4 * KERN_SLABALLOC.C - Kernel SLAB memory allocator
6 * Copyright (c) 2003,2004,2010 The DragonFly Project. All rights reserved.
8 * This code is derived from software contributed to The DragonFly Project
9 * by Matthew Dillon <dillon@backplane.com>
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in
19 * the documentation and/or other materials provided with the
21 * 3. Neither the name of The DragonFly Project nor the names of its
22 * contributors may be used to endorse or promote products derived
23 * from this software without specific, prior written permission.
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
28 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
29 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
30 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
31 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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33 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
34 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
35 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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>
103 #include <sys/sysctl.h>
107 #include <vm/vm_param.h>
108 #include <vm/vm_kern.h>
109 #include <vm/vm_extern.h>
110 #include <vm/vm_object.h>
112 #include <vm/vm_map.h>
113 #include <vm/vm_page.h>
114 #include <vm/vm_pageout.h>
116 #include <machine/cpu.h>
118 #include <sys/thread2.h>
120 #define btokup(z) (&pmap_kvtom((vm_offset_t)(z))->ku_pagecnt)
122 #define MEMORY_STRING "ptr=%p type=%p size=%d flags=%04x"
123 #define MEMORY_ARG_SIZE (sizeof(void *) * 2 + sizeof(unsigned long) + \
126 #if !defined(KTR_MEMORY)
127 #define KTR_MEMORY KTR_ALL
129 KTR_INFO_MASTER(memory);
130 KTR_INFO(KTR_MEMORY, memory, malloc_beg, 0, "malloc begin", 0);
131 KTR_INFO(KTR_MEMORY, memory, malloc_end, 1, MEMORY_STRING, MEMORY_ARG_SIZE);
132 KTR_INFO(KTR_MEMORY, memory, free_zero, 2, MEMORY_STRING, MEMORY_ARG_SIZE);
133 KTR_INFO(KTR_MEMORY, memory, free_ovsz, 3, MEMORY_STRING, MEMORY_ARG_SIZE);
134 KTR_INFO(KTR_MEMORY, memory, free_ovsz_delayed, 4, MEMORY_STRING, MEMORY_ARG_SIZE);
135 KTR_INFO(KTR_MEMORY, memory, free_chunk, 5, MEMORY_STRING, MEMORY_ARG_SIZE);
137 KTR_INFO(KTR_MEMORY, memory, free_request, 6, MEMORY_STRING, MEMORY_ARG_SIZE);
138 KTR_INFO(KTR_MEMORY, memory, free_rem_beg, 7, MEMORY_STRING, MEMORY_ARG_SIZE);
139 KTR_INFO(KTR_MEMORY, memory, free_rem_end, 8, MEMORY_STRING, MEMORY_ARG_SIZE);
141 KTR_INFO(KTR_MEMORY, memory, free_beg, 9, "free begin", 0);
142 KTR_INFO(KTR_MEMORY, memory, free_end, 10, "free end", 0);
144 #define logmemory(name, ptr, type, size, flags) \
145 KTR_LOG(memory_ ## name, ptr, type, size, flags)
146 #define logmemory_quick(name) \
147 KTR_LOG(memory_ ## name)
150 * Fixed globals (not per-cpu)
153 static int ZoneLimit;
154 static int ZonePageCount;
155 static uintptr_t ZoneMask;
156 static int ZoneBigAlloc; /* in KB */
157 static int ZoneGenAlloc; /* in KB */
158 struct malloc_type *kmemstatistics; /* exported to vmstat */
159 static int32_t weirdary[16];
161 static void *kmem_slab_alloc(vm_size_t bytes, vm_offset_t align, int flags);
162 static void kmem_slab_free(void *ptr, vm_size_t bytes);
164 #if defined(INVARIANTS)
165 static void chunk_mark_allocated(SLZone *z, void *chunk);
166 static void chunk_mark_free(SLZone *z, void *chunk);
168 #define chunk_mark_allocated(z, chunk)
169 #define chunk_mark_free(z, chunk)
173 * Misc constants. Note that allocations that are exact multiples of
174 * PAGE_SIZE, or exceed the zone limit, fall through to the kmem module.
175 * IN_SAME_PAGE_MASK is used to sanity-check the per-page free lists.
177 #define MIN_CHUNK_SIZE 8 /* in bytes */
178 #define MIN_CHUNK_MASK (MIN_CHUNK_SIZE - 1)
179 #define ZONE_RELS_THRESH 32 /* threshold number of zones */
180 #define IN_SAME_PAGE_MASK (~(intptr_t)PAGE_MASK | MIN_CHUNK_MASK)
183 * The WEIRD_ADDR is used as known text to copy into free objects to
184 * try to create deterministic failure cases if the data is accessed after
187 #define WEIRD_ADDR 0xdeadc0de
188 #define MAX_COPY sizeof(weirdary)
189 #define ZERO_LENGTH_PTR ((void *)-8)
192 * Misc global malloc buckets
195 MALLOC_DEFINE(M_CACHE, "cache", "Various Dynamically allocated caches");
196 MALLOC_DEFINE(M_DEVBUF, "devbuf", "device driver memory");
197 MALLOC_DEFINE(M_TEMP, "temp", "misc temporary data buffers");
199 MALLOC_DEFINE(M_IP6OPT, "ip6opt", "IPv6 options");
200 MALLOC_DEFINE(M_IP6NDP, "ip6ndp", "IPv6 Neighbor Discovery");
203 * Initialize the slab memory allocator. We have to choose a zone size based
204 * on available physical memory. We choose a zone side which is approximately
205 * 1/1024th of our memory, so if we have 128MB of ram we have a zone size of
206 * 128K. The zone size is limited to the bounds set in slaballoc.h
207 * (typically 32K min, 128K max).
209 static void kmeminit(void *dummy);
213 SYSINIT(kmem, SI_BOOT1_ALLOCATOR, SI_ORDER_FIRST, kmeminit, NULL)
217 * If enabled any memory allocated without M_ZERO is initialized to -1.
219 static int use_malloc_pattern;
220 SYSCTL_INT(_debug, OID_AUTO, use_malloc_pattern, CTLFLAG_RW,
221 &use_malloc_pattern, 0,
222 "Initialize memory to -1 if M_ZERO not specified");
225 static int ZoneRelsThresh = ZONE_RELS_THRESH;
226 SYSCTL_INT(_kern, OID_AUTO, zone_big_alloc, CTLFLAG_RD, &ZoneBigAlloc, 0, "");
227 SYSCTL_INT(_kern, OID_AUTO, zone_gen_alloc, CTLFLAG_RD, &ZoneGenAlloc, 0, "");
228 SYSCTL_INT(_kern, OID_AUTO, zone_cache, CTLFLAG_RW, &ZoneRelsThresh, 0, "");
231 * Returns the kernel memory size limit for the purposes of initializing
232 * various subsystem caches. The smaller of available memory and the KVM
233 * memory space is returned.
235 * The size in megabytes is returned.
242 limsize = (size_t)vmstats.v_page_count * PAGE_SIZE;
243 if (limsize > KvaSize)
245 return (limsize / (1024 * 1024));
249 kmeminit(void *dummy)
255 limsize = kmem_lim_size();
256 usesize = (int)(limsize * 1024); /* convert to KB */
259 * If the machine has a large KVM space and more than 8G of ram,
260 * double the zone release threshold to reduce SMP invalidations.
261 * If more than 16G of ram, do it again.
263 * The BIOS eats a little ram so add some slop. We want 8G worth of
264 * memory sticks to trigger the first adjustment.
266 if (ZoneRelsThresh == ZONE_RELS_THRESH) {
267 if (limsize >= 7 * 1024)
269 if (limsize >= 15 * 1024)
274 * Calculate the zone size. This typically calculates to
275 * ZALLOC_MAX_ZONE_SIZE
277 ZoneSize = ZALLOC_MIN_ZONE_SIZE;
278 while (ZoneSize < ZALLOC_MAX_ZONE_SIZE && (ZoneSize << 1) < usesize)
280 ZoneLimit = ZoneSize / 4;
281 if (ZoneLimit > ZALLOC_ZONE_LIMIT)
282 ZoneLimit = ZALLOC_ZONE_LIMIT;
283 ZoneMask = ~(uintptr_t)(ZoneSize - 1);
284 ZonePageCount = ZoneSize / PAGE_SIZE;
286 for (i = 0; i < NELEM(weirdary); ++i)
287 weirdary[i] = WEIRD_ADDR;
289 ZeroPage = kmem_slab_alloc(PAGE_SIZE, PAGE_SIZE, M_WAITOK|M_ZERO);
292 kprintf("Slab ZoneSize set to %dKB\n", ZoneSize / 1024);
296 * Initialize a malloc type tracking structure.
299 malloc_init(void *data)
301 struct malloc_type *type = data;
304 if (type->ks_magic != M_MAGIC)
305 panic("malloc type lacks magic");
307 if (type->ks_limit != 0)
310 if (vmstats.v_page_count == 0)
311 panic("malloc_init not allowed before vm init");
313 limsize = kmem_lim_size() * (1024 * 1024);
314 type->ks_limit = limsize / 10;
316 type->ks_next = kmemstatistics;
317 kmemstatistics = type;
321 malloc_uninit(void *data)
323 struct malloc_type *type = data;
324 struct malloc_type *t;
330 if (type->ks_magic != M_MAGIC)
331 panic("malloc type lacks magic");
333 if (vmstats.v_page_count == 0)
334 panic("malloc_uninit not allowed before vm init");
336 if (type->ks_limit == 0)
337 panic("malloc_uninit on uninitialized type");
340 /* Make sure that all pending kfree()s are finished. */
341 lwkt_synchronize_ipiqs("muninit");
346 * memuse is only correct in aggregation. Due to memory being allocated
347 * on one cpu and freed on another individual array entries may be
348 * negative or positive (canceling each other out).
350 for (i = ttl = 0; i < ncpus; ++i)
351 ttl += type->ks_memuse[i];
353 kprintf("malloc_uninit: %ld bytes of '%s' still allocated on cpu %d\n",
354 ttl, type->ks_shortdesc, i);
357 if (type == kmemstatistics) {
358 kmemstatistics = type->ks_next;
360 for (t = kmemstatistics; t->ks_next != NULL; t = t->ks_next) {
361 if (t->ks_next == type) {
362 t->ks_next = type->ks_next;
367 type->ks_next = NULL;
372 * Increase the kmalloc pool limit for the specified pool. No changes
373 * are the made if the pool would shrink.
376 kmalloc_raise_limit(struct malloc_type *type, size_t bytes)
378 if (type->ks_limit == 0)
382 if (type->ks_limit < bytes)
383 type->ks_limit = bytes;
387 * Dynamically create a malloc pool. This function is a NOP if *typep is
391 kmalloc_create(struct malloc_type **typep, const char *descr)
393 struct malloc_type *type;
395 if (*typep == NULL) {
396 type = kmalloc(sizeof(*type), M_TEMP, M_WAITOK | M_ZERO);
397 type->ks_magic = M_MAGIC;
398 type->ks_shortdesc = descr;
405 * Destroy a dynamically created malloc pool. This function is a NOP if
406 * the pool has already been destroyed.
409 kmalloc_destroy(struct malloc_type **typep)
411 if (*typep != NULL) {
412 malloc_uninit(*typep);
413 kfree(*typep, M_TEMP);
419 * Calculate the zone index for the allocation request size and set the
420 * allocation request size to that particular zone's chunk size.
423 zoneindex(unsigned long *bytes)
425 unsigned int n = (unsigned int)*bytes; /* unsigned for shift opt */
427 *bytes = n = (n + 7) & ~7;
428 return(n / 8 - 1); /* 8 byte chunks, 16 zones */
431 *bytes = n = (n + 15) & ~15;
436 *bytes = n = (n + 31) & ~31;
440 *bytes = n = (n + 63) & ~63;
444 *bytes = n = (n + 127) & ~127;
445 return(n / 128 + 31);
448 *bytes = n = (n + 255) & ~255;
449 return(n / 256 + 39);
451 *bytes = n = (n + 511) & ~511;
452 return(n / 512 + 47);
454 #if ZALLOC_ZONE_LIMIT > 8192
456 *bytes = n = (n + 1023) & ~1023;
457 return(n / 1024 + 55);
460 #if ZALLOC_ZONE_LIMIT > 16384
462 *bytes = n = (n + 2047) & ~2047;
463 return(n / 2048 + 63);
466 panic("Unexpected byte count %d", n);
472 * Used to debug memory corruption issues. Record up to (typically 32)
473 * allocation sources for this zone (for a particular chunk size).
477 slab_record_source(SLZone *z, const char *file, int line)
480 int b = line & (SLAB_DEBUG_ENTRIES - 1);
484 if (z->z_Sources[i].file == file && z->z_Sources[i].line == line)
486 if (z->z_Sources[i].file == NULL)
488 i = (i + 1) & (SLAB_DEBUG_ENTRIES - 1);
490 z->z_Sources[i].file = file;
491 z->z_Sources[i].line = line;
497 * kmalloc() (SLAB ALLOCATOR)
499 * Allocate memory via the slab allocator. If the request is too large,
500 * or if it page-aligned beyond a certain size, we fall back to the
501 * KMEM subsystem. A SLAB tracking descriptor must be specified, use
502 * &SlabMisc if you don't care.
504 * M_RNOWAIT - don't block.
505 * M_NULLOK - return NULL instead of blocking.
506 * M_ZERO - zero the returned memory.
507 * M_USE_RESERVE - allow greater drawdown of the free list
508 * M_USE_INTERRUPT_RESERVE - allow the freelist to be exhausted
515 kmalloc_debug(unsigned long size, struct malloc_type *type, int flags,
516 const char *file, int line)
519 kmalloc(unsigned long size, struct malloc_type *type, int flags)
528 struct globaldata *gd;
534 logmemory_quick(malloc_beg);
539 * XXX silly to have this in the critical path.
541 if (type->ks_limit == 0) {
543 if (type->ks_limit == 0)
550 * Handle the case where the limit is reached. Panic if we can't return
551 * NULL. The original malloc code looped, but this tended to
552 * simply deadlock the computer.
554 * ks_loosememuse is an up-only limit that is NOT MP-synchronized, used
555 * to determine if a more complete limit check should be done. The
556 * actual memory use is tracked via ks_memuse[cpu].
558 while (type->ks_loosememuse >= type->ks_limit) {
562 for (i = ttl = 0; i < ncpus; ++i)
563 ttl += type->ks_memuse[i];
564 type->ks_loosememuse = ttl; /* not MP synchronized */
565 if ((ssize_t)ttl < 0) /* deal with occassional race */
567 if (ttl >= type->ks_limit) {
568 if (flags & M_NULLOK) {
569 logmemory(malloc_end, NULL, type, size, flags);
572 panic("%s: malloc limit exceeded", type->ks_shortdesc);
577 * Handle the degenerate size == 0 case. Yes, this does happen.
578 * Return a special pointer. This is to maintain compatibility with
579 * the original malloc implementation. Certain devices, such as the
580 * adaptec driver, not only allocate 0 bytes, they check for NULL and
581 * also realloc() later on. Joy.
584 logmemory(malloc_end, ZERO_LENGTH_PTR, type, size, flags);
585 return(ZERO_LENGTH_PTR);
589 * Handle hysteresis from prior frees here in malloc(). We cannot
590 * safely manipulate the kernel_map in free() due to free() possibly
591 * being called via an IPI message or from sensitive interrupt code.
593 * NOTE: ku_pagecnt must be cleared before we free the slab or we
594 * might race another cpu allocating the kva and setting
597 while (slgd->NFreeZones > ZoneRelsThresh && (flags & M_RNOWAIT) == 0) {
599 if (slgd->NFreeZones > ZoneRelsThresh) { /* crit sect race */
603 slgd->FreeZones = z->z_Next;
607 kmem_slab_free(z, ZoneSize); /* may block */
608 atomic_add_int(&ZoneGenAlloc, -(int)ZoneSize / 1024);
614 * XXX handle oversized frees that were queued from kfree().
616 while (slgd->FreeOvZones && (flags & M_RNOWAIT) == 0) {
618 if ((z = slgd->FreeOvZones) != NULL) {
621 KKASSERT(z->z_Magic == ZALLOC_OVSZ_MAGIC);
622 slgd->FreeOvZones = z->z_Next;
623 tsize = z->z_ChunkSize;
624 kmem_slab_free(z, tsize); /* may block */
625 atomic_add_int(&ZoneBigAlloc, -(int)tsize / 1024);
631 * Handle large allocations directly. There should not be very many of
632 * these so performance is not a big issue.
634 * The backend allocator is pretty nasty on a SMP system. Use the
635 * slab allocator for one and two page-sized chunks even though we lose
636 * some efficiency. XXX maybe fix mmio and the elf loader instead.
638 if (size >= ZoneLimit || ((size & PAGE_MASK) == 0 && size > PAGE_SIZE*2)) {
641 size = round_page(size);
642 chunk = kmem_slab_alloc(size, PAGE_SIZE, flags);
644 logmemory(malloc_end, NULL, type, size, flags);
647 atomic_add_int(&ZoneBigAlloc, (int)size / 1024);
648 flags &= ~M_ZERO; /* result already zero'd if M_ZERO was set */
649 flags |= M_PASSIVE_ZERO;
651 *kup = size / PAGE_SIZE;
657 * Attempt to allocate out of an existing zone. First try the free list,
658 * then allocate out of unallocated space. If we find a good zone move
659 * it to the head of the list so later allocations find it quickly
660 * (we might have thousands of zones in the list).
662 * Note: zoneindex() will panic of size is too large.
664 zi = zoneindex(&size);
665 KKASSERT(zi < NZONES);
668 if ((z = slgd->ZoneAry[zi]) != NULL) {
670 * Locate a chunk - we have to have at least one. If this is the
671 * last chunk go ahead and do the work to retrieve chunks freed
672 * from remote cpus, and if the zone is still empty move it off
675 if (--z->z_NFree <= 0) {
676 KKASSERT(z->z_NFree == 0);
680 * WARNING! This code competes with other cpus. It is ok
681 * for us to not drain RChunks here but we might as well, and
682 * it is ok if more accumulate after we're done.
684 * Set RSignal before pulling rchunks off, indicating that we
685 * will be moving ourselves off of the ZoneAry. Remote ends will
686 * read RSignal before putting rchunks on thus interlocking
687 * their IPI signaling.
689 if (z->z_RChunks == NULL)
690 atomic_swap_int(&z->z_RSignal, 1);
692 while ((bchunk = z->z_RChunks) != NULL) {
694 if (atomic_cmpset_ptr(&z->z_RChunks, bchunk, NULL)) {
695 *z->z_LChunksp = bchunk;
697 chunk_mark_free(z, bchunk);
698 z->z_LChunksp = &bchunk->c_Next;
699 bchunk = bchunk->c_Next;
707 * Remove from the zone list if no free chunks remain.
710 if (z->z_NFree == 0) {
711 slgd->ZoneAry[zi] = z->z_Next;
719 * Fast path, we have chunks available in z_LChunks.
721 chunk = z->z_LChunks;
723 chunk_mark_allocated(z, chunk);
724 z->z_LChunks = chunk->c_Next;
725 if (z->z_LChunks == NULL)
726 z->z_LChunksp = &z->z_LChunks;
728 slab_record_source(z, file, line);
734 * No chunks are available in LChunks, the free chunk MUST be
735 * in the never-before-used memory area, controlled by UIndex.
737 * The consequences are very serious if our zone got corrupted so
738 * we use an explicit panic rather than a KASSERT.
740 if (z->z_UIndex + 1 != z->z_NMax)
745 if (z->z_UIndex == z->z_UEndIndex)
746 panic("slaballoc: corrupted zone");
748 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size);
749 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) {
751 flags |= M_PASSIVE_ZERO;
753 chunk_mark_allocated(z, chunk);
755 slab_record_source(z, file, line);
761 * If all zones are exhausted we need to allocate a new zone for this
762 * index. Use M_ZERO to take advantage of pre-zerod pages. Also see
763 * UAlloc use above in regards to M_ZERO. Note that when we are reusing
764 * a zone from the FreeZones list UAlloc'd data will not be zero'd, and
765 * we do not pre-zero it because we do not want to mess up the L1 cache.
767 * At least one subsystem, the tty code (see CROUND) expects power-of-2
768 * allocations to be power-of-2 aligned. We maintain compatibility by
769 * adjusting the base offset below.
775 if ((z = slgd->FreeZones) != NULL) {
776 slgd->FreeZones = z->z_Next;
778 bzero(z, sizeof(SLZone));
779 z->z_Flags |= SLZF_UNOTZEROD;
781 z = kmem_slab_alloc(ZoneSize, ZoneSize, flags|M_ZERO);
784 atomic_add_int(&ZoneGenAlloc, (int)ZoneSize / 1024);
788 * How big is the base structure?
790 #if defined(INVARIANTS)
792 * Make room for z_Bitmap. An exact calculation is somewhat more
793 * complicated so don't make an exact calculation.
795 off = offsetof(SLZone, z_Bitmap[(ZoneSize / size + 31) / 32]);
796 bzero(z->z_Bitmap, (ZoneSize / size + 31) / 8);
798 off = sizeof(SLZone);
802 * Guarentee power-of-2 alignment for power-of-2-sized chunks.
803 * Otherwise just 8-byte align the data.
805 if ((size | (size - 1)) + 1 == (size << 1))
806 off = (off + size - 1) & ~(size - 1);
808 off = (off + MIN_CHUNK_MASK) & ~MIN_CHUNK_MASK;
809 z->z_Magic = ZALLOC_SLAB_MAGIC;
811 z->z_NMax = (ZoneSize - off) / size;
812 z->z_NFree = z->z_NMax - 1;
813 z->z_BasePtr = (char *)z + off;
814 z->z_UIndex = z->z_UEndIndex = slgd->JunkIndex % z->z_NMax;
815 z->z_ChunkSize = size;
817 z->z_Cpu = gd->gd_cpuid;
818 z->z_LChunksp = &z->z_LChunks;
820 bcopy(z->z_Sources, z->z_AltSources, sizeof(z->z_Sources));
821 bzero(z->z_Sources, sizeof(z->z_Sources));
823 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size);
824 z->z_Next = slgd->ZoneAry[zi];
825 slgd->ZoneAry[zi] = z;
826 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) {
827 flags &= ~M_ZERO; /* already zero'd */
828 flags |= M_PASSIVE_ZERO;
831 *kup = -(z->z_Cpu + 1); /* -1 to -(N+1) */
832 chunk_mark_allocated(z, chunk);
834 slab_record_source(z, file, line);
838 * Slide the base index for initial allocations out of the next
839 * zone we create so we do not over-weight the lower part of the
842 slgd->JunkIndex = (slgd->JunkIndex + ZALLOC_SLAB_SLIDE)
843 & (ZALLOC_MAX_ZONE_SIZE - 1);
847 ++type->ks_inuse[gd->gd_cpuid];
848 type->ks_memuse[gd->gd_cpuid] += size;
849 type->ks_loosememuse += size; /* not MP synchronized */
855 else if ((flags & (M_ZERO|M_PASSIVE_ZERO)) == 0) {
856 if (use_malloc_pattern) {
857 for (i = 0; i < size; i += sizeof(int)) {
858 *(int *)((char *)chunk + i) = -1;
861 chunk->c_Next = (void *)-1; /* avoid accidental double-free check */
864 logmemory(malloc_end, chunk, type, size, flags);
868 logmemory(malloc_end, NULL, type, size, flags);
873 * kernel realloc. (SLAB ALLOCATOR) (MP SAFE)
875 * Generally speaking this routine is not called very often and we do
876 * not attempt to optimize it beyond reusing the same pointer if the
877 * new size fits within the chunking of the old pointer's zone.
881 krealloc_debug(void *ptr, unsigned long size,
882 struct malloc_type *type, int flags,
883 const char *file, int line)
886 krealloc(void *ptr, unsigned long size, struct malloc_type *type, int flags)
894 KKASSERT((flags & M_ZERO) == 0); /* not supported */
896 if (ptr == NULL || ptr == ZERO_LENGTH_PTR)
897 return(kmalloc_debug(size, type, flags, file, line));
904 * Handle oversized allocations. XXX we really should require that a
905 * size be passed to free() instead of this nonsense.
909 osize = *kup << PAGE_SHIFT;
910 if (osize == round_page(size))
912 if ((nptr = kmalloc_debug(size, type, flags, file, line)) == NULL)
914 bcopy(ptr, nptr, min(size, osize));
920 * Get the original allocation's zone. If the new request winds up
921 * using the same chunk size we do not have to do anything.
923 z = (SLZone *)((uintptr_t)ptr & ZoneMask);
926 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC);
929 * Allocate memory for the new request size. Note that zoneindex has
930 * already adjusted the request size to the appropriate chunk size, which
931 * should optimize our bcopy(). Then copy and return the new pointer.
933 * Resizing a non-power-of-2 allocation to a power-of-2 size does not
934 * necessary align the result.
936 * We can only zoneindex (to align size to the chunk size) if the new
937 * size is not too large.
939 if (size < ZoneLimit) {
941 if (z->z_ChunkSize == size)
944 if ((nptr = kmalloc_debug(size, type, flags, file, line)) == NULL)
946 bcopy(ptr, nptr, min(size, z->z_ChunkSize));
952 * Return the kmalloc limit for this type, in bytes.
955 kmalloc_limit(struct malloc_type *type)
957 if (type->ks_limit == 0) {
959 if (type->ks_limit == 0)
963 return(type->ks_limit);
967 * Allocate a copy of the specified string.
969 * (MP SAFE) (MAY BLOCK)
973 kstrdup_debug(const char *str, struct malloc_type *type,
974 const char *file, int line)
977 kstrdup(const char *str, struct malloc_type *type)
980 int zlen; /* length inclusive of terminating NUL */
985 zlen = strlen(str) + 1;
986 nstr = kmalloc_debug(zlen, type, M_WAITOK, file, line);
987 bcopy(str, nstr, zlen);
993 * Notify our cpu that a remote cpu has freed some chunks in a zone that
994 * we own. RCount will be bumped so the memory should be good, but validate
999 kfree_remote(void *ptr)
1007 slgd = &mycpu->gd_slab;
1010 KKASSERT(*kup == -((int)mycpuid + 1));
1011 KKASSERT(z->z_RCount > 0);
1012 atomic_subtract_int(&z->z_RCount, 1);
1014 logmemory(free_rem_beg, z, NULL, 0, 0);
1015 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC);
1016 KKASSERT(z->z_Cpu == mycpu->gd_cpuid);
1020 * Indicate that we will no longer be off of the ZoneAry by
1027 * Atomically extract the bchunks list and then process it back
1028 * into the lchunks list. We want to append our bchunks to the
1029 * lchunks list and not prepend since we likely do not have
1030 * cache mastership of the related data (not that it helps since
1031 * we are using c_Next).
1033 while ((bchunk = z->z_RChunks) != NULL) {
1035 if (atomic_cmpset_ptr(&z->z_RChunks, bchunk, NULL)) {
1036 *z->z_LChunksp = bchunk;
1038 chunk_mark_free(z, bchunk);
1039 z->z_LChunksp = &bchunk->c_Next;
1040 bchunk = bchunk->c_Next;
1046 if (z->z_NFree && nfree == 0) {
1047 z->z_Next = slgd->ZoneAry[z->z_ZoneIndex];
1048 slgd->ZoneAry[z->z_ZoneIndex] = z;
1052 * If the zone becomes totally free, and there are other zones we
1053 * can allocate from, move this zone to the FreeZones list. Since
1054 * this code can be called from an IPI callback, do *NOT* try to mess
1055 * with kernel_map here. Hysteresis will be performed at malloc() time.
1057 * Do not move the zone if there is an IPI inflight, otherwise MP
1058 * races can result in our free_remote code accessing a destroyed
1061 if (z->z_NFree == z->z_NMax &&
1062 (z->z_Next || slgd->ZoneAry[z->z_ZoneIndex] != z) &&
1068 for (pz = &slgd->ZoneAry[z->z_ZoneIndex];
1070 pz = &(*pz)->z_Next) {
1075 z->z_Next = slgd->FreeZones;
1076 slgd->FreeZones = z;
1081 logmemory(free_rem_end, z, bchunk, 0, 0);
1087 * free (SLAB ALLOCATOR)
1089 * Free a memory block previously allocated by malloc. Note that we do not
1090 * attempt to update ks_loosememuse as MP races could prevent us from
1091 * checking memory limits in malloc.
1096 kfree(void *ptr, struct malloc_type *type)
1101 struct globaldata *gd;
1109 logmemory_quick(free_beg);
1111 slgd = &gd->gd_slab;
1114 panic("trying to free NULL pointer");
1117 * Handle special 0-byte allocations
1119 if (ptr == ZERO_LENGTH_PTR) {
1120 logmemory(free_zero, ptr, type, -1, 0);
1121 logmemory_quick(free_end);
1126 * Panic on bad malloc type
1128 if (type->ks_magic != M_MAGIC)
1129 panic("free: malloc type lacks magic");
1132 * Handle oversized allocations. XXX we really should require that a
1133 * size be passed to free() instead of this nonsense.
1135 * This code is never called via an ipi.
1139 size = *kup << PAGE_SHIFT;
1142 KKASSERT(sizeof(weirdary) <= size);
1143 bcopy(weirdary, ptr, sizeof(weirdary));
1146 * NOTE: For oversized allocations we do not record the
1147 * originating cpu. It gets freed on the cpu calling
1148 * kfree(). The statistics are in aggregate.
1150 * note: XXX we have still inherited the interrupts-can't-block
1151 * assumption. An interrupt thread does not bump
1152 * gd_intr_nesting_level so check TDF_INTTHREAD. This is
1153 * primarily until we can fix softupdate's assumptions about free().
1156 --type->ks_inuse[gd->gd_cpuid];
1157 type->ks_memuse[gd->gd_cpuid] -= size;
1158 if (mycpu->gd_intr_nesting_level ||
1159 (gd->gd_curthread->td_flags & TDF_INTTHREAD))
1161 logmemory(free_ovsz_delayed, ptr, type, size, 0);
1163 z->z_Magic = ZALLOC_OVSZ_MAGIC;
1164 z->z_Next = slgd->FreeOvZones;
1165 z->z_ChunkSize = size;
1166 slgd->FreeOvZones = z;
1170 logmemory(free_ovsz, ptr, type, size, 0);
1171 kmem_slab_free(ptr, size); /* may block */
1172 atomic_add_int(&ZoneBigAlloc, -(int)size / 1024);
1174 logmemory_quick(free_end);
1179 * Zone case. Figure out the zone based on the fact that it is
1182 z = (SLZone *)((uintptr_t)ptr & ZoneMask);
1185 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC);
1188 * If we do not own the zone then use atomic ops to free to the
1189 * remote cpu linked list and notify the target zone using a
1192 * The target zone cannot be deallocated while we own a chunk of it,
1193 * so the zone header's storage is stable until the very moment
1194 * we adjust z_RChunks. After that we cannot safely dereference (z).
1196 * (no critical section needed)
1198 if (z->z_CpuGd != gd) {
1201 * Making these adjustments now allow us to avoid passing (type)
1202 * to the remote cpu. Note that ks_inuse/ks_memuse is being
1203 * adjusted on OUR cpu, not the zone cpu, but it should all still
1204 * sum up properly and cancel out.
1207 --type->ks_inuse[gd->gd_cpuid];
1208 type->ks_memuse[gd->gd_cpuid] -= z->z_ChunkSize;
1212 * WARNING! This code competes with other cpus. Once we
1213 * successfully link the chunk to RChunks the remote
1214 * cpu can rip z's storage out from under us.
1216 * Bumping RCount prevents z's storage from getting
1219 rsignal = z->z_RSignal;
1222 atomic_add_int(&z->z_RCount, 1);
1226 bchunk = z->z_RChunks;
1228 chunk->c_Next = bchunk;
1231 if (atomic_cmpset_ptr(&z->z_RChunks, bchunk, chunk))
1236 * We have to signal the remote cpu if our actions will cause
1237 * the remote zone to be placed back on ZoneAry so it can
1238 * move the zone back on.
1240 * We only need to deal with NULL->non-NULL RChunk transitions
1241 * and only if z_RSignal is set. We interlock by reading rsignal
1242 * before adding our chunk to RChunks. This should result in
1243 * virtually no IPI traffic.
1245 * We can use a passive IPI to reduce overhead even further.
1247 if (bchunk == NULL && rsignal) {
1248 logmemory(free_request, ptr, type, z->z_ChunkSize, 0);
1249 lwkt_send_ipiq_passive(z->z_CpuGd, kfree_remote, z);
1250 /* z can get ripped out from under us from this point on */
1251 } else if (rsignal) {
1252 atomic_subtract_int(&z->z_RCount, 1);
1253 /* z can get ripped out from under us from this point on */
1256 panic("Corrupt SLZone");
1258 logmemory_quick(free_end);
1265 logmemory(free_chunk, ptr, type, z->z_ChunkSize, 0);
1269 chunk_mark_free(z, chunk);
1272 * Put weird data into the memory to detect modifications after freeing,
1273 * illegal pointer use after freeing (we should fault on the odd address),
1274 * and so forth. XXX needs more work, see the old malloc code.
1277 if (z->z_ChunkSize < sizeof(weirdary))
1278 bcopy(weirdary, chunk, z->z_ChunkSize);
1280 bcopy(weirdary, chunk, sizeof(weirdary));
1284 * Add this free non-zero'd chunk to a linked list for reuse. Add
1285 * to the front of the linked list so it is more likely to be
1286 * reallocated, since it is already in our L1 cache.
1289 if ((vm_offset_t)chunk < KvaStart || (vm_offset_t)chunk >= KvaEnd)
1290 panic("BADFREE %p", chunk);
1292 chunk->c_Next = z->z_LChunks;
1293 z->z_LChunks = chunk;
1294 if (chunk->c_Next == NULL)
1295 z->z_LChunksp = &chunk->c_Next;
1298 if (chunk->c_Next && (vm_offset_t)chunk->c_Next < KvaStart)
1303 * Bump the number of free chunks. If it becomes non-zero the zone
1304 * must be added back onto the appropriate list.
1306 if (z->z_NFree++ == 0) {
1307 z->z_Next = slgd->ZoneAry[z->z_ZoneIndex];
1308 slgd->ZoneAry[z->z_ZoneIndex] = z;
1311 --type->ks_inuse[z->z_Cpu];
1312 type->ks_memuse[z->z_Cpu] -= z->z_ChunkSize;
1315 * If the zone becomes totally free, and there are other zones we
1316 * can allocate from, move this zone to the FreeZones list. Since
1317 * this code can be called from an IPI callback, do *NOT* try to mess
1318 * with kernel_map here. Hysteresis will be performed at malloc() time.
1320 if (z->z_NFree == z->z_NMax &&
1321 (z->z_Next || slgd->ZoneAry[z->z_ZoneIndex] != z) &&
1327 for (pz = &slgd->ZoneAry[z->z_ZoneIndex]; z != *pz; pz = &(*pz)->z_Next)
1331 z->z_Next = slgd->FreeZones;
1332 slgd->FreeZones = z;
1337 logmemory_quick(free_end);
1341 #if defined(INVARIANTS)
1344 * Helper routines for sanity checks
1348 chunk_mark_allocated(SLZone *z, void *chunk)
1350 int bitdex = ((char *)chunk - (char *)z->z_BasePtr) / z->z_ChunkSize;
1353 KKASSERT((((intptr_t)chunk ^ (intptr_t)z) & ZoneMask) == 0);
1354 KASSERT(bitdex >= 0 && bitdex < z->z_NMax,
1355 ("memory chunk %p bit index %d is illegal", chunk, bitdex));
1356 bitptr = &z->z_Bitmap[bitdex >> 5];
1358 KASSERT((*bitptr & (1 << bitdex)) == 0,
1359 ("memory chunk %p is already allocated!", chunk));
1360 *bitptr |= 1 << bitdex;
1365 chunk_mark_free(SLZone *z, void *chunk)
1367 int bitdex = ((char *)chunk - (char *)z->z_BasePtr) / z->z_ChunkSize;
1370 KKASSERT((((intptr_t)chunk ^ (intptr_t)z) & ZoneMask) == 0);
1371 KASSERT(bitdex >= 0 && bitdex < z->z_NMax,
1372 ("memory chunk %p bit index %d is illegal!", chunk, bitdex));
1373 bitptr = &z->z_Bitmap[bitdex >> 5];
1375 KASSERT((*bitptr & (1 << bitdex)) != 0,
1376 ("memory chunk %p is already free!", chunk));
1377 *bitptr &= ~(1 << bitdex);
1385 * Directly allocate and wire kernel memory in PAGE_SIZE chunks with the
1386 * specified alignment. M_* flags are expected in the flags field.
1388 * Alignment must be a multiple of PAGE_SIZE.
1390 * NOTE! XXX For the moment we use vm_map_entry_reserve/release(),
1391 * but when we move zalloc() over to use this function as its backend
1392 * we will have to switch to kreserve/krelease and call reserve(0)
1393 * after the new space is made available.
1395 * Interrupt code which has preempted other code is not allowed to
1396 * use PQ_CACHE pages. However, if an interrupt thread is run
1397 * non-preemptively or blocks and then runs non-preemptively, then
1398 * it is free to use PQ_CACHE pages. <--- may not apply any longer XXX
1401 kmem_slab_alloc(vm_size_t size, vm_offset_t align, int flags)
1405 int count, vmflags, base_vmflags;
1406 vm_page_t mbase = NULL;
1410 size = round_page(size);
1411 addr = vm_map_min(&kernel_map);
1413 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
1415 vm_map_lock(&kernel_map);
1416 if (vm_map_findspace(&kernel_map, addr, size, align, 0, &addr)) {
1417 vm_map_unlock(&kernel_map);
1418 if ((flags & M_NULLOK) == 0)
1419 panic("kmem_slab_alloc(): kernel_map ran out of space!");
1420 vm_map_entry_release(count);
1426 * kernel_object maps 1:1 to kernel_map.
1428 vm_object_hold(&kernel_object);
1429 vm_object_reference_locked(&kernel_object);
1430 vm_map_insert(&kernel_map, &count,
1431 &kernel_object, addr, addr, addr + size,
1433 VM_PROT_ALL, VM_PROT_ALL,
1435 vm_object_drop(&kernel_object);
1436 vm_map_set_wired_quick(&kernel_map, addr, size, &count);
1437 vm_map_unlock(&kernel_map);
1443 base_vmflags |= VM_ALLOC_ZERO;
1444 if (flags & M_USE_RESERVE)
1445 base_vmflags |= VM_ALLOC_SYSTEM;
1446 if (flags & M_USE_INTERRUPT_RESERVE)
1447 base_vmflags |= VM_ALLOC_INTERRUPT;
1448 if ((flags & (M_RNOWAIT|M_WAITOK)) == 0) {
1449 panic("kmem_slab_alloc: bad flags %08x (%p)",
1450 flags, ((int **)&size)[-1]);
1454 * Allocate the pages. Do not mess with the PG_ZERO flag or map
1455 * them yet. VM_ALLOC_NORMAL can only be set if we are not preempting.
1457 * VM_ALLOC_SYSTEM is automatically set if we are preempting and
1458 * M_WAITOK was specified as an alternative (i.e. M_USE_RESERVE is
1459 * implied in this case), though I'm not sure if we really need to
1462 vmflags = base_vmflags;
1463 if (flags & M_WAITOK) {
1464 if (td->td_preempted)
1465 vmflags |= VM_ALLOC_SYSTEM;
1467 vmflags |= VM_ALLOC_NORMAL;
1470 vm_object_hold(&kernel_object);
1471 for (i = 0; i < size; i += PAGE_SIZE) {
1472 m = vm_page_alloc(&kernel_object, OFF_TO_IDX(addr + i), vmflags);
1477 * If the allocation failed we either return NULL or we retry.
1479 * If M_WAITOK is specified we wait for more memory and retry.
1480 * If M_WAITOK is specified from a preemption we yield instead of
1481 * wait. Livelock will not occur because the interrupt thread
1482 * will not be preempting anyone the second time around after the
1486 if (flags & M_WAITOK) {
1487 if (td->td_preempted) {
1492 i -= PAGE_SIZE; /* retry */
1500 * Check and deal with an allocation failure
1505 m = vm_page_lookup(&kernel_object, OFF_TO_IDX(addr + i));
1506 /* page should already be busy */
1509 vm_map_lock(&kernel_map);
1510 vm_map_delete(&kernel_map, addr, addr + size, &count);
1511 vm_map_unlock(&kernel_map);
1512 vm_object_drop(&kernel_object);
1514 vm_map_entry_release(count);
1522 * NOTE: The VM pages are still busied. mbase points to the first one
1523 * but we have to iterate via vm_page_next()
1525 vm_object_drop(&kernel_object);
1529 * Enter the pages into the pmap and deal with PG_ZERO and M_ZERO.
1536 * page should already be busy
1538 m->valid = VM_PAGE_BITS_ALL;
1540 pmap_enter(&kernel_pmap, addr + i, m, VM_PROT_ALL | VM_PROT_NOSYNC, 1);
1541 if ((m->flags & PG_ZERO) == 0 && (flags & M_ZERO))
1542 bzero((char *)addr + i, PAGE_SIZE);
1543 vm_page_flag_clear(m, PG_ZERO);
1544 KKASSERT(m->flags & (PG_WRITEABLE | PG_MAPPED));
1545 vm_page_flag_set(m, PG_REFERENCED);
1549 vm_object_hold(&kernel_object);
1550 m = vm_page_next(m);
1551 vm_object_drop(&kernel_object);
1554 vm_map_entry_release(count);
1555 return((void *)addr);
1562 kmem_slab_free(void *ptr, vm_size_t size)
1565 vm_map_remove(&kernel_map, (vm_offset_t)ptr, (vm_offset_t)ptr + size);