The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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

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    1 /*-
    2  * Copyright (c) 1987, 1991, 1993
    3  *      The Regents of the University of California.
    4  * Copyright (c) 2005-2009 Robert N. M. Watson
    5  * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net> (mallocarray)
    6  * All rights reserved.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 4. Neither the name of the University nor the names of its contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  *
   32  *      @(#)kern_malloc.c       8.3 (Berkeley) 1/4/94
   33  */
   34 
   35 /*
   36  * Kernel malloc(9) implementation -- general purpose kernel memory allocator
   37  * based on memory types.  Back end is implemented using the UMA(9) zone
   38  * allocator.  A set of fixed-size buckets are used for smaller allocations,
   39  * and a special UMA allocation interface is used for larger allocations.
   40  * Callers declare memory types, and statistics are maintained independently
   41  * for each memory type.  Statistics are maintained per-CPU for performance
   42  * reasons.  See malloc(9) and comments in malloc.h for a detailed
   43  * description.
   44  */
   45 
   46 #include <sys/cdefs.h>
   47 __FBSDID("$FreeBSD: stable/10/sys/kern/kern_malloc.c 328276 2018-01-23 04:37:31Z kp $");
   48 
   49 #include "opt_ddb.h"
   50 #include "opt_kdtrace.h"
   51 #include "opt_vm.h"
   52 
   53 #include <sys/param.h>
   54 #include <sys/systm.h>
   55 #include <sys/kdb.h>
   56 #include <sys/kernel.h>
   57 #include <sys/lock.h>
   58 #include <sys/malloc.h>
   59 #include <sys/mutex.h>
   60 #include <sys/vmmeter.h>
   61 #include <sys/proc.h>
   62 #include <sys/sbuf.h>
   63 #include <sys/sysctl.h>
   64 #include <sys/time.h>
   65 #include <sys/vmem.h>
   66 
   67 #include <vm/vm.h>
   68 #include <vm/pmap.h>
   69 #include <vm/vm_pageout.h>
   70 #include <vm/vm_param.h>
   71 #include <vm/vm_kern.h>
   72 #include <vm/vm_extern.h>
   73 #include <vm/vm_map.h>
   74 #include <vm/vm_page.h>
   75 #include <vm/uma.h>
   76 #include <vm/uma_int.h>
   77 #include <vm/uma_dbg.h>
   78 
   79 #ifdef DEBUG_MEMGUARD
   80 #include <vm/memguard.h>
   81 #endif
   82 #ifdef DEBUG_REDZONE
   83 #include <vm/redzone.h>
   84 #endif
   85 
   86 #if defined(INVARIANTS) && defined(__i386__)
   87 #include <machine/cpu.h>
   88 #endif
   89 
   90 #include <ddb/ddb.h>
   91 
   92 #ifdef KDTRACE_HOOKS
   93 #include <sys/dtrace_bsd.h>
   94 
   95 dtrace_malloc_probe_func_t      dtrace_malloc_probe;
   96 #endif
   97 
   98 /*
   99  * When realloc() is called, if the new size is sufficiently smaller than
  100  * the old size, realloc() will allocate a new, smaller block to avoid
  101  * wasting memory. 'Sufficiently smaller' is defined as: newsize <=
  102  * oldsize / 2^n, where REALLOC_FRACTION defines the value of 'n'.
  103  */
  104 #ifndef REALLOC_FRACTION
  105 #define REALLOC_FRACTION        1       /* new block if <= half the size */
  106 #endif
  107 
  108 /*
  109  * Centrally define some common malloc types.
  110  */
  111 MALLOC_DEFINE(M_CACHE, "cache", "Various Dynamically allocated caches");
  112 MALLOC_DEFINE(M_DEVBUF, "devbuf", "device driver memory");
  113 MALLOC_DEFINE(M_TEMP, "temp", "misc temporary data buffers");
  114 
  115 MALLOC_DEFINE(M_IP6OPT, "ip6opt", "IPv6 options");
  116 MALLOC_DEFINE(M_IP6NDP, "ip6ndp", "IPv6 Neighbor Discovery");
  117 
  118 static struct malloc_type *kmemstatistics;
  119 static int kmemcount;
  120 
  121 #define KMEM_ZSHIFT     4
  122 #define KMEM_ZBASE      16
  123 #define KMEM_ZMASK      (KMEM_ZBASE - 1)
  124 
  125 #define KMEM_ZMAX       65536
  126 #define KMEM_ZSIZE      (KMEM_ZMAX >> KMEM_ZSHIFT)
  127 static uint8_t kmemsize[KMEM_ZSIZE + 1];
  128 
  129 #ifndef MALLOC_DEBUG_MAXZONES
  130 #define MALLOC_DEBUG_MAXZONES   1
  131 #endif
  132 static int numzones = MALLOC_DEBUG_MAXZONES;
  133 
  134 /*
  135  * Small malloc(9) memory allocations are allocated from a set of UMA buckets
  136  * of various sizes.
  137  *
  138  * XXX: The comment here used to read "These won't be powers of two for
  139  * long."  It's possible that a significant amount of wasted memory could be
  140  * recovered by tuning the sizes of these buckets.
  141  */
  142 struct {
  143         int kz_size;
  144         char *kz_name;
  145         uma_zone_t kz_zone[MALLOC_DEBUG_MAXZONES];
  146 } kmemzones[] = {
  147         {16, "16", },
  148         {32, "32", },
  149         {64, "64", },
  150         {128, "128", },
  151         {256, "256", },
  152         {512, "512", },
  153         {1024, "1024", },
  154         {2048, "2048", },
  155         {4096, "4096", },
  156         {8192, "8192", },
  157         {16384, "16384", },
  158         {32768, "32768", },
  159         {65536, "65536", },
  160         {0, NULL},
  161 };
  162 
  163 /*
  164  * Zone to allocate malloc type descriptions from.  For ABI reasons, memory
  165  * types are described by a data structure passed by the declaring code, but
  166  * the malloc(9) implementation has its own data structure describing the
  167  * type and statistics.  This permits the malloc(9)-internal data structures
  168  * to be modified without breaking binary-compiled kernel modules that
  169  * declare malloc types.
  170  */
  171 static uma_zone_t mt_zone;
  172 
  173 u_long vm_kmem_size;
  174 SYSCTL_ULONG(_vm, OID_AUTO, kmem_size, CTLFLAG_RDTUN, &vm_kmem_size, 0,
  175     "Size of kernel memory");
  176 
  177 static u_long kmem_zmax = KMEM_ZMAX;
  178 SYSCTL_ULONG(_vm, OID_AUTO, kmem_zmax, CTLFLAG_RDTUN, &kmem_zmax, 0,
  179     "Maximum allocation size that malloc(9) would use UMA as backend");
  180 
  181 static u_long vm_kmem_size_min;
  182 SYSCTL_ULONG(_vm, OID_AUTO, kmem_size_min, CTLFLAG_RDTUN, &vm_kmem_size_min, 0,
  183     "Minimum size of kernel memory");
  184 
  185 static u_long vm_kmem_size_max;
  186 SYSCTL_ULONG(_vm, OID_AUTO, kmem_size_max, CTLFLAG_RDTUN, &vm_kmem_size_max, 0,
  187     "Maximum size of kernel memory");
  188 
  189 static u_int vm_kmem_size_scale;
  190 SYSCTL_UINT(_vm, OID_AUTO, kmem_size_scale, CTLFLAG_RDTUN, &vm_kmem_size_scale, 0,
  191     "Scale factor for kernel memory size");
  192 
  193 static int sysctl_kmem_map_size(SYSCTL_HANDLER_ARGS);
  194 SYSCTL_PROC(_vm, OID_AUTO, kmem_map_size,
  195     CTLFLAG_RD | CTLTYPE_ULONG | CTLFLAG_MPSAFE, NULL, 0,
  196     sysctl_kmem_map_size, "LU", "Current kmem allocation size");
  197 
  198 static int sysctl_kmem_map_free(SYSCTL_HANDLER_ARGS);
  199 SYSCTL_PROC(_vm, OID_AUTO, kmem_map_free,
  200     CTLFLAG_RD | CTLTYPE_ULONG | CTLFLAG_MPSAFE, NULL, 0,
  201     sysctl_kmem_map_free, "LU", "Free space in kmem");
  202 
  203 /*
  204  * The malloc_mtx protects the kmemstatistics linked list.
  205  */
  206 struct mtx malloc_mtx;
  207 
  208 #ifdef MALLOC_PROFILE
  209 uint64_t krequests[KMEM_ZSIZE + 1];
  210 
  211 static int sysctl_kern_mprof(SYSCTL_HANDLER_ARGS);
  212 #endif
  213 
  214 static int sysctl_kern_malloc_stats(SYSCTL_HANDLER_ARGS);
  215 
  216 /*
  217  * time_uptime of the last malloc(9) failure (induced or real).
  218  */
  219 static time_t t_malloc_fail;
  220 
  221 #if defined(MALLOC_MAKE_FAILURES) || (MALLOC_DEBUG_MAXZONES > 1)
  222 static SYSCTL_NODE(_debug, OID_AUTO, malloc, CTLFLAG_RD, 0,
  223     "Kernel malloc debugging options");
  224 #endif
  225 
  226 /*
  227  * malloc(9) fault injection -- cause malloc failures every (n) mallocs when
  228  * the caller specifies M_NOWAIT.  If set to 0, no failures are caused.
  229  */
  230 #ifdef MALLOC_MAKE_FAILURES
  231 static int malloc_failure_rate;
  232 static int malloc_nowait_count;
  233 static int malloc_failure_count;
  234 SYSCTL_INT(_debug_malloc, OID_AUTO, failure_rate, CTLFLAG_RW,
  235     &malloc_failure_rate, 0, "Every (n) mallocs with M_NOWAIT will fail");
  236 TUNABLE_INT("debug.malloc.failure_rate", &malloc_failure_rate);
  237 SYSCTL_INT(_debug_malloc, OID_AUTO, failure_count, CTLFLAG_RD,
  238     &malloc_failure_count, 0, "Number of imposed M_NOWAIT malloc failures");
  239 #endif
  240 
  241 static int
  242 sysctl_kmem_map_size(SYSCTL_HANDLER_ARGS)
  243 {
  244         u_long size;
  245 
  246         size = vmem_size(kmem_arena, VMEM_ALLOC);
  247         return (sysctl_handle_long(oidp, &size, 0, req));
  248 }
  249 
  250 static int
  251 sysctl_kmem_map_free(SYSCTL_HANDLER_ARGS)
  252 {
  253         u_long size;
  254 
  255         size = vmem_size(kmem_arena, VMEM_FREE);
  256         return (sysctl_handle_long(oidp, &size, 0, req));
  257 }
  258 
  259 /*
  260  * malloc(9) uma zone separation -- sub-page buffer overruns in one
  261  * malloc type will affect only a subset of other malloc types.
  262  */
  263 #if MALLOC_DEBUG_MAXZONES > 1
  264 static void
  265 tunable_set_numzones(void)
  266 {
  267 
  268         TUNABLE_INT_FETCH("debug.malloc.numzones",
  269             &numzones);
  270 
  271         /* Sanity check the number of malloc uma zones. */
  272         if (numzones <= 0)
  273                 numzones = 1;
  274         if (numzones > MALLOC_DEBUG_MAXZONES)
  275                 numzones = MALLOC_DEBUG_MAXZONES;
  276 }
  277 SYSINIT(numzones, SI_SUB_TUNABLES, SI_ORDER_ANY, tunable_set_numzones, NULL);
  278 SYSCTL_INT(_debug_malloc, OID_AUTO, numzones, CTLFLAG_RDTUN,
  279     &numzones, 0, "Number of malloc uma subzones");
  280 
  281 /*
  282  * Any number that changes regularly is an okay choice for the
  283  * offset.  Build numbers are pretty good of you have them.
  284  */
  285 static u_int zone_offset = __FreeBSD_version;
  286 TUNABLE_INT("debug.malloc.zone_offset", &zone_offset);
  287 SYSCTL_UINT(_debug_malloc, OID_AUTO, zone_offset, CTLFLAG_RDTUN,
  288     &zone_offset, 0, "Separate malloc types by examining the "
  289     "Nth character in the malloc type short description.");
  290 
  291 static u_int
  292 mtp_get_subzone(const char *desc)
  293 {
  294         size_t len;
  295         u_int val;
  296 
  297         if (desc == NULL || (len = strlen(desc)) == 0)
  298                 return (0);
  299         val = desc[zone_offset % len];
  300         return (val % numzones);
  301 }
  302 #elif MALLOC_DEBUG_MAXZONES == 0
  303 #error "MALLOC_DEBUG_MAXZONES must be positive."
  304 #else
  305 static inline u_int
  306 mtp_get_subzone(const char *desc)
  307 {
  308 
  309         return (0);
  310 }
  311 #endif /* MALLOC_DEBUG_MAXZONES > 1 */
  312 
  313 int
  314 malloc_last_fail(void)
  315 {
  316 
  317         return (time_uptime - t_malloc_fail);
  318 }
  319 
  320 /*
  321  * An allocation has succeeded -- update malloc type statistics for the
  322  * amount of bucket size.  Occurs within a critical section so that the
  323  * thread isn't preempted and doesn't migrate while updating per-PCU
  324  * statistics.
  325  */
  326 static void
  327 malloc_type_zone_allocated(struct malloc_type *mtp, unsigned long size,
  328     int zindx)
  329 {
  330         struct malloc_type_internal *mtip;
  331         struct malloc_type_stats *mtsp;
  332 
  333         critical_enter();
  334         mtip = mtp->ks_handle;
  335         mtsp = &mtip->mti_stats[curcpu];
  336         if (size > 0) {
  337                 mtsp->mts_memalloced += size;
  338                 mtsp->mts_numallocs++;
  339         }
  340         if (zindx != -1)
  341                 mtsp->mts_size |= 1 << zindx;
  342 
  343 #ifdef KDTRACE_HOOKS
  344         if (dtrace_malloc_probe != NULL) {
  345                 uint32_t probe_id = mtip->mti_probes[DTMALLOC_PROBE_MALLOC];
  346                 if (probe_id != 0)
  347                         (dtrace_malloc_probe)(probe_id,
  348                             (uintptr_t) mtp, (uintptr_t) mtip,
  349                             (uintptr_t) mtsp, size, zindx);
  350         }
  351 #endif
  352 
  353         critical_exit();
  354 }
  355 
  356 void
  357 malloc_type_allocated(struct malloc_type *mtp, unsigned long size)
  358 {
  359 
  360         if (size > 0)
  361                 malloc_type_zone_allocated(mtp, size, -1);
  362 }
  363 
  364 /*
  365  * A free operation has occurred -- update malloc type statistics for the
  366  * amount of the bucket size.  Occurs within a critical section so that the
  367  * thread isn't preempted and doesn't migrate while updating per-CPU
  368  * statistics.
  369  */
  370 void
  371 malloc_type_freed(struct malloc_type *mtp, unsigned long size)
  372 {
  373         struct malloc_type_internal *mtip;
  374         struct malloc_type_stats *mtsp;
  375 
  376         critical_enter();
  377         mtip = mtp->ks_handle;
  378         mtsp = &mtip->mti_stats[curcpu];
  379         mtsp->mts_memfreed += size;
  380         mtsp->mts_numfrees++;
  381 
  382 #ifdef KDTRACE_HOOKS
  383         if (dtrace_malloc_probe != NULL) {
  384                 uint32_t probe_id = mtip->mti_probes[DTMALLOC_PROBE_FREE];
  385                 if (probe_id != 0)
  386                         (dtrace_malloc_probe)(probe_id,
  387                             (uintptr_t) mtp, (uintptr_t) mtip,
  388                             (uintptr_t) mtsp, size, 0);
  389         }
  390 #endif
  391 
  392         critical_exit();
  393 }
  394 
  395 /*
  396  *      contigmalloc:
  397  *
  398  *      Allocate a block of physically contiguous memory.
  399  *
  400  *      If M_NOWAIT is set, this routine will not block and return NULL if
  401  *      the allocation fails.
  402  */
  403 void *
  404 contigmalloc(unsigned long size, struct malloc_type *type, int flags,
  405     vm_paddr_t low, vm_paddr_t high, unsigned long alignment,
  406     vm_paddr_t boundary)
  407 {
  408         void *ret;
  409 
  410         ret = (void *)kmem_alloc_contig(kernel_arena, size, flags, low, high,
  411             alignment, boundary, VM_MEMATTR_DEFAULT);
  412         if (ret != NULL)
  413                 malloc_type_allocated(type, round_page(size));
  414         return (ret);
  415 }
  416 
  417 /*
  418  *      contigfree:
  419  *
  420  *      Free a block of memory allocated by contigmalloc.
  421  *
  422  *      This routine may not block.
  423  */
  424 void
  425 contigfree(void *addr, unsigned long size, struct malloc_type *type)
  426 {
  427 
  428         kmem_free(kernel_arena, (vm_offset_t)addr, size);
  429         malloc_type_freed(type, round_page(size));
  430 }
  431 
  432 /*
  433  *      malloc:
  434  *
  435  *      Allocate a block of memory.
  436  *
  437  *      If M_NOWAIT is set, this routine will not block and return NULL if
  438  *      the allocation fails.
  439  */
  440 void *
  441 malloc(unsigned long size, struct malloc_type *mtp, int flags)
  442 {
  443         int indx;
  444         struct malloc_type_internal *mtip;
  445         caddr_t va;
  446         uma_zone_t zone;
  447 #if defined(DIAGNOSTIC) || defined(DEBUG_REDZONE)
  448         unsigned long osize = size;
  449 #endif
  450 
  451 #ifdef INVARIANTS
  452         KASSERT(mtp->ks_magic == M_MAGIC, ("malloc: bad malloc type magic"));
  453         /*
  454          * Check that exactly one of M_WAITOK or M_NOWAIT is specified.
  455          */
  456         indx = flags & (M_WAITOK | M_NOWAIT);
  457         if (indx != M_NOWAIT && indx != M_WAITOK) {
  458                 static  struct timeval lasterr;
  459                 static  int curerr, once;
  460                 if (once == 0 && ppsratecheck(&lasterr, &curerr, 1)) {
  461                         printf("Bad malloc flags: %x\n", indx);
  462                         kdb_backtrace();
  463                         flags |= M_WAITOK;
  464                         once++;
  465                 }
  466         }
  467 #endif
  468 #ifdef MALLOC_MAKE_FAILURES
  469         if ((flags & M_NOWAIT) && (malloc_failure_rate != 0)) {
  470                 atomic_add_int(&malloc_nowait_count, 1);
  471                 if ((malloc_nowait_count % malloc_failure_rate) == 0) {
  472                         atomic_add_int(&malloc_failure_count, 1);
  473                         t_malloc_fail = time_uptime;
  474                         return (NULL);
  475                 }
  476         }
  477 #endif
  478         if (flags & M_WAITOK)
  479                 KASSERT(curthread->td_intr_nesting_level == 0,
  480                    ("malloc(M_WAITOK) in interrupt context"));
  481 
  482 #ifdef DEBUG_MEMGUARD
  483         if (memguard_cmp_mtp(mtp, size)) {
  484                 va = memguard_alloc(size, flags);
  485                 if (va != NULL)
  486                         return (va);
  487                 /* This is unfortunate but should not be fatal. */
  488         }
  489 #endif
  490 
  491 #ifdef DEBUG_REDZONE
  492         size = redzone_size_ntor(size);
  493 #endif
  494 
  495         if (size <= kmem_zmax) {
  496                 mtip = mtp->ks_handle;
  497                 if (size & KMEM_ZMASK)
  498                         size = (size & ~KMEM_ZMASK) + KMEM_ZBASE;
  499                 indx = kmemsize[size >> KMEM_ZSHIFT];
  500                 KASSERT(mtip->mti_zone < numzones,
  501                     ("mti_zone %u out of range %d",
  502                     mtip->mti_zone, numzones));
  503                 zone = kmemzones[indx].kz_zone[mtip->mti_zone];
  504 #ifdef MALLOC_PROFILE
  505                 krequests[size >> KMEM_ZSHIFT]++;
  506 #endif
  507                 va = uma_zalloc(zone, flags);
  508                 if (va != NULL)
  509                         size = zone->uz_size;
  510                 malloc_type_zone_allocated(mtp, va == NULL ? 0 : size, indx);
  511         } else {
  512                 size = roundup(size, PAGE_SIZE);
  513                 zone = NULL;
  514                 va = uma_large_malloc(size, flags);
  515                 malloc_type_allocated(mtp, va == NULL ? 0 : size);
  516         }
  517         if (flags & M_WAITOK)
  518                 KASSERT(va != NULL, ("malloc(M_WAITOK) returned NULL"));
  519         else if (va == NULL)
  520                 t_malloc_fail = time_uptime;
  521 #ifdef DIAGNOSTIC
  522         if (va != NULL && !(flags & M_ZERO)) {
  523                 memset(va, 0x70, osize);
  524         }
  525 #endif
  526 #ifdef DEBUG_REDZONE
  527         if (va != NULL)
  528                 va = redzone_setup(va, osize);
  529 #endif
  530         return ((void *) va);
  531 }
  532 
  533 void *
  534 mallocarray(size_t nmemb, size_t size, struct malloc_type *type, int flags)
  535 {
  536 
  537         if (WOULD_OVERFLOW(nmemb, size))
  538                 panic("mallocarray: %zu * %zu overflowed", nmemb, size);
  539 
  540         return (malloc(size * nmemb, type, flags));
  541 }
  542 
  543 /*
  544  *      free:
  545  *
  546  *      Free a block of memory allocated by malloc.
  547  *
  548  *      This routine may not block.
  549  */
  550 void
  551 free(void *addr, struct malloc_type *mtp)
  552 {
  553         uma_slab_t slab;
  554         u_long size;
  555 
  556         KASSERT(mtp->ks_magic == M_MAGIC, ("free: bad malloc type magic"));
  557 
  558         /* free(NULL, ...) does nothing */
  559         if (addr == NULL)
  560                 return;
  561 
  562 #ifdef DEBUG_MEMGUARD
  563         if (is_memguard_addr(addr)) {
  564                 memguard_free(addr);
  565                 return;
  566         }
  567 #endif
  568 
  569 #ifdef DEBUG_REDZONE
  570         redzone_check(addr);
  571         addr = redzone_addr_ntor(addr);
  572 #endif
  573 
  574         slab = vtoslab((vm_offset_t)addr & (~UMA_SLAB_MASK));
  575 
  576         if (slab == NULL)
  577                 panic("free: address %p(%p) has not been allocated.\n",
  578                     addr, (void *)((u_long)addr & (~UMA_SLAB_MASK)));
  579 
  580         if (!(slab->us_flags & UMA_SLAB_MALLOC)) {
  581 #ifdef INVARIANTS
  582                 struct malloc_type **mtpp = addr;
  583 #endif
  584                 size = slab->us_keg->uk_size;
  585 #ifdef INVARIANTS
  586                 /*
  587                  * Cache a pointer to the malloc_type that most recently freed
  588                  * this memory here.  This way we know who is most likely to
  589                  * have stepped on it later.
  590                  *
  591                  * This code assumes that size is a multiple of 8 bytes for
  592                  * 64 bit machines
  593                  */
  594                 mtpp = (struct malloc_type **)
  595                     ((unsigned long)mtpp & ~UMA_ALIGN_PTR);
  596                 mtpp += (size - sizeof(struct malloc_type *)) /
  597                     sizeof(struct malloc_type *);
  598                 *mtpp = mtp;
  599 #endif
  600                 uma_zfree_arg(LIST_FIRST(&slab->us_keg->uk_zones), addr, slab);
  601         } else {
  602                 size = slab->us_size;
  603                 uma_large_free(slab);
  604         }
  605         malloc_type_freed(mtp, size);
  606 }
  607 
  608 /*
  609  *      realloc: change the size of a memory block
  610  */
  611 void *
  612 realloc(void *addr, unsigned long size, struct malloc_type *mtp, int flags)
  613 {
  614         uma_slab_t slab;
  615         unsigned long alloc;
  616         void *newaddr;
  617 
  618         KASSERT(mtp->ks_magic == M_MAGIC,
  619             ("realloc: bad malloc type magic"));
  620 
  621         /* realloc(NULL, ...) is equivalent to malloc(...) */
  622         if (addr == NULL)
  623                 return (malloc(size, mtp, flags));
  624 
  625         /*
  626          * XXX: Should report free of old memory and alloc of new memory to
  627          * per-CPU stats.
  628          */
  629 
  630 #ifdef DEBUG_MEMGUARD
  631         if (is_memguard_addr(addr))
  632                 return (memguard_realloc(addr, size, mtp, flags));
  633 #endif
  634 
  635 #ifdef DEBUG_REDZONE
  636         slab = NULL;
  637         alloc = redzone_get_size(addr);
  638 #else
  639         slab = vtoslab((vm_offset_t)addr & ~(UMA_SLAB_MASK));
  640 
  641         /* Sanity check */
  642         KASSERT(slab != NULL,
  643             ("realloc: address %p out of range", (void *)addr));
  644 
  645         /* Get the size of the original block */
  646         if (!(slab->us_flags & UMA_SLAB_MALLOC))
  647                 alloc = slab->us_keg->uk_size;
  648         else
  649                 alloc = slab->us_size;
  650 
  651         /* Reuse the original block if appropriate */
  652         if (size <= alloc
  653             && (size > (alloc >> REALLOC_FRACTION) || alloc == MINALLOCSIZE))
  654                 return (addr);
  655 #endif /* !DEBUG_REDZONE */
  656 
  657         /* Allocate a new, bigger (or smaller) block */
  658         if ((newaddr = malloc(size, mtp, flags)) == NULL)
  659                 return (NULL);
  660 
  661         /* Copy over original contents */
  662         bcopy(addr, newaddr, min(size, alloc));
  663         free(addr, mtp);
  664         return (newaddr);
  665 }
  666 
  667 /*
  668  *      reallocf: same as realloc() but free memory on failure.
  669  */
  670 void *
  671 reallocf(void *addr, unsigned long size, struct malloc_type *mtp, int flags)
  672 {
  673         void *mem;
  674 
  675         if ((mem = realloc(addr, size, mtp, flags)) == NULL)
  676                 free(addr, mtp);
  677         return (mem);
  678 }
  679 
  680 /*
  681  * Wake the uma reclamation pagedaemon thread when we exhaust KVA.  It
  682  * will call the lowmem handler and uma_reclaim() callbacks in a
  683  * context that is safe.
  684  */
  685 static void
  686 kmem_reclaim(vmem_t *vm, int flags)
  687 {
  688 
  689         uma_reclaim_wakeup();
  690         pagedaemon_wakeup();
  691 }
  692 
  693 CTASSERT(VM_KMEM_SIZE_SCALE >= 1);
  694 
  695 /*
  696  * Initialize the kernel memory (kmem) arena.
  697  */
  698 void
  699 kmeminit(void)
  700 {
  701         u_long mem_size, tmp;
  702 
  703         /*
  704          * Calculate the amount of kernel virtual address (KVA) space that is
  705          * preallocated to the kmem arena.  In order to support a wide range
  706          * of machines, it is a function of the physical memory size,
  707          * specifically,
  708          *
  709          *      min(max(physical memory size / VM_KMEM_SIZE_SCALE,
  710          *          VM_KMEM_SIZE_MIN), VM_KMEM_SIZE_MAX)
  711          *
  712          * Every architecture must define an integral value for
  713          * VM_KMEM_SIZE_SCALE.  However, the definitions of VM_KMEM_SIZE_MIN
  714          * and VM_KMEM_SIZE_MAX, which represent respectively the floor and
  715          * ceiling on this preallocation, are optional.  Typically,
  716          * VM_KMEM_SIZE_MAX is itself a function of the available KVA space on
  717          * a given architecture.
  718          */
  719         mem_size = cnt.v_page_count;
  720 
  721         vm_kmem_size_scale = VM_KMEM_SIZE_SCALE;
  722         TUNABLE_INT_FETCH("vm.kmem_size_scale", &vm_kmem_size_scale);
  723         if (vm_kmem_size_scale < 1)
  724                 vm_kmem_size_scale = VM_KMEM_SIZE_SCALE;
  725 
  726         vm_kmem_size = (mem_size / vm_kmem_size_scale) * PAGE_SIZE;
  727 
  728 #if defined(VM_KMEM_SIZE_MIN)
  729         vm_kmem_size_min = VM_KMEM_SIZE_MIN;
  730 #endif
  731         TUNABLE_ULONG_FETCH("vm.kmem_size_min", &vm_kmem_size_min);
  732         if (vm_kmem_size_min > 0 && vm_kmem_size < vm_kmem_size_min)
  733                 vm_kmem_size = vm_kmem_size_min;
  734 
  735 #if defined(VM_KMEM_SIZE_MAX)
  736         vm_kmem_size_max = VM_KMEM_SIZE_MAX;
  737 #endif
  738         TUNABLE_ULONG_FETCH("vm.kmem_size_max", &vm_kmem_size_max);
  739         if (vm_kmem_size_max > 0 && vm_kmem_size >= vm_kmem_size_max)
  740                 vm_kmem_size = vm_kmem_size_max;
  741 
  742         /*
  743          * Alternatively, the amount of KVA space that is preallocated to the
  744          * kmem arena can be set statically at compile-time or manually
  745          * through the kernel environment.  However, it is still limited to
  746          * twice the physical memory size, which has been sufficient to handle
  747          * the most severe cases of external fragmentation in the kmem arena. 
  748          */
  749 #if defined(VM_KMEM_SIZE)
  750         vm_kmem_size = VM_KMEM_SIZE;
  751 #endif
  752         TUNABLE_ULONG_FETCH("vm.kmem_size", &vm_kmem_size);
  753         if (vm_kmem_size / 2 / PAGE_SIZE > mem_size)
  754                 vm_kmem_size = 2 * mem_size * PAGE_SIZE;
  755 
  756         vm_kmem_size = round_page(vm_kmem_size);
  757 #ifdef DEBUG_MEMGUARD
  758         tmp = memguard_fudge(vm_kmem_size, kernel_map);
  759 #else
  760         tmp = vm_kmem_size;
  761 #endif
  762         vmem_init(kmem_arena, "kmem arena", kva_alloc(tmp), tmp, PAGE_SIZE,
  763             0, 0);
  764         vmem_set_reclaim(kmem_arena, kmem_reclaim);
  765 
  766 #ifdef DEBUG_MEMGUARD
  767         /*
  768          * Initialize MemGuard if support compiled in.  MemGuard is a
  769          * replacement allocator used for detecting tamper-after-free
  770          * scenarios as they occur.  It is only used for debugging.
  771          */
  772         memguard_init(kmem_arena);
  773 #endif
  774 }
  775 
  776 /*
  777  * Initialize the kernel memory allocator
  778  */
  779 /* ARGSUSED*/
  780 static void
  781 mallocinit(void *dummy)
  782 {
  783         int i;
  784         uint8_t indx;
  785 
  786         mtx_init(&malloc_mtx, "malloc", NULL, MTX_DEF);
  787 
  788         kmeminit();
  789 
  790         uma_startup2();
  791 
  792         if (kmem_zmax < PAGE_SIZE || kmem_zmax > KMEM_ZMAX)
  793                 kmem_zmax = KMEM_ZMAX;
  794 
  795         mt_zone = uma_zcreate("mt_zone", sizeof(struct malloc_type_internal),
  796 #ifdef INVARIANTS
  797             mtrash_ctor, mtrash_dtor, mtrash_init, mtrash_fini,
  798 #else
  799             NULL, NULL, NULL, NULL,
  800 #endif
  801             UMA_ALIGN_PTR, UMA_ZONE_MALLOC);
  802         for (i = 0, indx = 0; kmemzones[indx].kz_size != 0; indx++) {
  803                 int size = kmemzones[indx].kz_size;
  804                 char *name = kmemzones[indx].kz_name;
  805                 int subzone;
  806 
  807                 for (subzone = 0; subzone < numzones; subzone++) {
  808                         kmemzones[indx].kz_zone[subzone] =
  809                             uma_zcreate(name, size,
  810 #ifdef INVARIANTS
  811                             mtrash_ctor, mtrash_dtor, mtrash_init, mtrash_fini,
  812 #else
  813                             NULL, NULL, NULL, NULL,
  814 #endif
  815                             UMA_ALIGN_PTR, UMA_ZONE_MALLOC);
  816                 }                   
  817                 for (;i <= size; i+= KMEM_ZBASE)
  818                         kmemsize[i >> KMEM_ZSHIFT] = indx;
  819 
  820         }
  821 }
  822 SYSINIT(kmem, SI_SUB_KMEM, SI_ORDER_FIRST, mallocinit, NULL);
  823 
  824 void
  825 malloc_init(void *data)
  826 {
  827         struct malloc_type_internal *mtip;
  828         struct malloc_type *mtp;
  829 
  830         KASSERT(cnt.v_page_count != 0, ("malloc_register before vm_init"));
  831 
  832         mtp = data;
  833         if (mtp->ks_magic != M_MAGIC)
  834                 panic("malloc_init: bad malloc type magic");
  835 
  836         mtip = uma_zalloc(mt_zone, M_WAITOK | M_ZERO);
  837         mtp->ks_handle = mtip;
  838         mtip->mti_zone = mtp_get_subzone(mtp->ks_shortdesc);
  839 
  840         mtx_lock(&malloc_mtx);
  841         mtp->ks_next = kmemstatistics;
  842         kmemstatistics = mtp;
  843         kmemcount++;
  844         mtx_unlock(&malloc_mtx);
  845 }
  846 
  847 void
  848 malloc_uninit(void *data)
  849 {
  850         struct malloc_type_internal *mtip;
  851         struct malloc_type_stats *mtsp;
  852         struct malloc_type *mtp, *temp;
  853         uma_slab_t slab;
  854         long temp_allocs, temp_bytes;
  855         int i;
  856 
  857         mtp = data;
  858         KASSERT(mtp->ks_magic == M_MAGIC,
  859             ("malloc_uninit: bad malloc type magic"));
  860         KASSERT(mtp->ks_handle != NULL, ("malloc_deregister: cookie NULL"));
  861 
  862         mtx_lock(&malloc_mtx);
  863         mtip = mtp->ks_handle;
  864         mtp->ks_handle = NULL;
  865         if (mtp != kmemstatistics) {
  866                 for (temp = kmemstatistics; temp != NULL;
  867                     temp = temp->ks_next) {
  868                         if (temp->ks_next == mtp) {
  869                                 temp->ks_next = mtp->ks_next;
  870                                 break;
  871                         }
  872                 }
  873                 KASSERT(temp,
  874                     ("malloc_uninit: type '%s' not found", mtp->ks_shortdesc));
  875         } else
  876                 kmemstatistics = mtp->ks_next;
  877         kmemcount--;
  878         mtx_unlock(&malloc_mtx);
  879 
  880         /*
  881          * Look for memory leaks.
  882          */
  883         temp_allocs = temp_bytes = 0;
  884         for (i = 0; i < MAXCPU; i++) {
  885                 mtsp = &mtip->mti_stats[i];
  886                 temp_allocs += mtsp->mts_numallocs;
  887                 temp_allocs -= mtsp->mts_numfrees;
  888                 temp_bytes += mtsp->mts_memalloced;
  889                 temp_bytes -= mtsp->mts_memfreed;
  890         }
  891         if (temp_allocs > 0 || temp_bytes > 0) {
  892                 printf("Warning: memory type %s leaked memory on destroy "
  893                     "(%ld allocations, %ld bytes leaked).\n", mtp->ks_shortdesc,
  894                     temp_allocs, temp_bytes);
  895         }
  896 
  897         slab = vtoslab((vm_offset_t) mtip & (~UMA_SLAB_MASK));
  898         uma_zfree_arg(mt_zone, mtip, slab);
  899 }
  900 
  901 struct malloc_type *
  902 malloc_desc2type(const char *desc)
  903 {
  904         struct malloc_type *mtp;
  905 
  906         mtx_assert(&malloc_mtx, MA_OWNED);
  907         for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
  908                 if (strcmp(mtp->ks_shortdesc, desc) == 0)
  909                         return (mtp);
  910         }
  911         return (NULL);
  912 }
  913 
  914 static int
  915 sysctl_kern_malloc_stats(SYSCTL_HANDLER_ARGS)
  916 {
  917         struct malloc_type_stream_header mtsh;
  918         struct malloc_type_internal *mtip;
  919         struct malloc_type_header mth;
  920         struct malloc_type *mtp;
  921         int error, i;
  922         struct sbuf sbuf;
  923 
  924         error = sysctl_wire_old_buffer(req, 0);
  925         if (error != 0)
  926                 return (error);
  927         sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
  928         mtx_lock(&malloc_mtx);
  929 
  930         /*
  931          * Insert stream header.
  932          */
  933         bzero(&mtsh, sizeof(mtsh));
  934         mtsh.mtsh_version = MALLOC_TYPE_STREAM_VERSION;
  935         mtsh.mtsh_maxcpus = MAXCPU;
  936         mtsh.mtsh_count = kmemcount;
  937         (void)sbuf_bcat(&sbuf, &mtsh, sizeof(mtsh));
  938 
  939         /*
  940          * Insert alternating sequence of type headers and type statistics.
  941          */
  942         for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
  943                 mtip = (struct malloc_type_internal *)mtp->ks_handle;
  944 
  945                 /*
  946                  * Insert type header.
  947                  */
  948                 bzero(&mth, sizeof(mth));
  949                 strlcpy(mth.mth_name, mtp->ks_shortdesc, MALLOC_MAX_NAME);
  950                 (void)sbuf_bcat(&sbuf, &mth, sizeof(mth));
  951 
  952                 /*
  953                  * Insert type statistics for each CPU.
  954                  */
  955                 for (i = 0; i < MAXCPU; i++) {
  956                         (void)sbuf_bcat(&sbuf, &mtip->mti_stats[i],
  957                             sizeof(mtip->mti_stats[i]));
  958                 }
  959         }
  960         mtx_unlock(&malloc_mtx);
  961         error = sbuf_finish(&sbuf);
  962         sbuf_delete(&sbuf);
  963         return (error);
  964 }
  965 
  966 SYSCTL_PROC(_kern, OID_AUTO, malloc_stats, CTLFLAG_RD|CTLTYPE_STRUCT,
  967     0, 0, sysctl_kern_malloc_stats, "s,malloc_type_ustats",
  968     "Return malloc types");
  969 
  970 SYSCTL_INT(_kern, OID_AUTO, malloc_count, CTLFLAG_RD, &kmemcount, 0,
  971     "Count of kernel malloc types");
  972 
  973 void
  974 malloc_type_list(malloc_type_list_func_t *func, void *arg)
  975 {
  976         struct malloc_type *mtp, **bufmtp;
  977         int count, i;
  978         size_t buflen;
  979 
  980         mtx_lock(&malloc_mtx);
  981 restart:
  982         mtx_assert(&malloc_mtx, MA_OWNED);
  983         count = kmemcount;
  984         mtx_unlock(&malloc_mtx);
  985 
  986         buflen = sizeof(struct malloc_type *) * count;
  987         bufmtp = malloc(buflen, M_TEMP, M_WAITOK);
  988 
  989         mtx_lock(&malloc_mtx);
  990 
  991         if (count < kmemcount) {
  992                 free(bufmtp, M_TEMP);
  993                 goto restart;
  994         }
  995 
  996         for (mtp = kmemstatistics, i = 0; mtp != NULL; mtp = mtp->ks_next, i++)
  997                 bufmtp[i] = mtp;
  998 
  999         mtx_unlock(&malloc_mtx);
 1000 
 1001         for (i = 0; i < count; i++)
 1002                 (func)(bufmtp[i], arg);
 1003 
 1004         free(bufmtp, M_TEMP);
 1005 }
 1006 
 1007 #ifdef DDB
 1008 DB_SHOW_COMMAND(malloc, db_show_malloc)
 1009 {
 1010         struct malloc_type_internal *mtip;
 1011         struct malloc_type *mtp;
 1012         uint64_t allocs, frees;
 1013         uint64_t alloced, freed;
 1014         int i;
 1015 
 1016         db_printf("%18s %12s  %12s %12s\n", "Type", "InUse", "MemUse",
 1017             "Requests");
 1018         for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
 1019                 mtip = (struct malloc_type_internal *)mtp->ks_handle;
 1020                 allocs = 0;
 1021                 frees = 0;
 1022                 alloced = 0;
 1023                 freed = 0;
 1024                 for (i = 0; i < MAXCPU; i++) {
 1025                         allocs += mtip->mti_stats[i].mts_numallocs;
 1026                         frees += mtip->mti_stats[i].mts_numfrees;
 1027                         alloced += mtip->mti_stats[i].mts_memalloced;
 1028                         freed += mtip->mti_stats[i].mts_memfreed;
 1029                 }
 1030                 db_printf("%18s %12ju %12juK %12ju\n",
 1031                     mtp->ks_shortdesc, allocs - frees,
 1032                     (alloced - freed + 1023) / 1024, allocs);
 1033                 if (db_pager_quit)
 1034                         break;
 1035         }
 1036 }
 1037 
 1038 #if MALLOC_DEBUG_MAXZONES > 1
 1039 DB_SHOW_COMMAND(multizone_matches, db_show_multizone_matches)
 1040 {
 1041         struct malloc_type_internal *mtip;
 1042         struct malloc_type *mtp;
 1043         u_int subzone;
 1044 
 1045         if (!have_addr) {
 1046                 db_printf("Usage: show multizone_matches <malloc type/addr>\n");
 1047                 return;
 1048         }
 1049         mtp = (void *)addr;
 1050         if (mtp->ks_magic != M_MAGIC) {
 1051                 db_printf("Magic %lx does not match expected %x\n",
 1052                     mtp->ks_magic, M_MAGIC);
 1053                 return;
 1054         }
 1055 
 1056         mtip = mtp->ks_handle;
 1057         subzone = mtip->mti_zone;
 1058 
 1059         for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
 1060                 mtip = mtp->ks_handle;
 1061                 if (mtip->mti_zone != subzone)
 1062                         continue;
 1063                 db_printf("%s\n", mtp->ks_shortdesc);
 1064                 if (db_pager_quit)
 1065                         break;
 1066         }
 1067 }
 1068 #endif /* MALLOC_DEBUG_MAXZONES > 1 */
 1069 #endif /* DDB */
 1070 
 1071 #ifdef MALLOC_PROFILE
 1072 
 1073 static int
 1074 sysctl_kern_mprof(SYSCTL_HANDLER_ARGS)
 1075 {
 1076         struct sbuf sbuf;
 1077         uint64_t count;
 1078         uint64_t waste;
 1079         uint64_t mem;
 1080         int error;
 1081         int rsize;
 1082         int size;
 1083         int i;
 1084 
 1085         waste = 0;
 1086         mem = 0;
 1087 
 1088         error = sysctl_wire_old_buffer(req, 0);
 1089         if (error != 0)
 1090                 return (error);
 1091         sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
 1092         sbuf_printf(&sbuf, 
 1093             "\n  Size                    Requests  Real Size\n");
 1094         for (i = 0; i < KMEM_ZSIZE; i++) {
 1095                 size = i << KMEM_ZSHIFT;
 1096                 rsize = kmemzones[kmemsize[i]].kz_size;
 1097                 count = (long long unsigned)krequests[i];
 1098 
 1099                 sbuf_printf(&sbuf, "%6d%28llu%11d\n", size,
 1100                     (unsigned long long)count, rsize);
 1101 
 1102                 if ((rsize * count) > (size * count))
 1103                         waste += (rsize * count) - (size * count);
 1104                 mem += (rsize * count);
 1105         }
 1106         sbuf_printf(&sbuf,
 1107             "\nTotal memory used:\t%30llu\nTotal Memory wasted:\t%30llu\n",
 1108             (unsigned long long)mem, (unsigned long long)waste);
 1109         error = sbuf_finish(&sbuf);
 1110         sbuf_delete(&sbuf);
 1111         return (error);
 1112 }
 1113 
 1114 SYSCTL_OID(_kern, OID_AUTO, mprof, CTLTYPE_STRING|CTLFLAG_RD,
 1115     NULL, 0, sysctl_kern_mprof, "A", "Malloc Profiling");
 1116 #endif /* MALLOC_PROFILE */

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