xref: /dragonfly/sys/vm/vm_zone.c (revision dbeb2594)
1 /*
2  * (MPSAFE)
3  *
4  * Copyright (c) 1997, 1998 John S. Dyson
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *	notice immediately at the beginning of the file, without modification,
12  *	this list of conditions, and the following disclaimer.
13  * 2. Absolutely no warranty of function or purpose is made by the author
14  *	John S. Dyson.
15  *
16  * $FreeBSD: src/sys/vm/vm_zone.c,v 1.30.2.6 2002/10/10 19:50:16 dillon Exp $
17  */
18 
19 #include <sys/param.h>
20 #include <sys/queue.h>
21 #include <sys/systm.h>
22 #include <sys/kernel.h>
23 #include <sys/lock.h>
24 #include <sys/malloc.h>
25 #include <sys/sysctl.h>
26 #include <sys/vmmeter.h>
27 
28 #include <vm/vm.h>
29 #include <vm/vm_object.h>
30 #include <vm/vm_page.h>
31 #include <vm/vm_map.h>
32 #include <vm/vm_kern.h>
33 #include <vm/vm_extern.h>
34 #include <vm/vm_zone.h>
35 
36 #include <sys/spinlock2.h>
37 #include <vm/vm_page2.h>
38 
39 static MALLOC_DEFINE(M_ZONE, "ZONE", "Zone header");
40 
41 #define	ZONE_ERROR_INVALID 0
42 #define	ZONE_ERROR_NOTFREE 1
43 #define	ZONE_ERROR_ALREADYFREE 2
44 
45 #define ZONE_ROUNDING	32
46 
47 #define	ZENTRY_FREE	0x12342378
48 
49 int zone_burst = 32;
50 
51 static void *zget(vm_zone_t z);
52 
53 /*
54  * Return an item from the specified zone.   This function is non-blocking for
55  * ZONE_INTERRUPT zones.
56  *
57  * No requirements.
58  */
59 void *
60 zalloc(vm_zone_t z)
61 {
62 	globaldata_t gd = mycpu;
63 	vm_zpcpu_t *zpcpu;
64 	void *item;
65 	int n;
66 
67 #ifdef INVARIANTS
68 	if (z == NULL)
69 		zerror(ZONE_ERROR_INVALID);
70 #endif
71 	zpcpu = &z->zpcpu[gd->gd_cpuid];
72 retry:
73 	/*
74 	 * Avoid spinlock contention by allocating from a per-cpu queue
75 	 */
76 	if (zpcpu->zfreecnt > 0) {
77 		crit_enter_gd(gd);
78 		if (zpcpu->zfreecnt > 0) {
79 			item = zpcpu->zitems;
80 #ifdef INVARIANTS
81 			KASSERT(item != NULL,
82 				("zitems_pcpu unexpectedly NULL"));
83 			if (((void **)item)[1] != (void *)ZENTRY_FREE)
84 				zerror(ZONE_ERROR_NOTFREE);
85 			((void **)item)[1] = NULL;
86 #endif
87 			zpcpu->zitems = ((void **) item)[0];
88 			--zpcpu->zfreecnt;
89 			++zpcpu->znalloc;
90 			crit_exit_gd(gd);
91 
92 			return item;
93 		}
94 		crit_exit_gd(gd);
95 	}
96 
97 	/*
98 	 * Per-zone spinlock for the remainder.  Always load at least one
99 	 * item.
100 	 */
101 	spin_lock(&z->zlock);
102 	if (z->zfreecnt > z->zfreemin) {
103 		n = zone_burst;
104 		do {
105 			item = z->zitems;
106 #ifdef INVARIANTS
107 			KASSERT(item != NULL, ("zitems unexpectedly NULL"));
108 			if (((void **)item)[1] != (void *)ZENTRY_FREE)
109 				zerror(ZONE_ERROR_NOTFREE);
110 #endif
111 			z->zitems = ((void **)item)[0];
112 			--z->zfreecnt;
113 			((void **)item)[0] = zpcpu->zitems;
114 			zpcpu->zitems = item;
115 			++zpcpu->zfreecnt;
116 		} while (--n > 0 && z->zfreecnt > z->zfreemin);
117 		spin_unlock(&z->zlock);
118 		goto retry;
119 	} else {
120 		spin_unlock(&z->zlock);
121 		item = zget(z);
122 		/*
123 		 * PANICFAIL allows the caller to assume that the zalloc()
124 		 * will always succeed.  If it doesn't, we panic here.
125 		 */
126 		if (item == NULL && (z->zflags & ZONE_PANICFAIL))
127 			panic("zalloc(%s) failed", z->zname);
128 	}
129 	return item;
130 }
131 
132 /*
133  * Free an item to the specified zone.
134  *
135  * No requirements.
136  */
137 void
138 zfree(vm_zone_t z, void *item)
139 {
140 	globaldata_t gd = mycpu;
141 	vm_zpcpu_t *zpcpu;
142 	void *tail_item;
143 	int count;
144 	int zmax;
145 
146 	zpcpu = &z->zpcpu[gd->gd_cpuid];
147 
148 	/*
149 	 * Avoid spinlock contention by freeing into a per-cpu queue
150 	 */
151 	zmax = z->zmax_pcpu;
152 	if (zmax < 1024)
153 		zmax = 1024;
154 
155 	/*
156 	 * Add to pcpu cache
157 	 */
158 	crit_enter_gd(gd);
159 	((void **)item)[0] = zpcpu->zitems;
160 #ifdef INVARIANTS
161 	if (((void **)item)[1] == (void *)ZENTRY_FREE)
162 		zerror(ZONE_ERROR_ALREADYFREE);
163 	((void **)item)[1] = (void *)ZENTRY_FREE;
164 #endif
165 	zpcpu->zitems = item;
166 	++zpcpu->zfreecnt;
167 
168 	if (zpcpu->zfreecnt < zmax) {
169 		crit_exit_gd(gd);
170 		return;
171 	}
172 
173 	/*
174 	 * Hystereis, move (zmax) (calculated below) items to the pool.
175 	 */
176 	zmax = zmax / 2;
177 	if (zmax > zone_burst)
178 		zmax = zone_burst;
179 	tail_item = item;
180 	count = 1;
181 
182 	while (count < zmax) {
183 		tail_item = ((void **)tail_item)[0];
184 		++count;
185 	}
186 	zpcpu->zitems = ((void **)tail_item)[0];
187 	zpcpu->zfreecnt -= count;
188 
189 	/*
190 	 * Per-zone spinlock for the remainder.
191 	 *
192 	 * Also implement hysteresis by freeing a number of pcpu
193 	 * entries.
194 	 */
195 	spin_lock(&z->zlock);
196 	((void **)tail_item)[0] = z->zitems;
197 	z->zitems = item;
198 	z->zfreecnt += count;
199 	spin_unlock(&z->zlock);
200 
201 	crit_exit_gd(gd);
202 }
203 
204 /*
205  * This file comprises a very simple zone allocator.  This is used
206  * in lieu of the malloc allocator, where needed or more optimal.
207  *
208  * Note that the initial implementation of this had coloring, and
209  * absolutely no improvement (actually perf degradation) occurred.
210  *
211  * Note also that the zones are type stable.  The only restriction is
212  * that the first two longwords of a data structure can be changed
213  * between allocations.  Any data that must be stable between allocations
214  * must reside in areas after the first two longwords.
215  *
216  * zinitna, zinit, zbootinit are the initialization routines.
217  * zalloc, zfree, are the allocation/free routines.
218  */
219 
220 LIST_HEAD(zlist, vm_zone) zlist = LIST_HEAD_INITIALIZER(zlist);
221 static int sysctl_vm_zone(SYSCTL_HANDLER_ARGS);
222 static int zone_kmem_pages, zone_kern_pages;
223 static long zone_kmem_kvaspace;
224 
225 /*
226  * Create a zone, but don't allocate the zone structure.  If the
227  * zone had been previously created by the zone boot code, initialize
228  * various parts of the zone code.
229  *
230  * If waits are not allowed during allocation (e.g. during interrupt
231  * code), a-priori allocate the kernel virtual space, and allocate
232  * only pages when needed.
233  *
234  * Arguments:
235  * z		pointer to zone structure.
236  * obj		pointer to VM object (opt).
237  * name		name of zone.
238  * size		size of zone entries.
239  * nentries	number of zone entries allocated (only ZONE_INTERRUPT.)
240  * flags	ZONE_INTERRUPT -- items can be allocated at interrupt time.
241  * zalloc	number of pages allocated when memory is needed.
242  *
243  * Note that when using ZONE_INTERRUPT, the size of the zone is limited
244  * by the nentries argument.  The size of the memory allocatable is
245  * unlimited if ZONE_INTERRUPT is not set.
246  *
247  * No requirements.
248  */
249 int
250 zinitna(vm_zone_t z, vm_object_t obj, char *name, int size,
251 	int nentries, int flags)
252 {
253 	size_t totsize;
254 
255 	/*
256 	 * Only zones created with zinit() are destroyable.
257 	 */
258 	if (z->zflags & ZONE_DESTROYABLE)
259 		panic("zinitna: can't create destroyable zone");
260 
261 	/*
262 	 * NOTE: We can only adjust zsize if we previously did not
263 	 * 	 use zbootinit().
264 	 */
265 	if ((z->zflags & ZONE_BOOT) == 0) {
266 		z->zsize = roundup2(size, ZONE_ROUNDING);
267 		spin_init(&z->zlock, "zinitna");
268 		z->zfreecnt = 0;
269 		z->ztotal = 0;
270 		z->zmax = 0;
271 		z->zname = name;
272 		z->zitems = NULL;
273 
274 		lwkt_gettoken(&vm_token);
275 		LIST_INSERT_HEAD(&zlist, z, zlink);
276 		lwkt_reltoken(&vm_token);
277 
278 		bzero(z->zpcpu, sizeof(z->zpcpu));
279 	}
280 
281 	z->zkmvec = NULL;
282 	z->zkmcur = z->zkmmax = 0;
283 	z->zflags |= flags;
284 
285 	/*
286 	 * If we cannot wait, allocate KVA space up front, and we will fill
287 	 * in pages as needed.  This is particularly required when creating
288 	 * an allocation space for map entries in kernel_map, because we
289 	 * do not want to go into a recursion deadlock with
290 	 * vm_map_entry_reserve().
291 	 */
292 	if (z->zflags & ZONE_INTERRUPT) {
293 		totsize = round_page((size_t)z->zsize * nentries);
294 		atomic_add_long(&zone_kmem_kvaspace, totsize);
295 
296 		z->zkva = kmem_alloc_pageable(&kernel_map, totsize,
297 					      VM_SUBSYS_ZALLOC);
298 		if (z->zkva == 0) {
299 			LIST_REMOVE(z, zlink);
300 			return 0;
301 		}
302 
303 		z->zpagemax = totsize / PAGE_SIZE;
304 		if (obj == NULL) {
305 			z->zobj = vm_object_allocate(OBJT_DEFAULT, z->zpagemax);
306 		} else {
307 			z->zobj = obj;
308 			_vm_object_allocate(OBJT_DEFAULT, z->zpagemax, obj);
309 			vm_object_drop(obj);
310 		}
311 		z->zallocflag = VM_ALLOC_SYSTEM | VM_ALLOC_INTERRUPT |
312 				VM_ALLOC_NORMAL | VM_ALLOC_RETRY;
313 		z->zmax += nentries;
314 		z->zmax_pcpu = z->zmax / ncpus / 16;
315 		if (z->zmax_pcpu < 1024)
316 			z->zmax_pcpu = 1024;
317 	} else {
318 		z->zallocflag = VM_ALLOC_NORMAL | VM_ALLOC_SYSTEM;
319 		z->zmax = 0;
320 		z->zmax_pcpu = 8192;
321 	}
322 
323 
324 	if (z->zsize > PAGE_SIZE)
325 		z->zfreemin = 1;
326 	else
327 		z->zfreemin = PAGE_SIZE / z->zsize;
328 
329 	z->zpagecount = 0;
330 
331 	/*
332 	 * Reduce kernel_map spam by allocating in chunks of 4 pages.
333 	 */
334 	z->zalloc = 4;
335 
336 	/*
337 	 * Populate the interrrupt zone at creation time rather than
338 	 * on first allocation, as this is a potentially long operation.
339 	 */
340 	if (z->zflags & ZONE_INTERRUPT) {
341 		void *buf;
342 
343 		buf = zget(z);
344 		zfree(z, buf);
345 	}
346 
347 	return 1;
348 }
349 
350 /*
351  * Subroutine same as zinitna, except zone data structure is allocated
352  * automatically by malloc.  This routine should normally be used, except
353  * in certain tricky startup conditions in the VM system -- then
354  * zbootinit and zinitna can be used.  Zinit is the standard zone
355  * initialization call.
356  *
357  * No requirements.
358  */
359 vm_zone_t
360 zinit(char *name, int size, int nentries, int flags)
361 {
362 	vm_zone_t z;
363 
364 	z = (vm_zone_t) kmalloc(sizeof (struct vm_zone), M_ZONE, M_NOWAIT);
365 	if (z == NULL)
366 		return NULL;
367 
368 	z->zflags = 0;
369 	if (zinitna(z, NULL, name, size, nentries,
370 	            flags & ~ZONE_DESTROYABLE) == 0) {
371 		kfree(z, M_ZONE);
372 		return NULL;
373 	}
374 
375 	if (flags & ZONE_DESTROYABLE)
376 		z->zflags |= ZONE_DESTROYABLE;
377 
378 	return z;
379 }
380 
381 /*
382  * Initialize a zone before the system is fully up.  This routine should
383  * only be called before full VM startup.
384  *
385  * Called from the low level boot code only.
386  */
387 void
388 zbootinit(vm_zone_t z, char *name, int size, void *item, int nitems)
389 {
390 	int i;
391 
392 	spin_init(&z->zlock, "zbootinit");
393 	bzero(z->zpcpu, sizeof(z->zpcpu));
394 	z->zname = name;
395 	z->zsize = size;
396 	z->zpagemax = 0;
397 	z->zobj = NULL;
398 	z->zflags = ZONE_BOOT;
399 	z->zfreemin = 0;
400 	z->zallocflag = 0;
401 	z->zpagecount = 0;
402 	z->zalloc = 0;
403 
404 	bzero(item, (size_t)nitems * z->zsize);
405 	z->zitems = NULL;
406 	for (i = 0; i < nitems; i++) {
407 		((void **)item)[0] = z->zitems;
408 #ifdef INVARIANTS
409 		((void **)item)[1] = (void *)ZENTRY_FREE;
410 #endif
411 		z->zitems = item;
412 		item = (uint8_t *)item + z->zsize;
413 	}
414 	z->zfreecnt = nitems;
415 	z->zmax = nitems;
416 	z->ztotal = nitems;
417 
418 	lwkt_gettoken(&vm_token);
419 	LIST_INSERT_HEAD(&zlist, z, zlink);
420 	lwkt_reltoken(&vm_token);
421 }
422 
423 /*
424  * Release all resources owned by zone created with zinit().
425  *
426  * No requirements.
427  */
428 void
429 zdestroy(vm_zone_t z)
430 {
431 	vm_page_t m;
432 	int i;
433 
434 	if (z == NULL)
435 		panic("zdestroy: null zone");
436 	if ((z->zflags & ZONE_DESTROYABLE) == 0)
437 		panic("zdestroy: undestroyable zone");
438 
439 	lwkt_gettoken(&vm_token);
440 	LIST_REMOVE(z, zlink);
441 	lwkt_reltoken(&vm_token);
442 
443 	/*
444 	 * Release virtual mappings, physical memory and update sysctl stats.
445 	 */
446 	if (z->zflags & ZONE_INTERRUPT) {
447 		/*
448 		 * Pages mapped via pmap_kenter() must be removed from the
449 		 * kernel_pmap() before calling kmem_free() to avoid issues
450 		 * with kernel_pmap.pm_stats.resident_count.
451 		 */
452 		pmap_qremove(z->zkva, z->zpagemax);
453 		vm_object_hold(z->zobj);
454 		for (i = 0; i < z->zpagecount; ++i) {
455 			m = vm_page_lookup_busy_wait(z->zobj, i, TRUE, "vmzd");
456 			vm_page_unwire(m, 0);
457 			vm_page_free(m);
458 		}
459 
460 		/*
461 		 * Free the mapping.
462 		 */
463 		kmem_free(&kernel_map, z->zkva,
464 			  (size_t)z->zpagemax * PAGE_SIZE);
465 		atomic_subtract_long(&zone_kmem_kvaspace,
466 				     (size_t)z->zpagemax * PAGE_SIZE);
467 
468 		/*
469 		 * Free the backing object and physical pages.
470 		 */
471 		vm_object_deallocate(z->zobj);
472 		vm_object_drop(z->zobj);
473 		atomic_subtract_int(&zone_kmem_pages, z->zpagecount);
474 	} else {
475 		for (i = 0; i < z->zkmcur; i++) {
476 			kmem_free(&kernel_map, z->zkmvec[i],
477 				  (size_t)z->zalloc * PAGE_SIZE);
478 			atomic_subtract_int(&zone_kern_pages, z->zalloc);
479 		}
480 		if (z->zkmvec != NULL)
481 			kfree(z->zkmvec, M_ZONE);
482 	}
483 
484 	spin_uninit(&z->zlock);
485 	kfree(z, M_ZONE);
486 }
487 
488 
489 /*
490  * void *zalloc(vm_zone_t zone) --
491  *	Returns an item from a specified zone.  May not be called from a
492  *	FAST interrupt or IPI function.
493  *
494  * void zfree(vm_zone_t zone, void *item) --
495  *	Frees an item back to a specified zone.  May not be called from a
496  *	FAST interrupt or IPI function.
497  */
498 
499 /*
500  * Internal zone routine.  Not to be called from external (non vm_zone) code.
501  *
502  * No requirements.
503  */
504 static void *
505 zget(vm_zone_t z)
506 {
507 	int i;
508 	vm_page_t m;
509 	int nitems;
510 	int npages;
511 	int savezpc;
512 	size_t nbytes;
513 	size_t noffset;
514 	void *item;
515 
516 	if (z == NULL)
517 		panic("zget: null zone");
518 
519 	if (z->zflags & ZONE_INTERRUPT) {
520 		/*
521 		 * Interrupt zones do not mess with the kernel_map, they
522 		 * simply populate an existing mapping.
523 		 *
524 		 * First reserve the required space.
525 		 */
526 		vm_object_hold(z->zobj);
527 		noffset = (size_t)z->zpagecount * PAGE_SIZE;
528 		noffset -= noffset % z->zsize;
529 		savezpc = z->zpagecount;
530 		if (z->zpagecount + z->zalloc > z->zpagemax)
531 			z->zpagecount = z->zpagemax;
532 		else
533 			z->zpagecount += z->zalloc;
534 		item = (char *)z->zkva + noffset;
535 		npages = z->zpagecount - savezpc;
536 		nitems = ((size_t)(savezpc + npages) * PAGE_SIZE - noffset) /
537 			 z->zsize;
538 		atomic_add_int(&zone_kmem_pages, npages);
539 
540 		/*
541 		 * Now allocate the pages.  Note that we can block in the
542 		 * loop, so we've already done all the necessary calculations
543 		 * and reservations above.
544 		 */
545 		for (i = 0; i < npages; ++i) {
546 			vm_offset_t zkva;
547 
548 			m = vm_page_alloc(z->zobj, savezpc + i, z->zallocflag);
549 			KKASSERT(m != NULL);
550 			/* note: z might be modified due to blocking */
551 
552 			KKASSERT(m->queue == PQ_NONE);
553 			m->valid = VM_PAGE_BITS_ALL;
554 			vm_page_wire(m);
555 			vm_page_wakeup(m);
556 
557 			zkva = z->zkva + (size_t)(savezpc + i) * PAGE_SIZE;
558 			pmap_kenter(zkva, VM_PAGE_TO_PHYS(m));
559 			bzero((void *)zkva, PAGE_SIZE);
560 		}
561 		vm_object_drop(z->zobj);
562 	} else if (z->zflags & ZONE_SPECIAL) {
563 		/*
564 		 * The special zone is the one used for vm_map_entry_t's.
565 		 * We have to avoid an infinite recursion in
566 		 * vm_map_entry_reserve() by using vm_map_entry_kreserve()
567 		 * instead.  The map entries are pre-reserved by the kernel
568 		 * by vm_map_entry_reserve_cpu_init().
569 		 */
570 		nbytes = (size_t)z->zalloc * PAGE_SIZE;
571 
572 		item = (void *)kmem_alloc3(&kernel_map, nbytes,
573 					   VM_SUBSYS_ZALLOC, KM_KRESERVE);
574 
575 		/* note: z might be modified due to blocking */
576 		if (item != NULL) {
577 			atomic_add_int(&zone_kern_pages, z->zalloc);
578 			bzero(item, nbytes);
579 		} else {
580 			nbytes = 0;
581 		}
582 		nitems = nbytes / z->zsize;
583 	} else {
584 		/*
585 		 * Otherwise allocate KVA from the kernel_map.
586 		 */
587 		nbytes = (size_t)z->zalloc * PAGE_SIZE;
588 
589 		item = (void *)kmem_alloc3(&kernel_map, nbytes,
590 					   VM_SUBSYS_ZALLOC, 0);
591 
592 		/* note: z might be modified due to blocking */
593 		if (item != NULL) {
594 			atomic_add_int(&zone_kern_pages, z->zalloc);
595 			bzero(item, nbytes);
596 
597 			if (z->zflags & ZONE_DESTROYABLE) {
598 				if (z->zkmcur == z->zkmmax) {
599 					z->zkmmax =
600 						z->zkmmax==0 ? 1 : z->zkmmax*2;
601 					z->zkmvec = krealloc(z->zkmvec,
602 					    z->zkmmax * sizeof(z->zkmvec[0]),
603 					    M_ZONE, M_WAITOK);
604 				}
605 				z->zkmvec[z->zkmcur++] = (vm_offset_t)item;
606 			}
607 		} else {
608 			nbytes = 0;
609 		}
610 		nitems = nbytes / z->zsize;
611 	}
612 
613 	spin_lock(&z->zlock);
614 	z->ztotal += nitems;
615 
616 	/*
617 	 * Save one for immediate allocation
618 	 */
619 	if (nitems != 0) {
620 		nitems -= 1;
621 		for (i = 0; i < nitems; i++) {
622 			((void **)item)[0] = z->zitems;
623 #ifdef INVARIANTS
624 			((void **)item)[1] = (void *)ZENTRY_FREE;
625 #endif
626 			z->zitems = item;
627 			item = (uint8_t *)item + z->zsize;
628 		}
629 		z->zfreecnt += nitems;
630 		++z->znalloc;
631 	} else if (z->zfreecnt > 0) {
632 		item = z->zitems;
633 		z->zitems = ((void **)item)[0];
634 #ifdef INVARIANTS
635 		if (((void **)item)[1] != (void *)ZENTRY_FREE)
636 			zerror(ZONE_ERROR_NOTFREE);
637 		((void **) item)[1] = NULL;
638 #endif
639 		--z->zfreecnt;
640 		++z->znalloc;
641 	} else {
642 		item = NULL;
643 	}
644 	spin_unlock(&z->zlock);
645 
646 	/*
647 	 * A special zone may have used a kernel-reserved vm_map_entry.  If
648 	 * so we have to be sure to recover our reserve so we don't run out.
649 	 * We will panic if we run out.
650 	 */
651 	if (z->zflags & ZONE_SPECIAL)
652 		vm_map_entry_reserve(0);
653 
654 	return item;
655 }
656 
657 /*
658  * No requirements.
659  */
660 static int
661 sysctl_vm_zone(SYSCTL_HANDLER_ARGS)
662 {
663 	int error=0;
664 	vm_zone_t curzone;
665 	char tmpbuf[128];
666 	char tmpname[14];
667 
668 	ksnprintf(tmpbuf, sizeof(tmpbuf),
669 	    "\nITEM            SIZE     LIMIT    USED    FREE  REQUESTS\n");
670 	error = SYSCTL_OUT(req, tmpbuf, strlen(tmpbuf));
671 	if (error)
672 		return (error);
673 
674 	lwkt_gettoken(&vm_token);
675 	LIST_FOREACH(curzone, &zlist, zlink) {
676 		int i;
677 		int n;
678 		int len;
679 		int offset;
680 		int freecnt;
681 		int znalloc;
682 
683 		len = strlen(curzone->zname);
684 		if (len >= (sizeof(tmpname) - 1))
685 			len = (sizeof(tmpname) - 1);
686 		for(i = 0; i < sizeof(tmpname) - 1; i++)
687 			tmpname[i] = ' ';
688 		tmpname[i] = 0;
689 		memcpy(tmpname, curzone->zname, len);
690 		tmpname[len] = ':';
691 		offset = 0;
692 		if (curzone == LIST_FIRST(&zlist)) {
693 			offset = 1;
694 			tmpbuf[0] = '\n';
695 		}
696 		freecnt = curzone->zfreecnt;
697 		znalloc = curzone->znalloc;
698 		for (n = 0; n < ncpus; ++n) {
699 			freecnt += curzone->zpcpu[n].zfreecnt;
700 			znalloc += curzone->zpcpu[n].znalloc;
701 		}
702 
703 		ksnprintf(tmpbuf + offset, sizeof(tmpbuf) - offset,
704 			"%s %6.6u, %8.8u, %6.6u, %6.6u, %8.8u\n",
705 			tmpname, curzone->zsize, curzone->zmax,
706 			(curzone->ztotal - freecnt),
707 			freecnt, znalloc);
708 
709 		len = strlen((char *)tmpbuf);
710 		if (LIST_NEXT(curzone, zlink) == NULL)
711 			tmpbuf[len - 1] = 0;
712 
713 		error = SYSCTL_OUT(req, tmpbuf, len);
714 
715 		if (error)
716 			break;
717 	}
718 	lwkt_reltoken(&vm_token);
719 	return (error);
720 }
721 
722 #if defined(INVARIANTS)
723 
724 /*
725  * Debugging only.
726  */
727 void
728 zerror(int error)
729 {
730 	char *msg;
731 
732 	switch (error) {
733 	case ZONE_ERROR_INVALID:
734 		msg = "zone: invalid zone";
735 		break;
736 	case ZONE_ERROR_NOTFREE:
737 		msg = "zone: entry not free";
738 		break;
739 	case ZONE_ERROR_ALREADYFREE:
740 		msg = "zone: freeing free entry";
741 		break;
742 	default:
743 		msg = "zone: invalid error";
744 		break;
745 	}
746 	panic("%s", msg);
747 }
748 #endif
749 
750 SYSCTL_OID(_vm, OID_AUTO, zone, CTLTYPE_STRING|CTLFLAG_RD, \
751 	NULL, 0, sysctl_vm_zone, "A", "Zone Info");
752 
753 SYSCTL_INT(_vm, OID_AUTO, zone_kmem_pages,
754 	CTLFLAG_RD, &zone_kmem_pages, 0, "Number of interrupt safe pages allocated by zone");
755 SYSCTL_INT(_vm, OID_AUTO, zone_burst,
756 	CTLFLAG_RW, &zone_burst, 0, "Burst from depot to pcpu cache");
757 SYSCTL_LONG(_vm, OID_AUTO, zone_kmem_kvaspace,
758 	CTLFLAG_RD, &zone_kmem_kvaspace, 0, "KVA space allocated by zone");
759 SYSCTL_INT(_vm, OID_AUTO, zone_kern_pages,
760 	CTLFLAG_RD, &zone_kern_pages, 0, "Number of non-interrupt safe pages allocated by zone");
761