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_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 void *zmalloc(size_t size) {
 120     void *ptr = malloc(size+PREFIX_SIZE);
 121
 122     if (!ptr) zmalloc_oom(size);
 123 #ifdef HAVE_MALLOC_SIZE
 124     update_zmalloc_stat_alloc(zmalloc_size(ptr),size);
 125     return ptr;
 126 #else
 127     *((size_t*)ptr) = size;
 128     update_zmalloc_stat_alloc(size+PREFIX_SIZE,size);
 129     return (char*)ptr+PREFIX_SIZE;
 130 #endif
 131 }
 132
 133 void *zcalloc(size_t size) {
 134     void *ptr = calloc(1, size+PREFIX_SIZE);
 135
 136     if (!ptr) zmalloc_oom(size);
 137 #ifdef HAVE_MALLOC_SIZE
 138     update_zmalloc_stat_alloc(zmalloc_size(ptr),size);
 139     return ptr;
 140 #else
 141     *((size_t*)ptr) = size;
 142     update_zmalloc_stat_alloc(size+PREFIX_SIZE,size);
 143     return (char*)ptr+PREFIX_SIZE;
 144 #endif
 145 }
 146
 147 void *zrealloc(void *ptr, size_t size) {
 148 #ifndef HAVE_MALLOC_SIZE
 149     void *realptr;
 150 #endif
 151     size_t oldsize;
 152     void *newptr;
 153
 154     if (ptr == NULL) return zmalloc(size);
 155 #ifdef HAVE_MALLOC_SIZE
 156     oldsize = zmalloc_size(ptr);
 157     newptr = realloc(ptr,size);
 158     if (!newptr) zmalloc_oom(size);
 159
 160     update_zmalloc_stat_free(oldsize);
 161     update_zmalloc_stat_alloc(zmalloc_size(newptr),size);
 162     return newptr;
 163 #else
 164     realptr = (char*)ptr-PREFIX_SIZE;
 165     oldsize = *((size_t*)realptr);
 166     newptr = realloc(realptr,size+PREFIX_SIZE);
 167     if (!newptr) zmalloc_oom(size);
 168
 169     *((size_t*)newptr) = size;
 170     update_zmalloc_stat_free(oldsize);
 171     update_zmalloc_stat_alloc(size,size);
 172     return (char*)newptr+PREFIX_SIZE;
 173 #endif
 174 }
 175
 176 /* Provide zmalloc_size() for systems where this function is not provided by
 177  * malloc itself, given that in that case we store an header with this
 178  * information as the first bytes of every allocation. */
 179 #ifndef HAVE_MALLOC_SIZE
 180 size_t zmalloc_size(void *ptr) {
 181     void *realptr = (char*)ptr-PREFIX_SIZE;
 182     size_t size = *((size_t*)realptr);
 183     /* Assume at least that all the allocations are padded at sizeof(long) by
 184      * the underlying allocator. */
 185     if (size&(sizeof(long)-1)) size += sizeof(long)-(size&(sizeof(long)-1));
 186     return size+PREFIX_SIZE;
 187 }
 188 #endif
 189
 190 void zfree(void *ptr) {
 191 #ifndef HAVE_MALLOC_SIZE
 192     void *realptr;
 193     size_t oldsize;
 194 #endif
 195
 196     if (ptr == NULL) return;
 197 #ifdef HAVE_MALLOC_SIZE
 198     update_zmalloc_stat_free(zmalloc_size(ptr));
 199     free(ptr);
 200 #else
 201     realptr = (char*)ptr-PREFIX_SIZE;
 202     oldsize = *((size_t*)realptr);
 203     update_zmalloc_stat_free(oldsize+PREFIX_SIZE);
 204     free(realptr);
 205 #endif
 206 }
 207
 208 char *zstrdup(const char *s) {
 209     size_t l = strlen(s)+1;
 210     char *p = zmalloc(l);
 211
 212     memcpy(p,s,l);
 213     return p;
 214 }
 215
 216 size_t zmalloc_used_memory(void) {
 217     size_t um;
 218
 219     if (zmalloc_thread_safe) {
 220 #ifdef HAVE_ATOMIC
 221         um = __sync_add_and_fetch(&used_memory, 0);
 222 #else
 223         pthread_mutex_lock(&used_memory_mutex);
 224         um = used_memory;
 225         pthread_mutex_unlock(&used_memory_mutex);
 226 #endif
 227     }
 228     else {
 229         um = used_memory;
 230     }
 231
 232     return um;
 233 }
 234
 235 void zmalloc_enable_thread_safeness(void) {
 236     zmalloc_thread_safe = 1;
 237 }
 238
 239 /* Get the RSS information in an OS-specific way.
 240  *
 241  * WARNING: the function zmalloc_get_rss() is not designed to be fast
 242  * and may not be called in the busy loops where Redis tries to release
 243  * memory expiring or swapping out objects.
 244  *
 245  * For this kind of "fast RSS reporting" usages use instead the
 246  * function RedisEstimateRSS() that is a much faster (and less precise)
 247  * version of the funciton. */
 248
 249 #if defined(HAVE_PROCFS)
 250 #include <unistd.h>
 251 #include <sys/types.h>
 252 #include <sys/stat.h>
 253 #include <fcntl.h>
 254
 255 size_t zmalloc_get_rss(void) {
 256     int page = sysconf(_SC_PAGESIZE);
 257     size_t rss;
 258     char buf[4096];
 259     char filename[256];
 260     int fd, count;
 261     char *p, *x;
 262
 263     snprintf(filename,256,"/proc/%d/stat",getpid());
 264     if ((fd = open(filename,O_RDONLY)) == -1) return 0;
 265     if (read(fd,buf,4096) <= 0) {
 266         close(fd);
 267         return 0;
 268     }
 269     close(fd);
 270
 271     p = buf;
 272     count = 23; /* RSS is the 24th field in /proc/<pid>/stat */
 273     while(p && count--) {
 274         p = strchr(p,' ');
 275         if (p) p++;
 276     }
 277     if (!p) return 0;
 278     x = strchr(p,' ');
 279     if (!x) return 0;
 280     *x = '\0';
 281
 282     rss = strtoll(p,NULL,10);
 283     rss *= page;
 284     return rss;
 285 }
 286 #elif defined(HAVE_TASKINFO)
 287 #include <unistd.h>
 288 #include <stdio.h>
 289 #include <stdlib.h>
 290 #include <sys/types.h>
 291 #include <sys/sysctl.h>
 292 #include <mach/task.h>
 293 #include <mach/mach_init.h>
 294
 295 size_t zmalloc_get_rss(void) {
 296     task_t task = MACH_PORT_NULL;
 297     struct task_basic_info t_info;
 298     mach_msg_type_number_t t_info_count = TASK_BASIC_INFO_COUNT;
 299
 300     if (task_for_pid(current_task(), getpid(), &task) != KERN_SUCCESS)
 301         return 0;
 302     task_info(task, TASK_BASIC_INFO, (task_info_t)&t_info, &t_info_count);
 303
 304     return t_info.resident_size;
 305 }
 306 #else
 307 size_t zmalloc_get_rss(void) {
 308     /* If we can't get the RSS in an OS-specific way for this system just
 309      * return the memory usage we estimated in zmalloc()..
 310      *
 311      * Fragmentation will appear to be always 1 (no fragmentation)
 312      * of course... */
 313     return zmalloc_used_memory();
 314 }
 315 #endif
 316
 317 /* Fragmentation = RSS / allocated-bytes */
 318 float zmalloc_get_fragmentation_ratio(void) {
 319     return (float)zmalloc_get_rss()/zmalloc_used_memory();
 320 }