xref: /openbsd-src/sys/kern/kern_malloc.c (revision 0b7734b3d77bb9b21afec6f4621cae6c805dbd45)
1 /*	$OpenBSD: kern_malloc.c,v 1.128 2015/03/14 03:38:50 jsg Exp $	*/
2 /*	$NetBSD: kern_malloc.c,v 1.15.4.2 1996/06/13 17:10:56 cgd Exp $	*/
3 
4 /*
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. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  *	@(#)kern_malloc.c	8.3 (Berkeley) 1/4/94
33  */
34 
35 #include <sys/param.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/stdint.h>
39 #include <sys/systm.h>
40 #include <sys/sysctl.h>
41 #include <sys/time.h>
42 #include <sys/rwlock.h>
43 
44 #include <uvm/uvm_extern.h>
45 
46 static
47 #ifndef SMALL_KERNEL
48 __inline__
49 #endif
50 long BUCKETINDX(size_t sz)
51 {
52 	long b, d;
53 
54 	/* note that this relies upon MINALLOCSIZE being 1 << MINBUCKET */
55 	b = 7 + MINBUCKET; d = 4;
56 	while (d != 0) {
57 		if (sz <= (1 << b))
58 			b -= d;
59 		else
60 			b += d;
61 		d >>= 1;
62 	}
63 	if (sz <= (1 << b))
64 		b += 0;
65 	else
66 		b += 1;
67 	return b;
68 }
69 
70 static struct vm_map kmem_map_store;
71 struct vm_map *kmem_map = NULL;
72 
73 /*
74  * Default number of pages in kmem_map.  We attempt to calculate this
75  * at run-time, but allow it to be either patched or set in the kernel
76  * config file.
77  */
78 #ifndef NKMEMPAGES
79 #define	NKMEMPAGES	0
80 #endif
81 u_int	nkmempages = NKMEMPAGES;
82 
83 /*
84  * Defaults for lower- and upper-bounds for the kmem_map page count.
85  * Can be overridden by kernel config options.
86  */
87 #ifndef	NKMEMPAGES_MIN
88 #define	NKMEMPAGES_MIN	0
89 #endif
90 u_int	nkmempages_min = 0;
91 
92 #ifndef NKMEMPAGES_MAX
93 #define	NKMEMPAGES_MAX	NKMEMPAGES_MAX_DEFAULT
94 #endif
95 u_int	nkmempages_max = 0;
96 
97 struct kmembuckets bucket[MINBUCKET + 16];
98 #ifdef KMEMSTATS
99 struct kmemstats kmemstats[M_LAST];
100 #endif
101 struct kmemusage *kmemusage;
102 char *kmembase, *kmemlimit;
103 char buckstring[16 * sizeof("123456,")];
104 int buckstring_init = 0;
105 #if defined(KMEMSTATS) || defined(DIAGNOSTIC) || defined(FFS_SOFTUPDATES)
106 char *memname[] = INITKMEMNAMES;
107 char *memall = NULL;
108 struct rwlock sysctl_kmemlock = RWLOCK_INITIALIZER("sysctlklk");
109 #endif
110 
111 /*
112  * Normally the freelist structure is used only to hold the list pointer
113  * for free objects.  However, when running with diagnostics, the first
114  * 8 bytes of the structure is unused except for diagnostic information,
115  * and the free list pointer is at offset 8 in the structure.  Since the
116  * first 8 bytes is the portion of the structure most often modified, this
117  * helps to detect memory reuse problems and avoid free list corruption.
118  */
119 struct kmem_freelist {
120 	int32_t	kf_spare0;
121 	int16_t	kf_type;
122 	int16_t	kf_spare1;
123 	XSIMPLEQ_ENTRY(kmem_freelist) kf_flist;
124 };
125 
126 #ifdef DIAGNOSTIC
127 /*
128  * This structure provides a set of masks to catch unaligned frees.
129  */
130 const long addrmask[] = { 0,
131 	0x00000001, 0x00000003, 0x00000007, 0x0000000f,
132 	0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff,
133 	0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff,
134 	0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff,
135 };
136 
137 #endif /* DIAGNOSTIC */
138 
139 #ifndef SMALL_KERNEL
140 struct timeval malloc_errintvl = { 5, 0 };
141 struct timeval malloc_lasterr;
142 #endif
143 
144 /*
145  * Allocate a block of memory
146  */
147 void *
148 malloc(size_t size, int type, int flags)
149 {
150 	struct kmembuckets *kbp;
151 	struct kmemusage *kup;
152 	struct kmem_freelist *freep;
153 	long indx, npg, allocsize;
154 	int s;
155 	caddr_t va, cp;
156 #ifdef DIAGNOSTIC
157 	int freshalloc;
158 	char *savedtype;
159 #endif
160 #ifdef KMEMSTATS
161 	struct kmemstats *ksp = &kmemstats[type];
162 
163 	if (((unsigned long)type) <= 1 || ((unsigned long)type) >= M_LAST)
164 		panic("malloc: bogus type %d", type);
165 #endif
166 
167 	KASSERT(flags & (M_WAITOK | M_NOWAIT));
168 
169 	if ((flags & M_NOWAIT) == 0) {
170 		extern int pool_debug;
171 #ifdef DIAGNOSTIC
172 		assertwaitok();
173 		if (pool_debug == 2)
174 			yield();
175 #endif
176 		if (!cold && pool_debug) {
177 			KERNEL_UNLOCK();
178 			KERNEL_LOCK();
179 		}
180 	}
181 
182 #ifdef MALLOC_DEBUG
183 	if (debug_malloc(size, type, flags, (void **)&va)) {
184 		if ((flags & M_ZERO) && va != NULL)
185 			memset(va, 0, size);
186 		return (va);
187 	}
188 #endif
189 
190 	if (size > 65535 * PAGE_SIZE) {
191 		if (flags & M_CANFAIL) {
192 #ifndef SMALL_KERNEL
193 			if (ratecheck(&malloc_lasterr, &malloc_errintvl))
194 				printf("malloc(): allocation too large, "
195 				    "type = %d, size = %lu\n", type, size);
196 #endif
197 			return (NULL);
198 		} else
199 			panic("malloc: allocation too large, "
200 			    "type = %d, size = %lu\n", type, size);
201 	}
202 
203 	indx = BUCKETINDX(size);
204 	kbp = &bucket[indx];
205 	s = splvm();
206 #ifdef KMEMSTATS
207 	while (ksp->ks_memuse >= ksp->ks_limit) {
208 		if (flags & M_NOWAIT) {
209 			splx(s);
210 			return (NULL);
211 		}
212 		if (ksp->ks_limblocks < 65535)
213 			ksp->ks_limblocks++;
214 		tsleep(ksp, PSWP+2, memname[type], 0);
215 	}
216 	ksp->ks_size |= 1 << indx;
217 #endif
218 	if (size > MAXALLOCSAVE)
219 		allocsize = round_page(size);
220 	else
221 		allocsize = 1 << indx;
222 	if (XSIMPLEQ_FIRST(&kbp->kb_freelist) == NULL) {
223 		npg = atop(round_page(allocsize));
224 		va = (caddr_t)uvm_km_kmemalloc_pla(kmem_map, NULL,
225 		    (vsize_t)ptoa(npg), 0,
226 		    ((flags & M_NOWAIT) ? UVM_KMF_NOWAIT : 0) |
227 		    ((flags & M_CANFAIL) ? UVM_KMF_CANFAIL : 0),
228 		    no_constraint.ucr_low, no_constraint.ucr_high,
229 		    0, 0, 0);
230 		if (va == NULL) {
231 			/*
232 			 * Kmem_malloc() can return NULL, even if it can
233 			 * wait, if there is no map space available, because
234 			 * it can't fix that problem.  Neither can we,
235 			 * right now.  (We should release pages which
236 			 * are completely free and which are in buckets
237 			 * with too many free elements.)
238 			 */
239 			if ((flags & (M_NOWAIT|M_CANFAIL)) == 0)
240 				panic("malloc: out of space in kmem_map");
241 			splx(s);
242 			return (NULL);
243 		}
244 #ifdef KMEMSTATS
245 		kbp->kb_total += kbp->kb_elmpercl;
246 #endif
247 		kup = btokup(va);
248 		kup->ku_indx = indx;
249 #ifdef DIAGNOSTIC
250 		freshalloc = 1;
251 #endif
252 		if (allocsize > MAXALLOCSAVE) {
253 			kup->ku_pagecnt = npg;
254 #ifdef KMEMSTATS
255 			ksp->ks_memuse += allocsize;
256 #endif
257 			goto out;
258 		}
259 #ifdef KMEMSTATS
260 		kup->ku_freecnt = kbp->kb_elmpercl;
261 		kbp->kb_totalfree += kbp->kb_elmpercl;
262 #endif
263 		cp = va + (npg * PAGE_SIZE) - allocsize;
264 		for (;;) {
265 			freep = (struct kmem_freelist *)cp;
266 #ifdef DIAGNOSTIC
267 			/*
268 			 * Copy in known text to detect modification
269 			 * after freeing.
270 			 */
271 			poison_mem(cp, allocsize);
272 			freep->kf_type = M_FREE;
273 #endif /* DIAGNOSTIC */
274 			XSIMPLEQ_INSERT_HEAD(&kbp->kb_freelist, freep, kf_flist);
275 			if (cp <= va)
276 				break;
277 			cp -= allocsize;
278 		}
279 	} else {
280 #ifdef DIAGNOSTIC
281 		freshalloc = 0;
282 #endif
283 	}
284 	freep = XSIMPLEQ_FIRST(&kbp->kb_freelist);
285 	XSIMPLEQ_REMOVE_HEAD(&kbp->kb_freelist, kf_flist);
286 	va = (caddr_t)freep;
287 #ifdef DIAGNOSTIC
288 	savedtype = (unsigned)freep->kf_type < M_LAST ?
289 		memname[freep->kf_type] : "???";
290 	if (freshalloc == 0 && XSIMPLEQ_FIRST(&kbp->kb_freelist)) {
291 		int rv;
292 		vaddr_t addr = (vaddr_t)XSIMPLEQ_FIRST(&kbp->kb_freelist);
293 
294 		vm_map_lock(kmem_map);
295 		rv = uvm_map_checkprot(kmem_map, addr,
296 		    addr + sizeof(struct kmem_freelist), PROT_WRITE);
297 		vm_map_unlock(kmem_map);
298 
299 		if (!rv)  {
300 			printf("%s %zd of object %p size 0x%lx %s %s"
301 			    " (invalid addr %p)\n",
302 			    "Data modified on freelist: word",
303 			    (int32_t *)&addr - (int32_t *)kbp, va, size,
304 			    "previous type", savedtype, (void *)addr);
305 		}
306 	}
307 
308 	/* Fill the fields that we've used with poison */
309 	poison_mem(freep, sizeof(*freep));
310 
311 	/* and check that the data hasn't been modified. */
312 	if (freshalloc == 0) {
313 		size_t pidx;
314 		uint32_t pval;
315 		if (poison_check(va, allocsize, &pidx, &pval)) {
316 			panic("%s %zd of object %p size 0x%lx %s %s"
317 			    " (0x%x != 0x%x)\n",
318 			    "Data modified on freelist: word",
319 			    pidx, va, size, "previous type",
320 			    savedtype, ((int32_t*)va)[pidx], pval);
321 		}
322 	}
323 
324 	freep->kf_spare0 = 0;
325 #endif /* DIAGNOSTIC */
326 #ifdef KMEMSTATS
327 	kup = btokup(va);
328 	if (kup->ku_indx != indx)
329 		panic("malloc: wrong bucket");
330 	if (kup->ku_freecnt == 0)
331 		panic("malloc: lost data");
332 	kup->ku_freecnt--;
333 	kbp->kb_totalfree--;
334 	ksp->ks_memuse += 1 << indx;
335 out:
336 	kbp->kb_calls++;
337 	ksp->ks_inuse++;
338 	ksp->ks_calls++;
339 	if (ksp->ks_memuse > ksp->ks_maxused)
340 		ksp->ks_maxused = ksp->ks_memuse;
341 #else
342 out:
343 #endif
344 	splx(s);
345 
346 	if ((flags & M_ZERO) && va != NULL)
347 		memset(va, 0, size);
348 	return (va);
349 }
350 
351 /*
352  * Free a block of memory allocated by malloc.
353  */
354 void
355 free(void *addr, int type, size_t freedsize)
356 {
357 	struct kmembuckets *kbp;
358 	struct kmemusage *kup;
359 	struct kmem_freelist *freep;
360 	long size;
361 	int s;
362 #ifdef DIAGNOSTIC
363 	long alloc;
364 #endif
365 #ifdef KMEMSTATS
366 	struct kmemstats *ksp = &kmemstats[type];
367 #endif
368 
369 	if (addr == NULL)
370 		return;
371 
372 #ifdef MALLOC_DEBUG
373 	if (debug_free(addr, type))
374 		return;
375 #endif
376 
377 #ifdef DIAGNOSTIC
378 	if (addr < (void *)kmembase || addr >= (void *)kmemlimit)
379 		panic("free: non-malloced addr %p type %s", addr,
380 		    memname[type]);
381 #endif
382 
383 	kup = btokup(addr);
384 	size = 1 << kup->ku_indx;
385 	kbp = &bucket[kup->ku_indx];
386 	if (size > MAXALLOCSAVE)
387 		size = kup->ku_pagecnt << PAGE_SHIFT;
388 	s = splvm();
389 #ifdef DIAGNOSTIC
390 	if (freedsize != 0 && freedsize > size)
391 		panic("free: size too large %zu > %ld (%p) type %s",
392 		    freedsize, size, addr, memname[type]);
393 	if (freedsize != 0 && size > MINALLOCSIZE && freedsize < size / 2)
394 		panic("free: size too small %zu < %ld / 2 (%p) type %s",
395 		    freedsize, size, addr, memname[type]);
396 	/*
397 	 * Check for returns of data that do not point to the
398 	 * beginning of the allocation.
399 	 */
400 	if (size > PAGE_SIZE)
401 		alloc = addrmask[BUCKETINDX(PAGE_SIZE)];
402 	else
403 		alloc = addrmask[kup->ku_indx];
404 	if (((u_long)addr & alloc) != 0)
405 		panic("free: unaligned addr %p, size %ld, type %s, mask %ld",
406 			addr, size, memname[type], alloc);
407 #endif /* DIAGNOSTIC */
408 	if (size > MAXALLOCSAVE) {
409 		uvm_km_free(kmem_map, (vaddr_t)addr, ptoa(kup->ku_pagecnt));
410 #ifdef KMEMSTATS
411 		ksp->ks_memuse -= size;
412 		kup->ku_indx = 0;
413 		kup->ku_pagecnt = 0;
414 		if (ksp->ks_memuse + size >= ksp->ks_limit &&
415 		    ksp->ks_memuse < ksp->ks_limit)
416 			wakeup(ksp);
417 		ksp->ks_inuse--;
418 		kbp->kb_total -= 1;
419 #endif
420 		splx(s);
421 		return;
422 	}
423 	freep = (struct kmem_freelist *)addr;
424 #ifdef DIAGNOSTIC
425 	/*
426 	 * Check for multiple frees. Use a quick check to see if
427 	 * it looks free before laboriously searching the freelist.
428 	 */
429 	if (freep->kf_spare0 == poison_value(freep)) {
430 		struct kmem_freelist *fp;
431 		XSIMPLEQ_FOREACH(fp, &kbp->kb_freelist, kf_flist) {
432 			if (addr != fp)
433 				continue;
434 			printf("multiply freed item %p\n", addr);
435 			panic("free: duplicated free");
436 		}
437 	}
438 	/*
439 	 * Copy in known text to detect modification after freeing
440 	 * and to make it look free. Also, save the type being freed
441 	 * so we can list likely culprit if modification is detected
442 	 * when the object is reallocated.
443 	 */
444 	poison_mem(addr, size);
445 	freep->kf_spare0 = poison_value(freep);
446 
447 	freep->kf_type = type;
448 #endif /* DIAGNOSTIC */
449 #ifdef KMEMSTATS
450 	kup->ku_freecnt++;
451 	if (kup->ku_freecnt >= kbp->kb_elmpercl) {
452 		if (kup->ku_freecnt > kbp->kb_elmpercl)
453 			panic("free: multiple frees");
454 		else if (kbp->kb_totalfree > kbp->kb_highwat)
455 			kbp->kb_couldfree++;
456 	}
457 	kbp->kb_totalfree++;
458 	ksp->ks_memuse -= size;
459 	if (ksp->ks_memuse + size >= ksp->ks_limit &&
460 	    ksp->ks_memuse < ksp->ks_limit)
461 		wakeup(ksp);
462 	ksp->ks_inuse--;
463 #endif
464 	XSIMPLEQ_INSERT_TAIL(&kbp->kb_freelist, freep, kf_flist);
465 	splx(s);
466 }
467 
468 /*
469  * Compute the number of pages that kmem_map will map, that is,
470  * the size of the kernel malloc arena.
471  */
472 void
473 kmeminit_nkmempages(void)
474 {
475 	u_int npages;
476 
477 	if (nkmempages != 0) {
478 		/*
479 		 * It's already been set (by us being here before, or
480 		 * by patching or kernel config options), bail out now.
481 		 */
482 		return;
483 	}
484 
485 	/*
486 	 * We can't initialize these variables at compilation time, since
487 	 * the page size may not be known (on sparc GENERIC kernels, for
488 	 * example). But we still want the MD code to be able to provide
489 	 * better values.
490 	 */
491 	if (nkmempages_min == 0)
492 		nkmempages_min = NKMEMPAGES_MIN;
493 	if (nkmempages_max == 0)
494 		nkmempages_max = NKMEMPAGES_MAX;
495 
496 	/*
497 	 * We use the following (simple) formula:
498 	 *
499 	 *	- Starting point is physical memory / 4.
500 	 *
501 	 *	- Clamp it down to nkmempages_max.
502 	 *
503 	 *	- Round it up to nkmempages_min.
504 	 */
505 	npages = physmem / 4;
506 
507 	if (npages > nkmempages_max)
508 		npages = nkmempages_max;
509 
510 	if (npages < nkmempages_min)
511 		npages = nkmempages_min;
512 
513 	nkmempages = npages;
514 }
515 
516 /*
517  * Initialize the kernel memory allocator
518  */
519 void
520 kmeminit(void)
521 {
522 	vaddr_t base, limit;
523 	long indx;
524 
525 #ifdef DIAGNOSTIC
526 	if (sizeof(struct kmem_freelist) > (1 << MINBUCKET))
527 		panic("kmeminit: minbucket too small/struct freelist too big");
528 #endif
529 
530 	/*
531 	 * Compute the number of kmem_map pages, if we have not
532 	 * done so already.
533 	 */
534 	kmeminit_nkmempages();
535 	base = vm_map_min(kernel_map);
536 	kmem_map = uvm_km_suballoc(kernel_map, &base, &limit,
537 	    (vsize_t)nkmempages << PAGE_SHIFT,
538 #ifdef KVA_GUARDPAGES
539 	    VM_MAP_INTRSAFE | VM_MAP_GUARDPAGES,
540 #else
541 	    VM_MAP_INTRSAFE,
542 #endif
543 	    FALSE, &kmem_map_store);
544 	kmembase = (char *)base;
545 	kmemlimit = (char *)limit;
546 	kmemusage = (struct kmemusage *) uvm_km_zalloc(kernel_map,
547 		(vsize_t)(nkmempages * sizeof(struct kmemusage)));
548 	for (indx = 0; indx < MINBUCKET + 16; indx++) {
549 		XSIMPLEQ_INIT(&bucket[indx].kb_freelist);
550 	}
551 #ifdef KMEMSTATS
552 	for (indx = 0; indx < MINBUCKET + 16; indx++) {
553 		if (1 << indx >= PAGE_SIZE)
554 			bucket[indx].kb_elmpercl = 1;
555 		else
556 			bucket[indx].kb_elmpercl = PAGE_SIZE / (1 << indx);
557 		bucket[indx].kb_highwat = 5 * bucket[indx].kb_elmpercl;
558 	}
559 	for (indx = 0; indx < M_LAST; indx++)
560 		kmemstats[indx].ks_limit = nkmempages * PAGE_SIZE * 6 / 10;
561 #endif
562 #ifdef MALLOC_DEBUG
563 	debug_malloc_init();
564 #endif
565 }
566 
567 /*
568  * Return kernel malloc statistics information.
569  */
570 int
571 sysctl_malloc(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
572     size_t newlen, struct proc *p)
573 {
574 	struct kmembuckets kb;
575 #if defined(KMEMSTATS) || defined(DIAGNOSTIC) || defined(FFS_SOFTUPDATES)
576 	int error;
577 #endif
578 	int i, siz;
579 
580 	if (namelen != 2 && name[0] != KERN_MALLOC_BUCKETS &&
581 	    name[0] != KERN_MALLOC_KMEMNAMES)
582 		return (ENOTDIR);		/* overloaded */
583 
584 	switch (name[0]) {
585 	case KERN_MALLOC_BUCKETS:
586 		/* Initialize the first time */
587 		if (buckstring_init == 0) {
588 			buckstring_init = 1;
589 			memset(buckstring, 0, sizeof(buckstring));
590 			for (siz = 0, i = MINBUCKET; i < MINBUCKET + 16; i++) {
591 				snprintf(buckstring + siz,
592 				    sizeof buckstring - siz,
593 				    "%d,", (u_int)(1<<i));
594 				siz += strlen(buckstring + siz);
595 			}
596 			/* Remove trailing comma */
597 			if (siz)
598 				buckstring[siz - 1] = '\0';
599 		}
600 		return (sysctl_rdstring(oldp, oldlenp, newp, buckstring));
601 
602 	case KERN_MALLOC_BUCKET:
603 		memcpy(&kb, &bucket[BUCKETINDX(name[1])], sizeof(kb));
604 		memset(&kb.kb_freelist, 0, sizeof(kb.kb_freelist));
605 		return (sysctl_rdstruct(oldp, oldlenp, newp, &kb, sizeof(kb)));
606 	case KERN_MALLOC_KMEMSTATS:
607 #ifdef KMEMSTATS
608 		if ((name[1] < 0) || (name[1] >= M_LAST))
609 			return (EINVAL);
610 		return (sysctl_rdstruct(oldp, oldlenp, newp,
611 		    &kmemstats[name[1]], sizeof(struct kmemstats)));
612 #else
613 		return (EOPNOTSUPP);
614 #endif
615 	case KERN_MALLOC_KMEMNAMES:
616 #if defined(KMEMSTATS) || defined(DIAGNOSTIC) || defined(FFS_SOFTUPDATES)
617 		error = rw_enter(&sysctl_kmemlock, RW_WRITE|RW_INTR);
618 		if (error)
619 			return (error);
620 		if (memall == NULL) {
621 			int totlen;
622 
623 			/* Figure out how large a buffer we need */
624 			for (totlen = 0, i = 0; i < M_LAST; i++) {
625 				if (memname[i])
626 					totlen += strlen(memname[i]);
627 				totlen++;
628 			}
629 			memall = malloc(totlen + M_LAST, M_SYSCTL,
630 			    M_WAITOK|M_ZERO);
631 			for (siz = 0, i = 0; i < M_LAST; i++) {
632 				snprintf(memall + siz,
633 				    totlen + M_LAST - siz,
634 				    "%s,", memname[i] ? memname[i] : "");
635 				siz += strlen(memall + siz);
636 			}
637 			/* Remove trailing comma */
638 			if (siz)
639 				memall[siz - 1] = '\0';
640 
641 			/* Now, convert all spaces to underscores */
642 			for (i = 0; i < totlen; i++)
643 				if (memall[i] == ' ')
644 					memall[i] = '_';
645 		}
646 		rw_exit_write(&sysctl_kmemlock);
647 		return (sysctl_rdstring(oldp, oldlenp, newp, memall));
648 #else
649 		return (EOPNOTSUPP);
650 #endif
651 	default:
652 		return (EOPNOTSUPP);
653 	}
654 	/* NOTREACHED */
655 }
656 
657 /*
658  * Round up a size to how much malloc would actually allocate.
659  */
660 size_t
661 malloc_roundup(size_t sz)
662 {
663 	if (sz > MAXALLOCSAVE)
664 		return round_page(sz);
665 
666 	return (1 << BUCKETINDX(sz));
667 }
668 
669 #if defined(DDB)
670 #include <machine/db_machdep.h>
671 #include <ddb/db_output.h>
672 
673 void
674 malloc_printit(
675     int (*pr)(const char *, ...) __attribute__((__format__(__kprintf__,1,2))))
676 {
677 #ifdef KMEMSTATS
678 	struct kmemstats *km;
679 	int i;
680 
681 	(*pr)("%15s %5s  %6s  %7s  %6s %9s %8s %8s\n",
682 	    "Type", "InUse", "MemUse", "HighUse", "Limit", "Requests",
683 	    "Type Lim", "Kern Lim");
684 	for (i = 0, km = kmemstats; i < M_LAST; i++, km++) {
685 		if (!km->ks_calls || !memname[i])
686 			continue;
687 
688 		(*pr)("%15s %5ld %6ldK %7ldK %6ldK %9ld %8d %8d\n",
689 		    memname[i], km->ks_inuse, km->ks_memuse / 1024,
690 		    km->ks_maxused / 1024, km->ks_limit / 1024,
691 		    km->ks_calls, km->ks_limblocks, km->ks_mapblocks);
692 	}
693 #else
694 	(*pr)("No KMEMSTATS compiled in\n");
695 #endif
696 }
697 #endif /* DDB */
698 
699 /*
700  * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
701  *
702  * Permission to use, copy, modify, and distribute this software for any
703  * purpose with or without fee is hereby granted, provided that the above
704  * copyright notice and this permission notice appear in all copies.
705  *
706  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
707  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
708  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
709  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
710  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
711  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
712  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
713  */
714 
715 /*
716  * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
717  * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
718  */
719 #define MUL_NO_OVERFLOW	(1UL << (sizeof(size_t) * 4))
720 
721 void *
722 mallocarray(size_t nmemb, size_t size, int type, int flags)
723 {
724 	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
725 	    nmemb > 0 && SIZE_MAX / nmemb < size) {
726 		if (flags & M_CANFAIL)
727 			return (NULL);
728 		panic("mallocarray: overflow %zu * %zu", nmemb, size);
729 	}
730 	return (malloc(size * nmemb, type, flags));
731 }
732