src/zmalloc.c

   1 /* zmalloc - total amount of allocated memory aware version of malloc()
   2  *
   3  * Copyright (c) 2009-2010, Salvatore Sanfilippo <antirez at gmail dot com>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are met:
   8  *
   9  *   * Redistributions of source code must retain the above copyright notice,
  10  *     this list of conditions and the following disclaimer.
  11  *   * Redistributions in binary form must reproduce the above copyright
  12  *     notice, this list of conditions and the following disclaimer in the
  13  *     documentation and/or other materials provided with the distribution.
  14  *   * Neither the name of Redis nor the names of its contributors may be used
  15  *     to endorse or promote products derived from this software without
  16  *     specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  19  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  22  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  28  * POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33
  34 /* This function provide us access to the original libc free(). This is useful
  35  * for instance to free results obtained by backtrace_symbols(). We need
  36  * to define this function before including zmalloc.h that may shadow the
  37  * free implementation if we use jemalloc or another non standard allocator. */
  38 void zlibc_free(void *ptr) {
  39     free(ptr);
  40 }
  41
  42 #include <string.h>
  43 #include <pthread.h>
  44 #include "config.h"
  45 #include "zmalloc.h"
  46
  47 #ifdef HAVE_MALLOC_SIZE
  48 #define PREFIX_SIZE (0)
  49 #else
  50 #if defined(__sun) || defined(__sparc) || defined(__sparc__)
  51 #define PREFIX_SIZE (sizeof(long long))
  52 #else
  53 #define PREFIX_SIZE (sizeof(size_t))
  54 #endif
  55 #endif
  56
  57 /* Explicitly override malloc/free etc when using tcmalloc. */
  58 #if defined(USE_TCMALLOC)
  59 #define malloc(size) tc_malloc(size)
  60 #define calloc(count,size) tc_calloc(count,size)
  61 #define realloc(ptr,size) tc_realloc(ptr,size)
  62 #define free(ptr) tc_free(ptr)
  63 #elif defined(USE_JEMALLOC)
  64 #define malloc(size) je_malloc(size)
  65 #define calloc(count,size) je_calloc(count,size)
  66 #define realloc(ptr,size) je_realloc(ptr,size)
  67 #define free(ptr) je_free(ptr)
  68 #endif
  69
  70 #ifdef HAVE_ATOMIC
  71 #define update_zmalloc_stat_add(__n) __sync_add_and_fetch(&used_memory, (__n))
  72 #define update_zmalloc_stat_sub(__n) __sync_sub_and_fetch(&used_memory, (__n))
  73 #else
  74 #define update_zmalloc_stat_add(__n) do { \
  75     pthread_mutex_lock(&used_memory_mutex); \
  76     used_memory += (__n); \
  77     pthread_mutex_unlock(&used_memory_mutex); \
  78 } while(0)
  79
  80 #define update_zmalloc_stat_sub(__n) do { \
  81     pthread_mutex_lock(&used_memory_mutex); \
  82     used_memory -= (__n); \
  83     pthread_mutex_unlock(&used_memory_mutex); \
  84 } while(0)
  85
  86 #endif
  87
  88 #define update_zmalloc_stat_alloc(__n,__size) do { \
  89     size_t _n = (__n); \
  90     if (_n&(sizeof(long)-1)) _n += sizeof(long)-(_n&(sizeof(long)-1)); \
  91     if (zmalloc_thread_safe) { \
  92         update_zmalloc_stat_add(_n); \
  93     } else { \
  94         used_memory += _n; \
  95     } \
  96 } while(0)
  97
  98 #define update_zmalloc_stat_free(__n) do { \
  99     size_t _n = (__n); \
 100     if (_n&(sizeof(long)-1)) _n += sizeof(long)-(_n&(sizeof(long)-1)); \
 101     if (zmalloc_thread_safe) { \
 102         update_zmalloc_stat_sub(_n); \
 103     } else { \
 104         used_memory -= _n; \
 105     } \
 106 } while(0)
 107
 108 static size_t used_memory = 0;
 109 static int zmalloc_thread_safe = 0;
 110 pthread_mutex_t used_memory_mutex = PTHREAD_MUTEX_INITIALIZER;
 111
 112 static void zmalloc_default_oom(size_t size) {
 113     fprintf(stderr, "zmalloc: Out of memory trying to allocate %zu bytes\n",
 114         size);
 115     fflush(stderr);
 116     abort();
 117 }
 118
 119 static void (*zmalloc_oom_handler)(size_t) = zmalloc_default_oom;
 120
 121 void *zmalloc(size_t size) {
 122     void *ptr = malloc(size+PREFIX_SIZE);
 123
 124     if (!ptr) zmalloc_oom_handler(size);
 125 #ifdef HAVE_MALLOC_SIZE
 126     update_zmalloc_stat_alloc(zmalloc_size(ptr),size);
 127     return ptr;
 128 #else
 129     *((size_t*)ptr) = size;
 130     update_zmalloc_stat_alloc(size+PREFIX_SIZE,size);
 131     return (char*)ptr+PREFIX_SIZE;
 132 #endif
 133 }
 134
 135 void *zcalloc(size_t size) {
 136     void *ptr = calloc(1, size+PREFIX_SIZE);
 137
 138     if (!ptr) zmalloc_oom_handler(size);
 139 #ifdef HAVE_MALLOC_SIZE
 140     update_zmalloc_stat_alloc(zmalloc_size(ptr),size);
 141     return ptr;
 142 #else
 143     *((size_t*)ptr) = size;
 144     update_zmalloc_stat_alloc(size+PREFIX_SIZE,size);
 145     return (char*)ptr+PREFIX_SIZE;
 146 #endif
 147 }
 148
 149 void *zrealloc(void *ptr, size_t size) {
 150 #ifndef HAVE_MALLOC_SIZE
 151     void *realptr;
 152 #endif
 153     size_t oldsize;
 154     void *newptr;
 155
 156     if (ptr == NULL) return zmalloc(size);
 157 #ifdef HAVE_MALLOC_SIZE
 158     oldsize = zmalloc_size(ptr);
 159     newptr = realloc(ptr,size);
 160     if (!newptr) zmalloc_oom_handler(size);
 161
 162     update_zmalloc_stat_free(oldsize);
 163     update_zmalloc_stat_alloc(zmalloc_size(newptr),size);
 164     return newptr;
 165 #else
 166     realptr = (char*)ptr-PREFIX_SIZE;
 167     oldsize = *((size_t*)realptr);
 168     newptr = realloc(realptr,size+PREFIX_SIZE);
 169     if (!newptr) zmalloc_oom(size);
 170
 171     *((size_t*)newptr) = size;
 172     update_zmalloc_stat_free(oldsize);
 173     update_zmalloc_stat_alloc(size,size);
 174     return (char*)newptr+PREFIX_SIZE;
 175 #endif
 176 }
 177
 178 /* Provide zmalloc_size() for systems where this function is not provided by
 179  * malloc itself, given that in that case we store an header with this
 180  * information as the first bytes of every allocation. */
 181 #ifndef HAVE_MALLOC_SIZE
 182 size_t zmalloc_size(void *ptr) {
 183     void *realptr = (char*)ptr-PREFIX_SIZE;
 184     size_t size = *((size_t*)realptr);
 185     /* Assume at least that all the allocations are padded at sizeof(long) by
 186      * the underlying allocator. */
 187     if (size&(sizeof(long)-1)) size += sizeof(long)-(size&(sizeof(long)-1));
 188     return size+PREFIX_SIZE;
 189 }
 190 #endif
 191
 192 void zfree(void *ptr) {
 193 #ifndef HAVE_MALLOC_SIZE
 194     void *realptr;
 195     size_t oldsize;
 196 #endif
 197
 198     if (ptr == NULL) return;
 199 #ifdef HAVE_MALLOC_SIZE
 200     update_zmalloc_stat_free(zmalloc_size(ptr));
 201     free(ptr);
 202 #else
 203     realptr = (char*)ptr-PREFIX_SIZE;
 204     oldsize = *((size_t*)realptr);
 205     update_zmalloc_stat_free(oldsize+PREFIX_SIZE);
 206     free(realptr);
 207 #endif
 208 }
 209
 210 char *zstrdup(const char *s) {
 211     size_t l = strlen(s)+1;
 212     char *p = zmalloc(l);
 213
 214     memcpy(p,s,l);
 215     return p;
 216 }
 217
 218 size_t zmalloc_used_memory(void) {
 219     size_t um;
 220
 221     if (zmalloc_thread_safe) {
 222 #ifdef HAVE_ATOMIC
 223         um = __sync_add_and_fetch(&used_memory, 0);
 224 #else
 225         pthread_mutex_lock(&used_memory_mutex);
 226         um = used_memory;
 227         pthread_mutex_unlock(&used_memory_mutex);
 228 #endif
 229     }
 230     else {
 231         um = used_memory;
 232     }
 233
 234     return um;
 235 }
 236
 237 void zmalloc_enable_thread_safeness(void) {
 238     zmalloc_thread_safe = 1;
 239 }
 240
 241 void zmalloc_set_oom_handler(void (*oom_handler)(size_t)) {
 242     zmalloc_oom_handler = oom_handler;
 243 }
 244
 245 /* Get the RSS information in an OS-specific way.
 246  *
 247  * WARNING: the function zmalloc_get_rss() is not designed to be fast
 248  * and may not be called in the busy loops where Redis tries to release
 249  * memory expiring or swapping out objects.
 250  *
 251  * For this kind of "fast RSS reporting" usages use instead the
 252  * function RedisEstimateRSS() that is a much faster (and less precise)
 253  * version of the funciton. */
 254
 255 #if defined(HAVE_PROCFS)
 256 #include <unistd.h>
 257 #include <sys/types.h>
 258 #include <sys/stat.h>
 259 #include <fcntl.h>
 260
 261 size_t zmalloc_get_rss(void) {
 262     int page = sysconf(_SC_PAGESIZE);
 263     size_t rss;
 264     char buf[4096];
 265     char filename[256];
 266     int fd, count;
 267     char *p, *x;
 268
 269     snprintf(filename,256,"/proc/%d/stat",getpid());
 270     if ((fd = open(filename,O_RDONLY)) == -1) return 0;
 271     if (read(fd,buf,4096) <= 0) {
 272         close(fd);
 273         return 0;
 274     }
 275     close(fd);
 276
 277     p = buf;
 278     count = 23; /* RSS is the 24th field in /proc/<pid>/stat */
 279     while(p && count--) {
 280         p = strchr(p,' ');
 281         if (p) p++;
 282     }
 283     if (!p) return 0;
 284     x = strchr(p,' ');
 285     if (!x) return 0;
 286     *x = '\0';
 287
 288     rss = strtoll(p,NULL,10);
 289     rss *= page;
 290     return rss;
 291 }
 292 #elif defined(HAVE_TASKINFO)
 293 #include <unistd.h>
 294 #include <stdio.h>
 295 #include <stdlib.h>
 296 #include <sys/types.h>
 297 #include <sys/sysctl.h>
 298 #include <mach/task.h>
 299 #include <mach/mach_init.h>
 300
 301 size_t zmalloc_get_rss(void) {
 302     task_t task = MACH_PORT_NULL;
 303     struct task_basic_info t_info;
 304     mach_msg_type_number_t t_info_count = TASK_BASIC_INFO_COUNT;
 305
 306     if (task_for_pid(current_task(), getpid(), &task) != KERN_SUCCESS)
 307         return 0;
 308     task_info(task, TASK_BASIC_INFO, (task_info_t)&t_info, &t_info_count);
 309
 310     return t_info.resident_size;
 311 }
 312 #else
 313 size_t zmalloc_get_rss(void) {
 314     /* If we can't get the RSS in an OS-specific way for this system just
 315      * return the memory usage we estimated in zmalloc()..
 316      *
 317      * Fragmentation will appear to be always 1 (no fragmentation)
 318      * of course... */
 319     return zmalloc_used_memory();
 320 }
 321 #endif
 322
 323 /* Fragmentation = RSS / allocated-bytes */
 324 float zmalloc_get_fragmentation_ratio(void) {
 325     return (float)zmalloc_get_rss()/zmalloc_used_memory();
 326 }