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  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  * 4. Neither the name of the University nor the names of its contributors
   16  *    may be used to endorse or promote products derived from this software
   17  *    without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29  * SUCH DAMAGE.
   30  *
   31  *      @(#)kern_malloc.c       8.3 (Berkeley) 1/4/94
   32  */
   33 
   34 /*
   35  * Kernel malloc(9) implementation -- general purpose kernel memory allocator
   36  * based on memory types.  Back end is implemented using the UMA(9) zone
   37  * allocator.  A set of fixed-size buckets are used for smaller allocations,
   38  * and a special UMA allocation interface is used for larger allocations.
   39  * Callers declare memory types, and statistics are maintained independently
   40  * for each memory type.  Statistics are maintained per-CPU for performance
   41  * reasons.  See malloc(9) and comments in malloc.h for a detailed
   42  * description.
   43  */
   44 
   45 #include <sys/cdefs.h>
   46 __FBSDID("$FreeBSD: releng/9.2/sys/kern/kern_malloc.c 248085 2013-03-09 02:36:32Z marius $");
   47 
   48 #include "opt_ddb.h"
   49 #include "opt_kdtrace.h"
   50 #include "opt_vm.h"
   51 
   52 #include <sys/param.h>
   53 #include <sys/systm.h>
   54 #include <sys/kdb.h>
   55 #include <sys/kernel.h>
   56 #include <sys/lock.h>
   57 #include <sys/malloc.h>
   58 #include <sys/mbuf.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 
   66 #include <vm/vm.h>
   67 #include <vm/pmap.h>
   68 #include <vm/vm_param.h>
   69 #include <vm/vm_kern.h>
   70 #include <vm/vm_extern.h>
   71 #include <vm/vm_map.h>
   72 #include <vm/vm_page.h>
   73 #include <vm/uma.h>
   74 #include <vm/uma_int.h>
   75 #include <vm/uma_dbg.h>
   76 
   77 #ifdef DEBUG_MEMGUARD
   78 #include <vm/memguard.h>
   79 #endif
   80 #ifdef DEBUG_REDZONE
   81 #include <vm/redzone.h>
   82 #endif
   83 
   84 #if defined(INVARIANTS) && defined(__i386__)
   85 #include <machine/cpu.h>
   86 #endif
   87 
   88 #include <ddb/ddb.h>
   89 
   90 #ifdef KDTRACE_HOOKS
   91 #include <sys/dtrace_bsd.h>
   92 
   93 dtrace_malloc_probe_func_t      dtrace_malloc_probe;
   94 #endif
   95 
   96 /*
   97  * When realloc() is called, if the new size is sufficiently smaller than
   98  * the old size, realloc() will allocate a new, smaller block to avoid
   99  * wasting memory. 'Sufficiently smaller' is defined as: newsize <=
  100  * oldsize / 2^n, where REALLOC_FRACTION defines the value of 'n'.
  101  */
  102 #ifndef REALLOC_FRACTION
  103 #define REALLOC_FRACTION        1       /* new block if <= half the size */
  104 #endif
  105 
  106 /*
  107  * Centrally define some common malloc types.
  108  */
  109 MALLOC_DEFINE(M_CACHE, "cache", "Various Dynamically allocated caches");
  110 MALLOC_DEFINE(M_DEVBUF, "devbuf", "device driver memory");
  111 MALLOC_DEFINE(M_TEMP, "temp", "misc temporary data buffers");
  112 
  113 MALLOC_DEFINE(M_IP6OPT, "ip6opt", "IPv6 options");
  114 MALLOC_DEFINE(M_IP6NDP, "ip6ndp", "IPv6 Neighbor Discovery");
  115 
  116 static void kmeminit(void *);
  117 SYSINIT(kmem, SI_SUB_KMEM, SI_ORDER_FIRST, kmeminit, NULL);
  118 
  119 static MALLOC_DEFINE(M_FREE, "free", "should be on free list");
  120 
  121 static struct malloc_type *kmemstatistics;
  122 static vm_offset_t kmembase;
  123 static vm_offset_t kmemlimit;
  124 static int kmemcount;
  125 
  126 #define KMEM_ZSHIFT     4
  127 #define KMEM_ZBASE      16
  128 #define KMEM_ZMASK      (KMEM_ZBASE - 1)
  129 
  130 #define KMEM_ZMAX       PAGE_SIZE
  131 #define KMEM_ZSIZE      (KMEM_ZMAX >> KMEM_ZSHIFT)
  132 static uint8_t kmemsize[KMEM_ZSIZE + 1];
  133 
  134 #ifndef MALLOC_DEBUG_MAXZONES
  135 #define MALLOC_DEBUG_MAXZONES   1
  136 #endif
  137 static int numzones = MALLOC_DEBUG_MAXZONES;
  138 
  139 /*
  140  * Small malloc(9) memory allocations are allocated from a set of UMA buckets
  141  * of various sizes.
  142  *
  143  * XXX: The comment here used to read "These won't be powers of two for
  144  * long."  It's possible that a significant amount of wasted memory could be
  145  * recovered by tuning the sizes of these buckets.
  146  */
  147 struct {
  148         int kz_size;
  149         char *kz_name;
  150         uma_zone_t kz_zone[MALLOC_DEBUG_MAXZONES];
  151 } kmemzones[] = {
  152         {16, "16", },
  153         {32, "32", },
  154         {64, "64", },
  155         {128, "128", },
  156         {256, "256", },
  157         {512, "512", },
  158         {1024, "1024", },
  159         {2048, "2048", },
  160         {4096, "4096", },
  161 #if PAGE_SIZE > 4096
  162         {8192, "8192", },
  163 #if PAGE_SIZE > 8192
  164         {16384, "16384", },
  165 #if PAGE_SIZE > 16384
  166         {32768, "32768", },
  167 #if PAGE_SIZE > 32768
  168         {65536, "65536", },
  169 #if PAGE_SIZE > 65536
  170 #error  "Unsupported PAGE_SIZE"
  171 #endif  /* 65536 */
  172 #endif  /* 32768 */
  173 #endif  /* 16384 */
  174 #endif  /* 8192 */
  175 #endif  /* 4096 */
  176         {0, NULL},
  177 };
  178 
  179 /*
  180  * Zone to allocate malloc type descriptions from.  For ABI reasons, memory
  181  * types are described by a data structure passed by the declaring code, but
  182  * the malloc(9) implementation has its own data structure describing the
  183  * type and statistics.  This permits the malloc(9)-internal data structures
  184  * to be modified without breaking binary-compiled kernel modules that
  185  * declare malloc types.
  186  */
  187 static uma_zone_t mt_zone;
  188 
  189 u_long vm_kmem_size;
  190 SYSCTL_ULONG(_vm, OID_AUTO, kmem_size, CTLFLAG_RDTUN, &vm_kmem_size, 0,
  191     "Size of kernel memory");
  192 
  193 static u_long vm_kmem_size_min;
  194 SYSCTL_ULONG(_vm, OID_AUTO, kmem_size_min, CTLFLAG_RDTUN, &vm_kmem_size_min, 0,
  195     "Minimum size of kernel memory");
  196 
  197 static u_long vm_kmem_size_max;
  198 SYSCTL_ULONG(_vm, OID_AUTO, kmem_size_max, CTLFLAG_RDTUN, &vm_kmem_size_max, 0,
  199     "Maximum size of kernel memory");
  200 
  201 static u_int vm_kmem_size_scale;
  202 SYSCTL_UINT(_vm, OID_AUTO, kmem_size_scale, CTLFLAG_RDTUN, &vm_kmem_size_scale, 0,
  203     "Scale factor for kernel memory size");
  204 
  205 static int sysctl_kmem_map_size(SYSCTL_HANDLER_ARGS);
  206 SYSCTL_PROC(_vm, OID_AUTO, kmem_map_size,
  207     CTLFLAG_RD | CTLTYPE_ULONG | CTLFLAG_MPSAFE, NULL, 0,
  208     sysctl_kmem_map_size, "LU", "Current kmem_map allocation size");
  209 
  210 static int sysctl_kmem_map_free(SYSCTL_HANDLER_ARGS);
  211 SYSCTL_PROC(_vm, OID_AUTO, kmem_map_free,
  212     CTLFLAG_RD | CTLTYPE_ULONG | CTLFLAG_MPSAFE, NULL, 0,
  213     sysctl_kmem_map_free, "LU", "Largest contiguous free range in kmem_map");
  214 
  215 /*
  216  * The malloc_mtx protects the kmemstatistics linked list.
  217  */
  218 struct mtx malloc_mtx;
  219 
  220 #ifdef MALLOC_PROFILE
  221 uint64_t krequests[KMEM_ZSIZE + 1];
  222 
  223 static int sysctl_kern_mprof(SYSCTL_HANDLER_ARGS);
  224 #endif
  225 
  226 static int sysctl_kern_malloc_stats(SYSCTL_HANDLER_ARGS);
  227 
  228 /*
  229  * time_uptime of the last malloc(9) failure (induced or real).
  230  */
  231 static time_t t_malloc_fail;
  232 
  233 #if defined(MALLOC_MAKE_FAILURES) || (MALLOC_DEBUG_MAXZONES > 1)
  234 static SYSCTL_NODE(_debug, OID_AUTO, malloc, CTLFLAG_RD, 0,
  235     "Kernel malloc debugging options");
  236 #endif
  237 
  238 /*
  239  * malloc(9) fault injection -- cause malloc failures every (n) mallocs when
  240  * the caller specifies M_NOWAIT.  If set to 0, no failures are caused.
  241  */
  242 #ifdef MALLOC_MAKE_FAILURES
  243 static int malloc_failure_rate;
  244 static int malloc_nowait_count;
  245 static int malloc_failure_count;
  246 SYSCTL_INT(_debug_malloc, OID_AUTO, failure_rate, CTLFLAG_RW,
  247     &malloc_failure_rate, 0, "Every (n) mallocs with M_NOWAIT will fail");
  248 TUNABLE_INT("debug.malloc.failure_rate", &malloc_failure_rate);
  249 SYSCTL_INT(_debug_malloc, OID_AUTO, failure_count, CTLFLAG_RD,
  250     &malloc_failure_count, 0, "Number of imposed M_NOWAIT malloc failures");
  251 #endif
  252 
  253 static int
  254 sysctl_kmem_map_size(SYSCTL_HANDLER_ARGS)
  255 {
  256         u_long size;
  257 
  258         size = kmem_map->size;
  259         return (sysctl_handle_long(oidp, &size, 0, req));
  260 }
  261 
  262 static int
  263 sysctl_kmem_map_free(SYSCTL_HANDLER_ARGS)
  264 {
  265         u_long size;
  266 
  267         vm_map_lock_read(kmem_map);
  268         size = kmem_map->root != NULL ? kmem_map->root->max_free :
  269             kmem_map->max_offset - kmem_map->min_offset;
  270         vm_map_unlock_read(kmem_map);
  271         return (sysctl_handle_long(oidp, &size, 0, req));
  272 }
  273 
  274 /*
  275  * malloc(9) uma zone separation -- sub-page buffer overruns in one
  276  * malloc type will affect only a subset of other malloc types.
  277  */
  278 #if MALLOC_DEBUG_MAXZONES > 1
  279 static void
  280 tunable_set_numzones(void)
  281 {
  282 
  283         TUNABLE_INT_FETCH("debug.malloc.numzones",
  284             &numzones);
  285 
  286         /* Sanity check the number of malloc uma zones. */
  287         if (numzones <= 0)
  288                 numzones = 1;
  289         if (numzones > MALLOC_DEBUG_MAXZONES)
  290                 numzones = MALLOC_DEBUG_MAXZONES;
  291 }
  292 SYSINIT(numzones, SI_SUB_TUNABLES, SI_ORDER_ANY, tunable_set_numzones, NULL);
  293 SYSCTL_INT(_debug_malloc, OID_AUTO, numzones, CTLFLAG_RDTUN,
  294     &numzones, 0, "Number of malloc uma subzones");
  295 
  296 /*
  297  * Any number that changes regularly is an okay choice for the
  298  * offset.  Build numbers are pretty good of you have them.
  299  */
  300 static u_int zone_offset = __FreeBSD_version;
  301 TUNABLE_INT("debug.malloc.zone_offset", &zone_offset);
  302 SYSCTL_UINT(_debug_malloc, OID_AUTO, zone_offset, CTLFLAG_RDTUN,
  303     &zone_offset, 0, "Separate malloc types by examining the "
  304     "Nth character in the malloc type short description.");
  305 
  306 static u_int
  307 mtp_get_subzone(const char *desc)
  308 {
  309         size_t len;
  310         u_int val;
  311 
  312         if (desc == NULL || (len = strlen(desc)) == 0)
  313                 return (0);
  314         val = desc[zone_offset % len];
  315         return (val % numzones);
  316 }
  317 #elif MALLOC_DEBUG_MAXZONES == 0
  318 #error "MALLOC_DEBUG_MAXZONES must be positive."
  319 #else
  320 static inline u_int
  321 mtp_get_subzone(const char *desc)
  322 {
  323 
  324         return (0);
  325 }
  326 #endif /* MALLOC_DEBUG_MAXZONES > 1 */
  327 
  328 int
  329 malloc_last_fail(void)
  330 {
  331 
  332         return (time_uptime - t_malloc_fail);
  333 }
  334 
  335 /*
  336  * An allocation has succeeded -- update malloc type statistics for the
  337  * amount of bucket size.  Occurs within a critical section so that the
  338  * thread isn't preempted and doesn't migrate while updating per-PCU
  339  * statistics.
  340  */
  341 static void
  342 malloc_type_zone_allocated(struct malloc_type *mtp, unsigned long size,
  343     int zindx)
  344 {
  345         struct malloc_type_internal *mtip;
  346         struct malloc_type_stats *mtsp;
  347 
  348         critical_enter();
  349         mtip = mtp->ks_handle;
  350         mtsp = &mtip->mti_stats[curcpu];
  351         if (size > 0) {
  352                 mtsp->mts_memalloced += size;
  353                 mtsp->mts_numallocs++;
  354         }
  355         if (zindx != -1)
  356                 mtsp->mts_size |= 1 << zindx;
  357 
  358 #ifdef KDTRACE_HOOKS
  359         if (dtrace_malloc_probe != NULL) {
  360                 uint32_t probe_id = mtip->mti_probes[DTMALLOC_PROBE_MALLOC];
  361                 if (probe_id != 0)
  362                         (dtrace_malloc_probe)(probe_id,
  363                             (uintptr_t) mtp, (uintptr_t) mtip,
  364                             (uintptr_t) mtsp, size, zindx);
  365         }
  366 #endif
  367 
  368         critical_exit();
  369 }
  370 
  371 void
  372 malloc_type_allocated(struct malloc_type *mtp, unsigned long size)
  373 {
  374 
  375         if (size > 0)
  376                 malloc_type_zone_allocated(mtp, size, -1);
  377 }
  378 
  379 /*
  380  * A free operation has occurred -- update malloc type statistics for the
  381  * amount of the bucket size.  Occurs within a critical section so that the
  382  * thread isn't preempted and doesn't migrate while updating per-CPU
  383  * statistics.
  384  */
  385 void
  386 malloc_type_freed(struct malloc_type *mtp, unsigned long size)
  387 {
  388         struct malloc_type_internal *mtip;
  389         struct malloc_type_stats *mtsp;
  390 
  391         critical_enter();
  392         mtip = mtp->ks_handle;
  393         mtsp = &mtip->mti_stats[curcpu];
  394         mtsp->mts_memfreed += size;
  395         mtsp->mts_numfrees++;
  396 
  397 #ifdef KDTRACE_HOOKS
  398         if (dtrace_malloc_probe != NULL) {
  399                 uint32_t probe_id = mtip->mti_probes[DTMALLOC_PROBE_FREE];
  400                 if (probe_id != 0)
  401                         (dtrace_malloc_probe)(probe_id,
  402                             (uintptr_t) mtp, (uintptr_t) mtip,
  403                             (uintptr_t) mtsp, size, 0);
  404         }
  405 #endif
  406 
  407         critical_exit();
  408 }
  409 
  410 /*
  411  *      malloc:
  412  *
  413  *      Allocate a block of memory.
  414  *
  415  *      If M_NOWAIT is set, this routine will not block and return NULL if
  416  *      the allocation fails.
  417  */
  418 void *
  419 malloc(unsigned long size, struct malloc_type *mtp, int flags)
  420 {
  421         int indx;
  422         struct malloc_type_internal *mtip;
  423         caddr_t va;
  424         uma_zone_t zone;
  425 #if defined(DIAGNOSTIC) || defined(DEBUG_REDZONE)
  426         unsigned long osize = size;
  427 #endif
  428 
  429 #ifdef INVARIANTS
  430         KASSERT(mtp->ks_magic == M_MAGIC, ("malloc: bad malloc type magic"));
  431         /*
  432          * Check that exactly one of M_WAITOK or M_NOWAIT is specified.
  433          */
  434         indx = flags & (M_WAITOK | M_NOWAIT);
  435         if (indx != M_NOWAIT && indx != M_WAITOK) {
  436                 static  struct timeval lasterr;
  437                 static  int curerr, once;
  438                 if (once == 0 && ppsratecheck(&lasterr, &curerr, 1)) {
  439                         printf("Bad malloc flags: %x\n", indx);
  440                         kdb_backtrace();
  441                         flags |= M_WAITOK;
  442                         once++;
  443                 }
  444         }
  445 #endif
  446 #ifdef MALLOC_MAKE_FAILURES
  447         if ((flags & M_NOWAIT) && (malloc_failure_rate != 0)) {
  448                 atomic_add_int(&malloc_nowait_count, 1);
  449                 if ((malloc_nowait_count % malloc_failure_rate) == 0) {
  450                         atomic_add_int(&malloc_failure_count, 1);
  451                         t_malloc_fail = time_uptime;
  452                         return (NULL);
  453                 }
  454         }
  455 #endif
  456         if (flags & M_WAITOK)
  457                 KASSERT(curthread->td_intr_nesting_level == 0,
  458                    ("malloc(M_WAITOK) in interrupt context"));
  459 
  460 #ifdef DEBUG_MEMGUARD
  461         if (memguard_cmp(mtp, size)) {
  462                 va = memguard_alloc(size, flags);
  463                 if (va != NULL)
  464                         return (va);
  465                 /* This is unfortunate but should not be fatal. */
  466         }
  467 #endif
  468 
  469 #ifdef DEBUG_REDZONE
  470         size = redzone_size_ntor(size);
  471 #endif
  472 
  473         if (size <= KMEM_ZMAX) {
  474                 mtip = mtp->ks_handle;
  475                 if (size & KMEM_ZMASK)
  476                         size = (size & ~KMEM_ZMASK) + KMEM_ZBASE;
  477                 indx = kmemsize[size >> KMEM_ZSHIFT];
  478                 KASSERT(mtip->mti_zone < numzones,
  479                     ("mti_zone %u out of range %d",
  480                     mtip->mti_zone, numzones));
  481                 zone = kmemzones[indx].kz_zone[mtip->mti_zone];
  482 #ifdef MALLOC_PROFILE
  483                 krequests[size >> KMEM_ZSHIFT]++;
  484 #endif
  485                 va = uma_zalloc(zone, flags);
  486                 if (va != NULL)
  487                         size = zone->uz_size;
  488                 malloc_type_zone_allocated(mtp, va == NULL ? 0 : size, indx);
  489         } else {
  490                 size = roundup(size, PAGE_SIZE);
  491                 zone = NULL;
  492                 va = uma_large_malloc(size, flags);
  493                 malloc_type_allocated(mtp, va == NULL ? 0 : size);
  494         }
  495         if (flags & M_WAITOK)
  496                 KASSERT(va != NULL, ("malloc(M_WAITOK) returned NULL"));
  497         else if (va == NULL)
  498                 t_malloc_fail = time_uptime;
  499 #ifdef DIAGNOSTIC
  500         if (va != NULL && !(flags & M_ZERO)) {
  501                 memset(va, 0x70, osize);
  502         }
  503 #endif
  504 #ifdef DEBUG_REDZONE
  505         if (va != NULL)
  506                 va = redzone_setup(va, osize);
  507 #endif
  508         return ((void *) va);
  509 }
  510 
  511 /*
  512  *      free:
  513  *
  514  *      Free a block of memory allocated by malloc.
  515  *
  516  *      This routine may not block.
  517  */
  518 void
  519 free(void *addr, struct malloc_type *mtp)
  520 {
  521         uma_slab_t slab;
  522         u_long size;
  523 
  524         KASSERT(mtp->ks_magic == M_MAGIC, ("free: bad malloc type magic"));
  525 
  526         /* free(NULL, ...) does nothing */
  527         if (addr == NULL)
  528                 return;
  529 
  530 #ifdef DEBUG_MEMGUARD
  531         if (is_memguard_addr(addr)) {
  532                 memguard_free(addr);
  533                 return;
  534         }
  535 #endif
  536 
  537 #ifdef DEBUG_REDZONE
  538         redzone_check(addr);
  539         addr = redzone_addr_ntor(addr);
  540 #endif
  541 
  542         slab = vtoslab((vm_offset_t)addr & (~UMA_SLAB_MASK));
  543 
  544         if (slab == NULL)
  545                 panic("free: address %p(%p) has not been allocated.\n",
  546                     addr, (void *)((u_long)addr & (~UMA_SLAB_MASK)));
  547 
  548 
  549         if (!(slab->us_flags & UMA_SLAB_MALLOC)) {
  550 #ifdef INVARIANTS
  551                 struct malloc_type **mtpp = addr;
  552 #endif
  553                 size = slab->us_keg->uk_size;
  554 #ifdef INVARIANTS
  555                 /*
  556                  * Cache a pointer to the malloc_type that most recently freed
  557                  * this memory here.  This way we know who is most likely to
  558                  * have stepped on it later.
  559                  *
  560                  * This code assumes that size is a multiple of 8 bytes for
  561                  * 64 bit machines
  562                  */
  563                 mtpp = (struct malloc_type **)
  564                     ((unsigned long)mtpp & ~UMA_ALIGN_PTR);
  565                 mtpp += (size - sizeof(struct malloc_type *)) /
  566                     sizeof(struct malloc_type *);
  567                 *mtpp = mtp;
  568 #endif
  569                 uma_zfree_arg(LIST_FIRST(&slab->us_keg->uk_zones), addr, slab);
  570         } else {
  571                 size = slab->us_size;
  572                 uma_large_free(slab);
  573         }
  574         malloc_type_freed(mtp, size);
  575 }
  576 
  577 /*
  578  *      realloc: change the size of a memory block
  579  */
  580 void *
  581 realloc(void *addr, unsigned long size, struct malloc_type *mtp, int flags)
  582 {
  583         uma_slab_t slab;
  584         unsigned long alloc;
  585         void *newaddr;
  586 
  587         KASSERT(mtp->ks_magic == M_MAGIC,
  588             ("realloc: bad malloc type magic"));
  589 
  590         /* realloc(NULL, ...) is equivalent to malloc(...) */
  591         if (addr == NULL)
  592                 return (malloc(size, mtp, flags));
  593 
  594         /*
  595          * XXX: Should report free of old memory and alloc of new memory to
  596          * per-CPU stats.
  597          */
  598 
  599 #ifdef DEBUG_MEMGUARD
  600         if (is_memguard_addr(addr))
  601                 return (memguard_realloc(addr, size, mtp, flags));
  602 #endif
  603 
  604 #ifdef DEBUG_REDZONE
  605         slab = NULL;
  606         alloc = redzone_get_size(addr);
  607 #else
  608         slab = vtoslab((vm_offset_t)addr & ~(UMA_SLAB_MASK));
  609 
  610         /* Sanity check */
  611         KASSERT(slab != NULL,
  612             ("realloc: address %p out of range", (void *)addr));
  613 
  614         /* Get the size of the original block */
  615         if (!(slab->us_flags & UMA_SLAB_MALLOC))
  616                 alloc = slab->us_keg->uk_size;
  617         else
  618                 alloc = slab->us_size;
  619 
  620         /* Reuse the original block if appropriate */
  621         if (size <= alloc
  622             && (size > (alloc >> REALLOC_FRACTION) || alloc == MINALLOCSIZE))
  623                 return (addr);
  624 #endif /* !DEBUG_REDZONE */
  625 
  626         /* Allocate a new, bigger (or smaller) block */
  627         if ((newaddr = malloc(size, mtp, flags)) == NULL)
  628                 return (NULL);
  629 
  630         /* Copy over original contents */
  631         bcopy(addr, newaddr, min(size, alloc));
  632         free(addr, mtp);
  633         return (newaddr);
  634 }
  635 
  636 /*
  637  *      reallocf: same as realloc() but free memory on failure.
  638  */
  639 void *
  640 reallocf(void *addr, unsigned long size, struct malloc_type *mtp, int flags)
  641 {
  642         void *mem;
  643 
  644         if ((mem = realloc(addr, size, mtp, flags)) == NULL)
  645                 free(addr, mtp);
  646         return (mem);
  647 }
  648 
  649 /*
  650  * Initialize the kernel memory allocator
  651  */
  652 /* ARGSUSED*/
  653 static void
  654 kmeminit(void *dummy)
  655 {
  656         uint8_t indx;
  657         u_long mem_size, tmp;
  658         int i;
  659  
  660         mtx_init(&malloc_mtx, "malloc", NULL, MTX_DEF);
  661 
  662         /*
  663          * Try to auto-tune the kernel memory size, so that it is
  664          * more applicable for a wider range of machine sizes.  The
  665          * VM_KMEM_SIZE_MAX is dependent on the maximum KVA space
  666          * available.
  667          *
  668          * Note that the kmem_map is also used by the zone allocator,
  669          * so make sure that there is enough space.
  670          */
  671         vm_kmem_size = VM_KMEM_SIZE + nmbclusters * PAGE_SIZE;
  672         mem_size = cnt.v_page_count;
  673 
  674 #if defined(VM_KMEM_SIZE_SCALE)
  675         vm_kmem_size_scale = VM_KMEM_SIZE_SCALE;
  676 #endif
  677         TUNABLE_INT_FETCH("vm.kmem_size_scale", &vm_kmem_size_scale);
  678         if (vm_kmem_size_scale > 0 &&
  679             (mem_size / vm_kmem_size_scale) > (vm_kmem_size / PAGE_SIZE))
  680                 vm_kmem_size = (mem_size / vm_kmem_size_scale) * PAGE_SIZE;
  681 
  682 #if defined(VM_KMEM_SIZE_MIN)
  683         vm_kmem_size_min = VM_KMEM_SIZE_MIN;
  684 #endif
  685         TUNABLE_ULONG_FETCH("vm.kmem_size_min", &vm_kmem_size_min);
  686         if (vm_kmem_size_min > 0 && vm_kmem_size < vm_kmem_size_min) {
  687                 vm_kmem_size = vm_kmem_size_min;
  688         }
  689 
  690 #if defined(VM_KMEM_SIZE_MAX)
  691         vm_kmem_size_max = VM_KMEM_SIZE_MAX;
  692 #endif
  693         TUNABLE_ULONG_FETCH("vm.kmem_size_max", &vm_kmem_size_max);
  694         if (vm_kmem_size_max > 0 && vm_kmem_size >= vm_kmem_size_max)
  695                 vm_kmem_size = vm_kmem_size_max;
  696 
  697         /* Allow final override from the kernel environment */
  698         TUNABLE_ULONG_FETCH("vm.kmem_size", &vm_kmem_size);
  699 
  700         /*
  701          * Limit kmem virtual size to twice the physical memory.
  702          * This allows for kmem map sparseness, but limits the size
  703          * to something sane.  Be careful to not overflow the 32bit
  704          * ints while doing the check or the adjustment.
  705          */
  706         if (vm_kmem_size / 2 / PAGE_SIZE > mem_size)
  707                 vm_kmem_size = 2 * mem_size * PAGE_SIZE;
  708 
  709 #ifdef DEBUG_MEMGUARD
  710         tmp = memguard_fudge(vm_kmem_size, kernel_map);
  711 #else
  712         tmp = vm_kmem_size;
  713 #endif
  714         kmem_map = kmem_suballoc(kernel_map, &kmembase, &kmemlimit,
  715             tmp, TRUE);
  716         kmem_map->system_map = 1;
  717 
  718 #ifdef DEBUG_MEMGUARD
  719         /*
  720          * Initialize MemGuard if support compiled in.  MemGuard is a
  721          * replacement allocator used for detecting tamper-after-free
  722          * scenarios as they occur.  It is only used for debugging.
  723          */
  724         memguard_init(kmem_map);
  725 #endif
  726 
  727         uma_startup2();
  728 
  729         mt_zone = uma_zcreate("mt_zone", sizeof(struct malloc_type_internal),
  730 #ifdef INVARIANTS
  731             mtrash_ctor, mtrash_dtor, mtrash_init, mtrash_fini,
  732 #else
  733             NULL, NULL, NULL, NULL,
  734 #endif
  735             UMA_ALIGN_PTR, UMA_ZONE_MALLOC);
  736         for (i = 0, indx = 0; kmemzones[indx].kz_size != 0; indx++) {
  737                 int size = kmemzones[indx].kz_size;
  738                 char *name = kmemzones[indx].kz_name;
  739                 int subzone;
  740 
  741                 for (subzone = 0; subzone < numzones; subzone++) {
  742                         kmemzones[indx].kz_zone[subzone] =
  743                             uma_zcreate(name, size,
  744 #ifdef INVARIANTS
  745                             mtrash_ctor, mtrash_dtor, mtrash_init, mtrash_fini,
  746 #else
  747                             NULL, NULL, NULL, NULL,
  748 #endif
  749                             UMA_ALIGN_PTR, UMA_ZONE_MALLOC);
  750                 }                   
  751                 for (;i <= size; i+= KMEM_ZBASE)
  752                         kmemsize[i >> KMEM_ZSHIFT] = indx;
  753                 
  754         }
  755 }
  756 
  757 void
  758 malloc_init(void *data)
  759 {
  760         struct malloc_type_internal *mtip;
  761         struct malloc_type *mtp;
  762 
  763         KASSERT(cnt.v_page_count != 0, ("malloc_register before vm_init"));
  764 
  765         mtp = data;
  766         if (mtp->ks_magic != M_MAGIC)
  767                 panic("malloc_init: bad malloc type magic");
  768 
  769         mtip = uma_zalloc(mt_zone, M_WAITOK | M_ZERO);
  770         mtp->ks_handle = mtip;
  771         mtip->mti_zone = mtp_get_subzone(mtp->ks_shortdesc);
  772 
  773         mtx_lock(&malloc_mtx);
  774         mtp->ks_next = kmemstatistics;
  775         kmemstatistics = mtp;
  776         kmemcount++;
  777         mtx_unlock(&malloc_mtx);
  778 }
  779 
  780 void
  781 malloc_uninit(void *data)
  782 {
  783         struct malloc_type_internal *mtip;
  784         struct malloc_type_stats *mtsp;
  785         struct malloc_type *mtp, *temp;
  786         uma_slab_t slab;
  787         long temp_allocs, temp_bytes;
  788         int i;
  789 
  790         mtp = data;
  791         KASSERT(mtp->ks_magic == M_MAGIC,
  792             ("malloc_uninit: bad malloc type magic"));
  793         KASSERT(mtp->ks_handle != NULL, ("malloc_deregister: cookie NULL"));
  794 
  795         mtx_lock(&malloc_mtx);
  796         mtip = mtp->ks_handle;
  797         mtp->ks_handle = NULL;
  798         if (mtp != kmemstatistics) {
  799                 for (temp = kmemstatistics; temp != NULL;
  800                     temp = temp->ks_next) {
  801                         if (temp->ks_next == mtp) {
  802                                 temp->ks_next = mtp->ks_next;
  803                                 break;
  804                         }
  805                 }
  806                 KASSERT(temp,
  807                     ("malloc_uninit: type '%s' not found", mtp->ks_shortdesc));
  808         } else
  809                 kmemstatistics = mtp->ks_next;
  810         kmemcount--;
  811         mtx_unlock(&malloc_mtx);
  812 
  813         /*
  814          * Look for memory leaks.
  815          */
  816         temp_allocs = temp_bytes = 0;
  817         for (i = 0; i < MAXCPU; i++) {
  818                 mtsp = &mtip->mti_stats[i];
  819                 temp_allocs += mtsp->mts_numallocs;
  820                 temp_allocs -= mtsp->mts_numfrees;
  821                 temp_bytes += mtsp->mts_memalloced;
  822                 temp_bytes -= mtsp->mts_memfreed;
  823         }
  824         if (temp_allocs > 0 || temp_bytes > 0) {
  825                 printf("Warning: memory type %s leaked memory on destroy "
  826                     "(%ld allocations, %ld bytes leaked).\n", mtp->ks_shortdesc,
  827                     temp_allocs, temp_bytes);
  828         }
  829 
  830         slab = vtoslab((vm_offset_t) mtip & (~UMA_SLAB_MASK));
  831         uma_zfree_arg(mt_zone, mtip, slab);
  832 }
  833 
  834 struct malloc_type *
  835 malloc_desc2type(const char *desc)
  836 {
  837         struct malloc_type *mtp;
  838 
  839         mtx_assert(&malloc_mtx, MA_OWNED);
  840         for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
  841                 if (strcmp(mtp->ks_shortdesc, desc) == 0)
  842                         return (mtp);
  843         }
  844         return (NULL);
  845 }
  846 
  847 static int
  848 sysctl_kern_malloc_stats(SYSCTL_HANDLER_ARGS)
  849 {
  850         struct malloc_type_stream_header mtsh;
  851         struct malloc_type_internal *mtip;
  852         struct malloc_type_header mth;
  853         struct malloc_type *mtp;
  854         int error, i;
  855         struct sbuf sbuf;
  856 
  857         error = sysctl_wire_old_buffer(req, 0);
  858         if (error != 0)
  859                 return (error);
  860         sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
  861         mtx_lock(&malloc_mtx);
  862 
  863         /*
  864          * Insert stream header.
  865          */
  866         bzero(&mtsh, sizeof(mtsh));
  867         mtsh.mtsh_version = MALLOC_TYPE_STREAM_VERSION;
  868         mtsh.mtsh_maxcpus = MAXCPU;
  869         mtsh.mtsh_count = kmemcount;
  870         (void)sbuf_bcat(&sbuf, &mtsh, sizeof(mtsh));
  871 
  872         /*
  873          * Insert alternating sequence of type headers and type statistics.
  874          */
  875         for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
  876                 mtip = (struct malloc_type_internal *)mtp->ks_handle;
  877 
  878                 /*
  879                  * Insert type header.
  880                  */
  881                 bzero(&mth, sizeof(mth));
  882                 strlcpy(mth.mth_name, mtp->ks_shortdesc, MALLOC_MAX_NAME);
  883                 (void)sbuf_bcat(&sbuf, &mth, sizeof(mth));
  884 
  885                 /*
  886                  * Insert type statistics for each CPU.
  887                  */
  888                 for (i = 0; i < MAXCPU; i++) {
  889                         (void)sbuf_bcat(&sbuf, &mtip->mti_stats[i],
  890                             sizeof(mtip->mti_stats[i]));
  891                 }
  892         }
  893         mtx_unlock(&malloc_mtx);
  894         error = sbuf_finish(&sbuf);
  895         sbuf_delete(&sbuf);
  896         return (error);
  897 }
  898 
  899 SYSCTL_PROC(_kern, OID_AUTO, malloc_stats, CTLFLAG_RD|CTLTYPE_STRUCT,
  900     0, 0, sysctl_kern_malloc_stats, "s,malloc_type_ustats",
  901     "Return malloc types");
  902 
  903 SYSCTL_INT(_kern, OID_AUTO, malloc_count, CTLFLAG_RD, &kmemcount, 0,
  904     "Count of kernel malloc types");
  905 
  906 void
  907 malloc_type_list(malloc_type_list_func_t *func, void *arg)
  908 {
  909         struct malloc_type *mtp, **bufmtp;
  910         int count, i;
  911         size_t buflen;
  912 
  913         mtx_lock(&malloc_mtx);
  914 restart:
  915         mtx_assert(&malloc_mtx, MA_OWNED);
  916         count = kmemcount;
  917         mtx_unlock(&malloc_mtx);
  918 
  919         buflen = sizeof(struct malloc_type *) * count;
  920         bufmtp = malloc(buflen, M_TEMP, M_WAITOK);
  921 
  922         mtx_lock(&malloc_mtx);
  923 
  924         if (count < kmemcount) {
  925                 free(bufmtp, M_TEMP);
  926                 goto restart;
  927         }
  928 
  929         for (mtp = kmemstatistics, i = 0; mtp != NULL; mtp = mtp->ks_next, i++)
  930                 bufmtp[i] = mtp;
  931 
  932         mtx_unlock(&malloc_mtx);
  933 
  934         for (i = 0; i < count; i++)
  935                 (func)(bufmtp[i], arg);
  936 
  937         free(bufmtp, M_TEMP);
  938 }
  939 
  940 #ifdef DDB
  941 DB_SHOW_COMMAND(malloc, db_show_malloc)
  942 {
  943         struct malloc_type_internal *mtip;
  944         struct malloc_type *mtp;
  945         uint64_t allocs, frees;
  946         uint64_t alloced, freed;
  947         int i;
  948 
  949         db_printf("%18s %12s  %12s %12s\n", "Type", "InUse", "MemUse",
  950             "Requests");
  951         for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
  952                 mtip = (struct malloc_type_internal *)mtp->ks_handle;
  953                 allocs = 0;
  954                 frees = 0;
  955                 alloced = 0;
  956                 freed = 0;
  957                 for (i = 0; i < MAXCPU; i++) {
  958                         allocs += mtip->mti_stats[i].mts_numallocs;
  959                         frees += mtip->mti_stats[i].mts_numfrees;
  960                         alloced += mtip->mti_stats[i].mts_memalloced;
  961                         freed += mtip->mti_stats[i].mts_memfreed;
  962                 }
  963                 db_printf("%18s %12ju %12juK %12ju\n",
  964                     mtp->ks_shortdesc, allocs - frees,
  965                     (alloced - freed + 1023) / 1024, allocs);
  966                 if (db_pager_quit)
  967                         break;
  968         }
  969 }
  970 
  971 #if MALLOC_DEBUG_MAXZONES > 1
  972 DB_SHOW_COMMAND(multizone_matches, db_show_multizone_matches)
  973 {
  974         struct malloc_type_internal *mtip;
  975         struct malloc_type *mtp;
  976         u_int subzone;
  977 
  978         if (!have_addr) {
  979                 db_printf("Usage: show multizone_matches <malloc type/addr>\n");
  980                 return;
  981         }
  982         mtp = (void *)addr;
  983         if (mtp->ks_magic != M_MAGIC) {
  984                 db_printf("Magic %lx does not match expected %x\n",
  985                     mtp->ks_magic, M_MAGIC);
  986                 return;
  987         }
  988 
  989         mtip = mtp->ks_handle;
  990         subzone = mtip->mti_zone;
  991 
  992         for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
  993                 mtip = mtp->ks_handle;
  994                 if (mtip->mti_zone != subzone)
  995                         continue;
  996                 db_printf("%s\n", mtp->ks_shortdesc);
  997                 if (db_pager_quit)
  998                         break;
  999         }
 1000 }
 1001 #endif /* MALLOC_DEBUG_MAXZONES > 1 */
 1002 #endif /* DDB */
 1003 
 1004 #ifdef MALLOC_PROFILE
 1005 
 1006 static int
 1007 sysctl_kern_mprof(SYSCTL_HANDLER_ARGS)
 1008 {
 1009         struct sbuf sbuf;
 1010         uint64_t count;
 1011         uint64_t waste;
 1012         uint64_t mem;
 1013         int error;
 1014         int rsize;
 1015         int size;
 1016         int i;
 1017 
 1018         waste = 0;
 1019         mem = 0;
 1020 
 1021         error = sysctl_wire_old_buffer(req, 0);
 1022         if (error != 0)
 1023                 return (error);
 1024         sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
 1025         sbuf_printf(&sbuf, 
 1026             "\n  Size                    Requests  Real Size\n");
 1027         for (i = 0; i < KMEM_ZSIZE; i++) {
 1028                 size = i << KMEM_ZSHIFT;
 1029                 rsize = kmemzones[kmemsize[i]].kz_size;
 1030                 count = (long long unsigned)krequests[i];
 1031 
 1032                 sbuf_printf(&sbuf, "%6d%28llu%11d\n", size,
 1033                     (unsigned long long)count, rsize);
 1034 
 1035                 if ((rsize * count) > (size * count))
 1036                         waste += (rsize * count) - (size * count);
 1037                 mem += (rsize * count);
 1038         }
 1039         sbuf_printf(&sbuf,
 1040             "\nTotal memory used:\t%30llu\nTotal Memory wasted:\t%30llu\n",
 1041             (unsigned long long)mem, (unsigned long long)waste);
 1042         error = sbuf_finish(&sbuf);
 1043         sbuf_delete(&sbuf);
 1044         return (error);
 1045 }
 1046 
 1047 SYSCTL_OID(_kern, OID_AUTO, mprof, CTLTYPE_STRING|CTLFLAG_RD,
 1048     NULL, 0, sysctl_kern_mprof, "A", "Malloc Profiling");
 1049 #endif /* MALLOC_PROFILE */

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