kern_malloc.c revision 8876 
1/*
2 * Copyright (c) 1987, 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 *	@(#)kern_malloc.c	8.3 (Berkeley) 1/4/94
34 * $Id: kern_malloc.c,v 1.11 1995/04/16 11:25:15 davidg Exp $
35 */
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/proc.h>
40#include <sys/kernel.h>
41#include <sys/malloc.h>
42
43#include <vm/vm.h>
44#include <vm/vm_kern.h>
45
46struct kmembuckets bucket[MINBUCKET + 16];
47struct kmemstats kmemstats[M_LAST];
48struct kmemusage *kmemusage;
49char *kmembase, *kmemlimit;
50char *memname[] = INITKMEMNAMES;
51
52#ifdef DIAGNOSTIC
53/*
54 * This structure provides a set of masks to catch unaligned frees.
55 */
56long addrmask[] = { 0,
57	0x00000001, 0x00000003, 0x00000007, 0x0000000f,
58	0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff,
59	0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff,
60	0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff,
61};
62
63/*
64 * The WEIRD_ADDR is used as known text to copy into free objects so
65 * that modifications after frees can be detected.
66 */
67#define WEIRD_ADDR	0xdeadc0de
68#define MAX_COPY	64
69
70/*
71 * Normally the first word of the structure is used to hold the list
72 * pointer for free objects. However, when running with diagnostics,
73 * we use the third and fourth fields, so as to catch modifications
74 * in the most commonly trashed first two words.
75 */
76struct freelist {
77	long	spare0;
78	short	type;
79	long	spare1;
80	caddr_t	next;
81};
82#else /* !DIAGNOSTIC */
83struct freelist {
84	caddr_t	next;
85};
86#endif /* DIAGNOSTIC */
87
88/*
89 * Allocate a block of memory
90 */
91void *
92malloc(size, type, flags)
93	unsigned long size;
94	int type, flags;
95{
96	register struct kmembuckets *kbp;
97	register struct kmemusage *kup;
98	register struct freelist *freep;
99	long indx, npg, allocsize;
100	int s;
101	caddr_t va, cp, savedlist;
102#ifdef DIAGNOSTIC
103	long *end, *lp;
104	int copysize;
105	char *savedtype;
106#endif
107#ifdef KMEMSTATS
108	register struct kmemstats *ksp = &kmemstats[type];
109
110	if (((unsigned long)type) > M_LAST)
111		panic("malloc - bogus type");
112#endif
113	indx = BUCKETINDX(size);
114	kbp = &bucket[indx];
115	s = splhigh();
116#ifdef KMEMSTATS
117	while (ksp->ks_memuse >= ksp->ks_limit) {
118		if (flags & M_NOWAIT) {
119			splx(s);
120			return ((void *) NULL);
121		}
122		if (ksp->ks_limblocks < 65535)
123			ksp->ks_limblocks++;
124		tsleep((caddr_t)ksp, PSWP+2, memname[type], 0);
125	}
126	ksp->ks_size |= 1 << indx;
127#endif
128#ifdef DIAGNOSTIC
129	copysize = 1 << indx < MAX_COPY ? 1 << indx : MAX_COPY;
130#endif
131	if (kbp->kb_next == NULL) {
132		kbp->kb_last = NULL;
133		if (size > MAXALLOCSAVE)
134			allocsize = roundup(size, CLBYTES);
135		else
136			allocsize = 1 << indx;
137		npg = clrnd(btoc(allocsize));
138		va = (caddr_t) kmem_malloc(kmem_map, (vm_size_t)ctob(npg), flags);
139		if (va == NULL) {
140			splx(s);
141			return ((void *) NULL);
142		}
143#ifdef KMEMSTATS
144		kbp->kb_total += kbp->kb_elmpercl;
145#endif
146		kup = btokup(va);
147		kup->ku_indx = indx;
148		if (allocsize > MAXALLOCSAVE) {
149			if (npg > 65535)
150				panic("malloc: allocation too large");
151			kup->ku_pagecnt = npg;
152#ifdef KMEMSTATS
153			ksp->ks_memuse += allocsize;
154#endif
155			goto out;
156		}
157#ifdef KMEMSTATS
158		kup->ku_freecnt = kbp->kb_elmpercl;
159		kbp->kb_totalfree += kbp->kb_elmpercl;
160#endif
161		/*
162		 * Just in case we blocked while allocating memory,
163		 * and someone else also allocated memory for this
164		 * bucket, don't assume the list is still empty.
165		 */
166		savedlist = kbp->kb_next;
167		kbp->kb_next = cp = va + (npg * NBPG) - allocsize;
168		for (;;) {
169			freep = (struct freelist *)cp;
170#ifdef DIAGNOSTIC
171			/*
172			 * Copy in known text to detect modification
173			 * after freeing.
174			 */
175			end = (long *)&cp[copysize];
176			for (lp = (long *)cp; lp < end; lp++)
177				*lp = WEIRD_ADDR;
178			freep->type = M_FREE;
179#endif /* DIAGNOSTIC */
180			if (cp <= va)
181				break;
182			cp -= allocsize;
183			freep->next = cp;
184		}
185		freep->next = savedlist;
186		if (kbp->kb_last == NULL)
187			kbp->kb_last = (caddr_t)freep;
188	}
189	va = kbp->kb_next;
190	kbp->kb_next = ((struct freelist *)va)->next;
191#ifdef DIAGNOSTIC
192	freep = (struct freelist *)va;
193	savedtype = (unsigned)freep->type < M_LAST ?
194		memname[freep->type] : "???";
195	if (kbp->kb_next &&
196	    !kernacc(kbp->kb_next, sizeof(struct freelist), 0)) {
197		printf("%s of object %p size %ld %s %s (invalid addr %p)\n",
198			"Data modified on freelist: word 2.5", va, size,
199			"previous type", savedtype, kbp->kb_next);
200		kbp->kb_next = NULL;
201	}
202#if BYTE_ORDER == BIG_ENDIAN
203	freep->type = WEIRD_ADDR >> 16;
204#endif
205#if BYTE_ORDER == LITTLE_ENDIAN
206	freep->type = (short)WEIRD_ADDR;
207#endif
208	if (((long)(&freep->next)) & 0x2)
209		freep->next = (caddr_t)((WEIRD_ADDR >> 16)|(WEIRD_ADDR << 16));
210	else
211		freep->next = (caddr_t)WEIRD_ADDR;
212	end = (long *)&va[copysize];
213	for (lp = (long *)va; lp < end; lp++) {
214		if (*lp == WEIRD_ADDR)
215			continue;
216		printf("%s %d of object %p size %ld %s %s (0x%lx != 0x%x)\n",
217			"Data modified on freelist: word", lp - (long *)va,
218			va, size, "previous type", savedtype, *lp, WEIRD_ADDR);
219		break;
220	}
221	freep->spare0 = 0;
222#endif /* DIAGNOSTIC */
223#ifdef KMEMSTATS
224	kup = btokup(va);
225	if (kup->ku_indx != indx)
226		panic("malloc: wrong bucket");
227	if (kup->ku_freecnt == 0)
228		panic("malloc: lost data");
229	kup->ku_freecnt--;
230	kbp->kb_totalfree--;
231	ksp->ks_memuse += 1 << indx;
232out:
233	kbp->kb_calls++;
234	ksp->ks_inuse++;
235	ksp->ks_calls++;
236	if (ksp->ks_memuse > ksp->ks_maxused)
237		ksp->ks_maxused = ksp->ks_memuse;
238#else
239out:
240#endif
241	splx(s);
242	return ((void *) va);
243}
244
245/*
246 * Free a block of memory allocated by malloc.
247 */
248void
249free(addr, type)
250	void *addr;
251	int type;
252{
253	register struct kmembuckets *kbp;
254	register struct kmemusage *kup;
255	register struct freelist *freep;
256	long size;
257	int s;
258#ifdef DIAGNOSTIC
259	caddr_t cp;
260	long *end, *lp, alloc, copysize;
261#endif
262#ifdef KMEMSTATS
263	register struct kmemstats *ksp = &kmemstats[type];
264#endif
265
266#ifdef DIAGNOSTIC
267	if ((char *)addr < kmembase || (char *)addr >= kmemlimit) {
268		panic("free: address 0x%x out of range", addr);
269	}
270	if ((u_long)type > M_LAST) {
271		panic("free: type %d out of range", type);
272	}
273#endif
274	kup = btokup(addr);
275	size = 1 << kup->ku_indx;
276	kbp = &bucket[kup->ku_indx];
277	s = splhigh();
278#ifdef DIAGNOSTIC
279	/*
280	 * Check for returns of data that do not point to the
281	 * beginning of the allocation.
282	 */
283	if (size > NBPG * CLSIZE)
284		alloc = addrmask[BUCKETINDX(NBPG * CLSIZE)];
285	else
286		alloc = addrmask[kup->ku_indx];
287	if (((u_long)addr & alloc) != 0)
288		panic("free: unaligned addr 0x%x, size %d, type %s, mask %d",
289			addr, size, memname[type], alloc);
290#endif /* DIAGNOSTIC */
291	if (size > MAXALLOCSAVE) {
292		kmem_free(kmem_map, (vm_offset_t)addr, ctob(kup->ku_pagecnt));
293#ifdef KMEMSTATS
294		size = kup->ku_pagecnt << PGSHIFT;
295		ksp->ks_memuse -= size;
296		kup->ku_indx = 0;
297		kup->ku_pagecnt = 0;
298		if (ksp->ks_memuse + size >= ksp->ks_limit &&
299		    ksp->ks_memuse < ksp->ks_limit)
300			wakeup((caddr_t)ksp);
301		ksp->ks_inuse--;
302		kbp->kb_total -= 1;
303#endif
304		splx(s);
305		return;
306	}
307	freep = (struct freelist *)addr;
308#ifdef DIAGNOSTIC
309	/*
310	 * Check for multiple frees. Use a quick check to see if
311	 * it looks free before laboriously searching the freelist.
312	 */
313	if (freep->spare0 == WEIRD_ADDR) {
314		for (cp = kbp->kb_next; cp; cp = *(caddr_t *)cp) {
315			if (addr != cp)
316				continue;
317			printf("multiply freed item %p\n", addr);
318			panic("free: duplicated free");
319		}
320	}
321	/*
322	 * Copy in known text to detect modification after freeing
323	 * and to make it look free. Also, save the type being freed
324	 * so we can list likely culprit if modification is detected
325	 * when the object is reallocated.
326	 */
327	copysize = size < MAX_COPY ? size : MAX_COPY;
328	end = (long *)&((caddr_t)addr)[copysize];
329	for (lp = (long *)addr; lp < end; lp++)
330		*lp = WEIRD_ADDR;
331	freep->type = type;
332#endif /* DIAGNOSTIC */
333#ifdef KMEMSTATS
334	kup->ku_freecnt++;
335	if (kup->ku_freecnt >= kbp->kb_elmpercl)
336		if (kup->ku_freecnt > kbp->kb_elmpercl)
337			panic("free: multiple frees");
338		else if (kbp->kb_totalfree > kbp->kb_highwat)
339			kbp->kb_couldfree++;
340	kbp->kb_totalfree++;
341	ksp->ks_memuse -= size;
342	if (ksp->ks_memuse + size >= ksp->ks_limit &&
343	    ksp->ks_memuse < ksp->ks_limit)
344		wakeup((caddr_t)ksp);
345	ksp->ks_inuse--;
346#endif
347	if (kbp->kb_next == NULL)
348		kbp->kb_next = addr;
349	else
350		((struct freelist *)kbp->kb_last)->next = addr;
351	freep->next = NULL;
352	kbp->kb_last = addr;
353	splx(s);
354}
355
356/*
357 * Initialize the kernel memory allocator
358 */
359void
360kmeminit()
361{
362	register long indx;
363	int npg;
364
365#if	((MAXALLOCSAVE & (MAXALLOCSAVE - 1)) != 0)
366		ERROR!_kmeminit:_MAXALLOCSAVE_not_power_of_2
367#endif
368#if	(MAXALLOCSAVE > MINALLOCSIZE * 32768)
369		ERROR!_kmeminit:_MAXALLOCSAVE_too_big
370#endif
371#if	(MAXALLOCSAVE < CLBYTES)
372		ERROR!_kmeminit:_MAXALLOCSAVE_too_small
373#endif
374	npg = VM_KMEM_SIZE/ NBPG;
375	if( npg > cnt.v_page_count)
376		npg = cnt.v_page_count;
377
378	kmemusage = (struct kmemusage *) kmem_alloc(kernel_map,
379		(vm_size_t)(npg * sizeof(struct kmemusage)));
380	kmem_map = kmem_suballoc(kernel_map, (vm_offset_t *)&kmembase,
381		(vm_offset_t *)&kmemlimit, (vm_size_t)(npg * NBPG), FALSE);
382#ifdef KMEMSTATS
383	for (indx = 0; indx < MINBUCKET + 16; indx++) {
384		if (1 << indx >= CLBYTES)
385			bucket[indx].kb_elmpercl = 1;
386		else
387			bucket[indx].kb_elmpercl = CLBYTES / (1 << indx);
388		bucket[indx].kb_highwat = 5 * bucket[indx].kb_elmpercl;
389	}
390	for (indx = 0; indx < M_LAST; indx++)
391		kmemstats[indx].ks_limit = npg * NBPG * 6 / 10;
392#endif
393}
394