text: /* zmalloc - total amount of allocated memory aware version of malloc()
   *
   * Copyright (c) 2009-2010, Salvatore Sanfilippo <antirez at gmail dot com>
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   *   * Redistributions of source code must retain the above copyright notice,
   *     this list of conditions and the following disclaimer.
   *   * Redistributions in binary form must reproduce the above copyright
   *     notice, this list of conditions and the following disclaimer in the
   *     documentation and/or other materials provided with the distribution.
   *   * Neither the name of Redis nor the names of its contributors may be used
   *     to endorse or promote products derived from this software without
   *     specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  #ifdef _WIN32
  #include "win32_Interop/win32_util.h"
  #include "win32_Interop/win32_types.h"
  #endif
  
  #include <stdio.h>
  #include <stdlib.h>
  
  /* This function provide us access to the original libc free(). This is useful
   * for instance to free results obtained by backtrace_symbols(). We need
   * to define this function before including zmalloc.h that may shadow the
   * free implementation if we use jemalloc or another non standard allocator. */
  void zlibc_free(void *ptr) {
      free(ptr);
  }
  
  #include <string.h>
  #ifdef _WIN32
  #include "win32_Interop/win32fixes.h"
  #else
  #include <pthread.h>
  #endif
  #include "config.h"
  #include "zmalloc.h"
  
  #ifdef HAVE_MALLOC_SIZE
  #define PREFIX_SIZE (0)
  #else
  #if defined(__sun) || defined(__sparc) || defined(__sparc__)
  #define PREFIX_SIZE (sizeof(PORT_LONGLONG))
  #else
  #define PREFIX_SIZE (sizeof(size_t))
  #endif
  #endif
  
  /* Explicitly override malloc/free etc when using tcmalloc. */
  #if defined(USE_TCMALLOC)
  #define malloc(size) tc_malloc(size)
  #define calloc(count,size) tc_calloc(count,size)
  #define realloc(ptr,size) tc_realloc(ptr,size)
  #define free(ptr) tc_free(ptr)
  #elif defined(USE_JEMALLOC)
  #define malloc(size) je_malloc(size)
  #define calloc(count,size) je_calloc(count,size)
  #define realloc(ptr,size) je_realloc(ptr,size)
  #define free(ptr) je_free(ptr)
  #elif defined(USE_DLMALLOC)
  #define malloc(size) g_malloc(size)
  #define calloc(count,size) g_calloc(count,size)
  #define realloc(ptr,size) g_realloc(ptr,size)
  #define free(ptr) g_free(ptr)
  #endif
  
  #if defined(__ATOMIC_RELAXED)
  #define update_zmalloc_stat_add(__n) __atomic_add_fetch(&used_memory, (__n), __ATOMIC_RELAXED)
  #define update_zmalloc_stat_sub(__n) __atomic_sub_fetch(&used_memory, (__n), __ATOMIC_RELAXED)
  #elif defined(HAVE_ATOMIC)
  #define update_zmalloc_stat_add(__n) __sync_add_and_fetch(&used_memory, (__n))
  #define update_zmalloc_stat_sub(__n) __sync_sub_and_fetch(&used_memory, (__n))
  #else
  #define update_zmalloc_stat_add(__n) do { \
      pthread_mutex_lock(&used_memory_mutex); \
      used_memory += (__n); \
      pthread_mutex_unlock(&used_memory_mutex); \
  } while(0)
  
  #define update_zmalloc_stat_sub(__n) do { \
      pthread_mutex_lock(&used_memory_mutex); \
      used_memory -= (__n); \
      pthread_mutex_unlock(&used_memory_mutex); \
  } while(0)
  
  #endif
  
  #define update_zmalloc_stat_alloc(__n) do { \
      size_t _n = (__n); \
      if (_n&(sizeof(PORT_LONG)-1)) _n += sizeof(PORT_LONG)-(_n&(sizeof(PORT_LONG)-1)); \
      if (zmalloc_thread_safe) { \
          update_zmalloc_stat_add(_n); \
      } else { \
          used_memory += _n; \
      } \
  } while(0)
  
  #define update_zmalloc_stat_free(__n) do { \
      size_t _n = (__n); \
      if (_n&(sizeof(PORT_LONG)-1)) _n += sizeof(PORT_LONG)-(_n&(sizeof(PORT_LONG)-1)); \
      if (zmalloc_thread_safe) { \
          update_zmalloc_stat_sub(_n); \
      } else { \
          used_memory -= _n; \
      } \
  } while(0)
  
  static size_t used_memory = 0;
  static int zmalloc_thread_safe = 0;
  #ifdef _WIN32
  pthread_mutex_t used_memory_mutex;
  #else
  pthread_mutex_t used_memory_mutex = PTHREAD_MUTEX_INITIALIZER;
  #endif
  
  static void zmalloc_default_oom(size_t size) {
      fprintf(stderr, "zmalloc: Out of memory trying to allocate %Iu bytes\n",    WIN_PORT_FIX /* %zu -> %Iu */
          size);
      fflush(stderr);
      abort();
  }
  
  static void (*zmalloc_oom_handler)(size_t) = zmalloc_default_oom;
  
  void *zmalloc(size_t size) {
      void *ptr = malloc(size+PREFIX_SIZE);
  
      if (!ptr) zmalloc_oom_handler(size);
  #ifdef HAVE_MALLOC_SIZE
      update_zmalloc_stat_alloc(zmalloc_size(ptr));
      return ptr;
  #else
      *((size_t*)ptr) = size;
      update_zmalloc_stat_alloc(size+PREFIX_SIZE);
      return (char*)ptr+PREFIX_SIZE;
  #endif
  }
  
  void *zcalloc(size_t size) {
      void *ptr = calloc(1, size+PREFIX_SIZE);
  
      if (!ptr) zmalloc_oom_handler(size);
  #ifdef HAVE_MALLOC_SIZE
      update_zmalloc_stat_alloc(zmalloc_size(ptr));
      return ptr;
  #else
      *((size_t*)ptr) = size;
      update_zmalloc_stat_alloc(size+PREFIX_SIZE);
      return (char*)ptr+PREFIX_SIZE;
  #endif
  }
  
  void *zrealloc(void *ptr, size_t size) {
  #ifndef HAVE_MALLOC_SIZE
      void *realptr;
  #endif
      size_t oldsize;
      void *newptr;
  
      if (ptr == NULL) return zmalloc(size);
  #ifdef HAVE_MALLOC_SIZE
      oldsize = zmalloc_size(ptr);
      newptr = realloc(ptr,size);
      if (!newptr) zmalloc_oom_handler(size);
  
      update_zmalloc_stat_free(oldsize);
      update_zmalloc_stat_alloc(zmalloc_size(newptr));
      return newptr;
  #else
      realptr = (char*)ptr-PREFIX_SIZE;
      oldsize = *((size_t*)realptr);
      newptr = realloc(realptr,size+PREFIX_SIZE);
      if (!newptr) zmalloc_oom_handler(size);
  
      *((size_t*)newptr) = size;
      update_zmalloc_stat_free(oldsize);
      update_zmalloc_stat_alloc(size);
      return (char*)newptr+PREFIX_SIZE;
  #endif
  }
  
  /* Provide zmalloc_size() for systems where this function is not provided by
   * malloc itself, given that in that case we store a header with this
   * information as the first bytes of every allocation. */
  #ifndef HAVE_MALLOC_SIZE
  size_t zmalloc_size(void *ptr) {
      void *realptr = (char*)ptr-PREFIX_SIZE;
      size_t size = *((size_t*)realptr);
      /* Assume at least that all the allocations are padded at sizeof(PORT_LONG) by
       * the underlying allocator. */
      if (size&(sizeof(PORT_LONG)-1)) size += sizeof(PORT_LONG)-(size&(sizeof(PORT_LONG)-1));
      return size+PREFIX_SIZE;
  }
  #endif
  
  void zfree(void *ptr) {
  #ifndef HAVE_MALLOC_SIZE
      void *realptr;
      size_t oldsize;
  #endif
  
      if (ptr == NULL) return;
  #ifdef HAVE_MALLOC_SIZE
      update_zmalloc_stat_free(zmalloc_size(ptr));
      free(ptr);
  #else
      realptr = (char*)ptr-PREFIX_SIZE;
      oldsize = *((size_t*)realptr);
      update_zmalloc_stat_free(oldsize+PREFIX_SIZE);
      free(realptr);
  #endif
  }
  
  char *zstrdup(const char *s) {
      size_t l = strlen(s)+1;
      char *p = zmalloc(l);
  
      memcpy(p,s,l);
      return p;
  }
  
  size_t zmalloc_used_memory(void) {
      size_t um;
  
      if (zmalloc_thread_safe) {
  #if defined(__ATOMIC_RELAXED) || defined(HAVE_ATOMIC)
          um = update_zmalloc_stat_add(0);
  #else
          pthread_mutex_lock(&used_memory_mutex);
          um = used_memory;
          pthread_mutex_unlock(&used_memory_mutex);
  #endif
      }
      else {
          um = used_memory;
      }
  
      return um;
  }
  
  #ifdef _WIN32
  void zmalloc_free_used_memory_mutex(void) {
      /* Windows fix: Callabe mutex destroy.  */
      if (zmalloc_thread_safe)
          pthread_mutex_destroy(&used_memory_mutex);
  }
  void zmalloc_enable_thread_safeness(void) {
      if (!zmalloc_thread_safe)
          pthread_mutex_init(&used_memory_mutex,0);
  
      zmalloc_thread_safe = 1;
  }
  #else
  void zmalloc_enable_thread_safeness(void) {
      zmalloc_thread_safe = 1;
  }
  #endif
  
  void zmalloc_set_oom_handler(void (*oom_handler)(size_t)) {
      zmalloc_oom_handler = oom_handler;
  }
  
  /* Get the RSS information in an OS-specific way.
   *
   * WARNING: the function zmalloc_get_rss() is not designed to be fast
   * and may not be called in the busy loops where Redis tries to release
   * memory expiring or swapping out objects.
   *
   * For this kind of "fast RSS reporting" usages use instead the
   * function RedisEstimateRSS() that is a much faster (and less precise)
   * version of the function. */
  
  #if defined(HAVE_PROC_STAT)
  #include <unistd.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  
  size_t zmalloc_get_rss(void) {
      int page = sysconf(_SC_PAGESIZE);
      size_t rss;
      char buf[4096];
      char filename[256];
      int fd, count;
      char *p, *x;
  
      snprintf(filename,256,"/proc/%d/stat",getpid());
      if ((fd = open(filename,O_RDONLY)) == -1) return 0;
      if (read(fd,buf,4096) <= 0) {
          close(fd);
          return 0;
      }
      close(fd);
  
      p = buf;
      count = 23; /* RSS is the 24th field in /proc/<pid>/stat */
      while(p && count--) {
          p = strchr(p,' ');
          if (p) p++;
      }
      if (!p) return 0;
      x = strchr(p,' ');
      if (!x) return 0;
      *x = '\0';
  
      rss = strtoll(p,NULL,10);
      rss *= page;
      return rss;
  }
  #elif defined(HAVE_TASKINFO)
  #include <unistd.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <sys/types.h>
  #include <sys/sysctl.h>
  #include <mach/task.h>
  #include <mach/mach_init.h>
  
  size_t zmalloc_get_rss(void) {
      task_t task = MACH_PORT_NULL;
      struct task_basic_info t_info;
      mach_msg_type_number_t t_info_count = TASK_BASIC_INFO_COUNT;
  
      if (task_for_pid(current_task(), getpid(), &task) != KERN_SUCCESS)
          return 0;
      task_info(task, TASK_BASIC_INFO, (task_info_t)&t_info, &t_info_count);
  
      return t_info.resident_size;
  }
  #else
  size_t zmalloc_get_rss(void) {
      /* If we can't get the RSS in an OS-specific way for this system just
       * return the memory usage we estimated in zmalloc()..
       *
       * Fragmentation will appear to be always 1 (no fragmentation)
       * of course... */
      return zmalloc_used_memory();
  }
  #endif
  
  /* Fragmentation = RSS / allocated-bytes */
  float zmalloc_get_fragmentation_ratio(size_t rss) {
      return (float)rss/zmalloc_used_memory();
  }
  
  /* Get the sum of the specified field (converted form kb to bytes) in
   * /proc/self/smaps. The field must be specified with trailing ":" as it
   * apperas in the smaps output.
   *
   * Example: zmalloc_get_smap_bytes_by_field("Rss:");
   */
  #if defined(HAVE_PROC_SMAPS)
  size_t zmalloc_get_smap_bytes_by_field(char *field) {
      char line[1024];
      size_t bytes = 0;
      FILE *fp = fopen("/proc/self/smaps","r");
      int flen = strlen(field);
  
      if (!fp) return 0;
      while(fgets(line,sizeof(line),fp) != NULL) {
          if (strncmp(line,field,flen) == 0) {
              char *p = strchr(line,'k');
              if (p) {
                  *p = '\0';
                  bytes += strtol(line+flen,NULL,10) * 1024;
              }
          }
      }
      fclose(fp);
      return bytes;
  }
  #else
  size_t zmalloc_get_smap_bytes_by_field(char *field) {
      ((void) field);
      return 0;
  }
  #endif
  
  size_t zmalloc_get_private_dirty(void) {
      return zmalloc_get_smap_bytes_by_field("Private_Dirty:");
  }
  