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protect free list from lossage if multiple procs try to fill bucket
[unix-history] / usr / src / sys / kern / kern_malloc.c
/*
* Copyright (c) 1987 Regents of the University of California.
* All rights reserved.
*
* %sccs.include.redist.c%
*
* @(#)kern_malloc.c 7.22 (Berkeley) %G%
*/
#include "param.h"
#include "cmap.h"
#include "time.h"
#include "proc.h"
#include "map.h"
#include "kernel.h"
#include "malloc.h"
#include "../vm/vm_param.h"
#include "../vm/vm_map.h"
#include "../vm/vm_kern.h"
struct kmembuckets bucket[MINBUCKET + 16];
struct kmemstats kmemstats[M_LAST];
struct kmemusage *kmemusage;
char *memname[] = INITKMEMNAMES;
char *kmembase, *kmemlimit;
char *memname[] = INITKMEMNAMES;
long malloc_reentered;
#define IN { if (malloc_reentered) panic("malloc reentered");\
else malloc_reentered = 1;}
#define OUT (malloc_reentered = 0)
/*
* Allocate a block of memory
*/
qaddr_t
malloc(size, type, flags)
unsigned long size;
int type, flags;
{
register struct kmembuckets *kbp;
register struct kmemusage *kup;
long indx, npg, alloc, allocsize;
int s;
caddr_t va, cp, rp;
#ifdef KMEMSTATS
register struct kmemstats *ksp = &kmemstats[type];
if (((unsigned long)type) > M_LAST)
panic("malloc - bogus type");
indx = BUCKETINDX(size);
kbp = &bucket[indx];
s = splimp();
IN;
#ifdef KMEMSTATS
while (ksp->ks_memuse >= ksp->ks_limit) {
if (flags & M_NOWAIT) {
OUT;
splx(s);
return (0);
}
if (ksp->ks_limblocks < 65535)
ksp->ks_limblocks++;
OUT;
tsleep((caddr_t)ksp, PSWP+2, memname[type], 0);
IN;
}
#endif
if (kbp->kb_next == NULL) {
if (size > MAXALLOCSAVE)
allocsize = roundup(size, CLBYTES);
else
allocsize = 1 << indx;
npg = clrnd(btoc(allocsize));
va = (caddr_t) kmem_malloc(kmem_map, (vm_size_t)ctob(npg),
!(flags & M_NOWAIT));
if (va == NULL) {
OUT;
splx(s);
return (0);
}
#ifdef KMEMSTATS
kbp->kb_total += kbp->kb_elmpercl;
#endif
kup = btokup(va);
kup->ku_indx = indx;
if (allocsize > MAXALLOCSAVE) {
if (npg > 65535)
panic("malloc: allocation too large");
kup->ku_pagecnt = npg;
#ifdef KMEMSTATS
ksp->ks_memuse += allocsize;
#endif
goto out;
}
#ifdef KMEMSTATS
kup->ku_freecnt = kbp->kb_elmpercl;
kbp->kb_totalfree += kbp->kb_elmpercl;
#endif
/*
* Just in case we blocked while allocating memory,
* and someone else also allocated memory for this
* bucket, don't assume the list is still empty.
*/
savedlist = kbp->kb_next;
rp = kbp->kb_next; /* returned while blocked in vmemall */
kbp->kb_next = va + (npg * NBPG) - allocsize;
for (cp = kbp->kb_next; cp >= va; cp -= allocsize) {
((caddr_t *)cp)[2] = (cp > va ? cp - allocsize : rp);
if (indx == 7) {
long *lp = (long *)cp;
lp[0] = lp[1] = lp[3] = lp[4] = -1;
}
}
}
va = kbp->kb_next;
kbp->kb_next = ((caddr_t *)va)[2];
if (indx == 7) {
long *lp = (long *)va;
if (lp[0] != -1 || lp[1] != -1 || lp[3] != -1 || lp[4] != -1)
panic("malloc meddled");
}
#ifdef KMEMSTATS
kup = btokup(va);
if (kup->ku_indx != indx)
panic("malloc: wrong bucket");
if (kup->ku_freecnt == 0)
panic("malloc: lost data");
kup->ku_freecnt--;
kbp->kb_totalfree--;
ksp->ks_memuse += 1 << indx;
out:
kbp->kb_calls++;
ksp->ks_inuse++;
ksp->ks_calls++;
if (ksp->ks_memuse > ksp->ks_maxused)
ksp->ks_maxused = ksp->ks_memuse;
#else
out:
#endif
OUT;
splx(s);
return ((qaddr_t)va);
}
#ifdef DIAGNOSTIC
long addrmask[] = { 0x00000000,
0x00000001, 0x00000003, 0x00000007, 0x0000000f,
0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff,
0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff,
0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff,
};
#endif /* DIAGNOSTIC */
#ifdef DIAGNOSTIC
long addrmask[] = { 0x00000000,
0x00000001, 0x00000003, 0x00000007, 0x0000000f,
0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff,
0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff,
0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff,
};
#endif /* DIAGNOSTIC */
/*
* Free a block of memory allocated by malloc.
*/
void
free(addr, type)
caddr_t addr;
int type;
{
register struct kmembuckets *kbp;
register struct kmemusage *kup;
long alloc, size;
int s;
#ifdef KMEMSTATS
register struct kmemstats *ksp = &kmemstats[type];
#endif
kup = btokup(addr);
size = 1 << kup->ku_indx;
#ifdef DIAGNOSTIC
if (size > NBPG * CLSIZE)
alloc = addrmask[BUCKETINDX(NBPG * CLSIZE)];
else
alloc = addrmask[kup->ku_indx];
if (((u_long)addr & alloc) != 0) {
printf("free: unaligned addr 0x%x, size %d, type %d, mask %d\n",
addr, size, type, alloc);
panic("free: unaligned addr");
}
#endif /* DIAGNOSTIC */
size = 1 << kup->ku_indx;
#ifdef DIAGNOSTIC
if (size > NBPG * CLSIZE)
alloc = addrmask[BUCKETINDX(NBPG * CLSIZE)];
else
alloc = addrmask[kup->ku_indx];
if (((u_long)addr & alloc) != 0) {
printf("free: unaligned addr 0x%x, size %d, type %d, mask %d\n",
addr, size, type, alloc);
panic("free: unaligned addr");
}
#endif /* DIAGNOSTIC */
kbp = &bucket[kup->ku_indx];
s = splimp();
IN;
if (size > MAXALLOCSAVE) {
kmem_free(kmem_map, (vm_offset_t)addr, ctob(kup->ku_pagecnt));
#ifdef KMEMSTATS
size = kup->ku_pagecnt << PGSHIFT;
ksp->ks_memuse -= size;
kup->ku_indx = 0;
kup->ku_pagecnt = 0;
if (ksp->ks_memuse + size >= ksp->ks_limit &&
ksp->ks_memuse < ksp->ks_limit)
wakeup((caddr_t)ksp);
ksp->ks_inuse--;
kbp->kb_total -= 1;
#endif
splx(s);
return;
}
if (size == 128) {
long *lp = (long *)addr;
lp[0] = lp[1] = lp[3] = lp[4] = -1;
}
#ifdef KMEMSTATS
kup->ku_freecnt++;
if (kup->ku_freecnt >= kbp->kb_elmpercl)
if (kup->ku_freecnt > kbp->kb_elmpercl)
panic("free: multiple frees");
else if (kbp->kb_totalfree > kbp->kb_highwat)
kbp->kb_couldfree++;
kbp->kb_totalfree++;
ksp->ks_memuse -= size;
if (ksp->ks_memuse + size >= ksp->ks_limit &&
ksp->ks_memuse < ksp->ks_limit)
wakeup((caddr_t)ksp);
ksp->ks_inuse--;
#endif
((caddr_t *)addr)[2] = kbp->kb_next;
kbp->kb_next = addr;
OUT;
splx(s);
}
/*
* Initialize the kernel memory allocator
*/
kmeminit()
{
register long indx;
int npg;
#if ((MAXALLOCSAVE & (MAXALLOCSAVE - 1)) != 0)
ERROR!_kmeminit:_MAXALLOCSAVE_not_power_of_2
#endif
#if (MAXALLOCSAVE > MINALLOCSIZE * 32768)
ERROR!_kmeminit:_MAXALLOCSAVE_too_big
#endif
#if (MAXALLOCSAVE < CLBYTES)
ERROR!_kmeminit:_MAXALLOCSAVE_too_small
#endif
npg = VM_KMEM_SIZE/ NBPG;
kmemusage = (struct kmemusage *) kmem_alloc(kernel_map,
(vm_size_t)(npg * sizeof(struct kmemusage)));
kmem_map = kmem_suballoc(kernel_map, (vm_offset_t)&kmembase,
(vm_offset_t)&kmemlimit, (vm_size_t)(npg * NBPG), FALSE);
#ifdef KMEMSTATS
for (indx = 0; indx < MINBUCKET + 16; indx++) {
if (1 << indx >= CLBYTES)
bucket[indx].kb_elmpercl = 1;
else
bucket[indx].kb_elmpercl = CLBYTES / (1 << indx);
bucket[indx].kb_highwat = 5 * bucket[indx].kb_elmpercl;
}
for (indx = 0; indx < M_LAST; indx++)
kmemstats[indx].ks_limit = npg * NBPG * 6 / 10;
#endif
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.