kern_malloc.c

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/*-
 * Copyright (c) 1987, 1991, 1993
 *      The Regents of the University of California.
 * Copyright (c) 2005-2009 Robert N. M. Watson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)kern_malloc.c       8.3 (Berkeley) 1/4/94
 */

/*
 * Kernel malloc(9) implementation -- general purpose kernel memory allocator
 * based on memory types.  Back end is implemented using the UMA(9) zone
 * allocator.  A set of fixed-size buckets are used for smaller allocations,
 * and a special UMA allocation interface is used for larger allocations.
 * Callers declare memory types, and statistics are maintained independently
 * for each memory type.  Statistics are maintained per-CPU for performance
 * reasons.  See malloc(9) and comments in malloc.h for a detailed
 * description.
 */

#include <sys/cdefs.h>
__FBSDID("$BSDSUniX$");

#include "opt_ddb.h"
#include "opt_kdtrace.h"
#include "opt_vm.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/vmmeter.h>
#include <sys/proc.h>
#include <sys/sbuf.h>
#include <sys/sysctl.h>
#include <sys/time.h>

#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_param.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/uma.h>
#include <vm/uma_int.h>
#include <vm/uma_dbg.h>

#ifdef DEBUG_MEMGUARD
#include <vm/memguard.h>
#endif
#ifdef DEBUG_REDZONE
#include <vm/redzone.h>
#endif

#if defined(INVARIANTS) && defined(__i386__)
#include <machine/cpu.h>
#endif

#include <ddb/ddb.h>

#ifdef KDTRACE_HOOKS
#include <sys/dtrace_bsd.h>

dtrace_malloc_probe_func_t      dtrace_malloc_probe;
#endif

/*
 * When realloc() is called, if the new size is sufficiently smaller than
 * the old size, realloc() will allocate a new, smaller block to avoid
 * wasting memory. 'Sufficiently smaller' is defined as: newsize <=
 * oldsize / 2^n, where REALLOC_FRACTION defines the value of 'n'.
 */
#ifndef REALLOC_FRACTION
#define REALLOC_FRACTION        1       /* new block if <= half the size */
#endif

/*
 * Centrally define some common malloc types.
 */
MALLOC_DEFINE(M_CACHE, "cache", "Various Dynamically allocated caches");
MALLOC_DEFINE(M_DEVBUF, "devbuf", "device driver memory");
MALLOC_DEFINE(M_TEMP, "temp", "misc temporary data buffers");

MALLOC_DEFINE(M_IP6OPT, "ip6opt", "IPv6 options");
MALLOC_DEFINE(M_IP6NDP, "ip6ndp", "IPv6 Neighbor Discovery");

static void kmeminit(void *);
SYSINIT(kmem, SI_SUB_KMEM, SI_ORDER_FIRST, kmeminit, NULL);

static struct malloc_type *kmemstatistics;
static vm_offset_t kmembase;
static vm_offset_t kmemlimit;
static int kmemcount;

#define KMEM_ZSHIFT     4
#define KMEM_ZBASE      16
#define KMEM_ZMASK      (KMEM_ZBASE - 1)

#define KMEM_ZMAX       PAGE_SIZE
#define KMEM_ZSIZE      (KMEM_ZMAX >> KMEM_ZSHIFT)
static uint8_t kmemsize[KMEM_ZSIZE + 1];

#ifndef MALLOC_DEBUG_MAXZONES
#define MALLOC_DEBUG_MAXZONES   1
#endif
static int numzones = MALLOC_DEBUG_MAXZONES;

/*
 * Small malloc(9) memory allocations are allocated from a set of UMA buckets
 * of various sizes.
 *
 * XXX: The comment here used to read "These won't be powers of two for
 * long."  It's possible that a significant amount of wasted memory could be
 * recovered by tuning the sizes of these buckets.
 */
struct {
        int kz_size;
        char *kz_name;
        uma_zone_t kz_zone[MALLOC_DEBUG_MAXZONES];
} kmemzones[] = {
        {16, "16", },
        {32, "32", },
        {64, "64", },
        {128, "128", },
        {256, "256", },
        {512, "512", },
        {1024, "1024", },
        {2048, "2048", },
        {4096, "4096", },
#if PAGE_SIZE > 4096
        {8192, "8192", },
#if PAGE_SIZE > 8192
        {16384, "16384", },
#if PAGE_SIZE > 16384
        {32768, "32768", },
#if PAGE_SIZE > 32768
        {65536, "65536", },
#if PAGE_SIZE > 65536
#error  "Unsupported PAGE_SIZE"
#endif  /* 65536 */
#endif  /* 32768 */
#endif  /* 16384 */
#endif  /* 8192 */
#endif  /* 4096 */
        {0, NULL},
};

/*
 * Zone to allocate malloc type descriptions from.  For ABI reasons, memory
 * types are described by a data structure passed by the declaring code, but
 * the malloc(9) implementation has its own data structure describing the
 * type and statistics.  This permits the malloc(9)-internal data structures
 * to be modified without breaking binary-compiled kernel modules that
 * declare malloc types.
 */
static uma_zone_t mt_zone;

u_long vm_kmem_size;
SYSCTL_ULONG(_vm, OID_AUTO, kmem_size, CTLFLAG_RDTUN, &vm_kmem_size, 0,
    "Size of kernel memory");

static u_long vm_kmem_size_min;
SYSCTL_ULONG(_vm, OID_AUTO, kmem_size_min, CTLFLAG_RDTUN, &vm_kmem_size_min, 0,
    "Minimum size of kernel memory");

static u_long vm_kmem_size_max;
SYSCTL_ULONG(_vm, OID_AUTO, kmem_size_max, CTLFLAG_RDTUN, &vm_kmem_size_max, 0,
    "Maximum size of kernel memory");

static u_int vm_kmem_size_scale;
SYSCTL_UINT(_vm, OID_AUTO, kmem_size_scale, CTLFLAG_RDTUN, &vm_kmem_size_scale, 0,
    "Scale factor for kernel memory size");

static int sysctl_kmem_map_size(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_vm, OID_AUTO, kmem_map_size,
    CTLFLAG_RD | CTLTYPE_ULONG | CTLFLAG_MPSAFE, NULL, 0,
    sysctl_kmem_map_size, "LU", "Current kmem_map allocation size");

static int sysctl_kmem_map_free(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_vm, OID_AUTO, kmem_map_free,
    CTLFLAG_RD | CTLTYPE_ULONG | CTLFLAG_MPSAFE, NULL, 0,
    sysctl_kmem_map_free, "LU", "Largest contiguous free range in kmem_map");

/*
 * The malloc_mtx protects the kmemstatistics linked list.
 */
struct mtx malloc_mtx;

#ifdef MALLOC_PROFILE
uint64_t krequests[KMEM_ZSIZE + 1];

static int sysctl_kern_mprof(SYSCTL_HANDLER_ARGS);
#endif

static int sysctl_kern_malloc_stats(SYSCTL_HANDLER_ARGS);

/*
 * time_uptime of the last malloc(9) failure (induced or real).
 */
static time_t t_malloc_fail;

#if defined(MALLOC_MAKE_FAILURES) || (MALLOC_DEBUG_MAXZONES > 1)
static SYSCTL_NODE(_debug, OID_AUTO, malloc, CTLFLAG_RD, 0,
    "Kernel malloc debugging options");
#endif

/*
 * malloc(9) fault injection -- cause malloc failures every (n) mallocs when
 * the caller specifies M_NOWAIT.  If set to 0, no failures are caused.
 */
#ifdef MALLOC_MAKE_FAILURES
static int malloc_failure_rate;
static int malloc_nowait_count;
static int malloc_failure_count;
SYSCTL_INT(_debug_malloc, OID_AUTO, failure_rate, CTLFLAG_RW,
    &malloc_failure_rate, 0, "Every (n) mallocs with M_NOWAIT will fail");
TUNABLE_INT("debug.malloc.failure_rate", &malloc_failure_rate);
SYSCTL_INT(_debug_malloc, OID_AUTO, failure_count, CTLFLAG_RD,
    &malloc_failure_count, 0, "Number of imposed M_NOWAIT malloc failures");
#endif

static int
sysctl_kmem_map_size(SYSCTL_HANDLER_ARGS)
{
        u_long size;

        size = kmem_map->size;
        return (sysctl_handle_long(oidp, &size, 0, req));
}

static int
sysctl_kmem_map_free(SYSCTL_HANDLER_ARGS)
{
        u_long size;

        vm_map_lock_read(kmem_map);
        size = kmem_map->root != NULL ? kmem_map->root->max_free :
            kmem_map->max_offset - kmem_map->min_offset;
        vm_map_unlock_read(kmem_map);
        return (sysctl_handle_long(oidp, &size, 0, req));
}

/*
 * malloc(9) uma zone separation -- sub-page buffer overruns in one
 * malloc type will affect only a subset of other malloc types.
 */
#if MALLOC_DEBUG_MAXZONES > 1
static void
tunable_set_numzones(void)
{

        TUNABLE_INT_FETCH("debug.malloc.numzones",
            &numzones);

        /* Sanity check the number of malloc uma zones. */
        if (numzones <= 0)
                numzones = 1;
        if (numzones > MALLOC_DEBUG_MAXZONES)
                numzones = MALLOC_DEBUG_MAXZONES;
}
SYSINIT(numzones, SI_SUB_TUNABLES, SI_ORDER_ANY, tunable_set_numzones, NULL);
SYSCTL_INT(_debug_malloc, OID_AUTO, numzones, CTLFLAG_RDTUN,
    &numzones, 0, "Number of malloc uma subzones");

/*
 * Any number that changes regularly is an okay choice for the
 * offset.  Build numbers are pretty good of you have them.
 */
static u_int zone_offset = __BSDSUniX_version;
TUNABLE_INT("debug.malloc.zone_offset", &zone_offset);
SYSCTL_UINT(_debug_malloc, OID_AUTO, zone_offset, CTLFLAG_RDTUN,
    &zone_offset, 0, "Separate malloc types by examining the "
    "Nth character in the malloc type short description.");

static u_int
mtp_get_subzone(const char *desc)
{
        size_t len;
        u_int val;

        if (desc == NULL || (len = strlen(desc)) == 0)
                return (0);
        val = desc[zone_offset % len];
        return (val % numzones);
}
#elif MALLOC_DEBUG_MAXZONES == 0
#error "MALLOC_DEBUG_MAXZONES must be positive."
#else
static inline u_int
mtp_get_subzone(const char *desc)
{

        return (0);
}
#endif /* MALLOC_DEBUG_MAXZONES > 1 */

int
malloc_last_fail(void)
{

        return (time_uptime - t_malloc_fail);
}

/*
 * An allocation has succeeded -- update malloc type statistics for the
 * amount of bucket size.  Occurs within a critical section so that the
 * thread isn't preempted and doesn't migrate while updating per-PCU
 * statistics.
 */
static void
malloc_type_zone_allocated(struct malloc_type *mtp, unsigned long size,
    int zindx)
{
        struct malloc_type_internal *mtip;
        struct malloc_type_stats *mtsp;

        critical_enter();
        mtip = mtp->ks_handle;
        mtsp = &mtip->mti_stats[curcpu];
        if (size > 0) {
                mtsp->mts_memalloced += size;
                mtsp->mts_numallocs++;
        }
        if (zindx != -1)
                mtsp->mts_size |= 1 << zindx;

#ifdef KDTRACE_HOOKS
        if (dtrace_malloc_probe != NULL) {
                uint32_t probe_id = mtip->mti_probes[DTMALLOC_PROBE_MALLOC];
                if (probe_id != 0)
                        (dtrace_malloc_probe)(probe_id,
                            (uintptr_t) mtp, (uintptr_t) mtip,
                            (uintptr_t) mtsp, size, zindx);
        }
#endif

        critical_exit();
}

void
malloc_type_allocated(struct malloc_type *mtp, unsigned long size)
{

        if (size > 0)
                malloc_type_zone_allocated(mtp, size, -1);
}

/*
 * A free operation has occurred -- update malloc type statistics for the
 * amount of the bucket size.  Occurs within a critical section so that the
 * thread isn't preempted and doesn't migrate while updating per-CPU
 * statistics.
 */
void
malloc_type_freed(struct malloc_type *mtp, unsigned long size)
{
        struct malloc_type_internal *mtip;
        struct malloc_type_stats *mtsp;

        critical_enter();
        mtip = mtp->ks_handle;
        mtsp = &mtip->mti_stats[curcpu];
        mtsp->mts_memfreed += size;
        mtsp->mts_numfrees++;

#ifdef KDTRACE_HOOKS
        if (dtrace_malloc_probe != NULL) {
                uint32_t probe_id = mtip->mti_probes[DTMALLOC_PROBE_FREE];
                if (probe_id != 0)
                        (dtrace_malloc_probe)(probe_id,
                            (uintptr_t) mtp, (uintptr_t) mtip,
                            (uintptr_t) mtsp, size, 0);
        }
#endif

        critical_exit();
}

/*
 *      contigmalloc:
 *
 *      Allocate a block of physically contiguous memory.
 *
 *      If M_NOWAIT is set, this routine will not block and return NULL if
 *      the allocation fails.
 */
void *
contigmalloc(unsigned long size, struct malloc_type *type, int flags,
    vm_paddr_t low, vm_paddr_t high, unsigned long alignment,
    unsigned long boundary)
{
        void *ret;

        ret = (void *)kmem_alloc_contig(kernel_map, size, flags, low, high,
            alignment, boundary, VM_MEMATTR_DEFAULT);
        if (ret != NULL)
                malloc_type_allocated(type, round_page(size));
        return (ret);
}

/*
 *      contigfree:
 *
 *      Free a block of memory allocated by contigmalloc.
 *
 *      This routine may not block.
 */
void
contigfree(void *addr, unsigned long size, struct malloc_type *type)
{

        kmem_free(kernel_map, (vm_offset_t)addr, size);
        malloc_type_freed(type, round_page(size));
}

/*
 *      malloc:
 *
 *      Allocate a block of memory.
 *
 *      If M_NOWAIT is set, this routine will not block and return NULL if
 *      the allocation fails.
 */
void *
malloc(unsigned long size, struct malloc_type *mtp, int flags)
{
        int indx;
        struct malloc_type_internal *mtip;
        caddr_t va;
        uma_zone_t zone;
#if defined(DIAGNOSTIC) || defined(DEBUG_REDZONE)
        unsigned long osize = size;
#endif

#ifdef INVARIANTS
        KASSERT(mtp->ks_magic == M_MAGIC, ("malloc: bad malloc type magic"));
        /*
         * Check that exactly one of M_WAITOK or M_NOWAIT is specified.
         */
        indx = flags & (M_WAITOK | M_NOWAIT);
        if (indx != M_NOWAIT && indx != M_WAITOK) {
                static  struct timeval lasterr;
                static  int curerr, once;
                if (once == 0 && ppsratecheck(&lasterr, &curerr, 1)) {
                        printf("Bad malloc flags: %x\n", indx);
                        kdb_backtrace();
                        flags |= M_WAITOK;
                        once++;
                }
        }
#endif
#ifdef MALLOC_MAKE_FAILURES
        if ((flags & M_NOWAIT) && (malloc_failure_rate != 0)) {
                atomic_add_int(&malloc_nowait_count, 1);
                if ((malloc_nowait_count % malloc_failure_rate) == 0) {
                        atomic_add_int(&malloc_failure_count, 1);
                        t_malloc_fail = time_uptime;
                        return (NULL);
                }
        }
#endif
        if (flags & M_WAITOK)
                KASSERT(curthread->td_intr_nesting_level == 0,
                   ("malloc(M_WAITOK) in interrupt context"));

#ifdef DEBUG_MEMGUARD
        if (memguard_cmp(mtp, size)) {
                va = memguard_alloc(size, flags);
                if (va != NULL)
                        return (va);
                /* This is unfortunate but should not be fatal. */
        }
#endif

#ifdef DEBUG_REDZONE
        size = redzone_size_ntor(size);
#endif

        if (size <= KMEM_ZMAX) {
                mtip = mtp->ks_handle;
                if (size & KMEM_ZMASK)
                        size = (size & ~KMEM_ZMASK) + KMEM_ZBASE;
                indx = kmemsize[size >> KMEM_ZSHIFT];
                KASSERT(mtip->mti_zone < numzones,
                    ("mti_zone %u out of range %d",
                    mtip->mti_zone, numzones));
                zone = kmemzones[indx].kz_zone[mtip->mti_zone];
#ifdef MALLOC_PROFILE
                krequests[size >> KMEM_ZSHIFT]++;
#endif
                va = uma_zalloc(zone, flags);
                if (va != NULL)
                        size = zone->uz_size;
                malloc_type_zone_allocated(mtp, va == NULL ? 0 : size, indx);
        } else {
                size = roundup(size, PAGE_SIZE);
                zone = NULL;
                va = uma_large_malloc(size, flags);
                malloc_type_allocated(mtp, va == NULL ? 0 : size);
        }
        if (flags & M_WAITOK)
                KASSERT(va != NULL, ("malloc(M_WAITOK) returned NULL"));
        else if (va == NULL)
                t_malloc_fail = time_uptime;
#ifdef DIAGNOSTIC
        if (va != NULL && !(flags & M_ZERO)) {
                memset(va, 0x70, osize);
        }
#endif
#ifdef DEBUG_REDZONE
        if (va != NULL)
                va = redzone_setup(va, osize);
#endif
        return ((void *) va);
}

/*
 *      free:
 *
 *      Free a block of memory allocated by malloc.
 *
 *      This routine may not block.
 */
void
free(void *addr, struct malloc_type *mtp)
{
        uma_slab_t slab;
        u_long size;

        KASSERT(mtp->ks_magic == M_MAGIC, ("free: bad malloc type magic"));

        /* free(NULL, ...) does nothing */
        if (addr == NULL)
                return;

#ifdef DEBUG_MEMGUARD
        if (is_memguard_addr(addr)) {
                memguard_free(addr);
                return;
        }
#endif

#ifdef DEBUG_REDZONE
        redzone_check(addr);
        addr = redzone_addr_ntor(addr);
#endif

        slab = vtoslab((vm_offset_t)addr & (~UMA_SLAB_MASK));

        if (slab == NULL)
                panic("free: address %p(%p) has not been allocated.\n",
                    addr, (void *)((u_long)addr & (~UMA_SLAB_MASK)));


        if (!(slab->us_flags & UMA_SLAB_MALLOC)) {
#ifdef INVARIANTS
                struct malloc_type **mtpp = addr;
#endif
                size = slab->us_keg->uk_size;
#ifdef INVARIANTS
                /*
                 * Cache a pointer to the malloc_type that most recently freed
                 * this memory here.  This way we know who is most likely to
                 * have stepped on it later.
                 *
                 * This code assumes that size is a multiple of 8 bytes for
                 * 64 bit machines
                 */
                mtpp = (struct malloc_type **)
                    ((unsigned long)mtpp & ~UMA_ALIGN_PTR);
                mtpp += (size - sizeof(struct malloc_type *)) /
                    sizeof(struct malloc_type *);
                *mtpp = mtp;
#endif
                uma_zfree_arg(LIST_FIRST(&slab->us_keg->uk_zones), addr, slab);
        } else {
                size = slab->us_size;
                uma_large_free(slab);
        }
        malloc_type_freed(mtp, size);
}

/*
 *      realloc: change the size of a memory block
 */
void *
realloc(void *addr, unsigned long size, struct malloc_type *mtp, int flags)
{
        uma_slab_t slab;
        unsigned long alloc;
        void *newaddr;

        KASSERT(mtp->ks_magic == M_MAGIC,
            ("realloc: bad malloc type magic"));

        /* realloc(NULL, ...) is equivalent to malloc(...) */
        if (addr == NULL)
                return (malloc(size, mtp, flags));

        /*
         * XXX: Should report free of old memory and alloc of new memory to
         * per-CPU stats.
         */

#ifdef DEBUG_MEMGUARD
        if (is_memguard_addr(addr))
                return (memguard_realloc(addr, size, mtp, flags));
#endif

#ifdef DEBUG_REDZONE
        slab = NULL;
        alloc = redzone_get_size(addr);
#else
        slab = vtoslab((vm_offset_t)addr & ~(UMA_SLAB_MASK));

        /* Sanity check */
        KASSERT(slab != NULL,
            ("realloc: address %p out of range", (void *)addr));

        /* Get the size of the original block */
        if (!(slab->us_flags & UMA_SLAB_MALLOC))
                alloc = slab->us_keg->uk_size;
        else
                alloc = slab->us_size;

        /* Reuse the original block if appropriate */
        if (size <= alloc
            && (size > (alloc >> REALLOC_FRACTION) || alloc == MINALLOCSIZE))
                return (addr);
#endif /* !DEBUG_REDZONE */

        /* Allocate a new, bigger (or smaller) block */
        if ((newaddr = malloc(size, mtp, flags)) == NULL)
                return (NULL);

        /* Copy over original contents */
        bcopy(addr, newaddr, min(size, alloc));
        free(addr, mtp);
        return (newaddr);
}

/*
 *      reallocf: same as realloc() but free memory on failure.
 */
void *
reallocf(void *addr, unsigned long size, struct malloc_type *mtp, int flags)
{
        void *mem;

        if ((mem = realloc(addr, size, mtp, flags)) == NULL)
                free(addr, mtp);
        return (mem);
}

/*
 * Initialize the kernel memory allocator
 */
/* ARGSUSED*/
static void
kmeminit(void *dummy)
{
        uint8_t indx;
        u_long mem_size, tmp;
        int i;
 
        mtx_init(&malloc_mtx, "malloc", NULL, MTX_DEF);

        /*
         * Try to auto-tune the kernel memory size, so that it is
         * more applicable for a wider range of machine sizes.  The
         * VM_KMEM_SIZE_MAX is dependent on the maximum KVA space
         * available.
         *
         * Note that the kmem_map is also used by the zone allocator,
         * so make sure that there is enough space.
         */
        vm_kmem_size = VM_KMEM_SIZE + nmbclusters * PAGE_SIZE;
        mem_size = cnt.v_page_count;

#if defined(VM_KMEM_SIZE_SCALE)
        vm_kmem_size_scale = VM_KMEM_SIZE_SCALE;
#endif
        TUNABLE_INT_FETCH("vm.kmem_size_scale", &vm_kmem_size_scale);
        if (vm_kmem_size_scale > 0 &&
            (mem_size / vm_kmem_size_scale) > (vm_kmem_size / PAGE_SIZE))
                vm_kmem_size = (mem_size / vm_kmem_size_scale) * PAGE_SIZE;

#if defined(VM_KMEM_SIZE_MIN)
        vm_kmem_size_min = VM_KMEM_SIZE_MIN;
#endif
        TUNABLE_ULONG_FETCH("vm.kmem_size_min", &vm_kmem_size_min);
        if (vm_kmem_size_min > 0 && vm_kmem_size < vm_kmem_size_min) {
                vm_kmem_size = vm_kmem_size_min;
        }

#if defined(VM_KMEM_SIZE_MAX)
        vm_kmem_size_max = VM_KMEM_SIZE_MAX;
#endif
        TUNABLE_ULONG_FETCH("vm.kmem_size_max", &vm_kmem_size_max);
        if (vm_kmem_size_max > 0 && vm_kmem_size >= vm_kmem_size_max)
                vm_kmem_size = vm_kmem_size_max;

        /* Allow final override from the kernel environment */
        TUNABLE_ULONG_FETCH("vm.kmem_size", &vm_kmem_size);

        /*
         * Limit kmem virtual size to twice the physical memory.
         * This allows for kmem map sparseness, but limits the size
         * to something sane.  Be careful to not overflow the 32bit
         * ints while doing the check or the adjustment.
         */
        if (vm_kmem_size / 2 / PAGE_SIZE > mem_size)
                vm_kmem_size = 2 * mem_size * PAGE_SIZE;

#ifdef DEBUG_MEMGUARD
        tmp = memguard_fudge(vm_kmem_size, kernel_map);
#else
        tmp = vm_kmem_size;
#endif
        kmem_map = kmem_suballoc(kernel_map, &kmembase, &kmemlimit,
            tmp, TRUE);
        kmem_map->system_map = 1;

#ifdef DEBUG_MEMGUARD
        /*
         * Initialize MemGuard if support compiled in.  MemGuard is a
         * replacement allocator used for detecting tamper-after-free
         * scenarios as they occur.  It is only used for debugging.
         */
        memguard_init(kmem_map);
#endif

        uma_startup2();

        mt_zone = uma_zcreate("mt_zone", sizeof(struct malloc_type_internal),
#ifdef INVARIANTS
            mtrash_ctor, mtrash_dtor, mtrash_init, mtrash_fini,
#else
            NULL, NULL, NULL, NULL,
#endif
            UMA_ALIGN_PTR, UMA_ZONE_MALLOC);
        for (i = 0, indx = 0; kmemzones[indx].kz_size != 0; indx++) {
                int size = kmemzones[indx].kz_size;
                char *name = kmemzones[indx].kz_name;
                int subzone;

                for (subzone = 0; subzone < numzones; subzone++) {
                        kmemzones[indx].kz_zone[subzone] =
                            uma_zcreate(name, size,
#ifdef INVARIANTS
                            mtrash_ctor, mtrash_dtor, mtrash_init, mtrash_fini,
#else
                            NULL, NULL, NULL, NULL,
#endif
                            UMA_ALIGN_PTR, UMA_ZONE_MALLOC);
                }                   
                for (;i <= size; i+= KMEM_ZBASE)
                        kmemsize[i >> KMEM_ZSHIFT] = indx;
                
        }
}

void
malloc_init(void *data)
{
        struct malloc_type_internal *mtip;
        struct malloc_type *mtp;

        KASSERT(cnt.v_page_count != 0, ("malloc_register before vm_init"));

        mtp = data;
        if (mtp->ks_magic != M_MAGIC)
                panic("malloc_init: bad malloc type magic");

        mtip = uma_zalloc(mt_zone, M_WAITOK | M_ZERO);
        mtp->ks_handle = mtip;
        mtip->mti_zone = mtp_get_subzone(mtp->ks_shortdesc);

        mtx_lock(&malloc_mtx);
        mtp->ks_next = kmemstatistics;
        kmemstatistics = mtp;
        kmemcount++;
        mtx_unlock(&malloc_mtx);
}

void
malloc_uninit(void *data)
{
        struct malloc_type_internal *mtip;
        struct malloc_type_stats *mtsp;
        struct malloc_type *mtp, *temp;
        uma_slab_t slab;
        long temp_allocs, temp_bytes;
        int i;

        mtp = data;
        KASSERT(mtp->ks_magic == M_MAGIC,
            ("malloc_uninit: bad malloc type magic"));
        KASSERT(mtp->ks_handle != NULL, ("malloc_deregister: cookie NULL"));

        mtx_lock(&malloc_mtx);
        mtip = mtp->ks_handle;
        mtp->ks_handle = NULL;
        if (mtp != kmemstatistics) {
                for (temp = kmemstatistics; temp != NULL;
                    temp = temp->ks_next) {
                        if (temp->ks_next == mtp) {
                                temp->ks_next = mtp->ks_next;
                                break;
                        }
                }
                KASSERT(temp,
                    ("malloc_uninit: type '%s' not found", mtp->ks_shortdesc));
        } else
                kmemstatistics = mtp->ks_next;
        kmemcount--;
        mtx_unlock(&malloc_mtx);

        /*
         * Look for memory leaks.
         */
        temp_allocs = temp_bytes = 0;
        for (i = 0; i < MAXCPU; i++) {
                mtsp = &mtip->mti_stats[i];
                temp_allocs += mtsp->mts_numallocs;
                temp_allocs -= mtsp->mts_numfrees;
                temp_bytes += mtsp->mts_memalloced;
                temp_bytes -= mtsp->mts_memfreed;
        }
        if (temp_allocs > 0 || temp_bytes > 0) {
                printf("Warning: memory type %s leaked memory on destroy "
                    "(%ld allocations, %ld bytes leaked).\n", mtp->ks_shortdesc,
                    temp_allocs, temp_bytes);
        }

        slab = vtoslab((vm_offset_t) mtip & (~UMA_SLAB_MASK));
        uma_zfree_arg(mt_zone, mtip, slab);
}

struct malloc_type *
malloc_desc2type(const char *desc)
{
        struct malloc_type *mtp;

        mtx_assert(&malloc_mtx, MA_OWNED);
        for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
                if (strcmp(mtp->ks_shortdesc, desc) == 0)
                        return (mtp);
        }
        return (NULL);
}

static int
sysctl_kern_malloc_stats(SYSCTL_HANDLER_ARGS)
{
        struct malloc_type_stream_header mtsh;
        struct malloc_type_internal *mtip;
        struct malloc_type_header mth;
        struct malloc_type *mtp;
        int error, i;
        struct sbuf sbuf;

        error = sysctl_wire_old_buffer(req, 0);
        if (error != 0)
                return (error);
        sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
        mtx_lock(&malloc_mtx);

        /*
         * Insert stream header.
         */
        bzero(&mtsh, sizeof(mtsh));
        mtsh.mtsh_version = MALLOC_TYPE_STREAM_VERSION;
        mtsh.mtsh_maxcpus = MAXCPU;
        mtsh.mtsh_count = kmemcount;
        (void)sbuf_bcat(&sbuf, &mtsh, sizeof(mtsh));

        /*
         * Insert alternating sequence of type headers and type statistics.
         */
        for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
                mtip = (struct malloc_type_internal *)mtp->ks_handle;

                /*
                 * Insert type header.
                 */
                bzero(&mth, sizeof(mth));
                strlcpy(mth.mth_name, mtp->ks_shortdesc, MALLOC_MAX_NAME);
                (void)sbuf_bcat(&sbuf, &mth, sizeof(mth));

                /*
                 * Insert type statistics for each CPU.
                 */
                for (i = 0; i < MAXCPU; i++) {
                        (void)sbuf_bcat(&sbuf, &mtip->mti_stats[i],
                            sizeof(mtip->mti_stats[i]));
                }
        }
        mtx_unlock(&malloc_mtx);
        error = sbuf_finish(&sbuf);
        sbuf_delete(&sbuf);
        return (error);
}

SYSCTL_PROC(_kern, OID_AUTO, malloc_stats, CTLFLAG_RD|CTLTYPE_STRUCT,
    0, 0, sysctl_kern_malloc_stats, "s,malloc_type_ustats",
    "Return malloc types");

SYSCTL_INT(_kern, OID_AUTO, malloc_count, CTLFLAG_RD, &kmemcount, 0,
    "Count of kernel malloc types");

void
malloc_type_list(malloc_type_list_func_t *func, void *arg)
{
        struct malloc_type *mtp, **bufmtp;
        int count, i;
        size_t buflen;

        mtx_lock(&malloc_mtx);
restart:
        mtx_assert(&malloc_mtx, MA_OWNED);
        count = kmemcount;
        mtx_unlock(&malloc_mtx);

        buflen = sizeof(struct malloc_type *) * count;
        bufmtp = malloc(buflen, M_TEMP, M_WAITOK);

        mtx_lock(&malloc_mtx);

        if (count < kmemcount) {
                free(bufmtp, M_TEMP);
                goto restart;
        }

        for (mtp = kmemstatistics, i = 0; mtp != NULL; mtp = mtp->ks_next, i++)
                bufmtp[i] = mtp;

        mtx_unlock(&malloc_mtx);

        for (i = 0; i < count; i++)
                (func)(bufmtp[i], arg);

        free(bufmtp, M_TEMP);
}

#ifdef DDB
DB_SHOW_COMMAND(malloc, db_show_malloc)
{
        struct malloc_type_internal *mtip;
        struct malloc_type *mtp;
        uint64_t allocs, frees;
        uint64_t alloced, freed;
        int i;

        db_printf("%18s %12s  %12s %12s\n", "Type", "InUse", "MemUse",
            "Requests");
        for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
                mtip = (struct malloc_type_internal *)mtp->ks_handle;
                allocs = 0;
                frees = 0;
                alloced = 0;
                freed = 0;
                for (i = 0; i < MAXCPU; i++) {
                        allocs += mtip->mti_stats[i].mts_numallocs;
                        frees += mtip->mti_stats[i].mts_numfrees;
                        alloced += mtip->mti_stats[i].mts_memalloced;
                        freed += mtip->mti_stats[i].mts_memfreed;
                }
                db_printf("%18s %12ju %12juK %12ju\n",
                    mtp->ks_shortdesc, allocs - frees,
                    (alloced - freed + 1023) / 1024, allocs);
                if (db_pager_quit)
                        break;
        }
}

#if MALLOC_DEBUG_MAXZONES > 1
DB_SHOW_COMMAND(multizone_matches, db_show_multizone_matches)
{
        struct malloc_type_internal *mtip;
        struct malloc_type *mtp;
        u_int subzone;

        if (!have_addr) {
                db_printf("Usage: show multizone_matches <malloc type/addr>\n");
                return;
        }
        mtp = (void *)addr;
        if (mtp->ks_magic != M_MAGIC) {
                db_printf("Magic %lx does not match expected %x\n",
                    mtp->ks_magic, M_MAGIC);
                return;
        }

        mtip = mtp->ks_handle;
        subzone = mtip->mti_zone;

        for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
                mtip = mtp->ks_handle;
                if (mtip->mti_zone != subzone)
                        continue;
                db_printf("%s\n", mtp->ks_shortdesc);
                if (db_pager_quit)
                        break;
        }
}
#endif /* MALLOC_DEBUG_MAXZONES > 1 */
#endif /* DDB */

#ifdef MALLOC_PROFILE

static int
sysctl_kern_mprof(SYSCTL_HANDLER_ARGS)
{
        struct sbuf sbuf;
        uint64_t count;
        uint64_t waste;
        uint64_t mem;
        int error;
        int rsize;
        int size;
        int i;

        waste = 0;
        mem = 0;

        error = sysctl_wire_old_buffer(req, 0);
        if (error != 0)
                return (error);
        sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
        sbuf_printf(&sbuf, 
            "\n  Size                    Requests  Real Size\n");
        for (i = 0; i < KMEM_ZSIZE; i++) {
                size = i << KMEM_ZSHIFT;
                rsize = kmemzones[kmemsize[i]].kz_size;
                count = (long long unsigned)krequests[i];

                sbuf_printf(&sbuf, "%6d%28llu%11d\n", size,
                    (unsigned long long)count, rsize);

                if ((rsize * count) > (size * count))
                        waste += (rsize * count) - (size * count);
                mem += (rsize * count);
        }
        sbuf_printf(&sbuf,
            "\nTotal memory used:\t%30llu\nTotal Memory wasted:\t%30llu\n",
            (unsigned long long)mem, (unsigned long long)waste);
        error = sbuf_finish(&sbuf);
        sbuf_delete(&sbuf);
        return (error);
}

SYSCTL_OID(_kern, OID_AUTO, mprof, CTLTYPE_STRING|CTLFLAG_RD,
    NULL, 0, sysctl_kern_mprof, "A", "Malloc Profiling");
#endif /* MALLOC_PROFILE */