xref: /csrg-svn/sys/kern/kern_malloc.c (revision 50959)

/*
 * Copyright (c) 1987, 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)kern_malloc.c	7.28 (Berkeley) 09/03/91
 */

#include "param.h"
#include "proc.h"
#include "map.h"
#include "kernel.h"
#include "malloc.h"
#include "vm/vm.h"
#include "vm/vm_kern.h"

struct kmembuckets bucket[MINBUCKET + 16];
struct kmemstats kmemstats[M_LAST];
struct kmemusage *kmemusage;
char *kmembase, *kmemlimit;
char *memname[] = INITKMEMNAMES;

#ifdef DIAGNOSTIC
/*
 * This structure serves two purposes.
 * The first is to provide a set of masks to catch unaligned frees.
 * The second is to provide known text to copy into free objects so
 * that modifications after frees can be detected.
 */
#define WEIRD_ADDR 0xdeadbeef
long addrmask[] = { WEIRD_ADDR,
	0x00000001, 0x00000003, 0x00000007, 0x0000000f,
	0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff,
	0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff,
	0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff,
};

/*
 * Normally the first word of the structure is used to hold the list
 * pointer for free objects. However, when running with diagnostics,
 * we use the third and fourth fields, so as to catch modifications
 * in the most commonly trashed first two words.
 */
struct freelist {
	long	spare0;
	long	spare1;
	short	type;
	short	spare2;
	caddr_t	next;
};
#else /* !DIAGNOSTIC */
struct freelist {
	caddr_t	next;
};
#endif /* DIAGNOSTIC */

/*
 * Allocate a block of memory
 */
void *
malloc(size, type, flags)
	unsigned long size;
	int type, flags;
{
	register struct kmembuckets *kbp;
	register struct kmemusage *kup;
	register struct freelist *freep;
	long indx, npg, alloc, allocsize;
	int s;
	caddr_t va, cp, savedlist;
#ifdef DIAGNOSTIC
	int i, copysize;
	short savedtype;
#endif
#ifdef KMEMSTATS
	register struct kmemstats *ksp = &kmemstats[type];

	if (((unsigned long)type) > M_LAST)
		panic("malloc - bogus type");
#endif

	indx = BUCKETINDX(size);
	kbp = &bucket[indx];
	s = splimp();
#ifdef KMEMSTATS
	while (ksp->ks_memuse >= ksp->ks_limit) {
		if (flags & M_NOWAIT) {
			splx(s);
			return ((void *) NULL);
		}
		if (ksp->ks_limblocks < 65535)
			ksp->ks_limblocks++;
		tsleep((caddr_t)ksp, PSWP+2, memname[type], 0);
	}
#endif
#ifdef DIAGNOSTIC
	copysize = 1 << indx < sizeof addrmask ? 1 << indx : sizeof addrmask;
#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) {
			splx(s);
			return ((void *) NULL);
		}
#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;
		kbp->kb_next = va + (npg * NBPG) - allocsize;
		for (cp = kbp->kb_next; ; cp -= allocsize) {
			freep = (struct freelist *)cp;
#ifdef DIAGNOSTIC
			/*
			 * Copy in known text to detect modification
			 * after freeing.
			 */
			bcopy(addrmask, cp, copysize);
			freep->type = M_FREE;
#endif /* DIAGNOSTIC */
			if (cp <= va)
				break;
			freep->next = cp - allocsize;
		}
		freep->next = savedlist;
	}
	va = kbp->kb_next;
	kbp->kb_next = ((struct freelist *)va)->next;
#ifdef DIAGNOSTIC
	freep = (struct freelist *)va;
	savedtype = freep->type;
	freep->type = ((struct freelist *)addrmask)->type;
	freep->next = ((struct freelist *)addrmask)->next;
	if (bcmp(addrmask, va, copysize)) {
		copysize >>= 2;
		for (i = 0; i < copysize && addrmask[i] == ((int *)va)[i]; i++)
			/* void */;
		printf("%s %d of object 0x%x size %d %s %s (0x%x != 0x%x)\n",
		    "Data modified on freelist: word", i, va, size,
		    "previous type", memname[savedtype], ((int *)va)[i],
		    addrmask[i]);
		/* panic("malloc: data modified on freelist"); */
	}
	freep->spare0 = 0;
#endif /* DIAGNOSTIC */
#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
	splx(s);
	return ((void *) va);
}

/*
 * Free a block of memory allocated by malloc.
 */
void
free(addr, type)
	void *addr;
	int type;
{
	register struct kmembuckets *kbp;
	register struct kmemusage *kup;
	register struct freelist *freep;
	long size;
	int s;
#ifdef DIAGNOSTIC
	caddr_t cp;
	long alloc, copysize;
#endif
#ifdef KMEMSTATS
	register struct kmemstats *ksp = &kmemstats[type];
#endif

	kup = btokup(addr);
	size = 1 << kup->ku_indx;
	kbp = &bucket[kup->ku_indx];
	s = splimp();
#ifdef DIAGNOSTIC
	/*
	 * Check for returns of data that do not point to the
	 * beginning of the allocation.
	 */
	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 */
	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;
	}
	freep = (struct freelist *)addr;
#ifdef DIAGNOSTIC
	/*
	 * Check for multiple frees. Use a quick check to see if
	 * it looks free before laboriously searching the freelist.
	 */
	copysize = size < sizeof addrmask ? size : sizeof addrmask;
	if (freep->spare0 == WEIRD_ADDR) {
		freep->type = ((struct freelist *)addrmask)->type;
		freep->next = ((struct freelist *)addrmask)->next;
		if (!bcmp(addrmask, addr, copysize)) {
			for (cp = kbp->kb_next; cp; cp = *(caddr_t *)cp) {
				if (addr == cp) {
					printf("multiply freed item 0x%x\n",
					    addr);
					panic("free: duplicated free");
				}
			}
		}
	}
	/*
	 * Copy in known text to detect modification after freeing
	 * and to make it look free. Also, save the type being freed
	 * so we can list likely culprit if modification is detected
	 * when the object is reallocated.
	 */
	bcopy(addrmask, addr, copysize);
	freep->type = type;
#endif /* DIAGNOSTIC */
#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
	freep->next = kbp->kb_next;
	kbp->kb_next = addr;
	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
}