2 * KERN_SLABALLOC.C - Kernel SLAB memory allocator
4 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
6 * This code is derived from software contributed to The DragonFly Project
7 * by Matthew Dillon <dillon@backplane.com>
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
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23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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26 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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36 * $DragonFly: src/sys/kern/kern_slaballoc.c,v 1.25 2004/11/17 23:36:17 dillon Exp $
38 * This module implements a slab allocator drop-in replacement for the
41 * A slab allocator reserves a ZONE for each chunk size, then lays the
42 * chunks out in an array within the zone. Allocation and deallocation
43 * is nearly instantanious, and fragmentation/overhead losses are limited
44 * to a fixed worst-case amount.
46 * The downside of this slab implementation is in the chunk size
47 * multiplied by the number of zones. ~80 zones * 128K = 10MB of VM per cpu.
48 * In a kernel implementation all this memory will be physical so
49 * the zone size is adjusted downward on machines with less physical
50 * memory. The upside is that overhead is bounded... this is the *worst*
53 * Slab management is done on a per-cpu basis and no locking or mutexes
54 * are required, only a critical section. When one cpu frees memory
55 * belonging to another cpu's slab manager an asynchronous IPI message
56 * will be queued to execute the operation. In addition, both the
57 * high level slab allocator and the low level zone allocator optimize
58 * M_ZERO requests, and the slab allocator does not have to pre initialize
59 * the linked list of chunks.
61 * XXX Balancing is needed between cpus. Balance will be handled through
62 * asynchronous IPIs primarily by reassigning the z_Cpu ownership of chunks.
64 * XXX If we have to allocate a new zone and M_USE_RESERVE is set, use of
65 * the new zone should be restricted to M_USE_RESERVE requests only.
67 * Alloc Size Chunking Number of zones
77 * (if PAGE_SIZE is 4K the maximum zone allocation is 16383)
79 * Allocations >= ZoneLimit go directly to kmem.
81 * API REQUIREMENTS AND SIDE EFFECTS
83 * To operate as a drop-in replacement to the FreeBSD-4.x malloc() we
84 * have remained compatible with the following API requirements:
86 * + small power-of-2 sized allocations are power-of-2 aligned (kern_tty)
87 * + all power-of-2 sized allocations are power-of-2 aligned (twe)
88 * + malloc(0) is allowed and returns non-NULL (ahc driver)
89 * + ability to allocate arbitrarily large chunks of memory
94 #include <sys/param.h>
95 #include <sys/systm.h>
96 #include <sys/kernel.h>
97 #include <sys/slaballoc.h>
99 #include <sys/vmmeter.h>
100 #include <sys/lock.h>
101 #include <sys/thread.h>
102 #include <sys/globaldata.h>
105 #include <vm/vm_param.h>
106 #include <vm/vm_kern.h>
107 #include <vm/vm_extern.h>
108 #include <vm/vm_object.h>
110 #include <vm/vm_map.h>
111 #include <vm/vm_page.h>
112 #include <vm/vm_pageout.h>
114 #include <machine/cpu.h>
116 #include <sys/thread2.h>
118 #define arysize(ary) (sizeof(ary)/sizeof((ary)[0]))
121 * Fixed globals (not per-cpu)
124 static int ZoneLimit;
125 static int ZonePageCount;
127 static struct malloc_type *kmemstatistics;
128 static struct kmemusage *kmemusage;
129 static int32_t weirdary[16];
131 static void *kmem_slab_alloc(vm_size_t bytes, vm_offset_t align, int flags);
132 static void kmem_slab_free(void *ptr, vm_size_t bytes);
135 * Misc constants. Note that allocations that are exact multiples of
136 * PAGE_SIZE, or exceed the zone limit, fall through to the kmem module.
137 * IN_SAME_PAGE_MASK is used to sanity-check the per-page free lists.
139 #define MIN_CHUNK_SIZE 8 /* in bytes */
140 #define MIN_CHUNK_MASK (MIN_CHUNK_SIZE - 1)
141 #define ZONE_RELS_THRESH 2 /* threshold number of zones */
142 #define IN_SAME_PAGE_MASK (~(intptr_t)PAGE_MASK | MIN_CHUNK_MASK)
145 * The WEIRD_ADDR is used as known text to copy into free objects to
146 * try to create deterministic failure cases if the data is accessed after
149 #define WEIRD_ADDR 0xdeadc0de
150 #define MAX_COPY sizeof(weirdary)
151 #define ZERO_LENGTH_PTR ((void *)-8)
154 * Misc global malloc buckets
157 MALLOC_DEFINE(M_CACHE, "cache", "Various Dynamically allocated caches");
158 MALLOC_DEFINE(M_DEVBUF, "devbuf", "device driver memory");
159 MALLOC_DEFINE(M_TEMP, "temp", "misc temporary data buffers");
161 MALLOC_DEFINE(M_IP6OPT, "ip6opt", "IPv6 options");
162 MALLOC_DEFINE(M_IP6NDP, "ip6ndp", "IPv6 Neighbor Discovery");
165 * Initialize the slab memory allocator. We have to choose a zone size based
166 * on available physical memory. We choose a zone side which is approximately
167 * 1/1024th of our memory, so if we have 128MB of ram we have a zone size of
168 * 128K. The zone size is limited to the bounds set in slaballoc.h
169 * (typically 32K min, 128K max).
171 static void kmeminit(void *dummy);
173 SYSINIT(kmem, SI_SUB_KMEM, SI_ORDER_FIRST, kmeminit, NULL)
176 kmeminit(void *dummy)
183 limsize = (vm_poff_t)vmstats.v_page_count * PAGE_SIZE;
184 if (limsize > VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS)
185 limsize = VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS;
187 usesize = (int)(limsize / 1024); /* convert to KB */
189 ZoneSize = ZALLOC_MIN_ZONE_SIZE;
190 while (ZoneSize < ZALLOC_MAX_ZONE_SIZE && (ZoneSize << 1) < usesize)
192 ZoneLimit = ZoneSize / 4;
193 if (ZoneLimit > ZALLOC_ZONE_LIMIT)
194 ZoneLimit = ZALLOC_ZONE_LIMIT;
195 ZoneMask = ZoneSize - 1;
196 ZonePageCount = ZoneSize / PAGE_SIZE;
198 npg = (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / PAGE_SIZE;
199 kmemusage = kmem_slab_alloc(npg * sizeof(struct kmemusage), PAGE_SIZE, M_WAITOK|M_ZERO);
201 for (i = 0; i < arysize(weirdary); ++i)
202 weirdary[i] = WEIRD_ADDR;
205 printf("Slab ZoneSize set to %dKB\n", ZoneSize / 1024);
209 * Initialize a malloc type tracking structure.
212 malloc_init(void *data)
214 struct malloc_type *type = data;
217 if (type->ks_magic != M_MAGIC)
218 panic("malloc type lacks magic");
220 if (type->ks_limit != 0)
223 if (vmstats.v_page_count == 0)
224 panic("malloc_init not allowed before vm init");
226 limsize = (vm_poff_t)vmstats.v_page_count * PAGE_SIZE;
227 if (limsize > VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS)
228 limsize = VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS;
229 type->ks_limit = limsize / 10;
231 type->ks_next = kmemstatistics;
232 kmemstatistics = type;
236 malloc_uninit(void *data)
238 struct malloc_type *type = data;
239 struct malloc_type *t;
245 if (type->ks_magic != M_MAGIC)
246 panic("malloc type lacks magic");
248 if (vmstats.v_page_count == 0)
249 panic("malloc_uninit not allowed before vm init");
251 if (type->ks_limit == 0)
252 panic("malloc_uninit on uninitialized type");
256 * memuse is only correct in aggregation. Due to memory being allocated
257 * on one cpu and freed on another individual array entries may be
258 * negative or positive (canceling each other out).
260 for (i = ttl = 0; i < ncpus; ++i)
261 ttl += type->ks_memuse[i];
263 printf("malloc_uninit: %ld bytes of '%s' still allocated on cpu %d\n",
264 ttl, type->ks_shortdesc, i);
267 if (type == kmemstatistics) {
268 kmemstatistics = type->ks_next;
270 for (t = kmemstatistics; t->ks_next != NULL; t = t->ks_next) {
271 if (t->ks_next == type) {
272 t->ks_next = type->ks_next;
277 type->ks_next = NULL;
282 * Calculate the zone index for the allocation request size and set the
283 * allocation request size to that particular zone's chunk size.
286 zoneindex(unsigned long *bytes)
288 unsigned int n = (unsigned int)*bytes; /* unsigned for shift opt */
290 *bytes = n = (n + 7) & ~7;
291 return(n / 8 - 1); /* 8 byte chunks, 16 zones */
294 *bytes = n = (n + 15) & ~15;
299 *bytes = n = (n + 31) & ~31;
303 *bytes = n = (n + 63) & ~63;
307 *bytes = n = (n + 127) & ~127;
308 return(n / 128 + 31);
311 *bytes = n = (n + 255) & ~255;
312 return(n / 256 + 39);
314 *bytes = n = (n + 511) & ~511;
315 return(n / 512 + 47);
317 #if ZALLOC_ZONE_LIMIT > 8192
319 *bytes = n = (n + 1023) & ~1023;
320 return(n / 1024 + 55);
323 #if ZALLOC_ZONE_LIMIT > 16384
325 *bytes = n = (n + 2047) & ~2047;
326 return(n / 2048 + 63);
329 panic("Unexpected byte count %d", n);
334 * malloc() (SLAB ALLOCATOR)
336 * Allocate memory via the slab allocator. If the request is too large,
337 * or if it page-aligned beyond a certain size, we fall back to the
338 * KMEM subsystem. A SLAB tracking descriptor must be specified, use
339 * &SlabMisc if you don't care.
341 * M_RNOWAIT - return NULL instead of blocking.
342 * M_ZERO - zero the returned memory.
343 * M_USE_RESERVE - allow greater drawdown of the free list
344 * M_USE_INTERRUPT_RESERVE - allow the freelist to be exhausted
347 malloc(unsigned long size, struct malloc_type *type, int flags)
352 struct globaldata *gd;
359 * XXX silly to have this in the critical path.
361 if (type->ks_limit == 0) {
363 if (type->ks_limit == 0)
370 * Handle the case where the limit is reached. Panic if can't return
371 * NULL. XXX the original malloc code looped, but this tended to
372 * simply deadlock the computer.
374 while (type->ks_loosememuse >= type->ks_limit) {
378 for (i = ttl = 0; i < ncpus; ++i)
379 ttl += type->ks_memuse[i];
380 type->ks_loosememuse = ttl;
381 if (ttl >= type->ks_limit) {
382 if (flags & (M_RNOWAIT|M_NULLOK))
384 panic("%s: malloc limit exceeded", type->ks_shortdesc);
389 * Handle the degenerate size == 0 case. Yes, this does happen.
390 * Return a special pointer. This is to maintain compatibility with
391 * the original malloc implementation. Certain devices, such as the
392 * adaptec driver, not only allocate 0 bytes, they check for NULL and
393 * also realloc() later on. Joy.
396 return(ZERO_LENGTH_PTR);
399 * Handle hysteresis from prior frees here in malloc(). We cannot
400 * safely manipulate the kernel_map in free() due to free() possibly
401 * being called via an IPI message or from sensitive interrupt code.
403 while (slgd->NFreeZones > ZONE_RELS_THRESH && (flags & M_RNOWAIT) == 0) {
405 if (slgd->NFreeZones > ZONE_RELS_THRESH) { /* crit sect race */
407 slgd->FreeZones = z->z_Next;
409 kmem_slab_free(z, ZoneSize); /* may block */
414 * XXX handle oversized frees that were queued from free().
416 while (slgd->FreeOvZones && (flags & M_RNOWAIT) == 0) {
418 if ((z = slgd->FreeOvZones) != NULL) {
419 KKASSERT(z->z_Magic == ZALLOC_OVSZ_MAGIC);
420 slgd->FreeOvZones = z->z_Next;
421 kmem_slab_free(z, z->z_ChunkSize); /* may block */
427 * Handle large allocations directly. There should not be very many of
428 * these so performance is not a big issue.
430 * Guarentee page alignment for allocations in multiples of PAGE_SIZE
432 if (size >= ZoneLimit || (size & PAGE_MASK) == 0) {
433 struct kmemusage *kup;
435 size = round_page(size);
436 chunk = kmem_slab_alloc(size, PAGE_SIZE, flags);
439 flags &= ~M_ZERO; /* result already zero'd if M_ZERO was set */
440 flags |= M_PASSIVE_ZERO;
442 kup->ku_pagecnt = size / PAGE_SIZE;
443 kup->ku_cpu = gd->gd_cpuid;
449 * Attempt to allocate out of an existing zone. First try the free list,
450 * then allocate out of unallocated space. If we find a good zone move
451 * it to the head of the list so later allocations find it quickly
452 * (we might have thousands of zones in the list).
454 * Note: zoneindex() will panic of size is too large.
456 zi = zoneindex(&size);
457 KKASSERT(zi < NZONES);
459 if ((z = slgd->ZoneAry[zi]) != NULL) {
460 KKASSERT(z->z_NFree > 0);
463 * Remove us from the ZoneAry[] when we become empty
465 if (--z->z_NFree == 0) {
466 slgd->ZoneAry[zi] = z->z_Next;
471 * Locate a chunk in a free page. This attempts to localize
472 * reallocations into earlier pages without us having to sort
473 * the chunk list. A chunk may still overlap a page boundary.
475 while (z->z_FirstFreePg < ZonePageCount) {
476 if ((chunk = z->z_PageAry[z->z_FirstFreePg]) != NULL) {
479 * Diagnostic: c_Next is not total garbage.
481 KKASSERT(chunk->c_Next == NULL ||
482 ((intptr_t)chunk->c_Next & IN_SAME_PAGE_MASK) ==
483 ((intptr_t)chunk & IN_SAME_PAGE_MASK));
486 if ((uintptr_t)chunk < VM_MIN_KERNEL_ADDRESS)
487 panic("chunk %p FFPG %d/%d", chunk, z->z_FirstFreePg, ZonePageCount);
488 if (chunk->c_Next && (uintptr_t)chunk->c_Next < VM_MIN_KERNEL_ADDRESS)
489 panic("chunkNEXT %p %p FFPG %d/%d", chunk, chunk->c_Next, z->z_FirstFreePg, ZonePageCount);
491 z->z_PageAry[z->z_FirstFreePg] = chunk->c_Next;
498 * No chunks are available but NFree said we had some memory, so
499 * it must be available in the never-before-used-memory area
500 * governed by UIndex. The consequences are very serious if our zone
501 * got corrupted so we use an explicit panic rather then a KASSERT.
503 if (z->z_UIndex + 1 != z->z_NMax)
504 z->z_UIndex = z->z_UIndex + 1;
507 if (z->z_UIndex == z->z_UEndIndex)
508 panic("slaballoc: corrupted zone");
509 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size);
510 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) {
512 flags |= M_PASSIVE_ZERO;
518 * If all zones are exhausted we need to allocate a new zone for this
519 * index. Use M_ZERO to take advantage of pre-zerod pages. Also see
520 * UAlloc use above in regards to M_ZERO. Note that when we are reusing
521 * a zone from the FreeZones list UAlloc'd data will not be zero'd, and
522 * we do not pre-zero it because we do not want to mess up the L1 cache.
524 * At least one subsystem, the tty code (see CROUND) expects power-of-2
525 * allocations to be power-of-2 aligned. We maintain compatibility by
526 * adjusting the base offset below.
531 if ((z = slgd->FreeZones) != NULL) {
532 slgd->FreeZones = z->z_Next;
534 bzero(z, sizeof(SLZone));
535 z->z_Flags |= SLZF_UNOTZEROD;
537 z = kmem_slab_alloc(ZoneSize, ZoneSize, flags|M_ZERO);
543 * Guarentee power-of-2 alignment for power-of-2-sized chunks.
544 * Otherwise just 8-byte align the data.
546 if ((size | (size - 1)) + 1 == (size << 1))
547 off = (sizeof(SLZone) + size - 1) & ~(size - 1);
549 off = (sizeof(SLZone) + MIN_CHUNK_MASK) & ~MIN_CHUNK_MASK;
550 z->z_Magic = ZALLOC_SLAB_MAGIC;
552 z->z_NMax = (ZoneSize - off) / size;
553 z->z_NFree = z->z_NMax - 1;
554 z->z_BasePtr = (char *)z + off;
555 z->z_UIndex = z->z_UEndIndex = slgd->JunkIndex % z->z_NMax;
556 z->z_ChunkSize = size;
557 z->z_FirstFreePg = ZonePageCount;
559 z->z_Cpu = gd->gd_cpuid;
560 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size);
561 z->z_Next = slgd->ZoneAry[zi];
562 slgd->ZoneAry[zi] = z;
563 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) {
564 flags &= ~M_ZERO; /* already zero'd */
565 flags |= M_PASSIVE_ZERO;
569 * Slide the base index for initial allocations out of the next
570 * zone we create so we do not over-weight the lower part of the
573 slgd->JunkIndex = (slgd->JunkIndex + ZALLOC_SLAB_SLIDE)
574 & (ZALLOC_MAX_ZONE_SIZE - 1);
577 ++type->ks_inuse[gd->gd_cpuid];
578 type->ks_memuse[gd->gd_cpuid] += size;
579 type->ks_loosememuse += size;
584 else if ((flags & (M_ZERO|M_PASSIVE_ZERO)) == 0)
585 chunk->c_Next = (void *)-1; /* avoid accidental double-free check */
594 realloc(void *ptr, unsigned long size, struct malloc_type *type, int flags)
600 KKASSERT((flags & M_ZERO) == 0); /* not supported */
602 if (ptr == NULL || ptr == ZERO_LENGTH_PTR)
603 return(malloc(size, type, flags));
610 * Handle oversized allocations. XXX we really should require that a
611 * size be passed to free() instead of this nonsense.
614 struct kmemusage *kup;
617 if (kup->ku_pagecnt) {
618 osize = kup->ku_pagecnt << PAGE_SHIFT;
619 if (osize == round_page(size))
621 if ((nptr = malloc(size, type, flags)) == NULL)
623 bcopy(ptr, nptr, min(size, osize));
630 * Get the original allocation's zone. If the new request winds up
631 * using the same chunk size we do not have to do anything.
633 z = (SLZone *)((uintptr_t)ptr & ~(uintptr_t)ZoneMask);
634 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC);
637 if (z->z_ChunkSize == size)
641 * Allocate memory for the new request size. Note that zoneindex has
642 * already adjusted the request size to the appropriate chunk size, which
643 * should optimize our bcopy(). Then copy and return the new pointer.
645 if ((nptr = malloc(size, type, flags)) == NULL)
647 bcopy(ptr, nptr, min(size, z->z_ChunkSize));
653 strdup(const char *str, struct malloc_type *type)
655 int zlen; /* length inclusive of terminating NUL */
660 zlen = strlen(str) + 1;
661 nstr = malloc(zlen, type, M_WAITOK);
662 bcopy(str, nstr, zlen);
668 * free() (SLAB ALLOCATOR)
670 * Free the specified chunk of memory.
674 free_remote(void *ptr)
676 free(ptr, *(struct malloc_type **)ptr);
682 free(void *ptr, struct malloc_type *type)
687 struct globaldata *gd;
694 panic("trying to free NULL pointer");
697 * Handle special 0-byte allocations
699 if (ptr == ZERO_LENGTH_PTR)
703 * Handle oversized allocations. XXX we really should require that a
704 * size be passed to free() instead of this nonsense.
706 * This code is never called via an ipi.
709 struct kmemusage *kup;
713 if (kup->ku_pagecnt) {
714 size = kup->ku_pagecnt << PAGE_SHIFT;
717 KKASSERT(sizeof(weirdary) <= size);
718 bcopy(weirdary, ptr, sizeof(weirdary));
721 * note: we always adjust our cpu's slot, not the originating
722 * cpu (kup->ku_cpuid). The statistics are in aggregate.
724 * note: XXX we have still inherited the interrupts-can't-block
725 * assumption. An interrupt thread does not bump
726 * gd_intr_nesting_level so check TDF_INTTHREAD. This is
727 * primarily until we can fix softupdate's assumptions about free().
730 --type->ks_inuse[gd->gd_cpuid];
731 type->ks_memuse[gd->gd_cpuid] -= size;
732 if (mycpu->gd_intr_nesting_level || (gd->gd_curthread->td_flags & TDF_INTTHREAD)) {
734 z->z_Magic = ZALLOC_OVSZ_MAGIC;
735 z->z_Next = slgd->FreeOvZones;
736 z->z_ChunkSize = size;
737 slgd->FreeOvZones = z;
741 kmem_slab_free(ptr, size); /* may block */
748 * Zone case. Figure out the zone based on the fact that it is
751 z = (SLZone *)((uintptr_t)ptr & ~(uintptr_t)ZoneMask);
752 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC);
755 * If we do not own the zone then forward the request to the
758 if (z->z_CpuGd != gd) {
759 *(struct malloc_type **)ptr = type;
761 lwkt_send_ipiq(z->z_CpuGd, free_remote, ptr);
763 panic("Corrupt SLZone");
768 if (type->ks_magic != M_MAGIC)
769 panic("free: malloc type lacks magic");
772 pgno = ((char *)ptr - (char *)z) >> PAGE_SHIFT;
777 * Attempt to detect a double-free. To reduce overhead we only check
778 * if there appears to be link pointer at the base of the data.
780 if (((intptr_t)chunk->c_Next - (intptr_t)z) >> PAGE_SHIFT == pgno) {
782 for (scan = z->z_PageAry[pgno]; scan; scan = scan->c_Next) {
784 panic("Double free at %p", chunk);
790 * Put weird data into the memory to detect modifications after freeing,
791 * illegal pointer use after freeing (we should fault on the odd address),
792 * and so forth. XXX needs more work, see the old malloc code.
795 if (z->z_ChunkSize < sizeof(weirdary))
796 bcopy(weirdary, chunk, z->z_ChunkSize);
798 bcopy(weirdary, chunk, sizeof(weirdary));
802 * Add this free non-zero'd chunk to a linked list for reuse, adjust
806 if ((uintptr_t)chunk < VM_MIN_KERNEL_ADDRESS)
807 panic("BADFREE %p", chunk);
809 chunk->c_Next = z->z_PageAry[pgno];
810 z->z_PageAry[pgno] = chunk;
812 if (chunk->c_Next && (uintptr_t)chunk->c_Next < VM_MIN_KERNEL_ADDRESS)
815 if (z->z_FirstFreePg > pgno)
816 z->z_FirstFreePg = pgno;
819 * Bump the number of free chunks. If it becomes non-zero the zone
820 * must be added back onto the appropriate list.
822 if (z->z_NFree++ == 0) {
823 z->z_Next = slgd->ZoneAry[z->z_ZoneIndex];
824 slgd->ZoneAry[z->z_ZoneIndex] = z;
827 --type->ks_inuse[z->z_Cpu];
828 type->ks_memuse[z->z_Cpu] -= z->z_ChunkSize;
831 * If the zone becomes totally free, and there are other zones we
832 * can allocate from, move this zone to the FreeZones list. Since
833 * this code can be called from an IPI callback, do *NOT* try to mess
834 * with kernel_map here. Hysteresis will be performed at malloc() time.
836 if (z->z_NFree == z->z_NMax &&
837 (z->z_Next || slgd->ZoneAry[z->z_ZoneIndex] != z)
841 for (pz = &slgd->ZoneAry[z->z_ZoneIndex]; z != *pz; pz = &(*pz)->z_Next)
845 z->z_Next = slgd->FreeZones;
855 * Directly allocate and wire kernel memory in PAGE_SIZE chunks with the
856 * specified alignment. M_* flags are expected in the flags field.
858 * Alignment must be a multiple of PAGE_SIZE.
860 * NOTE! XXX For the moment we use vm_map_entry_reserve/release(),
861 * but when we move zalloc() over to use this function as its backend
862 * we will have to switch to kreserve/krelease and call reserve(0)
863 * after the new space is made available.
865 * Interrupt code which has preempted other code is not allowed to
866 * use PQ_CACHE pages. However, if an interrupt thread is run
867 * non-preemptively or blocks and then runs non-preemptively, then
868 * it is free to use PQ_CACHE pages.
871 kmem_slab_alloc(vm_size_t size, vm_offset_t align, int flags)
878 vm_map_t map = kernel_map;
880 size = round_page(size);
881 addr = vm_map_min(map);
884 * Reserve properly aligned space from kernel_map
886 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
889 if (vm_map_findspace(map, vm_map_min(map), size, align, &addr)) {
891 if ((flags & (M_RNOWAIT|M_NULLOK)) == 0)
892 panic("kmem_slab_alloc(): kernel_map ran out of space!");
894 vm_map_entry_release(count);
895 if ((flags & M_NULLOK) == 0)
896 panic("kmem_slab_alloc(): kernel_map ran out of space!");
899 offset = addr - VM_MIN_KERNEL_ADDRESS;
900 vm_object_reference(kernel_object);
901 vm_map_insert(map, &count,
902 kernel_object, offset, addr, addr + size,
903 VM_PROT_ALL, VM_PROT_ALL, 0);
908 * Allocate the pages. Do not mess with the PG_ZERO flag yet.
910 for (i = 0; i < size; i += PAGE_SIZE) {
912 vm_pindex_t idx = OFF_TO_IDX(offset + i);
916 vmflags |= VM_ALLOC_ZERO;
917 if (flags & M_USE_RESERVE)
918 vmflags |= VM_ALLOC_SYSTEM;
919 if (flags & M_USE_INTERRUPT_RESERVE)
920 vmflags |= VM_ALLOC_INTERRUPT;
921 if ((flags & (M_RNOWAIT|M_WAITOK)) == 0)
922 panic("kmem_slab_alloc: bad flags %08x (%p)", flags, ((int **)&size)[-1]);
925 * VM_ALLOC_NORMAL can only be set if we are not preempting.
927 * VM_ALLOC_SYSTEM is automatically set if we are preempting and
928 * M_WAITOK was specified as an alternative (i.e. M_USE_RESERVE is
929 * implied in this case), though I'm sure if we really need to do
932 if (flags & M_WAITOK) {
933 if (td->td_preempted) {
934 vmflags |= VM_ALLOC_SYSTEM;
936 vmflags |= VM_ALLOC_NORMAL;
940 m = vm_page_alloc(kernel_object, idx, vmflags);
943 * If the allocation failed we either return NULL or we retry.
945 * If M_WAITOK is specified we wait for more memory and retry.
946 * If M_WAITOK is specified from a preemption we yield instead of
947 * wait. Livelock will not occur because the interrupt thread
948 * will not be preempting anyone the second time around after the
952 if (flags & M_WAITOK) {
953 if (td->td_preempted) {
962 i -= PAGE_SIZE; /* retry */
967 * We were unable to recover, cleanup and return NULL
971 m = vm_page_lookup(kernel_object, OFF_TO_IDX(offset + i));
974 vm_map_delete(map, addr, addr + size, &count);
977 vm_map_entry_release(count);
985 * Mark the map entry as non-pageable using a routine that allows us to
986 * populate the underlying pages.
988 vm_map_set_wired_quick(map, addr, size, &count);
992 * Enter the pages into the pmap and deal with PG_ZERO and M_ZERO.
994 for (i = 0; i < size; i += PAGE_SIZE) {
997 m = vm_page_lookup(kernel_object, OFF_TO_IDX(offset + i));
998 m->valid = VM_PAGE_BITS_ALL;
1001 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 1);
1002 if ((m->flags & PG_ZERO) == 0 && (flags & M_ZERO))
1003 bzero((char *)addr + i, PAGE_SIZE);
1004 vm_page_flag_clear(m, PG_ZERO);
1005 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE | PG_REFERENCED);
1008 vm_map_entry_release(count);
1009 return((void *)addr);
1013 kmem_slab_free(void *ptr, vm_size_t size)
1016 vm_map_remove(kernel_map, (vm_offset_t)ptr, (vm_offset_t)ptr + size);