||
|
if (SWAP_Sbrk(n) == (char *)-1) {
|
||
|
return (NULL);
|
||
|
}
|
||
|
}
|
||
|
bucket = 0;
|
||
|
amt = 8;
|
||
|
while (pagesz > amt) {
|
||
|
amt <<= 1;
|
||
|
bucket++;
|
||
|
}
|
||
|
pagebucket = bucket;
|
||
|
}
|
||
|
/*
|
||
|
* Convert amount of memory requested into closest block size
|
||
|
* stored in hash buckets which satisfies request.
|
||
|
* Account for space used per block for accounting.
|
||
|
*/
|
||
|
if (nbytes <= (n = pagesz - sizeof (*op) - RSLOP)) {
|
||
|
#ifndef RCHECK
|
||
|
amt = 8; /* size of first bucket */
|
||
|
bucket = 0;
|
||
|
#else
|
||
|
amt = 16; /* size of first bucket */
|
||
|
bucket = 1;
|
||
|
#endif
|
||
|
n = -((long)sizeof (*op) + RSLOP);
|
||
|
} else {
|
||
|
amt = pagesz;
|
||
|
bucket = pagebucket;
|
||
|
}
|
||
|
while (nbytes > amt + n) {
|
||
|
amt <<= 1;
|
||
|
if (amt == 0) {
|
||
|
return (NULL);
|
||
|
}
|
||
|
bucket++;
|
||
|
}
|
||
|
/*
|
||
|
* If nothing in hash bucket right now,
|
||
|
* request more memory from the system.
|
||
|
*/
|
||
|
if ((op = nextf[bucket]) == NULL) {
|
||
|
morecore(bucket);
|
||
|
if ((op = nextf[bucket]) == NULL) {
|
||
|
return (NULL);
|
||
|
}
|
||
|
}
|
||
|
/* remove from linked list */
|
||
|
nextf[bucket] = op->ov_next;
|
||
|
op->ov_magic = MAGIC;
|
||
|
op->ov_index = bucket;
|
||
|
#ifdef MSTATS
|
||
|
nmalloc[bucket]++;
|
||
|
#endif
|
||
|
#ifdef RCHECK
|
||
|
/*
|
||
|
* Record allocated size of block and
|
||
|
* bound space with magic numbers.
|
||
|
*/
|
||
|
op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
|
||
|
op->ov_rmagic = RMAGIC;
|
||
|
*(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
|
||
|
#endif
|
||
|
return ((char *)(op + 1));
|
||
|
}
|
||
|
|
||
|
void * SWAP_Calloc(size_t nelem, size_t elsize) {
|
||
|
void * ptr = SWAP_Malloc (nelem * elsize);
|
||
|
// Zero out the malloc'd block.
|
||
|
memset (ptr, 0, nelem * elsize);
|
||
|
return ptr;
|
||
|
}
|
||
|
|
||
|
|
||
|
/*
|
||
|
* Allocate more memory to the indicated bucket.
|
||
|
*/
|
||
|
static void
|
||
|
morecore(int bucket)
|
||
|
{
|
||
|
register union overhead *op;
|
||
|
register long sz; /* size of desired block */
|
||
|
long amt; /* amount to allocate */
|
||
|
int nblks; /* how many blocks we get */
|
||
|
|
||
|
/*
|
||
|
* sbrk_size <= 0 only for big, FLUFFY, requests (about
|
||
|
* 2^30 bytes on a VAX, I think) or for a negative arg.
|
||
|
*/
|
||
|
sz = 1 << (bucket + 3);
|
||
|
#ifdef DEBUG
|
||
|
ASSERT(sz > 0);
|
||
|
#else
|
||
|
if (sz <= 0)
|
||
|
return;
|
||
|
#endif
|
||
|
if (sz < pagesz) {
|
||
|
amt = pagesz;
|
||
|
nblks = amt / sz;
|
||
|
} else {
|
||
|
amt = sz + pagesz;
|
||
|
nblks = 1;
|
||
|
}
|
||
|
op = (union overhead *)SWAP_Sbrk(amt);
|
||
|
/* no more room! */
|
||
|
if ((long)op == -1)
|
||
|
return;
|
||
|
/*
|
||
|
* Add new memory allocated to that on
|
||
|
* free list for this hash bucket.
|
||
|
*/
|
||
|
nextf[bucket] = op;
|
||
|
while (--nblks > 0) {
|
||
|
op->ov_next = (union overhead *)((caddr_t)op + sz);
|
||
|
op = (union overhead *)((caddr_t)op + sz);
|
||
|
}
|
||
|
}
|
||
|
/* */
|
||
|
/* free */
|
||
|
/* free */
|
||
|
void SWAP_Free( void *cp)
|
||
|
|
||
|
{
|
||
|
register long size;
|
||
|
register union overhead *op;
|
||
|
|
||
|
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)
|
||
|
return; /* sanity */
|
||
|
#endif
|
||
|
#ifdef RCHECK
|
||
|
ASSERT(op->ov_rmagic == RMAGIC);
|
||
|
ASSERT(*(u_short *)((caddr_t)(op + 1) + op->ov_size) == RMAGIC);
|
||
|
#endif
|
||
|
size = op->ov_index;
|
||
|
ASSERT(size < NBUCKETS);
|
||
|
op->ov_next = nextf[size]; /* also clobbers ov_magic */
|
||
|
nextf[size] = op;
|
||
|
#ifdef MSTATS
|
||
|
nmalloc[size]--;
|
||
|
#endif
|
||
|
}
|
||
|
|
||
|
|
||
|
/* EDB: added size lookup */
|
||
|
|
||
|
size_t SWAP_MallocUsableSize(void * cp)
|
||
|
{
|
||
|
register long size;
|
||
|
register union overhead *op;
|
||
|
|
||
|
if (cp == NULL)
|
||
|
return 0;
|
||
|
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)
|
||
|
return 0; /* sanity */
|
||
|
#endif
|
||
|
#ifdef RCHECK
|
||
|
ASSERT(op->ov_rmagic == RMAGIC);
|
||
|
ASSERT(*(u_short *)((caddr_t)(op + 1) + op->ov_size) == RMAGIC);
|
||
|
#endif
|
||
|
return op->ov_index;
|
||
|
}
|
||
|
/* End EDB */
|
||
|
|
||
|
|
||
|
/*
|
||
|
* 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
|
||
|
* ``realloc_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 realloc_srchlen = 4; /* 4 should be plenty, -1 =>'s whole list */
|
||
|
|
||
|
/* */
|
||
|
/* realloc */
|
||
|
/* realloc */
|
||
|
void *
|
||
|
SWAP_Realloc( void *cp,
|
||
|
size_t nbytes)
|
||
|
|
||
|
{
|
||
|
register u_long onb;
|
||
|
register long i;
|
||
|
union overhead *op;
|
||
|
char *res;
|
||
|
int was_alloced = 0;
|
||
|
|
||
|
if (cp == NULL)
|
||
|
return (SWAP_Malloc(nbytes));
|
||
|
if (nbytes == 0) {
|
||
|
SWAP_Free (cp);
|
||
|
return NULL;
|
||
|
}
|
||
|
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 ``realloc_srchlen'' items free'd.
|
||
|
* If all lookups fail, then assume the size of
|
||
|
* the memory block being realloc'd is the
|
||
|
* largest possible (so that all "nbytes" of new
|
||
|
* memory are copied into). Note that this could cause
|
||
|
* a memory fault if the old area was tiny, and the moon
|
||
|
* is gibbous. However, that is very unlikely.
|
||
|
*/
|
||
|
if ((i = findbucket(op, 1)) < 0 &&
|
||
|
(i = findbucket(op, realloc_srchlen)) < 0)
|
||
|
i = NBUCKETS;
|
||
|
}
|
||
|
onb = 1 << (i + 3);
|
||
|
if (onb < pagesz)
|
||
|
onb -= sizeof (*op) + RSLOP;
|
||
|
else
|
||
|
onb += pagesz - sizeof (*op) - RSLOP;
|
||
|
/* avoid the copy if same size block */
|
||
|
if (was_alloced) {
|
||
|
if (i) {
|
||
|
i = 1 << (i + 2);
|
||
|
if (i < pagesz)
|
||
|
i -= sizeof (*op) + RSLOP;
|
||
|
else
|
||
|
i += pagesz - sizeof (*op) - RSLOP;
|
||
|
}
|
||
|
if (nbytes <= onb && nbytes > i) {
|
||
|
#ifdef RCHECK
|
||
|
op->ov_size = (nbytes + RSLOP - 1) & ~(RSLOP - 1);
|
||
|
*(u_short *)((caddr_t)(op + 1) + op->ov_size) = RMAGIC;
|
||
|
#endif
|
||
|
return(cp);
|
||
|
} else
|
||
|
SWAP_Free(cp);
|
||
|
}
|
||
|
if ((res = SWAP_Malloc(nbytes)) == NULL)
|
||
|
return (NULL);
|
||
|
if (cp != res) /* common optimization if "compacting" */
|
||
|
bcopy(cp, res, (nbytes < onb) ? nbytes : onb);
|
||
|
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 int
|
||
|
findbucket( 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(void)
|
||
|
{
|
||
|
register int i, j;
|
||
|
register union overhead *p;
|
||
|
int totfree = 0,
|
||
|
totused = 0;
|
||
|
|
||
|
fprintf(stderr, "Memory allocation statistics\nfree:\t");
|
||
|
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, total allocated: %d\n",
|
||
|
totused, totfree, totused + totfree);
|
||
|
}
|
||
|
#endif
|
||
|
|