FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_malloc.c

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 1987, 1991, 1993
      *      The Regents of the University of California.
      * Copyright (c) 2005-2009 Robert N. M. Watson
      * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net> (mallocarray)
      * 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.
     * 3. 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("$FreeBSD$");
    
    #include "opt_ddb.h"
    #include "opt_vm.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/asan.h>
    #include <sys/kdb.h>
    #include <sys/kernel.h>
    #include <sys/lock.h>
    #include <sys/malloc.h>
    #include <sys/mutex.h>
    #include <sys/vmmeter.h>
    #include <sys/proc.h>
    #include <sys/queue.h>
    #include <sys/sbuf.h>
    #include <sys/smp.h>
    #include <sys/sysctl.h>
    #include <sys/time.h>
    #include <sys/vmem.h>
    #ifdef EPOCH_TRACE
    #include <sys/epoch.h>
    #endif
    
    #include <vm/vm.h>
    #include <vm/pmap.h>
    #include <vm/vm_domainset.h>
    #include <vm/vm_pageout.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/vm_phys.h>
    #include <vm/vm_pagequeue.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>
   
   bool    __read_frequently                       dtrace_malloc_enabled;
   dtrace_malloc_probe_func_t __read_mostly        dtrace_malloc_probe;
   #endif
   
   #if defined(INVARIANTS) || defined(MALLOC_MAKE_FAILURES) ||             \
       defined(DEBUG_MEMGUARD) || defined(DEBUG_REDZONE)
   #define MALLOC_DEBUG    1
   #endif
   
   #if defined(KASAN) || defined(DEBUG_REDZONE)
   #define DEBUG_REDZONE_ARG_DEF   , unsigned long osize
   #define DEBUG_REDZONE_ARG       , osize
   #else
   #define DEBUG_REDZONE_ARG_DEF
   #define DEBUG_REDZONE_ARG
   #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");
   
   static struct malloc_type *kmemstatistics;
   static int kmemcount;
   
   #define KMEM_ZSHIFT     4
   #define KMEM_ZBASE      16
   #define KMEM_ZMASK      (KMEM_ZBASE - 1)
   
   #define KMEM_ZMAX       65536
   #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.
    *
    * Warning: the layout of the struct is duplicated in libmemstat for KVM support.
    *
    * 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;
           const char *kz_name;
           uma_zone_t kz_zone[MALLOC_DEBUG_MAXZONES];
   } kmemzones[] = {
           {16, "malloc-16", },
           {32, "malloc-32", },
           {64, "malloc-64", },
           {128, "malloc-128", },
           {256, "malloc-256", },
           {384, "malloc-384", },
           {512, "malloc-512", },
           {1024, "malloc-1024", },
           {2048, "malloc-2048", },
           {4096, "malloc-4096", },
           {8192, "malloc-8192", },
           {16384, "malloc-16384", },
           {32768, "malloc-32768", },
           {65536, "malloc-65536", },
           {0, NULL},
   };
   
   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 kmem_zmax = KMEM_ZMAX;
   SYSCTL_ULONG(_vm, OID_AUTO, kmem_zmax, CTLFLAG_RDTUN, &kmem_zmax, 0,
       "Maximum allocation size that malloc(9) would use UMA as backend");
   
   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 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", "Free space in kmem");
   
   static SYSCTL_NODE(_vm, OID_AUTO, malloc, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
       "Malloc information");
   
   static u_int vm_malloc_zone_count = nitems(kmemzones);
   SYSCTL_UINT(_vm_malloc, OID_AUTO, zone_count,
       CTLFLAG_RD, &vm_malloc_zone_count, 0,
       "Number of malloc zones");
   
   static int sysctl_vm_malloc_zone_sizes(SYSCTL_HANDLER_ARGS);
   SYSCTL_PROC(_vm_malloc, OID_AUTO, zone_sizes,
       CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, NULL, 0,
       sysctl_vm_malloc_zone_sizes, "S", "Zone sizes used by malloc");
   
   /*
    * The malloc_mtx protects the kmemstatistics linked list.
    */
   struct mtx malloc_mtx;
   
   static int sysctl_kern_malloc_stats(SYSCTL_HANDLER_ARGS);
   
   #if defined(MALLOC_MAKE_FAILURES) || (MALLOC_DEBUG_MAXZONES > 1)
   static SYSCTL_NODE(_debug, OID_AUTO, malloc, CTLFLAG_RD | CTLFLAG_MPSAFE, 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_RWTUN,
       &malloc_failure_rate, 0, "Every (n) mallocs with M_NOWAIT will fail");
   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 = uma_size();
           return (sysctl_handle_long(oidp, &size, 0, req));
   }
   
   static int
   sysctl_kmem_map_free(SYSCTL_HANDLER_ARGS)
   {
           u_long size, limit;
   
           /* The sysctl is unsigned, implement as a saturation value. */
           size = uma_size();
           limit = uma_limit();
           if (size > limit)
                   size = 0;
           else
                   size = limit - size;
           return (sysctl_handle_long(oidp, &size, 0, req));
   }
   
   static int
   sysctl_vm_malloc_zone_sizes(SYSCTL_HANDLER_ARGS)
   {
           int sizes[nitems(kmemzones)];
           int i;
   
           for (i = 0; i < nitems(kmemzones); i++) {
                   sizes[i] = kmemzones[i].kz_size;
           }
   
           return (SYSCTL_OUT(req, &sizes, sizeof(sizes)));
   }
   
   /*
    * 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 | CTLFLAG_NOFETCH,
       &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 = __FreeBSD_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 void
   mtp_set_subzone(struct malloc_type *mtp)
   {
           struct malloc_type_internal *mtip;
           const char *desc;
           size_t len;
           u_int val;
   
           mtip = &mtp->ks_mti;
           desc = mtp->ks_shortdesc;
           if (desc == NULL || (len = strlen(desc)) == 0)
                   val = 0;
           else
                   val = desc[zone_offset % len];
           mtip->mti_zone = (val % numzones);
   }
   
   static inline u_int
   mtp_get_subzone(struct malloc_type *mtp)
   {
           struct malloc_type_internal *mtip;
   
           mtip = &mtp->ks_mti;
   
           KASSERT(mtip->mti_zone < numzones,
               ("mti_zone %u out of range %d",
               mtip->mti_zone, numzones));
           return (mtip->mti_zone);
   }
   #elif MALLOC_DEBUG_MAXZONES == 0
   #error "MALLOC_DEBUG_MAXZONES must be positive."
   #else
   static void
   mtp_set_subzone(struct malloc_type *mtp)
   {
           struct malloc_type_internal *mtip;
   
           mtip = &mtp->ks_mti;
           mtip->mti_zone = 0;
   }
   
   static inline u_int
   mtp_get_subzone(struct malloc_type *mtp)
   {
   
           return (0);
   }
   #endif /* MALLOC_DEBUG_MAXZONES > 1 */
   
   /*
    * 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_mti;
           mtsp = zpcpu_get(mtip->mti_stats);
           if (size > 0) {
                   mtsp->mts_memalloced += size;
                   mtsp->mts_numallocs++;
           }
           if (zindx != -1)
                   mtsp->mts_size |= 1 << zindx;
   
   #ifdef KDTRACE_HOOKS
           if (__predict_false(dtrace_malloc_enabled)) {
                   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_mti;
           mtsp = zpcpu_get(mtip->mti_stats);
           mtsp->mts_memfreed += size;
           mtsp->mts_numfrees++;
   
   #ifdef KDTRACE_HOOKS
           if (__predict_false(dtrace_malloc_enabled)) {
                   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,
       vm_paddr_t boundary)
   {
           void *ret;
   
           ret = (void *)kmem_alloc_contig(size, flags, low, high, alignment,
               boundary, VM_MEMATTR_DEFAULT);
           if (ret != NULL)
                   malloc_type_allocated(type, round_page(size));
           return (ret);
   }
   
   void *
   contigmalloc_domainset(unsigned long size, struct malloc_type *type,
       struct domainset *ds, int flags, vm_paddr_t low, vm_paddr_t high,
       unsigned long alignment, vm_paddr_t boundary)
   {
           void *ret;
   
           ret = (void *)kmem_alloc_contig_domainset(ds, 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((vm_offset_t)addr, size);
           malloc_type_freed(type, round_page(size));
   }
   
   #ifdef MALLOC_DEBUG
   static int
   malloc_dbg(caddr_t *vap, size_t *sizep, struct malloc_type *mtp,
       int flags)
   {
   #ifdef INVARIANTS
           int indx;
   
           KASSERT(mtp->ks_version == M_VERSION, ("malloc: bad malloc type version"));
           /*
            * 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);
                           *vap = NULL;
                           return (EJUSTRETURN);
                   }
           }
   #endif
           if (flags & M_WAITOK) {
                   KASSERT(curthread->td_intr_nesting_level == 0,
                      ("malloc(M_WAITOK) in interrupt context"));
                   if (__predict_false(!THREAD_CAN_SLEEP())) {
   #ifdef EPOCH_TRACE
                           epoch_trace_list(curthread);
   #endif
                           KASSERT(1, 
                               ("malloc(M_WAITOK) with sleeping prohibited"));
                   }
           }
           KASSERT(curthread->td_critnest == 0 || SCHEDULER_STOPPED(),
               ("malloc: called with spinlock or critical section held"));
   
   #ifdef DEBUG_MEMGUARD
           if (memguard_cmp_mtp(mtp, *sizep)) {
                   *vap = memguard_alloc(*sizep, flags);
                   if (*vap != NULL)
                           return (EJUSTRETURN);
                   /* This is unfortunate but should not be fatal. */
           }
   #endif
   
   #ifdef DEBUG_REDZONE
           *sizep = redzone_size_ntor(*sizep);
   #endif
   
           return (0);
   }
   #endif
   
   /*
    * Handle large allocations and frees by using kmem_malloc directly.
    */
   static inline bool
   malloc_large_slab(uma_slab_t slab)
   {
           uintptr_t va;
   
           va = (uintptr_t)slab;
           return ((va & 1) != 0);
   }
   
   static inline size_t
   malloc_large_size(uma_slab_t slab)
   {
           uintptr_t va;
   
           va = (uintptr_t)slab;
           return (va >> 1);
   }
   
   static caddr_t __noinline
   malloc_large(size_t *size, struct malloc_type *mtp, struct domainset *policy,
       int flags DEBUG_REDZONE_ARG_DEF)
   {
           vm_offset_t kva;
           caddr_t va;
           size_t sz;
   
           sz = roundup(*size, PAGE_SIZE);
           kva = kmem_malloc_domainset(policy, sz, flags);
           if (kva != 0) {
                   /* The low bit is unused for slab pointers. */
                   vsetzoneslab(kva, NULL, (void *)((sz << 1) | 1));
                   uma_total_inc(sz);
                   *size = sz;
           }
           va = (caddr_t)kva;
           malloc_type_allocated(mtp, va == NULL ? 0 : sz);
           if (__predict_false(va == NULL)) {
                   KASSERT((flags & M_WAITOK) == 0,
                       ("malloc(M_WAITOK) returned NULL"));
           } else {
   #ifdef DEBUG_REDZONE
                   va = redzone_setup(va, osize);
   #endif
                   kasan_mark((void *)va, osize, sz, KASAN_MALLOC_REDZONE);
           }
           return (va);
   }
   
   static void
   free_large(void *addr, size_t size)
   {
   
           kmem_free((vm_offset_t)addr, size);
           uma_total_dec(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)(size_t size, struct malloc_type *mtp, int flags)
   {
           int indx;
           caddr_t va;
           uma_zone_t zone;
   #if defined(DEBUG_REDZONE) || defined(KASAN)
           unsigned long osize = size;
   #endif
   
           MPASS((flags & M_EXEC) == 0);
   
   #ifdef MALLOC_DEBUG
           va = NULL;
           if (malloc_dbg(&va, &size, mtp, flags) != 0)
                   return (va);
   #endif
   
           if (__predict_false(size > kmem_zmax))
                   return (malloc_large(&size, mtp, DOMAINSET_RR(), flags
                       DEBUG_REDZONE_ARG));
   
           if (size & KMEM_ZMASK)
                   size = (size & ~KMEM_ZMASK) + KMEM_ZBASE;
           indx = kmemsize[size >> KMEM_ZSHIFT];
           zone = kmemzones[indx].kz_zone[mtp_get_subzone(mtp)];
           va = uma_zalloc(zone, flags);
           if (va != NULL)
                   size = zone->uz_size;
           malloc_type_zone_allocated(mtp, va == NULL ? 0 : size, indx);
           if (__predict_false(va == NULL)) {
                   KASSERT((flags & M_WAITOK) == 0,
                       ("malloc(M_WAITOK) returned NULL"));
           }
   #ifdef DEBUG_REDZONE
           if (va != NULL)
                   va = redzone_setup(va, osize);
   #endif
   #ifdef KASAN
           if (va != NULL)
                   kasan_mark((void *)va, osize, size, KASAN_MALLOC_REDZONE);
   #endif
           return ((void *) va);
   }
   
   static void *
   malloc_domain(size_t *sizep, int *indxp, struct malloc_type *mtp, int domain,
       int flags)
   {
           uma_zone_t zone;
           caddr_t va;
           size_t size;
           int indx;
   
           size = *sizep;
           KASSERT(size <= kmem_zmax && (flags & M_EXEC) == 0,
               ("malloc_domain: Called with bad flag / size combination."));
           if (size & KMEM_ZMASK)
                   size = (size & ~KMEM_ZMASK) + KMEM_ZBASE;
           indx = kmemsize[size >> KMEM_ZSHIFT];
           zone = kmemzones[indx].kz_zone[mtp_get_subzone(mtp)];
           va = uma_zalloc_domain(zone, NULL, domain, flags);
           if (va != NULL)
                   *sizep = zone->uz_size;
           *indxp = indx;
           return ((void *)va);
   }
   
   void *
   malloc_domainset(size_t size, struct malloc_type *mtp, struct domainset *ds,
       int flags)
   {
           struct vm_domainset_iter di;
           caddr_t va;
           int domain;
           int indx;
   #if defined(KASAN) || defined(DEBUG_REDZONE)
           unsigned long osize = size;
   #endif
   
           MPASS((flags & M_EXEC) == 0);
   
   #ifdef MALLOC_DEBUG
           va = NULL;
           if (malloc_dbg(&va, &size, mtp, flags) != 0)
                   return (va);
   #endif
   
           if (__predict_false(size > kmem_zmax))
                   return (malloc_large(&size, mtp, DOMAINSET_RR(), flags
                       DEBUG_REDZONE_ARG));
   
           vm_domainset_iter_policy_init(&di, ds, &domain, &flags);
           do {
                   va = malloc_domain(&size, &indx, mtp, domain, flags);
           } while (va == NULL && vm_domainset_iter_policy(&di, &domain) == 0);
           malloc_type_zone_allocated(mtp, va == NULL ? 0 : size, indx);
           if (__predict_false(va == NULL)) {
                   KASSERT((flags & M_WAITOK) == 0,
                       ("malloc(M_WAITOK) returned NULL"));
           }
   #ifdef DEBUG_REDZONE
           if (va != NULL)
                   va = redzone_setup(va, osize);
   #endif
   #ifdef KASAN
           if (va != NULL)
                   kasan_mark((void *)va, osize, size, KASAN_MALLOC_REDZONE);
   #endif
           return (va);
   }
   
   /*
    * Allocate an executable area.
    */
   void *
   malloc_exec(size_t size, struct malloc_type *mtp, int flags)
   {
   
           return (malloc_domainset_exec(size, mtp, DOMAINSET_RR(), flags));
   }
   
   void *
   malloc_domainset_exec(size_t size, struct malloc_type *mtp, struct domainset *ds,
       int flags)
   {
   #if defined(DEBUG_REDZONE) || defined(KASAN)
           unsigned long osize = size;
   #endif
   #ifdef MALLOC_DEBUG
           caddr_t va;
   #endif
   
           flags |= M_EXEC;
   
   #ifdef MALLOC_DEBUG
           va = NULL;
           if (malloc_dbg(&va, &size, mtp, flags) != 0)
                   return (va);
   #endif
   
           return (malloc_large(&size, mtp, ds, flags DEBUG_REDZONE_ARG));
   }
   
   void *
   malloc_aligned(size_t size, size_t align, struct malloc_type *type, int flags)
   {
           return (malloc_domainset_aligned(size, align, type, DOMAINSET_RR(),
               flags));
   }
   
   void *
   malloc_domainset_aligned(size_t size, size_t align,
       struct malloc_type *mtp, struct domainset *ds, int flags)
   {
           void *res;
           size_t asize;
   
           KASSERT(powerof2(align),
               ("malloc_domainset_aligned: wrong align %#zx size %#zx",
               align, size));
           KASSERT(align <= PAGE_SIZE,
               ("malloc_domainset_aligned: align %#zx (size %#zx) too large",
               align, size));
   
           /*
            * Round the allocation size up to the next power of 2,
            * because we can only guarantee alignment for
            * power-of-2-sized allocations.  Further increase the
            * allocation size to align if the rounded size is less than
            * align, since malloc zones provide alignment equal to their
            * size.
            */
           if (size == 0)
                   size = 1;
           asize = size <= align ? align : 1UL << flsl(size - 1);
   
           res = malloc_domainset(asize, mtp, ds, flags);
           KASSERT(res == NULL || ((uintptr_t)res & (align - 1)) == 0,
               ("malloc_domainset_aligned: result not aligned %p size %#zx "
               "allocsize %#zx align %#zx", res, size, asize, align));
           return (res);
   }
   
   void *
   mallocarray(size_t nmemb, size_t size, struct malloc_type *type, int flags)
   {
   
           if (WOULD_OVERFLOW(nmemb, size))
                   panic("mallocarray: %zu * %zu overflowed", nmemb, size);
   
           return (malloc(size * nmemb, type, flags));
   }
   
   void *
   mallocarray_domainset(size_t nmemb, size_t size, struct malloc_type *type,
       struct domainset *ds, int flags)
   {
   
           if (WOULD_OVERFLOW(nmemb, size))
                   panic("mallocarray_domainset: %zu * %zu overflowed", nmemb, size);
   
           return (malloc_domainset(size * nmemb, type, ds, flags));
   }
   
   #if defined(INVARIANTS) && !defined(KASAN)
   static void
   free_save_type(void *addr, struct malloc_type *mtp, u_long size)
   {
           struct malloc_type **mtpp = addr;
   
           /*
            * 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
   
   #ifdef MALLOC_DEBUG
   static int
   free_dbg(void **addrp, struct malloc_type *mtp)
   {
           void *addr;
   
           addr = *addrp;
           KASSERT(mtp->ks_version == M_VERSION, ("free: bad malloc type version"));
           KASSERT(curthread->td_critnest == 0 || SCHEDULER_STOPPED(),
               ("free: called with spinlock or critical section held"));
   
           /* free(NULL, ...) does nothing */
           if (addr == NULL)
                   return (EJUSTRETURN);
   
   #ifdef DEBUG_MEMGUARD
           if (is_memguard_addr(addr)) {
                   memguard_free(addr);
                   return (EJUSTRETURN);
           }
   #endif
   
   #ifdef DEBUG_REDZONE
           redzone_check(addr);
           *addrp = redzone_addr_ntor(addr);
   #endif
   
           return (0);
   }
   #endif
   
   /*
    *      free:
    *
    *      Free a block of memory allocated by malloc.
    *
    *      This routine may not block.
    */
   void
   free(void *addr, struct malloc_type *mtp)
   {
           uma_zone_t zone;
           uma_slab_t slab;
           u_long size;
   
   #ifdef MALLOC_DEBUG
           if (free_dbg(&addr, mtp) != 0)
                   return;
   #endif
           /* free(NULL, ...) does nothing */
           if (addr == NULL)
                   return;
   
           vtozoneslab((vm_offset_t)addr & (~UMA_SLAB_MASK), &zone, &slab);
           if (slab == NULL)
                   panic("free: address %p(%p) has not been allocated.\n",
                       addr, (void *)((u_long)addr & (~UMA_SLAB_MASK)));
   
           if (__predict_true(!malloc_large_slab(slab))) {
                   size = zone->uz_size;
   #if defined(INVARIANTS) && !defined(KASAN)
                   free_save_type(addr, mtp, size);
   #endif
                   uma_zfree_arg(zone, addr, slab);
           } else {
                   size = malloc_large_size(slab);
                   free_large(addr, size);
           }
           malloc_type_freed(mtp, size);
   }
   
   /*
    *      zfree:
    *
    *      Zero then free a block of memory allocated by malloc.
    *
    *      This routine may not block.
    */
   void
   zfree(void *addr, struct malloc_type *mtp)
   {
           uma_zone_t zone;
           uma_slab_t slab;
           u_long size;
   
   #ifdef MALLOC_DEBUG
           if (free_dbg(&addr, mtp) != 0)
                   return;
   #endif
           /* free(NULL, ...) does nothing */
           if (addr == NULL)
                   return;
   
           vtozoneslab((vm_offset_t)addr & (~UMA_SLAB_MASK), &zone, &slab);
           if (slab == NULL)
                   panic("free: address %p(%p) has not been allocated.\n",
                       addr, (void *)((u_long)addr & (~UMA_SLAB_MASK)));
   
           if (__predict_true(!malloc_large_slab(slab))) {
                   size = zone->uz_size;
   #if defined(INVARIANTS) && !defined(KASAN)
                   free_save_type(addr, mtp, size);
   #endif
                   kasan_mark(addr, size, size, 0);
                   explicit_bzero(addr, size);
                   uma_zfree_arg(zone, addr, slab);
           } else {
                   size = malloc_large_size(slab);
                   kasan_mark(addr, size, size, 0);
                   explicit_bzero(addr, size);
                   free_large(addr, size);
           }
           malloc_type_freed(mtp, size);
   }
   
   /*
    *      realloc: change the size of a memory block
    */
   void *
   realloc(void *addr, size_t size, struct malloc_type *mtp, int flags)
   {
           uma_zone_t zone;
           uma_slab_t slab;
           unsigned long alloc;
           void *newaddr;
   
           KASSERT(mtp->ks_version == M_VERSION,
               ("realloc: bad malloc type version"));
           KASSERT(curthread->td_critnest == 0 || SCHEDULER_STOPPED(),
               ("realloc: called with spinlock or critical section held"));
   
           /* 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;
          zone = NULL;
          alloc = redzone_get_size(addr);
  #else
          vtozoneslab((vm_offset_t)addr & (~UMA_SLAB_MASK), &zone, &slab);
  
          /* Sanity check */
          KASSERT(slab != NULL,
              ("realloc: address %p out of range", (void *)addr));
  
          /* Get the size of the original block */
          if (!malloc_large_slab(slab))
                  alloc = zone->uz_size;
          else
                  alloc = malloc_large_size(slab);
  
          /* Reuse the original block if appropriate */
          if (size <= alloc &&
              (size > (alloc >> REALLOC_FRACTION) || alloc == MINALLOCSIZE)) {
                  kasan_mark((void *)addr, size, alloc, KASAN_MALLOC_REDZONE);
                  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.  For KASAN, the redzone must be marked
           * valid before performing the copy.
           */
          kasan_mark(addr, alloc, alloc, 0);
          bcopy(addr, newaddr, min(size, alloc));
          free(addr, mtp);
          return (newaddr);
  }
  
  /*
   *      reallocf: same as realloc() but free memory on failure.
   */
  void *
  reallocf(void *addr, size_t size, struct malloc_type *mtp, int flags)
  {
          void *mem;
  
          if ((mem = realloc(addr, size, mtp, flags)) == NULL)
                  free(addr, mtp);
          return (mem);
  }
  
  /*
   *      malloc_size: returns the number of bytes allocated for a request of the
   *                   specified size
   */
  size_t
  malloc_size(size_t size)
  {
          int indx;
  
          if (size > kmem_zmax)
                  return (0);
          if (size & KMEM_ZMASK)
                  size = (size & ~KMEM_ZMASK) + KMEM_ZBASE;
          indx = kmemsize[size >> KMEM_ZSHIFT];
          return (kmemzones[indx].kz_size);
  }
  
  /*
   *      malloc_usable_size: returns the usable size of the allocation.
   */
  size_t
  malloc_usable_size(const void *addr)
  {
  #ifndef DEBUG_REDZONE
          uma_zone_t zone;
          uma_slab_t slab;
  #endif
          u_long size;
  
          if (addr == NULL)
                  return (0);
  
  #ifdef DEBUG_MEMGUARD
          if (is_memguard_addr(__DECONST(void *, addr)))
                  return (memguard_get_req_size(addr));
  #endif
  
  #ifdef DEBUG_REDZONE
          size = redzone_get_size(__DECONST(void *, addr));
  #else
          vtozoneslab((vm_offset_t)addr & (~UMA_SLAB_MASK), &zone, &slab);
          if (slab == NULL)
                  panic("malloc_usable_size: address %p(%p) is not allocated.\n",
                      addr, (void *)((u_long)addr & (~UMA_SLAB_MASK)));
  
          if (!malloc_large_slab(slab))
                  size = zone->uz_size;
          else
                  size = malloc_large_size(slab);
  #endif
          return (size);
  }
  
  CTASSERT(VM_KMEM_SIZE_SCALE >= 1);
  
  /*
   * Initialize the kernel memory (kmem) arena.
   */
  void
  kmeminit(void)
  {
          u_long mem_size;
          u_long tmp;
  
  #ifdef VM_KMEM_SIZE
          if (vm_kmem_size == 0)
                  vm_kmem_size = VM_KMEM_SIZE;
  #endif
  #ifdef VM_KMEM_SIZE_MIN
          if (vm_kmem_size_min == 0)
                  vm_kmem_size_min = VM_KMEM_SIZE_MIN;
  #endif
  #ifdef VM_KMEM_SIZE_MAX
          if (vm_kmem_size_max == 0)
                  vm_kmem_size_max = VM_KMEM_SIZE_MAX;
  #endif
          /*
           * Calculate the amount of kernel virtual address (KVA) space that is
           * preallocated to the kmem arena.  In order to support a wide range
           * of machines, it is a function of the physical memory size,
           * specifically,
           *
           *      min(max(physical memory size / VM_KMEM_SIZE_SCALE,
           *          VM_KMEM_SIZE_MIN), VM_KMEM_SIZE_MAX)
           *
           * Every architecture must define an integral value for
           * VM_KMEM_SIZE_SCALE.  However, the definitions of VM_KMEM_SIZE_MIN
           * and VM_KMEM_SIZE_MAX, which represent respectively the floor and
           * ceiling on this preallocation, are optional.  Typically,
           * VM_KMEM_SIZE_MAX is itself a function of the available KVA space on
           * a given architecture.
           */
          mem_size = vm_cnt.v_page_count;
          if (mem_size <= 32768) /* delphij XXX 128MB */
                  kmem_zmax = PAGE_SIZE;
  
          if (vm_kmem_size_scale < 1)
                  vm_kmem_size_scale = VM_KMEM_SIZE_SCALE;
  
          /*
           * Check if we should use defaults for the "vm_kmem_size"
           * variable:
           */
          if (vm_kmem_size == 0) {
                  vm_kmem_size = mem_size / vm_kmem_size_scale;
                  vm_kmem_size = vm_kmem_size * PAGE_SIZE < vm_kmem_size ?
                      vm_kmem_size_max : vm_kmem_size * PAGE_SIZE;
                  if (vm_kmem_size_min > 0 && vm_kmem_size < vm_kmem_size_min)
                          vm_kmem_size = vm_kmem_size_min;
                  if (vm_kmem_size_max > 0 && vm_kmem_size >= vm_kmem_size_max)
                          vm_kmem_size = vm_kmem_size_max;
          }
          if (vm_kmem_size == 0)
                  panic("Tune VM_KMEM_SIZE_* for the platform");
  
          /*
           * The amount of KVA space that is preallocated to the
           * kmem arena can be set statically at compile-time or manually
           * through the kernel environment.  However, it is still limited to
           * twice the physical memory size, which has been sufficient to handle
           * the most severe cases of external fragmentation in the kmem arena. 
           */
          if (vm_kmem_size / 2 / PAGE_SIZE > mem_size)
                  vm_kmem_size = 2 * mem_size * PAGE_SIZE;
  
          vm_kmem_size = round_page(vm_kmem_size);
  
  #ifdef KASAN
          /*
           * With KASAN enabled, dynamically allocated kernel memory is shadowed.
           * Account for this when setting the UMA limit.
           */
          vm_kmem_size = (vm_kmem_size * KASAN_SHADOW_SCALE) /
              (KASAN_SHADOW_SCALE + 1);
  #endif
  
  #ifdef DEBUG_MEMGUARD
          tmp = memguard_fudge(vm_kmem_size, kernel_map);
  #else
          tmp = vm_kmem_size;
  #endif
          uma_set_limit(tmp);
  
  #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(kernel_arena);
  #endif
  }
  
  /*
   * Initialize the kernel memory allocator
   */
  /* ARGSUSED*/
  static void
  mallocinit(void *dummy)
  {
          int i;
          uint8_t indx;
  
          mtx_init(&malloc_mtx, "malloc", NULL, MTX_DEF);
  
          kmeminit();
  
          if (kmem_zmax < PAGE_SIZE || kmem_zmax > KMEM_ZMAX)
                  kmem_zmax = KMEM_ZMAX;
  
          for (i = 0, indx = 0; kmemzones[indx].kz_size != 0; indx++) {
                  int size = kmemzones[indx].kz_size;
                  const char *name = kmemzones[indx].kz_name;
                  size_t align;
                  int subzone;
  
                  align = UMA_ALIGN_PTR;
                  if (powerof2(size) && size > sizeof(void *))
                          align = MIN(size, PAGE_SIZE) - 1;
                  for (subzone = 0; subzone < numzones; subzone++) {
                          kmemzones[indx].kz_zone[subzone] =
                              uma_zcreate(name, size,
  #if defined(INVARIANTS) && !defined(KASAN)
                              mtrash_ctor, mtrash_dtor, mtrash_init, mtrash_fini,
  #else
                              NULL, NULL, NULL, NULL,
  #endif
                              align, UMA_ZONE_MALLOC);
                  }
                  for (;i <= size; i+= KMEM_ZBASE)
                          kmemsize[i >> KMEM_ZSHIFT] = indx;
          }
  }
  SYSINIT(kmem, SI_SUB_KMEM, SI_ORDER_SECOND, mallocinit, NULL);
  
  void
  malloc_init(void *data)
  {
          struct malloc_type_internal *mtip;
          struct malloc_type *mtp;
  
          KASSERT(vm_cnt.v_page_count != 0, ("malloc_register before vm_init"));
  
          mtp = data;
          if (mtp->ks_version != M_VERSION)
                  panic("malloc_init: type %s with unsupported version %lu",
                      mtp->ks_shortdesc, mtp->ks_version);
  
          mtip = &mtp->ks_mti;
          mtip->mti_stats = uma_zalloc_pcpu(pcpu_zone_64, M_WAITOK | M_ZERO);
          mtp_set_subzone(mtp);
  
          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;
          long temp_allocs, temp_bytes;
          int i;
  
          mtp = data;
          KASSERT(mtp->ks_version == M_VERSION,
              ("malloc_uninit: bad malloc type version"));
  
          mtx_lock(&malloc_mtx);
          mtip = &mtp->ks_mti;
          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 <= mp_maxid; i++) {
                  mtsp = zpcpu_get_cpu(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);
          }
  
          uma_zfree_pcpu(pcpu_zone_64, mtip->mti_stats);
  }
  
  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_stats *mtsp, zeromts;
          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);
          sbuf_clear_flags(&sbuf, SBUF_INCLUDENUL);
          mtx_lock(&malloc_mtx);
  
          bzero(&zeromts, sizeof(zeromts));
  
          /*
           * 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 = &mtp->ks_mti;
  
                  /*
                   * 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 <= mp_maxid; i++) {
                          mtsp = zpcpu_get_cpu(mtip->mti_stats, i);
                          (void)sbuf_bcat(&sbuf, mtsp, sizeof(*mtsp));
                  }
                  /*
                   * Fill in the missing CPUs.
                   */
                  for (; i < MAXCPU; i++) {
                          (void)sbuf_bcat(&sbuf, &zeromts, sizeof(zeromts));
                  }
          }
          mtx_unlock(&malloc_mtx);
          error = sbuf_finish(&sbuf);
          sbuf_delete(&sbuf);
          return (error);
  }
  
  SYSCTL_PROC(_kern, OID_AUTO, malloc_stats,
      CTLFLAG_RD | CTLTYPE_STRUCT | CTLFLAG_MPSAFE, 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
  static int64_t
  get_malloc_stats(const struct malloc_type_internal *mtip, uint64_t *allocs,
      uint64_t *inuse)
  {
          const struct malloc_type_stats *mtsp;
          uint64_t frees, alloced, freed;
          int i;
  
          *allocs = 0;
          frees = 0;
          alloced = 0;
          freed = 0;
          for (i = 0; i <= mp_maxid; i++) {
                  mtsp = zpcpu_get_cpu(mtip->mti_stats, i);
  
                  *allocs += mtsp->mts_numallocs;
                  frees += mtsp->mts_numfrees;
                  alloced += mtsp->mts_memalloced;
                  freed += mtsp->mts_memfreed;
          }
          *inuse = *allocs - frees;
          return (alloced - freed);
  }
  
  DB_SHOW_COMMAND(malloc, db_show_malloc)
  {
          const char *fmt_hdr, *fmt_entry;
          struct malloc_type *mtp;
          uint64_t allocs, inuse;
          int64_t size;
          /* variables for sorting */
          struct malloc_type *last_mtype, *cur_mtype;
          int64_t cur_size, last_size;
          int ties;
  
          if (modif[0] == 'i') {
                  fmt_hdr = "%s,%s,%s,%s\n";
                  fmt_entry = "\"%s\",%ju,%jdK,%ju\n";
          } else {
                  fmt_hdr = "%18s %12s  %12s %12s\n";
                  fmt_entry = "%18s %12ju %12jdK %12ju\n";
          }
  
          db_printf(fmt_hdr, "Type", "InUse", "MemUse", "Requests");
  
          /* Select sort, largest size first. */
          last_mtype = NULL;
          last_size = INT64_MAX;
          for (;;) {
                  cur_mtype = NULL;
                  cur_size = -1;
                  ties = 0;
  
                  for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
                          /*
                           * In the case of size ties, print out mtypes
                           * in the order they are encountered.  That is,
                           * when we encounter the most recently output
                           * mtype, we have already printed all preceding
                           * ties, and we must print all following ties.
                           */
                          if (mtp == last_mtype) {
                                  ties = 1;
                                  continue;
                          }
                          size = get_malloc_stats(&mtp->ks_mti, &allocs,
                              &inuse);
                          if (size > cur_size && size < last_size + ties) {
                                  cur_size = size;
                                  cur_mtype = mtp;
                          }
                  }
                  if (cur_mtype == NULL)
                          break;
  
                  size = get_malloc_stats(&cur_mtype->ks_mti, &allocs, &inuse);
                  db_printf(fmt_entry, cur_mtype->ks_shortdesc, inuse,
                      howmany(size, 1024), allocs);
  
                  if (db_pager_quit)
                          break;
  
                  last_mtype = cur_mtype;
                  last_size = cur_size;
          }
  }
  
  #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_version != M_VERSION) {
                  db_printf("Version %lx does not match expected %x\n",
                      mtp->ks_version, M_VERSION);
                  return;
          }
  
          mtip = &mtp->ks_mti;
          subzone = mtip->mti_zone;
  
          for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
                  mtip = &mtp->ks_mti;
                  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 */

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