xref: /netbsd-src/sys/kern/kern_malloc.c (revision 27578b9aac214cc7796ead81dcc5427e79d5f2a0)
1 /*	$NetBSD: kern_malloc.c,v 1.63 2001/09/15 20:36:36 chs Exp $	*/
2 
3 /*
4  * Copyright (c) 1996 Christopher G. Demetriou.  All rights reserved.
5  * Copyright (c) 1987, 1991, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)kern_malloc.c	8.4 (Berkeley) 5/20/95
37  */
38 
39 #include "opt_lockdebug.h"
40 
41 #include <sys/param.h>
42 #include <sys/proc.h>
43 #include <sys/map.h>
44 #include <sys/kernel.h>
45 #include <sys/malloc.h>
46 #include <sys/systm.h>
47 
48 #include <uvm/uvm_extern.h>
49 
50 static struct vm_map kmem_map_store;
51 struct vm_map *kmem_map = NULL;
52 
53 #include "opt_kmempages.h"
54 
55 #ifdef NKMEMCLUSTERS
56 #error NKMEMCLUSTERS is obsolete; remove it from your kernel config file and use NKMEMPAGES instead or let the kernel auto-size
57 #endif
58 
59 /*
60  * Default number of pages in kmem_map.  We attempt to calculate this
61  * at run-time, but allow it to be either patched or set in the kernel
62  * config file.
63  */
64 #ifndef NKMEMPAGES
65 #define	NKMEMPAGES	0
66 #endif
67 int	nkmempages = NKMEMPAGES;
68 
69 /*
70  * Defaults for lower- and upper-bounds for the kmem_map page count.
71  * Can be overridden by kernel config options.
72  */
73 #ifndef	NKMEMPAGES_MIN
74 #define	NKMEMPAGES_MIN	NKMEMPAGES_MIN_DEFAULT
75 #endif
76 
77 #ifndef NKMEMPAGES_MAX
78 #define	NKMEMPAGES_MAX	NKMEMPAGES_MAX_DEFAULT
79 #endif
80 
81 #include "opt_kmemstats.h"
82 #include "opt_malloclog.h"
83 
84 struct kmembuckets bucket[MINBUCKET + 16];
85 struct kmemstats kmemstats[M_LAST];
86 struct kmemusage *kmemusage;
87 char *kmembase, *kmemlimit;
88 const char * const memname[] = INITKMEMNAMES;
89 
90 #ifdef MALLOCLOG
91 #ifndef MALLOCLOGSIZE
92 #define	MALLOCLOGSIZE	100000
93 #endif
94 
95 struct malloclog {
96 	void *addr;
97 	long size;
98 	int type;
99 	int action;
100 	const char *file;
101 	long line;
102 } malloclog[MALLOCLOGSIZE];
103 
104 long	malloclogptr;
105 
106 static void domlog __P((void *a, long size, int type, int action,
107 	const char *file, long line));
108 static void hitmlog __P((void *a));
109 
110 static void
111 domlog(a, size, type, action, file, line)
112 	void *a;
113 	long size;
114 	int type;
115 	int action;
116 	const char *file;
117 	long line;
118 {
119 
120 	malloclog[malloclogptr].addr = a;
121 	malloclog[malloclogptr].size = size;
122 	malloclog[malloclogptr].type = type;
123 	malloclog[malloclogptr].action = action;
124 	malloclog[malloclogptr].file = file;
125 	malloclog[malloclogptr].line = line;
126 	malloclogptr++;
127 	if (malloclogptr >= MALLOCLOGSIZE)
128 		malloclogptr = 0;
129 }
130 
131 static void
132 hitmlog(a)
133 	void *a;
134 {
135 	struct malloclog *lp;
136 	long l;
137 
138 #define	PRT \
139 	if (malloclog[l].addr == a && malloclog[l].action) { \
140 		lp = &malloclog[l]; \
141 		printf("malloc log entry %ld:\n", l); \
142 		printf("\taddr = %p\n", lp->addr); \
143 		printf("\tsize = %ld\n", lp->size); \
144 		printf("\ttype = %s\n", memname[lp->type]); \
145 		printf("\taction = %s\n", lp->action == 1 ? "alloc" : "free"); \
146 		printf("\tfile = %s\n", lp->file); \
147 		printf("\tline = %ld\n", lp->line); \
148 	}
149 
150 	for (l = malloclogptr; l < MALLOCLOGSIZE; l++)
151 		PRT
152 
153 	for (l = 0; l < malloclogptr; l++)
154 		PRT
155 }
156 #endif /* MALLOCLOG */
157 
158 #ifdef DIAGNOSTIC
159 /*
160  * This structure provides a set of masks to catch unaligned frees.
161  */
162 const long addrmask[] = { 0,
163 	0x00000001, 0x00000003, 0x00000007, 0x0000000f,
164 	0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff,
165 	0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff,
166 	0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff,
167 };
168 
169 /*
170  * The WEIRD_ADDR is used as known text to copy into free objects so
171  * that modifications after frees can be detected.
172  */
173 #define WEIRD_ADDR	((unsigned) 0xdeadbeef)
174 #ifdef DEBUG
175 #define MAX_COPY	PAGE_SIZE
176 #else
177 #define MAX_COPY	32
178 #endif
179 
180 /*
181  * Normally the freelist structure is used only to hold the list pointer
182  * for free objects.  However, when running with diagnostics, the first
183  * 8 bytes of the structure is unused except for diagnostic information,
184  * and the free list pointer is at offst 8 in the structure.  Since the
185  * first 8 bytes is the portion of the structure most often modified, this
186  * helps to detect memory reuse problems and avoid free list corruption.
187  */
188 struct freelist {
189 	int32_t	spare0;
190 	int16_t	type;
191 	int16_t	spare1;
192 	caddr_t	next;
193 };
194 #else /* !DIAGNOSTIC */
195 struct freelist {
196 	caddr_t	next;
197 };
198 #endif /* DIAGNOSTIC */
199 
200 /*
201  * Allocate a block of memory
202  */
203 #ifdef MALLOCLOG
204 void *
205 _malloc(size, type, flags, file, line)
206 	unsigned long size;
207 	int type, flags;
208 	const char *file;
209 	long line;
210 #else
211 void *
212 malloc(size, type, flags)
213 	unsigned long size;
214 	int type, flags;
215 #endif /* MALLOCLOG */
216 {
217 	struct kmembuckets *kbp;
218 	struct kmemusage *kup;
219 	struct freelist *freep;
220 	long indx, npg, allocsize;
221 	int s;
222 	caddr_t va, cp, savedlist;
223 #ifdef DIAGNOSTIC
224 	int32_t *end, *lp;
225 	int copysize;
226 	const char *savedtype;
227 #endif
228 #ifdef KMEMSTATS
229 	struct kmemstats *ksp = &kmemstats[type];
230 
231 	if (__predict_false(((unsigned long)type) > M_LAST))
232 		panic("malloc - bogus type");
233 #endif
234 #ifdef LOCKDEBUG
235 	if ((flags & M_NOWAIT) == 0)
236 		simple_lock_only_held(NULL, "malloc");
237 #endif
238 #ifdef MALLOC_DEBUG
239 	if (debug_malloc(size, type, flags, (void **) &va))
240 		return ((void *) va);
241 #endif
242 	indx = BUCKETINDX(size);
243 	kbp = &bucket[indx];
244 	s = splvm();
245 #ifdef KMEMSTATS
246 	while (ksp->ks_memuse >= ksp->ks_limit) {
247 		if (flags & M_NOWAIT) {
248 			splx(s);
249 			return ((void *) NULL);
250 		}
251 		if (ksp->ks_limblocks < 65535)
252 			ksp->ks_limblocks++;
253 		tsleep((caddr_t)ksp, PSWP+2, memname[type], 0);
254 	}
255 	ksp->ks_size |= 1 << indx;
256 #endif
257 #ifdef DIAGNOSTIC
258 	copysize = 1 << indx < MAX_COPY ? 1 << indx : MAX_COPY;
259 #endif
260 	if (kbp->kb_next == NULL) {
261 		kbp->kb_last = NULL;
262 		if (size > MAXALLOCSAVE)
263 			allocsize = roundup(size, PAGE_SIZE);
264 		else
265 			allocsize = 1 << indx;
266 		npg = btoc(allocsize);
267 		va = (caddr_t) uvm_km_kmemalloc(kmem_map, NULL,
268 				(vsize_t)ctob(npg),
269 				(flags & M_NOWAIT) ? UVM_KMF_NOWAIT : 0);
270 		if (__predict_false(va == NULL)) {
271 			/*
272 			 * Kmem_malloc() can return NULL, even if it can
273 			 * wait, if there is no map space avaiable, because
274 			 * it can't fix that problem.  Neither can we,
275 			 * right now.  (We should release pages which
276 			 * are completely free and which are in buckets
277 			 * with too many free elements.)
278 			 */
279 			if ((flags & M_NOWAIT) == 0)
280 				panic("malloc: out of space in kmem_map");
281 			splx(s);
282 			return ((void *) NULL);
283 		}
284 #ifdef KMEMSTATS
285 		kbp->kb_total += kbp->kb_elmpercl;
286 #endif
287 		kup = btokup(va);
288 		kup->ku_indx = indx;
289 		if (allocsize > MAXALLOCSAVE) {
290 			if (npg > 65535)
291 				panic("malloc: allocation too large");
292 			kup->ku_pagecnt = npg;
293 #ifdef KMEMSTATS
294 			ksp->ks_memuse += allocsize;
295 #endif
296 			goto out;
297 		}
298 #ifdef KMEMSTATS
299 		kup->ku_freecnt = kbp->kb_elmpercl;
300 		kbp->kb_totalfree += kbp->kb_elmpercl;
301 #endif
302 		/*
303 		 * Just in case we blocked while allocating memory,
304 		 * and someone else also allocated memory for this
305 		 * bucket, don't assume the list is still empty.
306 		 */
307 		savedlist = kbp->kb_next;
308 		kbp->kb_next = cp = va + (npg << PAGE_SHIFT) - allocsize;
309 		for (;;) {
310 			freep = (struct freelist *)cp;
311 #ifdef DIAGNOSTIC
312 			/*
313 			 * Copy in known text to detect modification
314 			 * after freeing.
315 			 */
316 			end = (int32_t *)&cp[copysize];
317 			for (lp = (int32_t *)cp; lp < end; lp++)
318 				*lp = WEIRD_ADDR;
319 			freep->type = M_FREE;
320 #endif /* DIAGNOSTIC */
321 			if (cp <= va)
322 				break;
323 			cp -= allocsize;
324 			freep->next = cp;
325 		}
326 		freep->next = savedlist;
327 		if (kbp->kb_last == NULL)
328 			kbp->kb_last = (caddr_t)freep;
329 	}
330 	va = kbp->kb_next;
331 	kbp->kb_next = ((struct freelist *)va)->next;
332 #ifdef DIAGNOSTIC
333 	freep = (struct freelist *)va;
334 	savedtype = (unsigned)freep->type < M_LAST ?
335 		memname[freep->type] : "???";
336 	if (kbp->kb_next) {
337 		int rv;
338 		vaddr_t addr = (vaddr_t)kbp->kb_next;
339 
340 		vm_map_lock(kmem_map);
341 		rv = uvm_map_checkprot(kmem_map, addr,
342 				       addr + sizeof(struct freelist),
343 				       VM_PROT_WRITE);
344 		vm_map_unlock(kmem_map);
345 
346 		if (__predict_false(rv == 0)) {
347 			printf(
348 		    "%s %ld of object %p size %ld %s %s (invalid addr %p)\n",
349 			    "Data modified on freelist: word",
350 			    (long)((int32_t *)&kbp->kb_next - (int32_t *)kbp),
351 			    va, size, "previous type", savedtype, kbp->kb_next);
352 #ifdef MALLOCLOG
353 			hitmlog(va);
354 #endif
355 			kbp->kb_next = NULL;
356 		}
357 	}
358 
359 	/* Fill the fields that we've used with WEIRD_ADDR */
360 #if BYTE_ORDER == BIG_ENDIAN
361 	freep->type = WEIRD_ADDR >> 16;
362 #endif
363 #if BYTE_ORDER == LITTLE_ENDIAN
364 	freep->type = (short)WEIRD_ADDR;
365 #endif
366 	end = (int32_t *)&freep->next +
367 	    (sizeof(freep->next) / sizeof(int32_t));
368 	for (lp = (int32_t *)&freep->next; lp < end; lp++)
369 		*lp = WEIRD_ADDR;
370 
371 	/* and check that the data hasn't been modified. */
372 	end = (int32_t *)&va[copysize];
373 	for (lp = (int32_t *)va; lp < end; lp++) {
374 		if (__predict_true(*lp == WEIRD_ADDR))
375 			continue;
376 		printf("%s %ld of object %p size %ld %s %s (0x%x != 0x%x)\n",
377 		    "Data modified on freelist: word",
378 		    (long)(lp - (int32_t *)va), va, size, "previous type",
379 		    savedtype, *lp, WEIRD_ADDR);
380 #ifdef MALLOCLOG
381 		hitmlog(va);
382 #endif
383 		break;
384 	}
385 
386 	freep->spare0 = 0;
387 #endif /* DIAGNOSTIC */
388 #ifdef KMEMSTATS
389 	kup = btokup(va);
390 	if (kup->ku_indx != indx)
391 		panic("malloc: wrong bucket");
392 	if (kup->ku_freecnt == 0)
393 		panic("malloc: lost data");
394 	kup->ku_freecnt--;
395 	kbp->kb_totalfree--;
396 	ksp->ks_memuse += 1 << indx;
397 out:
398 	kbp->kb_calls++;
399 	ksp->ks_inuse++;
400 	ksp->ks_calls++;
401 	if (ksp->ks_memuse > ksp->ks_maxused)
402 		ksp->ks_maxused = ksp->ks_memuse;
403 #else
404 out:
405 #endif
406 #ifdef MALLOCLOG
407 	domlog(va, size, type, 1, file, line);
408 #endif
409 	splx(s);
410 	return ((void *) va);
411 }
412 
413 /*
414  * Free a block of memory allocated by malloc.
415  */
416 #ifdef MALLOCLOG
417 void
418 _free(addr, type, file, line)
419 	void *addr;
420 	int type;
421 	const char *file;
422 	long line;
423 #else
424 void
425 free(addr, type)
426 	void *addr;
427 	int type;
428 #endif /* MALLOCLOG */
429 {
430 	struct kmembuckets *kbp;
431 	struct kmemusage *kup;
432 	struct freelist *freep;
433 	long size;
434 	int s;
435 #ifdef DIAGNOSTIC
436 	caddr_t cp;
437 	int32_t *end, *lp;
438 	long alloc, copysize;
439 #endif
440 #ifdef KMEMSTATS
441 	struct kmemstats *ksp = &kmemstats[type];
442 #endif
443 
444 #ifdef MALLOC_DEBUG
445 	if (debug_free(addr, type))
446 		return;
447 #endif
448 
449 #ifdef DIAGNOSTIC
450 	/*
451 	 * Ensure that we're free'ing something that we could
452 	 * have allocated in the first place.  That is, check
453 	 * to see that the address is within kmem_map.
454 	 */
455 	if (__predict_false((vaddr_t)addr < kmem_map->header.start ||
456 			    (vaddr_t)addr >= kmem_map->header.end))
457 		panic("free: addr %p not within kmem_map", addr);
458 #endif
459 
460 	kup = btokup(addr);
461 	size = 1 << kup->ku_indx;
462 	kbp = &bucket[kup->ku_indx];
463 	s = splvm();
464 #ifdef MALLOCLOG
465 	domlog(addr, 0, type, 2, file, line);
466 #endif
467 #ifdef DIAGNOSTIC
468 	/*
469 	 * Check for returns of data that do not point to the
470 	 * beginning of the allocation.
471 	 */
472 	if (size > PAGE_SIZE)
473 		alloc = addrmask[BUCKETINDX(PAGE_SIZE)];
474 	else
475 		alloc = addrmask[kup->ku_indx];
476 	if (((u_long)addr & alloc) != 0)
477 		panic("free: unaligned addr %p, size %ld, type %s, mask %ld\n",
478 			addr, size, memname[type], alloc);
479 #endif /* DIAGNOSTIC */
480 	if (size > MAXALLOCSAVE) {
481 		uvm_km_free(kmem_map, (vaddr_t)addr, ctob(kup->ku_pagecnt));
482 #ifdef KMEMSTATS
483 		size = kup->ku_pagecnt << PGSHIFT;
484 		ksp->ks_memuse -= size;
485 		kup->ku_indx = 0;
486 		kup->ku_pagecnt = 0;
487 		if (ksp->ks_memuse + size >= ksp->ks_limit &&
488 		    ksp->ks_memuse < ksp->ks_limit)
489 			wakeup((caddr_t)ksp);
490 		ksp->ks_inuse--;
491 		kbp->kb_total -= 1;
492 #endif
493 		splx(s);
494 		return;
495 	}
496 	freep = (struct freelist *)addr;
497 #ifdef DIAGNOSTIC
498 	/*
499 	 * Check for multiple frees. Use a quick check to see if
500 	 * it looks free before laboriously searching the freelist.
501 	 */
502 	if (__predict_false(freep->spare0 == WEIRD_ADDR)) {
503 		for (cp = kbp->kb_next; cp;
504 		    cp = ((struct freelist *)cp)->next) {
505 			if (addr != cp)
506 				continue;
507 			printf("multiply freed item %p\n", addr);
508 #ifdef MALLOCLOG
509 			hitmlog(addr);
510 #endif
511 			panic("free: duplicated free");
512 		}
513 	}
514 #ifdef LOCKDEBUG
515 	/*
516 	 * Check if we're freeing a locked simple lock.
517 	 */
518 	simple_lock_freecheck(addr, (char *)addr + size);
519 #endif
520 	/*
521 	 * Copy in known text to detect modification after freeing
522 	 * and to make it look free. Also, save the type being freed
523 	 * so we can list likely culprit if modification is detected
524 	 * when the object is reallocated.
525 	 */
526 	copysize = size < MAX_COPY ? size : MAX_COPY;
527 	end = (int32_t *)&((caddr_t)addr)[copysize];
528 	for (lp = (int32_t *)addr; lp < end; lp++)
529 		*lp = WEIRD_ADDR;
530 	freep->type = type;
531 #endif /* DIAGNOSTIC */
532 #ifdef KMEMSTATS
533 	kup->ku_freecnt++;
534 	if (kup->ku_freecnt >= kbp->kb_elmpercl) {
535 		if (kup->ku_freecnt > kbp->kb_elmpercl)
536 			panic("free: multiple frees");
537 		else if (kbp->kb_totalfree > kbp->kb_highwat)
538 			kbp->kb_couldfree++;
539 	}
540 	kbp->kb_totalfree++;
541 	ksp->ks_memuse -= size;
542 	if (ksp->ks_memuse + size >= ksp->ks_limit &&
543 	    ksp->ks_memuse < ksp->ks_limit)
544 		wakeup((caddr_t)ksp);
545 	ksp->ks_inuse--;
546 #endif
547 	if (kbp->kb_next == NULL)
548 		kbp->kb_next = addr;
549 	else
550 		((struct freelist *)kbp->kb_last)->next = addr;
551 	freep->next = NULL;
552 	kbp->kb_last = addr;
553 	splx(s);
554 }
555 
556 /*
557  * Change the size of a block of memory.
558  */
559 void *
560 realloc(curaddr, newsize, type, flags)
561 	void *curaddr;
562 	unsigned long newsize;
563 	int type, flags;
564 {
565 	struct kmemusage *kup;
566 	long cursize;
567 	void *newaddr;
568 #ifdef DIAGNOSTIC
569 	long alloc;
570 #endif
571 
572 	/*
573 	 * Realloc() with a NULL pointer is the same as malloc().
574 	 */
575 	if (curaddr == NULL)
576 		return (malloc(newsize, type, flags));
577 
578 	/*
579 	 * Realloc() with zero size is the same as free().
580 	 */
581 	if (newsize == 0) {
582 		free(curaddr, type);
583 		return (NULL);
584 	}
585 
586 #ifdef LOCKDEBUG
587 	if ((flags & M_NOWAIT) == 0)
588 		simple_lock_only_held(NULL, "realloc");
589 #endif
590 
591 	/*
592 	 * Find out how large the old allocation was (and do some
593 	 * sanity checking).
594 	 */
595 	kup = btokup(curaddr);
596 	cursize = 1 << kup->ku_indx;
597 
598 #ifdef DIAGNOSTIC
599 	/*
600 	 * Check for returns of data that do not point to the
601 	 * beginning of the allocation.
602 	 */
603 	if (cursize > PAGE_SIZE)
604 		alloc = addrmask[BUCKETINDX(PAGE_SIZE)];
605 	else
606 		alloc = addrmask[kup->ku_indx];
607 	if (((u_long)curaddr & alloc) != 0)
608 		panic("realloc: unaligned addr %p, size %ld, type %s, mask %ld\n",
609 			curaddr, cursize, memname[type], alloc);
610 #endif /* DIAGNOSTIC */
611 
612 	if (cursize > MAXALLOCSAVE)
613 		cursize = ctob(kup->ku_pagecnt);
614 
615 	/*
616 	 * If we already actually have as much as they want, we're done.
617 	 */
618 	if (newsize <= cursize)
619 		return (curaddr);
620 
621 	/*
622 	 * Can't satisfy the allocation with the existing block.
623 	 * Allocate a new one and copy the data.
624 	 */
625 	newaddr = malloc(newsize, type, flags);
626 	if (__predict_false(newaddr == NULL)) {
627 		/*
628 		 * Malloc() failed, because flags included M_NOWAIT.
629 		 * Return NULL to indicate that failure.  The old
630 		 * pointer is still valid.
631 		 */
632 		return NULL;
633 	}
634 	memcpy(newaddr, curaddr, cursize);
635 
636 	/*
637 	 * We were successful: free the old allocation and return
638 	 * the new one.
639 	 */
640 	free(curaddr, type);
641 	return (newaddr);
642 }
643 
644 /*
645  * Compute the number of pages that kmem_map will map, that is,
646  * the size of the kernel malloc arena.
647  */
648 void
649 kmeminit_nkmempages()
650 {
651 	int npages;
652 
653 	if (nkmempages != 0) {
654 		/*
655 		 * It's already been set (by us being here before, or
656 		 * by patching or kernel config options), bail out now.
657 		 */
658 		return;
659 	}
660 
661 	/*
662 	 * We use the following (simple) formula:
663 	 *
664 	 *	- Starting point is physical memory / 4.
665 	 *
666 	 *	- Clamp it down to NKMEMPAGES_MAX.
667 	 *
668 	 *	- Round it up to NKMEMPAGES_MIN.
669 	 */
670 	npages = physmem / 4;
671 
672 	if (npages > NKMEMPAGES_MAX)
673 		npages = NKMEMPAGES_MAX;
674 
675 	if (npages < NKMEMPAGES_MIN)
676 		npages = NKMEMPAGES_MIN;
677 
678 	nkmempages = npages;
679 }
680 
681 /*
682  * Initialize the kernel memory allocator
683  */
684 void
685 kmeminit()
686 {
687 #ifdef KMEMSTATS
688 	long indx;
689 #endif
690 
691 #if	((MAXALLOCSAVE & (MAXALLOCSAVE - 1)) != 0)
692 		ERROR!_kmeminit:_MAXALLOCSAVE_not_power_of_2
693 #endif
694 #if	(MAXALLOCSAVE > MINALLOCSIZE * 32768)
695 		ERROR!_kmeminit:_MAXALLOCSAVE_too_big
696 #endif
697 #if	(MAXALLOCSAVE < NBPG)
698 		ERROR!_kmeminit:_MAXALLOCSAVE_too_small
699 #endif
700 
701 	if (sizeof(struct freelist) > (1 << MINBUCKET))
702 		panic("minbucket too small/struct freelist too big");
703 
704 	/*
705 	 * Compute the number of kmem_map pages, if we have not
706 	 * done so already.
707 	 */
708 	kmeminit_nkmempages();
709 
710 	kmemusage = (struct kmemusage *) uvm_km_zalloc(kernel_map,
711 		(vsize_t)(nkmempages * sizeof(struct kmemusage)));
712 	kmem_map = uvm_km_suballoc(kernel_map, (vaddr_t *)&kmembase,
713 		(vaddr_t *)&kmemlimit, (vsize_t)(nkmempages << PAGE_SHIFT),
714 			VM_MAP_INTRSAFE, FALSE, &kmem_map_store);
715 #ifdef KMEMSTATS
716 	for (indx = 0; indx < MINBUCKET + 16; indx++) {
717 		if (1 << indx >= PAGE_SIZE)
718 			bucket[indx].kb_elmpercl = 1;
719 		else
720 			bucket[indx].kb_elmpercl = PAGE_SIZE / (1 << indx);
721 		bucket[indx].kb_highwat = 5 * bucket[indx].kb_elmpercl;
722 	}
723 	for (indx = 0; indx < M_LAST; indx++)
724 		kmemstats[indx].ks_limit =
725 		    ((u_long)nkmempages << PAGE_SHIFT) * 6U / 10U;
726 #endif
727 #ifdef MALLOC_DEBUG
728 	debug_malloc_init();
729 #endif
730 }
731 
732 #ifdef DDB
733 #include <ddb/db_output.h>
734 
735 /*
736  * Dump kmem statistics from ddb.
737  *
738  * usage: call dump_kmemstats
739  */
740 void	dump_kmemstats __P((void));
741 
742 void
743 dump_kmemstats()
744 {
745 #ifdef KMEMSTATS
746 	const char *name;
747 	int i;
748 
749 	for (i = 0; i < M_LAST; i++) {
750 		name = memname[i] ? memname[i] : "";
751 
752 		db_printf("%2d %s%.*s %ld\n", i, name,
753 		    (int)(20 - strlen(name)), "                    ",
754 		    kmemstats[i].ks_memuse);
755 	}
756 #else
757 	db_printf("Kmem stats are not being collected.\n");
758 #endif /* KMEMSTATS */
759 }
760 #endif /* DDB */
761