440 lines
10 KiB
C
440 lines
10 KiB
C
/* Copyright (c) 2002, 2004 Joerg Wunsch
|
|
All rights reserved.
|
|
|
|
Redistribution and use in source and binary forms, with or without
|
|
modification, are permitted provided that the following conditions are met:
|
|
|
|
* Redistributions of source code must retain the above copyright
|
|
notice, this list of conditions and the following disclaimer.
|
|
|
|
* 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.
|
|
|
|
* Neither the name of the copyright holders nor the names of
|
|
contributors may be used to endorse or promote products derived
|
|
from this software without specific prior written permission.
|
|
|
|
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
|
|
*/
|
|
|
|
|
|
/* $Id: malloc.c,v 1.1 2006/06/17 22:41:18 adamdunkels Exp $ */
|
|
|
|
#include <stdlib.h>
|
|
|
|
#ifdef MALLOC_TEST
|
|
#include "malloc.h"
|
|
char mymem[256];
|
|
#else
|
|
#include <sys/unistd.h>
|
|
#include "contiki.h"
|
|
#include "lib/malloc.h"
|
|
#endif /* !MALLOC_TEST */
|
|
|
|
/*
|
|
* Exported interface:
|
|
*
|
|
* When extending the data segment, the allocator will not try to go
|
|
* beyond the current stack limit, decreased by __malloc_margin bytes.
|
|
* Thus, all possible stack frames of interrupt routines that could
|
|
* interrupt the current function, plus all further nested function
|
|
* calls must not require more stack space, or they'll risk to collide
|
|
* with the data segment.
|
|
*/
|
|
|
|
char *__brkval;
|
|
struct __freelist *__flp;
|
|
|
|
#define handle nx
|
|
|
|
void *
|
|
malloc(size_t len)
|
|
{
|
|
struct __freelist *fp1, *fp2;
|
|
char *cp;
|
|
size_t s, avail;
|
|
|
|
if (len <= 0)
|
|
return 0;
|
|
|
|
len = (len + MALLOC_ROUNDUP) & ~MALLOC_ROUNDUP;
|
|
|
|
/*
|
|
* First, walk the free list and try finding a chunk that
|
|
* would match exactly. If we found one, we are done. While
|
|
* walking, note down the size of the largest chunk we found
|
|
* that would still fit the request -- we need it for step 2.
|
|
*
|
|
*/
|
|
for (s = 0, fp1 = __flp, fp2 = 0;
|
|
fp1;
|
|
fp2 = fp1, fp1 = fp1->nx) {
|
|
if (fp1->sz == len) {
|
|
/*
|
|
* Found it. Disconnect the chunk from the
|
|
* freelist, and return it.
|
|
*/
|
|
if (fp2)
|
|
fp2->nx = fp1->nx;
|
|
else
|
|
__flp = fp1->nx;
|
|
fp1->handle = NULL;
|
|
return &fp1[1];
|
|
}
|
|
if (fp1->sz > len) {
|
|
if (s == 0 || fp1->sz < s)
|
|
s = fp1->sz;
|
|
}
|
|
}
|
|
/*
|
|
* Step 2: If we found a chunk on the freelist that would fit
|
|
* (but was too large), look it up again and use it, since it
|
|
* is our closest match now. Since the freelist entry needs
|
|
* to be split into two entries then, watch out that the
|
|
* difference between the requested size and the size of the
|
|
* chunk found is large enough for another freelist entry; if
|
|
* not, just enlarge the request size to what we have found,
|
|
* and use the entire chunk.
|
|
*/
|
|
if (s) {
|
|
if (s - len < sizeof(struct __freelist))
|
|
len = s;
|
|
for (fp1 = __flp, fp2 = 0;
|
|
fp1;
|
|
fp2 = fp1, fp1 = fp1->nx) {
|
|
if (fp1->sz == s) {
|
|
if (len == s) {
|
|
/*
|
|
* Use entire chunk; same as
|
|
* above.
|
|
*/
|
|
if (fp2)
|
|
fp2->nx = fp1->nx;
|
|
else
|
|
__flp = fp1->nx;
|
|
fp1->handle = NULL;
|
|
return &fp1[1];
|
|
}
|
|
/*
|
|
* Split them up. Note that we leave
|
|
* the first part as the new (smaller)
|
|
* freelist entry, and return the
|
|
* upper portion to the caller. This
|
|
* saves us the work to fix up the
|
|
* freelist chain; we just need to
|
|
* fixup the size of the current
|
|
* entry, and note down the size of
|
|
* the new chunk before returning it
|
|
* to the caller.
|
|
*/
|
|
cp = (char *)fp1;
|
|
s -= len;
|
|
cp += s;
|
|
fp2 = (struct __freelist *)cp;
|
|
fp2->sz = len;
|
|
fp1->sz = s - sizeof(struct __freelist);
|
|
fp2->handle = NULL;
|
|
return &fp2[1];
|
|
}
|
|
}
|
|
}
|
|
/*
|
|
* Step 3: If the request could not be satisfied from a
|
|
* freelist entry, just prepare a new chunk. This means we
|
|
* need to obtain more memory first. The largest address just
|
|
* not allocated so far is remembered in the brkval variable.
|
|
* Under Unix, the "break value" was the end of the data
|
|
* segment as dynamically requested from the operating system.
|
|
* Since we don't have an operating system, just make sure
|
|
* that we don't collide with the stack.
|
|
*/
|
|
if (__brkval == 0)
|
|
__brkval = __malloc_heap_start;
|
|
cp = __malloc_heap_end;
|
|
avail = cp - __brkval;
|
|
/*
|
|
* Both tests below are needed to catch the case len >= 0xfffe.
|
|
*/
|
|
if (avail >= len && avail >= len + sizeof(struct __freelist)) {
|
|
fp1 = (struct __freelist *)__brkval;
|
|
__brkval += len + sizeof(struct __freelist);
|
|
fp1->sz = len;
|
|
fp1->handle = NULL;
|
|
return &fp1[1];
|
|
}
|
|
/*
|
|
* Step 4: There's no help, just fail. :-/
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
void
|
|
free(void *p)
|
|
{
|
|
struct __freelist *fp1, *fp2, *fpnew;
|
|
char *cp1, *cp2, *cpnew;
|
|
|
|
/* ISO C says free(NULL) must be a no-op */
|
|
if (p == 0)
|
|
return;
|
|
|
|
cpnew = p;
|
|
cpnew -= sizeof(struct __freelist);
|
|
fpnew = (struct __freelist *)cpnew;
|
|
fpnew->nx = 0;
|
|
|
|
/*
|
|
* Trivial case first: if there's no freelist yet, our entry
|
|
* will be the only one on it.
|
|
*/
|
|
if (__flp == 0) {
|
|
__flp = fpnew;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Now, find the position where our new entry belongs onto the
|
|
* freelist. Try to aggregate the chunk with adjacent chunks
|
|
* if possible.
|
|
*/
|
|
for (fp1 = __flp, fp2 = 0;
|
|
fp1;
|
|
fp2 = fp1, fp1 = fp1->nx) {
|
|
if (fp1 < fpnew)
|
|
continue;
|
|
cp1 = (char *)fp1;
|
|
fpnew->nx = fp1;
|
|
if (((char *)&fpnew[1]) + fpnew->sz == cp1) {
|
|
/* upper chunk adjacent, assimilate it */
|
|
fpnew->sz += fp1->sz + sizeof(struct __freelist);
|
|
fpnew->nx = fp1->nx;
|
|
}
|
|
if (fp2 == 0) {
|
|
/* new head of freelist */
|
|
__flp = fpnew;
|
|
return;
|
|
}
|
|
break;
|
|
}
|
|
/*
|
|
* Note that we get here either if we hit the "break" above,
|
|
* or if we fell off the end of the loop. The latter means
|
|
* we've got a new topmost chunk. Either way, try aggregating
|
|
* with the lower chunk if possible.
|
|
*/
|
|
fp2->nx = fpnew;
|
|
cp2 = (char *)&fp2[1];
|
|
if (cp2 + fp2->sz == cpnew) {
|
|
/* lower junk adjacent, merge */
|
|
fp2->sz += fpnew->sz + sizeof(struct __freelist);
|
|
fp2->nx = fpnew->nx;
|
|
}
|
|
}
|
|
|
|
#ifdef MALLOC_TEST
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <time.h>
|
|
#include <unistd.h>
|
|
|
|
void *handles[32];
|
|
size_t sizes[32];
|
|
|
|
|
|
void *
|
|
alloc(size_t s)
|
|
{
|
|
void *p;
|
|
|
|
if ((p = malloc(s)) == 0) {
|
|
malloc_compact();
|
|
if ((p = malloc(s)) == 0)
|
|
return 0;
|
|
}
|
|
memset(p, 0xd0, s);
|
|
return p;
|
|
}
|
|
|
|
void
|
|
printfreelist(void)
|
|
{
|
|
struct __freelist *fp1;
|
|
int i;
|
|
|
|
if (!__flp) {
|
|
printf("no free list\n");
|
|
return;
|
|
}
|
|
|
|
for (i = 0, fp1 = __flp; fp1; i++, fp1 = fp1->nx) {
|
|
printf("free %d @ %u: size %u, next ",
|
|
i, (char *)fp1 - mymem, fp1->sz);
|
|
if (fp1->nx)
|
|
printf("%u\n", (char *)fp1->nx - mymem);
|
|
else
|
|
printf("NULL\n");
|
|
}
|
|
}
|
|
|
|
int
|
|
compare(const void *p1, const void *p2)
|
|
{
|
|
return *((size_t *)p1) - *((size_t *)p2);
|
|
}
|
|
|
|
void
|
|
printalloc(void)
|
|
{
|
|
int j, k;
|
|
size_t i;
|
|
size_t sum, sum2;
|
|
void *sortedhandles[32];
|
|
struct __freelist *fp;
|
|
char *cp;
|
|
|
|
for (i = j = k = sum = sum2 = 0;
|
|
i < sizeof handles / sizeof (void *);
|
|
i++)
|
|
if (sizes[i]) {
|
|
j++;
|
|
sum += sizes[i];
|
|
if (handles[i]) {
|
|
k++;
|
|
sum2 += sizes[i];
|
|
}
|
|
}
|
|
printf("brkval: %d, %d request%s => sum %u bytes "
|
|
"(actually %d reqs => %u bytes)\n",
|
|
(char *)__brkval - mymem, j, j == 1? "": "s", sum, k, sum2);
|
|
memcpy(sortedhandles, handles, sizeof sortedhandles);
|
|
qsort(sortedhandles, 32, sizeof(void *), compare);
|
|
for (i = j = 0; i < sizeof sortedhandles / sizeof (void *); i++)
|
|
if ((cp = sortedhandles[i])) {
|
|
cp -= sizeof(struct __freelist);
|
|
fp = (struct __freelist *)cp;
|
|
printf("alloc %d @ %u: %u bytes, handle %p\n",
|
|
j, (char *)fp - mymem, fp->sz, fp->handle);
|
|
j++;
|
|
}
|
|
|
|
}
|
|
|
|
|
|
void
|
|
printblk(void)
|
|
{
|
|
struct __freelist *fp = __flp;
|
|
struct __freelist *ap = (struct __freelist *)__malloc_heap_start;
|
|
struct __freelist *end = (struct __freelist *)__brkval;
|
|
int b = 0;
|
|
int e = 0;
|
|
|
|
if (fp == 0)
|
|
fp = end;
|
|
|
|
alloclist:
|
|
while (ap < fp) {
|
|
printf("Alloc %d @ %u: %u bytes, handle %p\n",
|
|
b, (char *)ap - mymem, ap->sz, ap->handle);
|
|
ap = (void *)(((char *)ap) + sizeof(struct __freelist) + ap->sz);
|
|
b++;
|
|
}
|
|
|
|
if (fp < end) {
|
|
printf("Free %d @ %u: size %u, next ",
|
|
e, (char *)fp - mymem, fp->sz);
|
|
if (fp->nx)
|
|
printf("%u\n", (char *)fp->nx - mymem);
|
|
else
|
|
printf("NULL\n");
|
|
ap = (void *)(((char *)fp) + sizeof(struct __freelist) + fp->sz);
|
|
fp = fp->nx;
|
|
if (fp == 0)
|
|
fp = end;
|
|
e++;
|
|
}
|
|
|
|
if (ap < end)
|
|
goto alloclist;
|
|
}
|
|
|
|
int
|
|
main(void)
|
|
{
|
|
int i, j, k, l, m, om, p, f;
|
|
size_t s;
|
|
|
|
srand(time(0) ^ getpid());
|
|
|
|
for (k = 0; k < 100; k++) {
|
|
memset(handles, 0, sizeof handles);
|
|
memset(sizes, 0, sizeof sizes);
|
|
|
|
j = rand() % 16 + 15;
|
|
l = rand() % 80 + 7;
|
|
|
|
for (i = s = 0; i < j && s < 256; i++) {
|
|
sizes[i] = rand() % l + 1;
|
|
s += sizes[i];
|
|
}
|
|
j = i;
|
|
for (m = om = 1, p = 1, f = 0; m < 1000; m++) {
|
|
for (i = s = 0; i < j; i++)
|
|
if (handles[i])
|
|
s++;
|
|
if (s == (unsigned)j)
|
|
break;
|
|
|
|
if (m / om > 10) {
|
|
p <<= 1;
|
|
p |= 1;
|
|
}
|
|
|
|
for (i = 0; i < j; i++)
|
|
if (rand() & p) {
|
|
if (!handles[i]) {
|
|
if ((handles[i] = alloc(sizes[i])) == 0)
|
|
f++;
|
|
else if (sizes[i] & 1)
|
|
malloc_unlock(&handles[i]);
|
|
}
|
|
}
|
|
for (i = 0; i < j; i++) {
|
|
if (rand() & 1) {
|
|
free(handles[i]);
|
|
handles[i] = 0;
|
|
}
|
|
}
|
|
}
|
|
if (f)
|
|
printf("%d alloc failure%s total\n",
|
|
f, f == 1? "": "s");
|
|
printf("After alloc:\n");
|
|
printalloc();
|
|
//printfreelist();
|
|
printblk();
|
|
for (i = 0; i < j; i++)
|
|
free(handles[i]);
|
|
printf("After cleanup:\n");
|
|
printfreelist();
|
|
//printblk();
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#endif /* MALLOC_TEST */
|