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;
32 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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 * Alignment properties:
82 * - All power-of-2 sized allocations are power-of-2 aligned.
83 * - Allocations with M_POWEROF2 are power-of-2 aligned on the nearest
84 * power-of-2 round up of 'size'.
85 * - Non-power-of-2 sized allocations are zone chunk size aligned (see the
86 * above table 'Chunking' column).
88 * API REQUIREMENTS AND SIDE EFFECTS
90 * To operate as a drop-in replacement to the FreeBSD-4.x malloc() we
91 * have remained compatible with the following API requirements:
93 * + malloc(0) is allowed and returns non-NULL (ahc driver)
94 * + ability to allocate arbitrarily large chunks of memory
99 #include <sys/param.h>
100 #include <sys/systm.h>
101 #include <sys/kernel.h>
102 #include <sys/slaballoc.h>
103 #include <sys/mbuf.h>
104 #include <sys/vmmeter.h>
105 #include <sys/lock.h>
106 #include <sys/thread.h>
107 #include <sys/globaldata.h>
108 #include <sys/sysctl.h>
112 #include <vm/vm_param.h>
113 #include <vm/vm_kern.h>
114 #include <vm/vm_extern.h>
115 #include <vm/vm_object.h>
117 #include <vm/vm_map.h>
118 #include <vm/vm_page.h>
119 #include <vm/vm_pageout.h>
121 #include <machine/cpu.h>
123 #include <sys/thread2.h>
125 #define btokup(z) (&pmap_kvtom((vm_offset_t)(z))->ku_pagecnt)
127 #define MEMORY_STRING "ptr=%p type=%p size=%lu flags=%04x"
128 #define MEMORY_ARGS void *ptr, void *type, unsigned long size, int flags
130 #if !defined(KTR_MEMORY)
131 #define KTR_MEMORY KTR_ALL
133 KTR_INFO_MASTER(memory);
134 KTR_INFO(KTR_MEMORY, memory, malloc_beg, 0, "malloc begin");
135 KTR_INFO(KTR_MEMORY, memory, malloc_end, 1, MEMORY_STRING, MEMORY_ARGS);
136 KTR_INFO(KTR_MEMORY, memory, free_zero, 2, MEMORY_STRING, MEMORY_ARGS);
137 KTR_INFO(KTR_MEMORY, memory, free_ovsz, 3, MEMORY_STRING, MEMORY_ARGS);
138 KTR_INFO(KTR_MEMORY, memory, free_ovsz_delayed, 4, MEMORY_STRING, MEMORY_ARGS);
139 KTR_INFO(KTR_MEMORY, memory, free_chunk, 5, MEMORY_STRING, MEMORY_ARGS);
140 KTR_INFO(KTR_MEMORY, memory, free_request, 6, MEMORY_STRING, MEMORY_ARGS);
141 KTR_INFO(KTR_MEMORY, memory, free_rem_beg, 7, MEMORY_STRING, MEMORY_ARGS);
142 KTR_INFO(KTR_MEMORY, memory, free_rem_end, 8, MEMORY_STRING, MEMORY_ARGS);
143 KTR_INFO(KTR_MEMORY, memory, free_beg, 9, "free begin");
144 KTR_INFO(KTR_MEMORY, memory, free_end, 10, "free end");
146 #define logmemory(name, ptr, type, size, flags) \
147 KTR_LOG(memory_ ## name, ptr, type, size, flags)
148 #define logmemory_quick(name) \
149 KTR_LOG(memory_ ## name)
152 * Fixed globals (not per-cpu)
155 static int ZoneLimit;
156 static int ZonePageCount;
157 static uintptr_t ZoneMask;
158 static int ZoneBigAlloc; /* in KB */
159 static int ZoneGenAlloc; /* in KB */
160 struct malloc_type *kmemstatistics; /* exported to vmstat */
161 static int32_t weirdary[16];
163 static void *kmem_slab_alloc(vm_size_t bytes, vm_offset_t align, int flags);
164 static void kmem_slab_free(void *ptr, vm_size_t bytes);
166 #if defined(INVARIANTS)
167 static void chunk_mark_allocated(SLZone *z, void *chunk);
168 static void chunk_mark_free(SLZone *z, void *chunk);
170 #define chunk_mark_allocated(z, chunk)
171 #define chunk_mark_free(z, chunk)
175 * Misc constants. Note that allocations that are exact multiples of
176 * PAGE_SIZE, or exceed the zone limit, fall through to the kmem module.
178 #define ZONE_RELS_THRESH 32 /* threshold number of zones */
181 * The WEIRD_ADDR is used as known text to copy into free objects to
182 * try to create deterministic failure cases if the data is accessed after
185 #define WEIRD_ADDR 0xdeadc0de
186 #define MAX_COPY sizeof(weirdary)
187 #define ZERO_LENGTH_PTR ((void *)-8)
190 * Misc global malloc buckets
193 MALLOC_DEFINE(M_CACHE, "cache", "Various Dynamically allocated caches");
194 MALLOC_DEFINE(M_DEVBUF, "devbuf", "device driver memory");
195 MALLOC_DEFINE(M_TEMP, "temp", "misc temporary data buffers");
197 MALLOC_DEFINE(M_IP6OPT, "ip6opt", "IPv6 options");
198 MALLOC_DEFINE(M_IP6NDP, "ip6ndp", "IPv6 Neighbor Discovery");
201 * Initialize the slab memory allocator. We have to choose a zone size based
202 * on available physical memory. We choose a zone side which is approximately
203 * 1/1024th of our memory, so if we have 128MB of ram we have a zone size of
204 * 128K. The zone size is limited to the bounds set in slaballoc.h
205 * (typically 32K min, 128K max).
207 static void kmeminit(void *dummy);
211 SYSINIT(kmem, SI_BOOT1_ALLOCATOR, SI_ORDER_FIRST, kmeminit, NULL)
215 * If enabled any memory allocated without M_ZERO is initialized to -1.
217 static int use_malloc_pattern;
218 SYSCTL_INT(_debug, OID_AUTO, use_malloc_pattern, CTLFLAG_RW,
219 &use_malloc_pattern, 0,
220 "Initialize memory to -1 if M_ZERO not specified");
223 static int ZoneRelsThresh = ZONE_RELS_THRESH;
224 SYSCTL_INT(_kern, OID_AUTO, zone_big_alloc, CTLFLAG_RD, &ZoneBigAlloc, 0, "");
225 SYSCTL_INT(_kern, OID_AUTO, zone_gen_alloc, CTLFLAG_RD, &ZoneGenAlloc, 0, "");
226 SYSCTL_INT(_kern, OID_AUTO, zone_cache, CTLFLAG_RW, &ZoneRelsThresh, 0, "");
227 static long SlabsAllocated;
228 static long SlabsFreed;
229 SYSCTL_LONG(_kern, OID_AUTO, slabs_allocated, CTLFLAG_RD, &SlabsAllocated, 0, "");
230 SYSCTL_LONG(_kern, OID_AUTO, slabs_freed, CTLFLAG_RD, &SlabsFreed, 0, "");
233 * Returns the kernel memory size limit for the purposes of initializing
234 * various subsystem caches. The smaller of available memory and the KVM
235 * memory space is returned.
237 * The size in megabytes is returned.
244 limsize = (size_t)vmstats.v_page_count * PAGE_SIZE;
245 if (limsize > KvaSize)
247 return (limsize / (1024 * 1024));
251 kmeminit(void *dummy)
257 limsize = kmem_lim_size();
258 usesize = (int)(limsize * 1024); /* convert to KB */
261 * If the machine has a large KVM space and more than 8G of ram,
262 * double the zone release threshold to reduce SMP invalidations.
263 * If more than 16G of ram, do it again.
265 * The BIOS eats a little ram so add some slop. We want 8G worth of
266 * memory sticks to trigger the first adjustment.
268 if (ZoneRelsThresh == ZONE_RELS_THRESH) {
269 if (limsize >= 7 * 1024)
271 if (limsize >= 15 * 1024)
276 * Calculate the zone size. This typically calculates to
277 * ZALLOC_MAX_ZONE_SIZE
279 ZoneSize = ZALLOC_MIN_ZONE_SIZE;
280 while (ZoneSize < ZALLOC_MAX_ZONE_SIZE && (ZoneSize << 1) < usesize)
282 ZoneLimit = ZoneSize / 4;
283 if (ZoneLimit > ZALLOC_ZONE_LIMIT)
284 ZoneLimit = ZALLOC_ZONE_LIMIT;
285 ZoneMask = ~(uintptr_t)(ZoneSize - 1);
286 ZonePageCount = ZoneSize / PAGE_SIZE;
288 for (i = 0; i < NELEM(weirdary); ++i)
289 weirdary[i] = WEIRD_ADDR;
291 ZeroPage = kmem_slab_alloc(PAGE_SIZE, PAGE_SIZE, M_WAITOK|M_ZERO);
294 kprintf("Slab ZoneSize set to %dKB\n", ZoneSize / 1024);
298 * Initialize a malloc type tracking structure.
301 malloc_init(void *data)
303 struct malloc_type *type = data;
306 if (type->ks_magic != M_MAGIC)
307 panic("malloc type lacks magic");
309 if (type->ks_limit != 0)
312 if (vmstats.v_page_count == 0)
313 panic("malloc_init not allowed before vm init");
315 limsize = kmem_lim_size() * (1024 * 1024);
316 type->ks_limit = limsize / 10;
318 type->ks_next = kmemstatistics;
319 kmemstatistics = type;
323 malloc_uninit(void *data)
325 struct malloc_type *type = data;
326 struct malloc_type *t;
332 if (type->ks_magic != M_MAGIC)
333 panic("malloc type lacks magic");
335 if (vmstats.v_page_count == 0)
336 panic("malloc_uninit not allowed before vm init");
338 if (type->ks_limit == 0)
339 panic("malloc_uninit on uninitialized type");
341 /* Make sure that all pending kfree()s are finished. */
342 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, unsigned long *align)
425 unsigned int n = (unsigned int)*bytes; /* unsigned for shift opt */
427 *bytes = n = (n + 7) & ~7;
429 return(n / 8 - 1); /* 8 byte chunks, 16 zones */
432 *bytes = n = (n + 15) & ~15;
438 *bytes = n = (n + 31) & ~31;
443 *bytes = n = (n + 63) & ~63;
448 *bytes = n = (n + 127) & ~127;
450 return(n / 128 + 31);
453 *bytes = n = (n + 255) & ~255;
455 return(n / 256 + 39);
457 *bytes = n = (n + 511) & ~511;
459 return(n / 512 + 47);
461 #if ZALLOC_ZONE_LIMIT > 8192
463 *bytes = n = (n + 1023) & ~1023;
465 return(n / 1024 + 55);
468 #if ZALLOC_ZONE_LIMIT > 16384
470 *bytes = n = (n + 2047) & ~2047;
472 return(n / 2048 + 63);
475 panic("Unexpected byte count %d", n);
481 * Used to debug memory corruption issues. Record up to (typically 32)
482 * allocation sources for this zone (for a particular chunk size).
486 slab_record_source(SLZone *z, const char *file, int line)
489 int b = line & (SLAB_DEBUG_ENTRIES - 1);
493 if (z->z_Sources[i].file == file && z->z_Sources[i].line == line)
495 if (z->z_Sources[i].file == NULL)
497 i = (i + 1) & (SLAB_DEBUG_ENTRIES - 1);
499 z->z_Sources[i].file = file;
500 z->z_Sources[i].line = line;
505 static __inline unsigned long
506 powerof2_size(unsigned long size)
510 if (size == 0 || powerof2(size))
518 * kmalloc() (SLAB ALLOCATOR)
520 * Allocate memory via the slab allocator. If the request is too large,
521 * or if it page-aligned beyond a certain size, we fall back to the
522 * KMEM subsystem. A SLAB tracking descriptor must be specified, use
523 * &SlabMisc if you don't care.
525 * M_RNOWAIT - don't block.
526 * M_NULLOK - return NULL instead of blocking.
527 * M_ZERO - zero the returned memory.
528 * M_USE_RESERVE - allow greater drawdown of the free list
529 * M_USE_INTERRUPT_RESERVE - allow the freelist to be exhausted
530 * M_POWEROF2 - roundup size to the nearest power of 2
537 kmalloc_debug(unsigned long size, struct malloc_type *type, int flags,
538 const char *file, int line)
541 kmalloc(unsigned long size, struct malloc_type *type, int flags)
548 struct globaldata *gd;
555 logmemory_quick(malloc_beg);
560 * XXX silly to have this in the critical path.
562 if (type->ks_limit == 0) {
564 if (type->ks_limit == 0)
570 if (flags & M_POWEROF2)
571 size = powerof2_size(size);
574 * Handle the case where the limit is reached. Panic if we can't return
575 * NULL. The original malloc code looped, but this tended to
576 * simply deadlock the computer.
578 * ks_loosememuse is an up-only limit that is NOT MP-synchronized, used
579 * to determine if a more complete limit check should be done. The
580 * actual memory use is tracked via ks_memuse[cpu].
582 while (type->ks_loosememuse >= type->ks_limit) {
586 for (i = ttl = 0; i < ncpus; ++i)
587 ttl += type->ks_memuse[i];
588 type->ks_loosememuse = ttl; /* not MP synchronized */
589 if ((ssize_t)ttl < 0) /* deal with occassional race */
591 if (ttl >= type->ks_limit) {
592 if (flags & M_NULLOK) {
593 logmemory(malloc_end, NULL, type, size, flags);
596 panic("%s: malloc limit exceeded", type->ks_shortdesc);
601 * Handle the degenerate size == 0 case. Yes, this does happen.
602 * Return a special pointer. This is to maintain compatibility with
603 * the original malloc implementation. Certain devices, such as the
604 * adaptec driver, not only allocate 0 bytes, they check for NULL and
605 * also realloc() later on. Joy.
608 logmemory(malloc_end, ZERO_LENGTH_PTR, type, size, flags);
609 return(ZERO_LENGTH_PTR);
613 * Handle hysteresis from prior frees here in malloc(). We cannot
614 * safely manipulate the kernel_map in free() due to free() possibly
615 * being called via an IPI message or from sensitive interrupt code.
617 * NOTE: ku_pagecnt must be cleared before we free the slab or we
618 * might race another cpu allocating the kva and setting
621 while (slgd->NFreeZones > ZoneRelsThresh && (flags & M_RNOWAIT) == 0) {
623 if (slgd->NFreeZones > ZoneRelsThresh) { /* crit sect race */
627 slgd->FreeZones = z->z_Next;
631 kmem_slab_free(z, ZoneSize); /* may block */
632 atomic_add_int(&ZoneGenAlloc, -ZoneSize / 1024);
638 * XXX handle oversized frees that were queued from kfree().
640 while (slgd->FreeOvZones && (flags & M_RNOWAIT) == 0) {
642 if ((z = slgd->FreeOvZones) != NULL) {
645 KKASSERT(z->z_Magic == ZALLOC_OVSZ_MAGIC);
646 slgd->FreeOvZones = z->z_Next;
647 tsize = z->z_ChunkSize;
648 kmem_slab_free(z, tsize); /* may block */
649 atomic_add_int(&ZoneBigAlloc, -(int)tsize / 1024);
655 * Handle large allocations directly. There should not be very many of
656 * these so performance is not a big issue.
658 * The backend allocator is pretty nasty on a SMP system. Use the
659 * slab allocator for one and two page-sized chunks even though we lose
660 * some efficiency. XXX maybe fix mmio and the elf loader instead.
662 if (size >= ZoneLimit || ((size & PAGE_MASK) == 0 && size > PAGE_SIZE*2)) {
665 size = round_page(size);
666 chunk = kmem_slab_alloc(size, PAGE_SIZE, flags);
668 logmemory(malloc_end, NULL, type, size, flags);
671 atomic_add_int(&ZoneBigAlloc, (int)size / 1024);
672 flags &= ~M_ZERO; /* result already zero'd if M_ZERO was set */
673 flags |= M_PASSIVE_ZERO;
675 *kup = size / PAGE_SIZE;
681 * Attempt to allocate out of an existing zone. First try the free list,
682 * then allocate out of unallocated space. If we find a good zone move
683 * it to the head of the list so later allocations find it quickly
684 * (we might have thousands of zones in the list).
686 * Note: zoneindex() will panic of size is too large.
688 zi = zoneindex(&size, &align);
689 KKASSERT(zi < NZONES);
692 if ((z = slgd->ZoneAry[zi]) != NULL) {
694 * Locate a chunk - we have to have at least one. If this is the
695 * last chunk go ahead and do the work to retrieve chunks freed
696 * from remote cpus, and if the zone is still empty move it off
699 if (--z->z_NFree <= 0) {
700 KKASSERT(z->z_NFree == 0);
703 * WARNING! This code competes with other cpus. It is ok
704 * for us to not drain RChunks here but we might as well, and
705 * it is ok if more accumulate after we're done.
707 * Set RSignal before pulling rchunks off, indicating that we
708 * will be moving ourselves off of the ZoneAry. Remote ends will
709 * read RSignal before putting rchunks on thus interlocking
710 * their IPI signaling.
712 if (z->z_RChunks == NULL)
713 atomic_swap_int(&z->z_RSignal, 1);
715 while ((bchunk = z->z_RChunks) != NULL) {
717 if (atomic_cmpset_ptr(&z->z_RChunks, bchunk, NULL)) {
718 *z->z_LChunksp = bchunk;
720 chunk_mark_free(z, bchunk);
721 z->z_LChunksp = &bchunk->c_Next;
722 bchunk = bchunk->c_Next;
729 * Remove from the zone list if no free chunks remain.
732 if (z->z_NFree == 0) {
733 slgd->ZoneAry[zi] = z->z_Next;
741 * Fast path, we have chunks available in z_LChunks.
743 chunk = z->z_LChunks;
745 chunk_mark_allocated(z, chunk);
746 z->z_LChunks = chunk->c_Next;
747 if (z->z_LChunks == NULL)
748 z->z_LChunksp = &z->z_LChunks;
750 slab_record_source(z, file, line);
756 * No chunks are available in LChunks, the free chunk MUST be
757 * in the never-before-used memory area, controlled by UIndex.
759 * The consequences are very serious if our zone got corrupted so
760 * we use an explicit panic rather than a KASSERT.
762 if (z->z_UIndex + 1 != z->z_NMax)
767 if (z->z_UIndex == z->z_UEndIndex)
768 panic("slaballoc: corrupted zone");
770 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size);
771 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) {
773 flags |= M_PASSIVE_ZERO;
775 chunk_mark_allocated(z, chunk);
777 slab_record_source(z, file, line);
783 * If all zones are exhausted we need to allocate a new zone for this
784 * index. Use M_ZERO to take advantage of pre-zerod pages. Also see
785 * UAlloc use above in regards to M_ZERO. Note that when we are reusing
786 * a zone from the FreeZones list UAlloc'd data will not be zero'd, and
787 * we do not pre-zero it because we do not want to mess up the L1 cache.
789 * At least one subsystem, the tty code (see CROUND) expects power-of-2
790 * allocations to be power-of-2 aligned. We maintain compatibility by
791 * adjusting the base offset below.
797 if ((z = slgd->FreeZones) != NULL) {
798 slgd->FreeZones = z->z_Next;
800 bzero(z, sizeof(SLZone));
801 z->z_Flags |= SLZF_UNOTZEROD;
803 z = kmem_slab_alloc(ZoneSize, ZoneSize, flags|M_ZERO);
806 atomic_add_int(&ZoneGenAlloc, ZoneSize / 1024);
810 * How big is the base structure?
812 #if defined(INVARIANTS)
814 * Make room for z_Bitmap. An exact calculation is somewhat more
815 * complicated so don't make an exact calculation.
817 off = offsetof(SLZone, z_Bitmap[(ZoneSize / size + 31) / 32]);
818 bzero(z->z_Bitmap, (ZoneSize / size + 31) / 8);
820 off = sizeof(SLZone);
824 * Guarentee power-of-2 alignment for power-of-2-sized chunks.
825 * Otherwise properly align the data according to the chunk size.
829 off = (off + align - 1) & ~(align - 1);
831 z->z_Magic = ZALLOC_SLAB_MAGIC;
833 z->z_NMax = (ZoneSize - off) / size;
834 z->z_NFree = z->z_NMax - 1;
835 z->z_BasePtr = (char *)z + off;
836 z->z_UIndex = z->z_UEndIndex = slgd->JunkIndex % z->z_NMax;
837 z->z_ChunkSize = size;
839 z->z_Cpu = gd->gd_cpuid;
840 z->z_LChunksp = &z->z_LChunks;
842 bcopy(z->z_Sources, z->z_AltSources, sizeof(z->z_Sources));
843 bzero(z->z_Sources, sizeof(z->z_Sources));
845 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size);
846 z->z_Next = slgd->ZoneAry[zi];
847 slgd->ZoneAry[zi] = z;
848 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) {
849 flags &= ~M_ZERO; /* already zero'd */
850 flags |= M_PASSIVE_ZERO;
853 *kup = -(z->z_Cpu + 1); /* -1 to -(N+1) */
854 chunk_mark_allocated(z, chunk);
856 slab_record_source(z, file, line);
860 * Slide the base index for initial allocations out of the next
861 * zone we create so we do not over-weight the lower part of the
864 slgd->JunkIndex = (slgd->JunkIndex + ZALLOC_SLAB_SLIDE)
865 & (ZALLOC_MAX_ZONE_SIZE - 1);
869 ++type->ks_inuse[gd->gd_cpuid];
870 type->ks_memuse[gd->gd_cpuid] += size;
871 type->ks_loosememuse += size; /* not MP synchronized */
877 else if ((flags & (M_ZERO|M_PASSIVE_ZERO)) == 0) {
878 if (use_malloc_pattern) {
879 for (i = 0; i < size; i += sizeof(int)) {
880 *(int *)((char *)chunk + i) = -1;
883 chunk->c_Next = (void *)-1; /* avoid accidental double-free check */
886 logmemory(malloc_end, chunk, type, size, flags);
890 logmemory(malloc_end, NULL, type, size, flags);
895 * kernel realloc. (SLAB ALLOCATOR) (MP SAFE)
897 * Generally speaking this routine is not called very often and we do
898 * not attempt to optimize it beyond reusing the same pointer if the
899 * new size fits within the chunking of the old pointer's zone.
903 krealloc_debug(void *ptr, unsigned long size,
904 struct malloc_type *type, int flags,
905 const char *file, int line)
908 krealloc(void *ptr, unsigned long size, struct malloc_type *type, int flags)
917 KKASSERT((flags & M_ZERO) == 0); /* not supported */
919 if (ptr == NULL || ptr == ZERO_LENGTH_PTR)
920 return(kmalloc_debug(size, type, flags, file, line));
927 * Handle oversized allocations. XXX we really should require that a
928 * size be passed to free() instead of this nonsense.
932 osize = *kup << PAGE_SHIFT;
933 if (osize == round_page(size))
935 if ((nptr = kmalloc_debug(size, type, flags, file, line)) == NULL)
937 bcopy(ptr, nptr, min(size, osize));
943 * Get the original allocation's zone. If the new request winds up
944 * using the same chunk size we do not have to do anything.
946 z = (SLZone *)((uintptr_t)ptr & ZoneMask);
949 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC);
952 * Allocate memory for the new request size. Note that zoneindex has
953 * already adjusted the request size to the appropriate chunk size, which
954 * should optimize our bcopy(). Then copy and return the new pointer.
956 * Resizing a non-power-of-2 allocation to a power-of-2 size does not
957 * necessary align the result.
959 * We can only zoneindex (to align size to the chunk size) if the new
960 * size is not too large.
962 if (size < ZoneLimit) {
963 zoneindex(&size, &align);
964 if (z->z_ChunkSize == size)
967 if ((nptr = kmalloc_debug(size, type, flags, file, line)) == NULL)
969 bcopy(ptr, nptr, min(size, z->z_ChunkSize));
975 * Return the kmalloc limit for this type, in bytes.
978 kmalloc_limit(struct malloc_type *type)
980 if (type->ks_limit == 0) {
982 if (type->ks_limit == 0)
986 return(type->ks_limit);
990 * Allocate a copy of the specified string.
992 * (MP SAFE) (MAY BLOCK)
996 kstrdup_debug(const char *str, struct malloc_type *type,
997 const char *file, int line)
1000 kstrdup(const char *str, struct malloc_type *type)
1003 int zlen; /* length inclusive of terminating NUL */
1008 zlen = strlen(str) + 1;
1009 nstr = kmalloc_debug(zlen, type, M_WAITOK, file, line);
1010 bcopy(str, nstr, zlen);
1015 * Notify our cpu that a remote cpu has freed some chunks in a zone that
1016 * we own. RCount will be bumped so the memory should be good, but validate
1017 * that it really is.
1021 kfree_remote(void *ptr)
1029 slgd = &mycpu->gd_slab;
1032 KKASSERT(*kup == -((int)mycpuid + 1));
1033 KKASSERT(z->z_RCount > 0);
1034 atomic_subtract_int(&z->z_RCount, 1);
1036 logmemory(free_rem_beg, z, NULL, 0L, 0);
1037 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC);
1038 KKASSERT(z->z_Cpu == mycpu->gd_cpuid);
1042 * Indicate that we will no longer be off of the ZoneAry by
1049 * Atomically extract the bchunks list and then process it back
1050 * into the lchunks list. We want to append our bchunks to the
1051 * lchunks list and not prepend since we likely do not have
1052 * cache mastership of the related data (not that it helps since
1053 * we are using c_Next).
1055 while ((bchunk = z->z_RChunks) != NULL) {
1057 if (atomic_cmpset_ptr(&z->z_RChunks, bchunk, NULL)) {
1058 *z->z_LChunksp = bchunk;
1060 chunk_mark_free(z, bchunk);
1061 z->z_LChunksp = &bchunk->c_Next;
1062 bchunk = bchunk->c_Next;
1068 if (z->z_NFree && nfree == 0) {
1069 z->z_Next = slgd->ZoneAry[z->z_ZoneIndex];
1070 slgd->ZoneAry[z->z_ZoneIndex] = z;
1074 * If the zone becomes totally free, and there are other zones we
1075 * can allocate from, move this zone to the FreeZones list. Since
1076 * this code can be called from an IPI callback, do *NOT* try to mess
1077 * with kernel_map here. Hysteresis will be performed at malloc() time.
1079 * Do not move the zone if there is an IPI inflight, otherwise MP
1080 * races can result in our free_remote code accessing a destroyed
1083 if (z->z_NFree == z->z_NMax &&
1084 (z->z_Next || slgd->ZoneAry[z->z_ZoneIndex] != z) &&
1090 for (pz = &slgd->ZoneAry[z->z_ZoneIndex];
1092 pz = &(*pz)->z_Next) {
1097 z->z_Next = slgd->FreeZones;
1098 slgd->FreeZones = z;
1103 logmemory(free_rem_end, z, bchunk, 0L, 0);
1107 * free (SLAB ALLOCATOR)
1109 * Free a memory block previously allocated by malloc. Note that we do not
1110 * attempt to update ks_loosememuse as MP races could prevent us from
1111 * checking memory limits in malloc.
1116 kfree(void *ptr, struct malloc_type *type)
1121 struct globaldata *gd;
1127 logmemory_quick(free_beg);
1129 slgd = &gd->gd_slab;
1132 panic("trying to free NULL pointer");
1135 * Handle special 0-byte allocations
1137 if (ptr == ZERO_LENGTH_PTR) {
1138 logmemory(free_zero, ptr, type, -1UL, 0);
1139 logmemory_quick(free_end);
1144 * Panic on bad malloc type
1146 if (type->ks_magic != M_MAGIC)
1147 panic("free: malloc type lacks magic");
1150 * Handle oversized allocations. XXX we really should require that a
1151 * size be passed to free() instead of this nonsense.
1153 * This code is never called via an ipi.
1157 size = *kup << PAGE_SHIFT;
1160 KKASSERT(sizeof(weirdary) <= size);
1161 bcopy(weirdary, ptr, sizeof(weirdary));
1164 * NOTE: For oversized allocations we do not record the
1165 * originating cpu. It gets freed on the cpu calling
1166 * kfree(). The statistics are in aggregate.
1168 * note: XXX we have still inherited the interrupts-can't-block
1169 * assumption. An interrupt thread does not bump
1170 * gd_intr_nesting_level so check TDF_INTTHREAD. This is
1171 * primarily until we can fix softupdate's assumptions about free().
1174 --type->ks_inuse[gd->gd_cpuid];
1175 type->ks_memuse[gd->gd_cpuid] -= size;
1176 if (mycpu->gd_intr_nesting_level ||
1177 (gd->gd_curthread->td_flags & TDF_INTTHREAD))
1179 logmemory(free_ovsz_delayed, ptr, type, size, 0);
1181 z->z_Magic = ZALLOC_OVSZ_MAGIC;
1182 z->z_Next = slgd->FreeOvZones;
1183 z->z_ChunkSize = size;
1184 slgd->FreeOvZones = z;
1188 logmemory(free_ovsz, ptr, type, size, 0);
1189 kmem_slab_free(ptr, size); /* may block */
1190 atomic_add_int(&ZoneBigAlloc, -(int)size / 1024);
1192 logmemory_quick(free_end);
1197 * Zone case. Figure out the zone based on the fact that it is
1200 z = (SLZone *)((uintptr_t)ptr & ZoneMask);
1203 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC);
1206 * If we do not own the zone then use atomic ops to free to the
1207 * remote cpu linked list and notify the target zone using a
1210 * The target zone cannot be deallocated while we own a chunk of it,
1211 * so the zone header's storage is stable until the very moment
1212 * we adjust z_RChunks. After that we cannot safely dereference (z).
1214 * (no critical section needed)
1216 if (z->z_CpuGd != gd) {
1218 * Making these adjustments now allow us to avoid passing (type)
1219 * to the remote cpu. Note that ks_inuse/ks_memuse is being
1220 * adjusted on OUR cpu, not the zone cpu, but it should all still
1221 * sum up properly and cancel out.
1224 --type->ks_inuse[gd->gd_cpuid];
1225 type->ks_memuse[gd->gd_cpuid] -= z->z_ChunkSize;
1229 * WARNING! This code competes with other cpus. Once we
1230 * successfully link the chunk to RChunks the remote
1231 * cpu can rip z's storage out from under us.
1233 * Bumping RCount prevents z's storage from getting
1236 rsignal = z->z_RSignal;
1239 atomic_add_int(&z->z_RCount, 1);
1243 bchunk = z->z_RChunks;
1245 chunk->c_Next = bchunk;
1248 if (atomic_cmpset_ptr(&z->z_RChunks, bchunk, chunk))
1253 * We have to signal the remote cpu if our actions will cause
1254 * the remote zone to be placed back on ZoneAry so it can
1255 * move the zone back on.
1257 * We only need to deal with NULL->non-NULL RChunk transitions
1258 * and only if z_RSignal is set. We interlock by reading rsignal
1259 * before adding our chunk to RChunks. This should result in
1260 * virtually no IPI traffic.
1262 * We can use a passive IPI to reduce overhead even further.
1264 if (bchunk == NULL && rsignal) {
1265 logmemory(free_request, ptr, type, (unsigned long)z->z_ChunkSize, 0);
1266 lwkt_send_ipiq_passive(z->z_CpuGd, kfree_remote, z);
1267 /* z can get ripped out from under us from this point on */
1268 } else if (rsignal) {
1269 atomic_subtract_int(&z->z_RCount, 1);
1270 /* z can get ripped out from under us from this point on */
1272 logmemory_quick(free_end);
1279 logmemory(free_chunk, ptr, type, (unsigned long)z->z_ChunkSize, 0);
1283 chunk_mark_free(z, chunk);
1286 * Put weird data into the memory to detect modifications after freeing,
1287 * illegal pointer use after freeing (we should fault on the odd address),
1288 * and so forth. XXX needs more work, see the old malloc code.
1291 if (z->z_ChunkSize < sizeof(weirdary))
1292 bcopy(weirdary, chunk, z->z_ChunkSize);
1294 bcopy(weirdary, chunk, sizeof(weirdary));
1298 * Add this free non-zero'd chunk to a linked list for reuse. Add
1299 * to the front of the linked list so it is more likely to be
1300 * reallocated, since it is already in our L1 cache.
1303 if ((vm_offset_t)chunk < KvaStart || (vm_offset_t)chunk >= KvaEnd)
1304 panic("BADFREE %p", chunk);
1306 chunk->c_Next = z->z_LChunks;
1307 z->z_LChunks = chunk;
1308 if (chunk->c_Next == NULL)
1309 z->z_LChunksp = &chunk->c_Next;
1312 if (chunk->c_Next && (vm_offset_t)chunk->c_Next < KvaStart)
1317 * Bump the number of free chunks. If it becomes non-zero the zone
1318 * must be added back onto the appropriate list.
1320 if (z->z_NFree++ == 0) {
1321 z->z_Next = slgd->ZoneAry[z->z_ZoneIndex];
1322 slgd->ZoneAry[z->z_ZoneIndex] = z;
1325 --type->ks_inuse[z->z_Cpu];
1326 type->ks_memuse[z->z_Cpu] -= z->z_ChunkSize;
1329 * If the zone becomes totally free, and there are other zones we
1330 * can allocate from, move this zone to the FreeZones list. Since
1331 * this code can be called from an IPI callback, do *NOT* try to mess
1332 * with kernel_map here. Hysteresis will be performed at malloc() time.
1334 if (z->z_NFree == z->z_NMax &&
1335 (z->z_Next || slgd->ZoneAry[z->z_ZoneIndex] != z) &&
1341 for (pz = &slgd->ZoneAry[z->z_ZoneIndex]; z != *pz; pz = &(*pz)->z_Next)
1345 z->z_Next = slgd->FreeZones;
1346 slgd->FreeZones = z;
1351 logmemory_quick(free_end);
1355 #if defined(INVARIANTS)
1358 * Helper routines for sanity checks
1362 chunk_mark_allocated(SLZone *z, void *chunk)
1364 int bitdex = ((char *)chunk - (char *)z->z_BasePtr) / z->z_ChunkSize;
1367 KKASSERT((((intptr_t)chunk ^ (intptr_t)z) & ZoneMask) == 0);
1368 KASSERT(bitdex >= 0 && bitdex < z->z_NMax,
1369 ("memory chunk %p bit index %d is illegal", chunk, bitdex));
1370 bitptr = &z->z_Bitmap[bitdex >> 5];
1372 KASSERT((*bitptr & (1 << bitdex)) == 0,
1373 ("memory chunk %p is already allocated!", chunk));
1374 *bitptr |= 1 << bitdex;
1379 chunk_mark_free(SLZone *z, void *chunk)
1381 int bitdex = ((char *)chunk - (char *)z->z_BasePtr) / z->z_ChunkSize;
1384 KKASSERT((((intptr_t)chunk ^ (intptr_t)z) & ZoneMask) == 0);
1385 KASSERT(bitdex >= 0 && bitdex < z->z_NMax,
1386 ("memory chunk %p bit index %d is illegal!", chunk, bitdex));
1387 bitptr = &z->z_Bitmap[bitdex >> 5];
1389 KASSERT((*bitptr & (1 << bitdex)) != 0,
1390 ("memory chunk %p is already free!", chunk));
1391 *bitptr &= ~(1 << bitdex);
1399 * Directly allocate and wire kernel memory in PAGE_SIZE chunks with the
1400 * specified alignment. M_* flags are expected in the flags field.
1402 * Alignment must be a multiple of PAGE_SIZE.
1404 * NOTE! XXX For the moment we use vm_map_entry_reserve/release(),
1405 * but when we move zalloc() over to use this function as its backend
1406 * we will have to switch to kreserve/krelease and call reserve(0)
1407 * after the new space is made available.
1409 * Interrupt code which has preempted other code is not allowed to
1410 * use PQ_CACHE pages. However, if an interrupt thread is run
1411 * non-preemptively or blocks and then runs non-preemptively, then
1412 * it is free to use PQ_CACHE pages. <--- may not apply any longer XXX
1415 kmem_slab_alloc(vm_size_t size, vm_offset_t align, int flags)
1419 int count, vmflags, base_vmflags;
1420 vm_page_t mbase = NULL;
1424 size = round_page(size);
1425 addr = vm_map_min(&kernel_map);
1427 count = vm_map_entry_reserve(MAP_RESERVE_COUNT);
1429 vm_map_lock(&kernel_map);
1430 if (vm_map_findspace(&kernel_map, addr, size, align, 0, &addr)) {
1431 vm_map_unlock(&kernel_map);
1432 if ((flags & M_NULLOK) == 0)
1433 panic("kmem_slab_alloc(): kernel_map ran out of space!");
1434 vm_map_entry_release(count);
1440 * kernel_object maps 1:1 to kernel_map.
1442 vm_object_hold(&kernel_object);
1443 vm_object_reference_locked(&kernel_object);
1444 vm_map_insert(&kernel_map, &count,
1445 &kernel_object, addr, addr, addr + size,
1447 VM_PROT_ALL, VM_PROT_ALL,
1449 vm_object_drop(&kernel_object);
1450 vm_map_set_wired_quick(&kernel_map, addr, size, &count);
1451 vm_map_unlock(&kernel_map);
1457 base_vmflags |= VM_ALLOC_ZERO;
1458 if (flags & M_USE_RESERVE)
1459 base_vmflags |= VM_ALLOC_SYSTEM;
1460 if (flags & M_USE_INTERRUPT_RESERVE)
1461 base_vmflags |= VM_ALLOC_INTERRUPT;
1462 if ((flags & (M_RNOWAIT|M_WAITOK)) == 0) {
1463 panic("kmem_slab_alloc: bad flags %08x (%p)",
1464 flags, ((int **)&size)[-1]);
1468 * Allocate the pages. Do not mess with the PG_ZERO flag or map
1469 * them yet. VM_ALLOC_NORMAL can only be set if we are not preempting.
1471 * VM_ALLOC_SYSTEM is automatically set if we are preempting and
1472 * M_WAITOK was specified as an alternative (i.e. M_USE_RESERVE is
1473 * implied in this case), though I'm not sure if we really need to
1476 vmflags = base_vmflags;
1477 if (flags & M_WAITOK) {
1478 if (td->td_preempted)
1479 vmflags |= VM_ALLOC_SYSTEM;
1481 vmflags |= VM_ALLOC_NORMAL;
1484 vm_object_hold(&kernel_object);
1485 for (i = 0; i < size; i += PAGE_SIZE) {
1486 m = vm_page_alloc(&kernel_object, OFF_TO_IDX(addr + i), vmflags);
1491 * If the allocation failed we either return NULL or we retry.
1493 * If M_WAITOK is specified we wait for more memory and retry.
1494 * If M_WAITOK is specified from a preemption we yield instead of
1495 * wait. Livelock will not occur because the interrupt thread
1496 * will not be preempting anyone the second time around after the
1500 if (flags & M_WAITOK) {
1501 if (td->td_preempted) {
1506 i -= PAGE_SIZE; /* retry */
1514 * Check and deal with an allocation failure
1519 m = vm_page_lookup(&kernel_object, OFF_TO_IDX(addr + i));
1520 /* page should already be busy */
1523 vm_map_lock(&kernel_map);
1524 vm_map_delete(&kernel_map, addr, addr + size, &count);
1525 vm_map_unlock(&kernel_map);
1526 vm_object_drop(&kernel_object);
1528 vm_map_entry_release(count);
1536 * NOTE: The VM pages are still busied. mbase points to the first one
1537 * but we have to iterate via vm_page_next()
1539 vm_object_drop(&kernel_object);
1543 * Enter the pages into the pmap and deal with PG_ZERO and M_ZERO.
1550 * page should already be busy
1552 m->valid = VM_PAGE_BITS_ALL;
1554 pmap_enter(&kernel_pmap, addr + i, m, VM_PROT_ALL | VM_PROT_NOSYNC,
1556 if ((m->flags & PG_ZERO) == 0 && (flags & M_ZERO))
1557 bzero((char *)addr + i, PAGE_SIZE);
1558 vm_page_flag_clear(m, PG_ZERO);
1559 KKASSERT(m->flags & (PG_WRITEABLE | PG_MAPPED));
1560 vm_page_flag_set(m, PG_REFERENCED);
1564 vm_object_hold(&kernel_object);
1565 m = vm_page_next(m);
1566 vm_object_drop(&kernel_object);
1569 vm_map_entry_release(count);
1570 atomic_add_long(&SlabsAllocated, 1);
1571 return((void *)addr);
1578 kmem_slab_free(void *ptr, vm_size_t size)
1581 vm_map_remove(&kernel_map, (vm_offset_t)ptr, (vm_offset_t)ptr + size);
1582 atomic_add_long(&SlabsFreed, 1);
1587 kmalloc_cachealign(unsigned long size_alloc, struct malloc_type *type,
1590 #if (__VM_CACHELINE_SIZE == 32)
1591 #define CAN_CACHEALIGN(sz) ((sz) >= 256)
1592 #elif (__VM_CACHELINE_SIZE == 64)
1593 #define CAN_CACHEALIGN(sz) ((sz) >= 512)
1594 #elif (__VM_CACHELINE_SIZE == 128)
1595 #define CAN_CACHEALIGN(sz) ((sz) >= 1024)
1597 #error "unsupported cacheline size"
1602 if (size_alloc < __VM_CACHELINE_SIZE)
1603 size_alloc = __VM_CACHELINE_SIZE;
1604 else if (!CAN_CACHEALIGN(size_alloc))
1605 flags |= M_POWEROF2;
1607 ret = kmalloc(size_alloc, type, flags);
1608 KASSERT(((uintptr_t)ret & (__VM_CACHELINE_SIZE - 1)) == 0,
1609 ("%p(%lu) not cacheline %d aligned",
1610 ret, size_alloc, __VM_CACHELINE_SIZE));
1613 #undef CAN_CACHEALIGN