xref: /openbsd/sys/kern/kern_malloc.c (revision da5607f6)
1 /*	$OpenBSD: kern_malloc.c,v 1.152 2024/06/26 01:40:49 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/malloc.h>
37 #include <sys/proc.h>
38 #include <sys/stdint.h>
39 #include <sys/systm.h>
40 #include <sys/sysctl.h>
41 #include <sys/time.h>
42 #include <sys/mutex.h>
43 #include <sys/rwlock.h>
44 #include <sys/tracepoint.h>
45 
46 #include <uvm/uvm_extern.h>
47 
48 #if defined(DDB)
49 #include <machine/db_machdep.h>
50 #include <ddb/db_output.h>
51 #endif
52 
53 static
54 #ifndef SMALL_KERNEL
55 __inline__
56 #endif
57 long
BUCKETINDX(size_t sz)58 BUCKETINDX(size_t sz)
59 {
60 	long b, d;
61 
62 	/* note that this relies upon MINALLOCSIZE being 1 << MINBUCKET */
63 	b = 7 + MINBUCKET; d = 4;
64 	while (d != 0) {
65 		if (sz <= (1 << b))
66 			b -= d;
67 		else
68 			b += d;
69 		d >>= 1;
70 	}
71 	if (sz <= (1 << b))
72 		b += 0;
73 	else
74 		b += 1;
75 	return b;
76 }
77 
78 static struct vm_map kmem_map_store;
79 struct vm_map *kmem_map = NULL;
80 
81 /*
82  * Default number of pages in kmem_map.  We attempt to calculate this
83  * at run-time, but allow it to be either patched or set in the kernel
84  * config file.
85  */
86 #ifndef NKMEMPAGES
87 #define	NKMEMPAGES	-1
88 #endif
89 u_int	nkmempages = NKMEMPAGES;
90 
91 struct mutex malloc_mtx = MUTEX_INITIALIZER(IPL_VM);
92 struct kmembuckets bucket[MINBUCKET + 16];
93 #ifdef KMEMSTATS
94 struct kmemstats kmemstats[M_LAST];
95 #endif
96 struct kmemusage *kmemusage;
97 char *kmembase, *kmemlimit;
98 char buckstring[16 * sizeof("123456,")];
99 int buckstring_init = 0;
100 #if defined(KMEMSTATS) || defined(DIAGNOSTIC)
101 char *memname[] = INITKMEMNAMES;
102 char *memall = NULL;
103 struct rwlock sysctl_kmemlock = RWLOCK_INITIALIZER("sysctlklk");
104 #endif
105 
106 /*
107  * Normally the freelist structure is used only to hold the list pointer
108  * for free objects.  However, when running with diagnostics, the first
109  * 8 bytes of the structure is unused except for diagnostic information,
110  * and the free list pointer is at offset 8 in the structure.  Since the
111  * first 8 bytes is the portion of the structure most often modified, this
112  * helps to detect memory reuse problems and avoid free list corruption.
113  */
114 struct kmem_freelist {
115 	int32_t	kf_spare0;
116 	int16_t	kf_type;
117 	int16_t	kf_spare1;
118 	XSIMPLEQ_ENTRY(kmem_freelist) kf_flist;
119 };
120 
121 #ifdef DIAGNOSTIC
122 /*
123  * This structure provides a set of masks to catch unaligned frees.
124  */
125 const long addrmask[] = { 0,
126 	0x00000001, 0x00000003, 0x00000007, 0x0000000f,
127 	0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff,
128 	0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff,
129 	0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff,
130 };
131 
132 #endif /* DIAGNOSTIC */
133 
134 #ifndef SMALL_KERNEL
135 struct timeval malloc_errintvl = { 5, 0 };
136 struct timeval malloc_lasterr;
137 #endif
138 
139 /*
140  * Allocate a block of memory
141  */
142 void *
malloc(size_t size,int type,int flags)143 malloc(size_t size, int type, int flags)
144 {
145 	struct kmembuckets *kbp;
146 	struct kmemusage *kup;
147 	struct kmem_freelist *freep;
148 	long indx, npg, allocsize;
149 	caddr_t va, cp;
150 	int s;
151 #ifdef DIAGNOSTIC
152 	int freshalloc;
153 	char *savedtype;
154 #endif
155 #ifdef KMEMSTATS
156 	struct kmemstats *ksp = &kmemstats[type];
157 	int wake;
158 
159 	if (((unsigned long)type) <= 1 || ((unsigned long)type) >= M_LAST)
160 		panic("malloc: bogus type %d", type);
161 #endif
162 
163 	KASSERT(flags & (M_WAITOK | M_NOWAIT));
164 
165 #ifdef DIAGNOSTIC
166 	if ((flags & M_NOWAIT) == 0) {
167 		extern int pool_debug;
168 		assertwaitok();
169 		if (pool_debug == 2)
170 			yield();
171 	}
172 #endif
173 
174 	if (size > 65535 * PAGE_SIZE) {
175 		if (flags & M_CANFAIL) {
176 #ifndef SMALL_KERNEL
177 			if (ratecheck(&malloc_lasterr, &malloc_errintvl))
178 				printf("malloc(): allocation too large, "
179 				    "type = %d, size = %lu\n", type, size);
180 #endif
181 			return (NULL);
182 		} else
183 			panic("malloc: allocation too large, "
184 			    "type = %d, size = %lu", type, size);
185 	}
186 
187 	indx = BUCKETINDX(size);
188 	if (size > MAXALLOCSAVE)
189 		allocsize = round_page(size);
190 	else
191 		allocsize = 1 << indx;
192 	kbp = &bucket[indx];
193 	mtx_enter(&malloc_mtx);
194 #ifdef KMEMSTATS
195 	while (ksp->ks_memuse >= ksp->ks_limit) {
196 		if (flags & M_NOWAIT) {
197 			mtx_leave(&malloc_mtx);
198 			return (NULL);
199 		}
200 #ifdef DIAGNOSTIC
201 		if (ISSET(flags, M_WAITOK) && curproc == &proc0)
202 			panic("%s: cannot sleep for memory during boot",
203 			    __func__);
204 #endif
205 		if (ksp->ks_limblocks < 65535)
206 			ksp->ks_limblocks++;
207 		msleep_nsec(ksp, &malloc_mtx, PSWP+2, memname[type], INFSLP);
208 	}
209 	ksp->ks_memuse += allocsize; /* account for this early */
210 	ksp->ks_size |= 1 << indx;
211 #endif
212 	if (XSIMPLEQ_FIRST(&kbp->kb_freelist) == NULL) {
213 		mtx_leave(&malloc_mtx);
214 		npg = atop(round_page(allocsize));
215 		s = splvm();
216 		va = (caddr_t)uvm_km_kmemalloc_pla(kmem_map, NULL,
217 		    (vsize_t)ptoa(npg), 0,
218 		    ((flags & M_NOWAIT) ? UVM_KMF_NOWAIT : 0) |
219 		    ((flags & M_CANFAIL) ? UVM_KMF_CANFAIL : 0),
220 		    no_constraint.ucr_low, no_constraint.ucr_high,
221 		    0, 0, 0);
222 		splx(s);
223 		if (va == NULL) {
224 			/*
225 			 * Kmem_malloc() can return NULL, even if it can
226 			 * wait, if there is no map space available, because
227 			 * it can't fix that problem.  Neither can we,
228 			 * right now.  (We should release pages which
229 			 * are completely free and which are in buckets
230 			 * with too many free elements.)
231 			 */
232 			if ((flags & (M_NOWAIT|M_CANFAIL)) == 0)
233 				panic("malloc: out of space in kmem_map");
234 
235 #ifdef KMEMSTATS
236 			mtx_enter(&malloc_mtx);
237 			ksp->ks_memuse -= allocsize;
238 			wake = ksp->ks_memuse + allocsize >= ksp->ks_limit &&
239 			    ksp->ks_memuse < ksp->ks_limit;
240 			mtx_leave(&malloc_mtx);
241 			if (wake)
242 				wakeup(ksp);
243 #endif
244 			return (NULL);
245 		}
246 		mtx_enter(&malloc_mtx);
247 #ifdef KMEMSTATS
248 		kbp->kb_total += kbp->kb_elmpercl;
249 #endif
250 		kup = btokup(va);
251 		kup->ku_indx = indx;
252 #ifdef DIAGNOSTIC
253 		freshalloc = 1;
254 #endif
255 		if (allocsize > MAXALLOCSAVE) {
256 			kup->ku_pagecnt = npg;
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,
275 			    kf_flist);
276 			if (cp <= va)
277 				break;
278 			cp -= allocsize;
279 		}
280 	} else {
281 #ifdef DIAGNOSTIC
282 		freshalloc = 0;
283 #endif
284 	}
285 	freep = XSIMPLEQ_FIRST(&kbp->kb_freelist);
286 	XSIMPLEQ_REMOVE_HEAD(&kbp->kb_freelist, kf_flist);
287 	va = (caddr_t)freep;
288 #ifdef DIAGNOSTIC
289 	savedtype = (unsigned)freep->kf_type < M_LAST ?
290 		memname[freep->kf_type] : "???";
291 	if (freshalloc == 0 && XSIMPLEQ_FIRST(&kbp->kb_freelist)) {
292 		int rv;
293 		vaddr_t addr = (vaddr_t)XSIMPLEQ_FIRST(&kbp->kb_freelist);
294 
295 		vm_map_lock(kmem_map);
296 		rv = uvm_map_checkprot(kmem_map, addr,
297 		    addr + sizeof(struct kmem_freelist), PROT_WRITE);
298 		vm_map_unlock(kmem_map);
299 
300 		if (!rv)  {
301 			printf("%s %zd of object %p size 0x%lx %s %s"
302 			    " (invalid addr %p)\n",
303 			    "Data modified on freelist: word",
304 			    (int32_t *)&addr - (int32_t *)kbp, va, size,
305 			    "previous type", savedtype, (void *)addr);
306 		}
307 	}
308 
309 	/* Fill the fields that we've used with poison */
310 	poison_mem(freep, sizeof(*freep));
311 
312 	/* and check that the data hasn't been modified. */
313 	if (freshalloc == 0) {
314 		size_t pidx;
315 		uint32_t pval;
316 		if (poison_check(va, allocsize, &pidx, &pval)) {
317 			panic("%s %zd of object %p size 0x%lx %s %s"
318 			    " (0x%x != 0x%x)\n",
319 			    "Data modified on freelist: word",
320 			    pidx, va, size, "previous type",
321 			    savedtype, ((int32_t*)va)[pidx], pval);
322 		}
323 	}
324 
325 	freep->kf_spare0 = 0;
326 #endif /* DIAGNOSTIC */
327 #ifdef KMEMSTATS
328 	kup = btokup(va);
329 	if (kup->ku_indx != indx)
330 		panic("malloc: wrong bucket");
331 	if (kup->ku_freecnt == 0)
332 		panic("malloc: lost data");
333 	kup->ku_freecnt--;
334 	kbp->kb_totalfree--;
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 	mtx_leave(&malloc_mtx);
345 
346 	if ((flags & M_ZERO) && va != NULL)
347 		memset(va, 0, size);
348 
349 	TRACEPOINT(uvm, malloc, type, va, size, flags);
350 
351 	return (va);
352 }
353 
354 /*
355  * Free a block of memory allocated by malloc.
356  */
357 void
free(void * addr,int type,size_t freedsize)358 free(void *addr, int type, size_t freedsize)
359 {
360 	struct kmembuckets *kbp;
361 	struct kmemusage *kup;
362 	struct kmem_freelist *freep;
363 	long size;
364 	int s;
365 #ifdef DIAGNOSTIC
366 	long alloc;
367 #endif
368 #ifdef KMEMSTATS
369 	struct kmemstats *ksp = &kmemstats[type];
370 	int wake;
371 #endif
372 
373 	if (addr == NULL)
374 		return;
375 
376 #ifdef DIAGNOSTIC
377 	if (addr < (void *)kmembase || addr >= (void *)kmemlimit)
378 		panic("free: non-malloced addr %p type %s", addr,
379 		    memname[type]);
380 #endif
381 
382 	TRACEPOINT(uvm, free, type, addr, freedsize);
383 
384 	mtx_enter(&malloc_mtx);
385 	kup = btokup(addr);
386 	size = 1 << kup->ku_indx;
387 	kbp = &bucket[kup->ku_indx];
388 	if (size > MAXALLOCSAVE)
389 		size = kup->ku_pagecnt << PAGE_SHIFT;
390 #ifdef DIAGNOSTIC
391 #if 0
392 	if (freedsize == 0) {
393 		static int zerowarnings;
394 		if (zerowarnings < 5) {
395 			zerowarnings++;
396 			printf("free with zero size: (%d)\n", type);
397 #ifdef DDB
398 			db_stack_dump();
399 #endif
400 	}
401 #endif
402 	if (freedsize != 0 && freedsize > size)
403 		panic("free: size too large %zu > %ld (%p) type %s",
404 		    freedsize, size, addr, memname[type]);
405 	if (freedsize != 0 && size > MINALLOCSIZE && freedsize <= size / 2)
406 		panic("free: size too small %zu <= %ld / 2 (%p) type %s",
407 		    freedsize, size, addr, memname[type]);
408 	/*
409 	 * Check for returns of data that do not point to the
410 	 * beginning of the allocation.
411 	 */
412 	if (size > PAGE_SIZE)
413 		alloc = addrmask[BUCKETINDX(PAGE_SIZE)];
414 	else
415 		alloc = addrmask[kup->ku_indx];
416 	if (((u_long)addr & alloc) != 0)
417 		panic("free: unaligned addr %p, size %ld, type %s, mask %ld",
418 			addr, size, memname[type], alloc);
419 #endif /* DIAGNOSTIC */
420 	if (size > MAXALLOCSAVE) {
421 		u_short pagecnt = kup->ku_pagecnt;
422 
423 		kup->ku_indx = 0;
424 		kup->ku_pagecnt = 0;
425 		mtx_leave(&malloc_mtx);
426 		s = splvm();
427 		uvm_km_free(kmem_map, (vaddr_t)addr, ptoa(pagecnt));
428 		splx(s);
429 #ifdef KMEMSTATS
430 		mtx_enter(&malloc_mtx);
431 		ksp->ks_memuse -= size;
432 		wake = ksp->ks_memuse + size >= ksp->ks_limit &&
433 		    ksp->ks_memuse < ksp->ks_limit;
434 		ksp->ks_inuse--;
435 		kbp->kb_total -= 1;
436 		mtx_leave(&malloc_mtx);
437 		if (wake)
438 			wakeup(ksp);
439 #endif
440 		return;
441 	}
442 	freep = (struct kmem_freelist *)addr;
443 #ifdef DIAGNOSTIC
444 	/*
445 	 * Check for multiple frees. Use a quick check to see if
446 	 * it looks free before laboriously searching the freelist.
447 	 */
448 	if (freep->kf_spare0 == poison_value(freep)) {
449 		struct kmem_freelist *fp;
450 		XSIMPLEQ_FOREACH(fp, &kbp->kb_freelist, kf_flist) {
451 			if (addr != fp)
452 				continue;
453 			printf("multiply freed item %p\n", addr);
454 			panic("free: duplicated free");
455 		}
456 	}
457 	/*
458 	 * Copy in known text to detect modification after freeing
459 	 * and to make it look free. Also, save the type being freed
460 	 * so we can list likely culprit if modification is detected
461 	 * when the object is reallocated.
462 	 */
463 	poison_mem(addr, size);
464 	freep->kf_spare0 = poison_value(freep);
465 
466 	freep->kf_type = type;
467 #endif /* DIAGNOSTIC */
468 #ifdef KMEMSTATS
469 	kup->ku_freecnt++;
470 	if (kup->ku_freecnt >= kbp->kb_elmpercl) {
471 		if (kup->ku_freecnt > kbp->kb_elmpercl)
472 			panic("free: multiple frees");
473 		else if (kbp->kb_totalfree > kbp->kb_highwat)
474 			kbp->kb_couldfree++;
475 	}
476 	kbp->kb_totalfree++;
477 	ksp->ks_memuse -= size;
478 	wake = ksp->ks_memuse + size >= ksp->ks_limit &&
479 	    ksp->ks_memuse < ksp->ks_limit;
480 	ksp->ks_inuse--;
481 #endif
482 	XSIMPLEQ_INSERT_TAIL(&kbp->kb_freelist, freep, kf_flist);
483 	mtx_leave(&malloc_mtx);
484 #ifdef KMEMSTATS
485 	if (wake)
486 		wakeup(ksp);
487 #endif
488 }
489 
490 /*
491  * Compute the number of pages that kmem_map will map, that is,
492  * the size of the kernel malloc arena.
493  */
494 void
495 kmeminit_nkmempages(void)
496 {
497 	u_int npages;
498 
499 	if (nkmempages != -1) {
500 		/*
501 		 * It's already been set (by us being here before, or
502 		 * by patching or kernel config options), bail out now.
503 		 */
504 		return;
505 	}
506 
507 	/*
508 	 * We use the following (simple) formula:
509 	 *
510 	 * Up to 1G physmem use physical memory / 4,
511 	 * above 1G add an extra 16MB per 1G of memory.
512 	 *
513 	 * Clamp it down depending on VM_KERNEL_SPACE_SIZE
514 	 * - up and including 512M -> 64MB
515 	 * - between 512M and 1024M -> 128MB
516 	 * - over 1024M clamping to VM_KERNEL_SPACE_SIZE / 4
517 	 */
518 	npages = MIN(physmem, atop(1024 * 1024 * 1024)) / 4;
519 	if (physmem > atop(1024 * 1024 * 1024))
520 		npages += (physmem - atop(1024 * 1024 * 1024)) / 64;
521 
522 	if (VM_KERNEL_SPACE_SIZE <= 512 * 1024 * 1024) {
523 		if (npages > atop(64 * 1024 * 1024))
524 			npages = atop(64 * 1024 * 1024);
525 	} else if (VM_KERNEL_SPACE_SIZE <= 1024 * 1024 * 1024) {
526 		if (npages > atop(128 * 1024 * 1024))
527 			npages = atop(128 * 1024 * 1024);
528 	} else if (npages > atop(VM_KERNEL_SPACE_SIZE) / 4)
529 		npages = atop(VM_KERNEL_SPACE_SIZE) / 4;
530 
531 	nkmempages = npages;
532 }
533 
534 /*
535  * Initialize the kernel memory allocator
536  */
537 void
538 kmeminit(void)
539 {
540 	vaddr_t base, limit;
541 	long indx;
542 
543 #ifdef DIAGNOSTIC
544 	if (sizeof(struct kmem_freelist) > (1 << MINBUCKET))
545 		panic("kmeminit: minbucket too small/struct freelist too big");
546 #endif
547 
548 	/*
549 	 * Compute the number of kmem_map pages, if we have not
550 	 * done so already.
551 	 */
552 	kmeminit_nkmempages();
553 	base = vm_map_min(kernel_map);
554 	kmem_map = uvm_km_suballoc(kernel_map, &base, &limit,
555 	    (vsize_t)nkmempages << PAGE_SHIFT,
556 #ifdef KVA_GUARDPAGES
557 	    VM_MAP_INTRSAFE | VM_MAP_GUARDPAGES,
558 #else
559 	    VM_MAP_INTRSAFE,
560 #endif
561 	    FALSE, &kmem_map_store);
562 	kmembase = (char *)base;
563 	kmemlimit = (char *)limit;
564 	kmemusage = km_alloc(round_page(nkmempages * sizeof(struct kmemusage)),
565 	    &kv_any, &kp_zero, &kd_waitok);
566 	for (indx = 0; indx < MINBUCKET + 16; indx++) {
567 		XSIMPLEQ_INIT(&bucket[indx].kb_freelist);
568 	}
569 #ifdef KMEMSTATS
570 	for (indx = 0; indx < MINBUCKET + 16; indx++) {
571 		if (1 << indx >= PAGE_SIZE)
572 			bucket[indx].kb_elmpercl = 1;
573 		else
574 			bucket[indx].kb_elmpercl = PAGE_SIZE / (1 << indx);
575 		bucket[indx].kb_highwat = 5 * bucket[indx].kb_elmpercl;
576 	}
577 	for (indx = 0; indx < M_LAST; indx++)
578 		kmemstats[indx].ks_limit =
579 		    (long)nkmempages * PAGE_SIZE * 6 / 10;
580 #endif
581 }
582 
583 /*
584  * Return kernel malloc statistics information.
585  */
586 int
587 sysctl_malloc(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
588     size_t newlen, struct proc *p)
589 {
590 	struct kmembuckets kb;
591 #ifdef KMEMSTATS
592 	struct kmemstats km;
593 #endif
594 #if defined(KMEMSTATS) || defined(DIAGNOSTIC)
595 	int error;
596 #endif
597 	int i, siz;
598 
599 	if (namelen != 2 && name[0] != KERN_MALLOC_BUCKETS &&
600 	    name[0] != KERN_MALLOC_KMEMNAMES)
601 		return (ENOTDIR);		/* overloaded */
602 
603 	switch (name[0]) {
604 	case KERN_MALLOC_BUCKETS:
605 		/* Initialize the first time */
606 		if (buckstring_init == 0) {
607 			buckstring_init = 1;
608 			memset(buckstring, 0, sizeof(buckstring));
609 			for (siz = 0, i = MINBUCKET; i < MINBUCKET + 16; i++) {
610 				snprintf(buckstring + siz,
611 				    sizeof buckstring - siz,
612 				    "%d,", (u_int)(1<<i));
613 				siz += strlen(buckstring + siz);
614 			}
615 			/* Remove trailing comma */
616 			if (siz)
617 				buckstring[siz - 1] = '\0';
618 		}
619 		return (sysctl_rdstring(oldp, oldlenp, newp, buckstring));
620 
621 	case KERN_MALLOC_BUCKET:
622 		mtx_enter(&malloc_mtx);
623 		memcpy(&kb, &bucket[BUCKETINDX(name[1])], sizeof(kb));
624 		mtx_leave(&malloc_mtx);
625 		memset(&kb.kb_freelist, 0, sizeof(kb.kb_freelist));
626 		return (sysctl_rdstruct(oldp, oldlenp, newp, &kb, sizeof(kb)));
627 	case KERN_MALLOC_KMEMSTATS:
628 #ifdef KMEMSTATS
629 		if ((name[1] < 0) || (name[1] >= M_LAST))
630 			return (EINVAL);
631 		mtx_enter(&malloc_mtx);
632 		memcpy(&km, &kmemstats[name[1]], sizeof(km));
633 		mtx_leave(&malloc_mtx);
634 		return (sysctl_rdstruct(oldp, oldlenp, newp, &km, sizeof(km)));
635 #else
636 		return (EOPNOTSUPP);
637 #endif
638 	case KERN_MALLOC_KMEMNAMES:
639 #if defined(KMEMSTATS) || defined(DIAGNOSTIC)
640 		error = rw_enter(&sysctl_kmemlock, RW_WRITE|RW_INTR);
641 		if (error)
642 			return (error);
643 		if (memall == NULL) {
644 			int totlen;
645 
646 			/* Figure out how large a buffer we need */
647 			for (totlen = 0, i = 0; i < M_LAST; i++) {
648 				if (memname[i])
649 					totlen += strlen(memname[i]);
650 				totlen++;
651 			}
652 			memall = malloc(totlen + M_LAST, M_SYSCTL,
653 			    M_WAITOK|M_ZERO);
654 			for (siz = 0, i = 0; i < M_LAST; i++) {
655 				snprintf(memall + siz,
656 				    totlen + M_LAST - siz,
657 				    "%s,", memname[i] ? memname[i] : "");
658 				siz += strlen(memall + siz);
659 			}
660 			/* Remove trailing comma */
661 			if (siz)
662 				memall[siz - 1] = '\0';
663 
664 			/* Now, convert all spaces to underscores */
665 			for (i = 0; i < totlen; i++)
666 				if (memall[i] == ' ')
667 					memall[i] = '_';
668 		}
669 		rw_exit_write(&sysctl_kmemlock);
670 		return (sysctl_rdstring(oldp, oldlenp, newp, memall));
671 #else
672 		return (EOPNOTSUPP);
673 #endif
674 	default:
675 		return (EOPNOTSUPP);
676 	}
677 	/* NOTREACHED */
678 }
679 
680 #if defined(DDB)
681 
682 void
683 malloc_printit(
684     int (*pr)(const char *, ...) __attribute__((__format__(__kprintf__,1,2))))
685 {
686 #ifdef KMEMSTATS
687 	struct kmemstats *km;
688 	int i;
689 
690 	(*pr)("%15s %5s  %6s  %7s  %6s %9s %8s\n",
691 	    "Type", "InUse", "MemUse", "HighUse", "Limit", "Requests",
692 	    "Type Lim");
693 	for (i = 0, km = kmemstats; i < M_LAST; i++, km++) {
694 		if (!km->ks_calls || !memname[i])
695 			continue;
696 
697 		(*pr)("%15s %5ld %6ldK %7ldK %6ldK %9ld %8d\n",
698 		    memname[i], km->ks_inuse, km->ks_memuse / 1024,
699 		    km->ks_maxused / 1024, km->ks_limit / 1024,
700 		    km->ks_calls, km->ks_limblocks);
701 	}
702 #else
703 	(*pr)("No KMEMSTATS compiled in\n");
704 #endif
705 }
706 #endif /* DDB */
707 
708 /*
709  * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
710  *
711  * Permission to use, copy, modify, and distribute this software for any
712  * purpose with or without fee is hereby granted, provided that the above
713  * copyright notice and this permission notice appear in all copies.
714  *
715  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
716  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
717  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
718  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
719  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
720  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
721  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
722  */
723 
724 /*
725  * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
726  * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
727  */
728 #define MUL_NO_OVERFLOW	(1UL << (sizeof(size_t) * 4))
729 
730 void *
731 mallocarray(size_t nmemb, size_t size, int type, int flags)
732 {
733 	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
734 	    nmemb > 0 && SIZE_MAX / nmemb < size) {
735 		if (flags & M_CANFAIL)
736 			return (NULL);
737 		panic("mallocarray: overflow %zu * %zu", nmemb, size);
738 	}
739 	return (malloc(size * nmemb, type, flags));
740 }
741