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.
   */
  
  #include "fmacros.h"
  #include "config.h"
  #include "solarisfixes.h"
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <stdint.h>
  #include <unistd.h>
  #include <assert.h>
  
  #ifdef __linux__
  #include <sys/mman.h>
  #endif
  
  /* 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>
  #include <pthread.h>
  #include "zmalloc.h"
  #include "atomicvar.h"
  
  #ifdef HAVE_MALLOC_SIZE
  #define PREFIX_SIZE (0)
  #define ASSERT_NO_SIZE_OVERFLOW(sz)
  #else
  #if defined(__sun) || defined(__sparc) || defined(__sparc__)
  #define PREFIX_SIZE (sizeof(long long))
  #else
  #define PREFIX_SIZE (sizeof(size_t))
  #endif
  #define ASSERT_NO_SIZE_OVERFLOW(sz) assert((sz) + PREFIX_SIZE > (sz))
  #endif
  
  /* When using the libc allocator, use a minimum allocation size to match the
   * jemalloc behavior that doesn't return NULL in this case.
   */
  #define MALLOC_MIN_SIZE(x) ((x) > 0 ? (x) : sizeof(long))
  
  /* 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)
  #define mallocx(size,flags) je_mallocx(size,flags)
  #define dallocx(ptr,flags) je_dallocx(ptr,flags)
  #endif
  
  #define update_zmalloc_stat_alloc(__n) atomicIncr(used_memory,(__n))
  #define update_zmalloc_stat_free(__n) atomicDecr(used_memory,(__n))
  
  static redisAtomic size_t used_memory = 0;
  
  static void zmalloc_default_oom(size_t size) {
      fprintf(stderr, "zmalloc: Out of memory trying to allocate %zu bytes\n",
          size);
      fflush(stderr);
      abort();
  }
  
  static void (*zmalloc_oom_handler)(size_t) = zmalloc_default_oom;
  
  /* Try allocating memory, and return NULL if failed.
   * '*usable' is set to the usable size if non NULL. */
  void *ztrymalloc_usable(size_t size, size_t *usable) {
      ASSERT_NO_SIZE_OVERFLOW(size);
      void *ptr = malloc(MALLOC_MIN_SIZE(size)+PREFIX_SIZE);
  
      if (!ptr) return NULL;
  #ifdef HAVE_MALLOC_SIZE
      size = zmalloc_size(ptr);
      update_zmalloc_stat_alloc(size);
      if (usable) *usable = size;
      return ptr;
  #else
      *((size_t*)ptr) = size;
      update_zmalloc_stat_alloc(size+PREFIX_SIZE);
      if (usable) *usable = size;
      return (char*)ptr+PREFIX_SIZE;
  #endif
  }
  
  /* Allocate memory or panic */
  void *zmalloc(size_t size) {
      void *ptr = ztrymalloc_usable(size, NULL);
      if (!ptr) zmalloc_oom_handler(size);
      return ptr;
  }
  
  /* Try allocating memory, and return NULL if failed. */
  void *ztrymalloc(size_t size) {
      void *ptr = ztrymalloc_usable(size, NULL);
      return ptr;
  }
  
  /* Allocate memory or panic.
   * '*usable' is set to the usable size if non NULL. */
  void *zmalloc_usable(size_t size, size_t *usable) {
      void *ptr = ztrymalloc_usable(size, usable);
      if (!ptr) zmalloc_oom_handler(size);
      return ptr;
  }
  
  /* Allocation and free functions that bypass the thread cache
   * and go straight to the allocator arena bins.
   * Currently implemented only for jemalloc. Used for online defragmentation. */
  #ifdef HAVE_DEFRAG
  void *zmalloc_no_tcache(size_t size) {
      ASSERT_NO_SIZE_OVERFLOW(size);
      void *ptr = mallocx(size+PREFIX_SIZE, MALLOCX_TCACHE_NONE);
      if (!ptr) zmalloc_oom_handler(size);
      update_zmalloc_stat_alloc(zmalloc_size(ptr));
      return ptr;
  }
  
  void zfree_no_tcache(void *ptr) {
      if (ptr == NULL) return;
      update_zmalloc_stat_free(zmalloc_size(ptr));
      dallocx(ptr, MALLOCX_TCACHE_NONE);
  }
  #endif
  
  /* Try allocating memory and zero it, and return NULL if failed.
   * '*usable' is set to the usable size if non NULL. */
  void *ztrycalloc_usable(size_t size, size_t *usable) {
      ASSERT_NO_SIZE_OVERFLOW(size);
      void *ptr = calloc(1, MALLOC_MIN_SIZE(size)+PREFIX_SIZE);
      if (ptr == NULL) return NULL;
  
  #ifdef HAVE_MALLOC_SIZE
      size = zmalloc_size(ptr);
      update_zmalloc_stat_alloc(size);
      if (usable) *usable = size;
      return ptr;
  #else
      *((size_t*)ptr) = size;
      update_zmalloc_stat_alloc(size+PREFIX_SIZE);
      if (usable) *usable = size;
      return (char*)ptr+PREFIX_SIZE;
  #endif
  }
  
  /* Allocate memory and zero it or panic.
   * We need this wrapper to have a calloc compatible signature */
  void *zcalloc_num(size_t num, size_t size) {
      /* Ensure that the arguments to calloc(), when multiplied, do not wrap.
       * Division operations are susceptible to divide-by-zero errors so we also check it. */
      if ((size == 0) || (num > SIZE_MAX/size)) {
          zmalloc_oom_handler(SIZE_MAX);
          return NULL;
      }
      void *ptr = ztrycalloc_usable(num*size, NULL);
      if (!ptr) zmalloc_oom_handler(num*size);
      return ptr;
  }
  
  /* Allocate memory and zero it or panic */
  void *zcalloc(size_t size) {
      void *ptr = ztrycalloc_usable(size, NULL);
      if (!ptr) zmalloc_oom_handler(size);
      return ptr;
  }
  
  /* Try allocating memory, and return NULL if failed. */
  void *ztrycalloc(size_t size) {
      void *ptr = ztrycalloc_usable(size, NULL);
      return ptr;
  }
  
  /* Allocate memory or panic.
   * '*usable' is set to the usable size if non NULL. */
  void *zcalloc_usable(size_t size, size_t *usable) {
      void *ptr = ztrycalloc_usable(size, usable);
      if (!ptr) zmalloc_oom_handler(size);
      return ptr;
  }
  
  /* Try reallocating memory, and return NULL if failed.
   * '*usable' is set to the usable size if non NULL. */
  void *ztryrealloc_usable(void *ptr, size_t size, size_t *usable) {
      ASSERT_NO_SIZE_OVERFLOW(size);
  #ifndef HAVE_MALLOC_SIZE
      void *realptr;
  #endif
      size_t oldsize;
      void *newptr;
  
      /* not allocating anything, just redirect to free. */
      if (size == 0 && ptr != NULL) {
          zfree(ptr);
          if (usable) *usable = 0;
          return NULL;
      }
      /* Not freeing anything, just redirect to malloc. */
      if (ptr == NULL)
          return ztrymalloc_usable(size, usable);
  
  #ifdef HAVE_MALLOC_SIZE
      oldsize = zmalloc_size(ptr);
      newptr = realloc(ptr,size);
      if (newptr == NULL) {
          if (usable) *usable = 0;
          return NULL;
      }
  
      update_zmalloc_stat_free(oldsize);
      size = zmalloc_size(newptr);
      update_zmalloc_stat_alloc(size);
      if (usable) *usable = size;
      return newptr;
  #else
      realptr = (char*)ptr-PREFIX_SIZE;
      oldsize = *((size_t*)realptr);
      newptr = realloc(realptr,size+PREFIX_SIZE);
      if (newptr == NULL) {
          if (usable) *usable = 0;
          return NULL;
      }
  
      *((size_t*)newptr) = size;
      update_zmalloc_stat_free(oldsize);
      update_zmalloc_stat_alloc(size);
      if (usable) *usable = size;
      return (char*)newptr+PREFIX_SIZE;
  #endif
  }
  
  /* Reallocate memory and zero it or panic */
  void *zrealloc(void *ptr, size_t size) {
      ptr = ztryrealloc_usable(ptr, size, NULL);
      if (!ptr && size != 0) zmalloc_oom_handler(size);
      return ptr;
  }
  
  /* Try Reallocating memory, and return NULL if failed. */
  void *ztryrealloc(void *ptr, size_t size) {
      ptr = ztryrealloc_usable(ptr, size, NULL);
      return ptr;
  }
  
  /* Reallocate memory or panic.
   * '*usable' is set to the usable size if non NULL. */
  void *zrealloc_usable(void *ptr, size_t size, size_t *usable) {
      ptr = ztryrealloc_usable(ptr, size, usable);
      if (!ptr && size != 0) zmalloc_oom_handler(size);
      return ptr;
  }
  
  /* 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);
      return size+PREFIX_SIZE;
  }
  size_t zmalloc_usable_size(void *ptr) {
      return zmalloc_size(ptr)-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
  }
  
  /* Similar to zfree, '*usable' is set to the usable size being freed. */
  void zfree_usable(void *ptr, size_t *usable) {
  #ifndef HAVE_MALLOC_SIZE
      void *realptr;
      size_t oldsize;
  #endif
  
      if (ptr == NULL) return;
  #ifdef HAVE_MALLOC_SIZE
      update_zmalloc_stat_free(*usable = zmalloc_size(ptr));
      free(ptr);
  #else
      realptr = (char*)ptr-PREFIX_SIZE;
      *usable = 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;
      atomicGet(used_memory,um);
      return um;
  }
  
  void zmalloc_set_oom_handler(void (*oom_handler)(size_t)) {
      zmalloc_oom_handler = oom_handler;
  }
  
  /* Use 'MADV_DONTNEED' to release memory to operating system quickly.
   * We do that in a fork child process to avoid CoW when the parent modifies
   * these shared pages. */
  void zmadvise_dontneed(void *ptr) {
  #if defined(USE_JEMALLOC) && defined(__linux__)
      static size_t page_size = 0;
      if (page_size == 0) page_size = sysconf(_SC_PAGESIZE);
      size_t page_size_mask = page_size - 1;
  
      size_t real_size = zmalloc_size(ptr);
      if (real_size < page_size) return;
  
      /* We need to align the pointer upwards according to page size, because
       * the memory address is increased upwards and we only can free memory
       * based on page. */
      char *aligned_ptr = (char *)(((size_t)ptr+page_size_mask) & ~page_size_mask);
      real_size -= (aligned_ptr-(char*)ptr);
      if (real_size >= page_size) {
          madvise((void *)aligned_ptr, real_size&~page_size_mask, MADV_DONTNEED);
      }
  #else
      (void)(ptr);
  #endif
  }
  
  /* 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 <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/%ld/stat",(long) 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 <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;
  }
  #elif defined(__FreeBSD__) || defined(__DragonFly__)
  #include <sys/types.h>
  #include <sys/sysctl.h>
  #include <sys/user.h>
  
  size_t zmalloc_get_rss(void) {
      struct kinfo_proc info;
      size_t infolen = sizeof(info);
      int mib[4];
      mib[0] = CTL_KERN;
      mib[1] = KERN_PROC;
      mib[2] = KERN_PROC_PID;
      mib[3] = getpid();
  
      if (sysctl(mib, 4, &info, &infolen, NULL, 0) == 0)
  #if defined(__FreeBSD__)
          return (size_t)info.ki_rssize * getpagesize();
  #else
          return (size_t)info.kp_vm_rssize * getpagesize();
  #endif
  
      return 0L;
  }
  #elif defined(__NetBSD__) || defined(__OpenBSD__)
  #include <sys/types.h>
  #include <sys/sysctl.h>
  
  #if defined(__OpenBSD__)
  #define kinfo_proc2 kinfo_proc
  #define KERN_PROC2 KERN_PROC
  #define __arraycount(a) (sizeof(a) / sizeof(a[0]))
  #endif
  
  size_t zmalloc_get_rss(void) {
      struct kinfo_proc2 info;
      size_t infolen = sizeof(info);
      int mib[6];
      mib[0] = CTL_KERN;
      mib[1] = KERN_PROC2;
      mib[2] = KERN_PROC_PID;
      mib[3] = getpid();
      mib[4] = sizeof(info);
      mib[5] = 1;
      if (sysctl(mib, __arraycount(mib), &info, &infolen, NULL, 0) == 0)
          return (size_t)info.p_vm_rssize * getpagesize();
  
      return 0L;
  }
  #elif defined(__HAIKU__)
  #include <OS.h>
  
  size_t zmalloc_get_rss(void) {
      area_info info;
      thread_info th;
      size_t rss = 0;
      ssize_t cookie = 0;
  
      if (get_thread_info(find_thread(0), &th) != B_OK)
          return 0;
  
      while (get_next_area_info(th.team, &cookie, &info) == B_OK)
          rss += info.ram_size;
  
      return rss;
  }
  #elif defined(HAVE_PSINFO)
  #include <unistd.h>
  #include <sys/procfs.h>
  #include <fcntl.h>
  
  size_t zmalloc_get_rss(void) {
      struct prpsinfo info;
      char filename[256];
      int fd;
  
      snprintf(filename,256,"/proc/%ld/psinfo",(long) getpid());
  
      if ((fd = open(filename,O_RDONLY)) == -1) return 0;
      if (ioctl(fd, PIOCPSINFO, &info) == -1) {
          close(fd);
  	return 0;
      }
  
      close(fd);
      return info.pr_rssize;
  }
  #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
  
  #if defined(USE_JEMALLOC)
  
  int zmalloc_get_allocator_info(size_t *allocated,
                                 size_t *active,
                                 size_t *resident) {
      uint64_t epoch = 1;
      size_t sz;
      *allocated = *resident = *active = 0;
      /* Update the statistics cached by mallctl. */
      sz = sizeof(epoch);
      je_mallctl("epoch", &epoch, &sz, &epoch, sz);
      sz = sizeof(size_t);
      /* Unlike RSS, this does not include RSS from shared libraries and other non
       * heap mappings. */
      je_mallctl("stats.resident", resident, &sz, NULL, 0);
      /* Unlike resident, this doesn't not include the pages jemalloc reserves
       * for re-use (purge will clean that). */
      je_mallctl("stats.active", active, &sz, NULL, 0);
      /* Unlike zmalloc_used_memory, this matches the stats.resident by taking
       * into account all allocations done by this process (not only zmalloc). */
      je_mallctl("stats.allocated", allocated, &sz, NULL, 0);
      return 1;
  }
  
  void set_jemalloc_bg_thread(int enable) {
      /* let jemalloc do purging asynchronously, required when there's no traffic 
       * after flushdb */
      char val = !!enable;
      je_mallctl("background_thread", NULL, 0, &val, 1);
  }
  
  int jemalloc_purge() {
      /* return all unused (reserved) pages to the OS */
      char tmp[32];
      unsigned narenas = 0;
      size_t sz = sizeof(unsigned);
      if (!je_mallctl("arenas.narenas", &narenas, &sz, NULL, 0)) {
          sprintf(tmp, "arena.%d.purge", narenas);
          if (!je_mallctl(tmp, NULL, 0, NULL, 0))
              return 0;
      }
      return -1;
  }
  
  #else
  
  int zmalloc_get_allocator_info(size_t *allocated,
                                 size_t *active,
                                 size_t *resident) {
      *allocated = *resident = *active = 0;
      return 1;
  }
  
  void set_jemalloc_bg_thread(int enable) {
      ((void)(enable));
  }
  
  int jemalloc_purge() {
      return 0;
  }
  
  #endif
  
  #if defined(__APPLE__)
  /* For proc_pidinfo() used later in zmalloc_get_smap_bytes_by_field().
   * Note that this file cannot be included in zmalloc.h because it includes
   * a Darwin queue.h file where there is a "LIST_HEAD" macro (!) defined
   * conficting with Redis user code. */
  #include <libproc.h>
  #endif
  
  /* 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.
   *
   * If a pid is specified, the information is extracted for such a pid,
   * otherwise if pid is -1 the information is reported is about the
   * current process.
   *
   * Example: zmalloc_get_smap_bytes_by_field("Rss:",-1);
   */
  #if defined(HAVE_PROC_SMAPS)
  size_t zmalloc_get_smap_bytes_by_field(char *field, long pid) {
      char line[1024];
      size_t bytes = 0;
      int flen = strlen(field);
      FILE *fp;
  
      if (pid == -1) {
          fp = fopen("/proc/self/smaps","r");
      } else {
          char filename[128];
          snprintf(filename,sizeof(filename),"/proc/%ld/smaps",pid);
          fp = fopen(filename,"r");
      }
  
      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
  /* Get sum of the specified field from libproc api call.
   * As there are per page value basis we need to convert
   * them accordingly.
   *
   * Note that AnonHugePages is a no-op as THP feature
   * is not supported in this platform
   */
  size_t zmalloc_get_smap_bytes_by_field(char *field, long pid) {
  #if defined(__APPLE__)
      struct proc_regioninfo pri;
      if (pid == -1) pid = getpid();
      if (proc_pidinfo(pid, PROC_PIDREGIONINFO, 0, &pri,
                       PROC_PIDREGIONINFO_SIZE) == PROC_PIDREGIONINFO_SIZE)
      {
          int pagesize = getpagesize();
          if (!strcmp(field, "Private_Dirty:")) {
              return (size_t)pri.pri_pages_dirtied * pagesize;
          } else if (!strcmp(field, "Rss:")) {
              return (size_t)pri.pri_pages_resident * pagesize;
          } else if (!strcmp(field, "AnonHugePages:")) {
              return 0;
          }
      }
      return 0;
  #endif
      ((void) field);
      ((void) pid);
      return 0;
  }
  #endif
  
  /* Return the total number bytes in pages marked as Private Dirty.
   *
   * Note: depending on the platform and memory footprint of the process, this
   * call can be slow, exceeding 1000ms!
   */
  size_t zmalloc_get_private_dirty(long pid) {
      return zmalloc_get_smap_bytes_by_field("Private_Dirty:",pid);
  }
  
  /* Returns the size of physical memory (RAM) in bytes.
   * It looks ugly, but this is the cleanest way to achieve cross platform results.
   * Cleaned up from:
   *
   * http://nadeausoftware.com/articles/2012/09/c_c_tip_how_get_physical_memory_size_system
   *
   * Note that this function:
   * 1) Was released under the following CC attribution license:
   *    http://creativecommons.org/licenses/by/3.0/deed.en_US.
   * 2) Was originally implemented by David Robert Nadeau.
   * 3) Was modified for Redis by Matt Stancliff.
   * 4) This note exists in order to comply with the original license.
   */
  size_t zmalloc_get_memory_size(void) {
  #if defined(__unix__) || defined(__unix) || defined(unix) || \
      (defined(__APPLE__) && defined(__MACH__))
  #if defined(CTL_HW) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM64))
      int mib[2];
      mib[0] = CTL_HW;
  #if defined(HW_MEMSIZE)
      mib[1] = HW_MEMSIZE;            /* OSX. --------------------- */
  #elif defined(HW_PHYSMEM64)
      mib[1] = HW_PHYSMEM64;          /* NetBSD, OpenBSD. --------- */
  #endif
      int64_t size = 0;               /* 64-bit */
      size_t len = sizeof(size);
      if (sysctl( mib, 2, &size, &len, NULL, 0) == 0)
          return (size_t)size;
      return 0L;          /* Failed? */
  
  #elif defined(_SC_PHYS_PAGES) && defined(_SC_PAGESIZE)
      /* FreeBSD, Linux, OpenBSD, and Solaris. -------------------- */
      return (size_t)sysconf(_SC_PHYS_PAGES) * (size_t)sysconf(_SC_PAGESIZE);
  
  #elif defined(CTL_HW) && (defined(HW_PHYSMEM) || defined(HW_REALMEM))
      /* DragonFly BSD, FreeBSD, NetBSD, OpenBSD, and OSX. -------- */
      int mib[2];
      mib[0] = CTL_HW;
  #if defined(HW_REALMEM)
      mib[1] = HW_REALMEM;        /* FreeBSD. ----------------- */
  #elif defined(HW_PHYSMEM)
      mib[1] = HW_PHYSMEM;        /* Others. ------------------ */
  #endif
      unsigned int size = 0;      /* 32-bit */
      size_t len = sizeof(size);
      if (sysctl(mib, 2, &size, &len, NULL, 0) == 0)
          return (size_t)size;
      return 0L;          /* Failed? */
  #else
      return 0L;          /* Unknown method to get the data. */
  #endif
  #else
      return 0L;          /* Unknown OS. */
  #endif
  }
  
  #ifdef REDIS_TEST
  #define UNUSED(x) ((void)(x))
  int zmalloc_test(int argc, char **argv, int flags) {
      void *ptr;
  
      UNUSED(argc);
      UNUSED(argv);
      UNUSED(flags);
      printf("Malloc prefix size: %d\n", (int) PREFIX_SIZE);
      printf("Initial used memory: %zu\n", zmalloc_used_memory());
      ptr = zmalloc(123);
      printf("Allocated 123 bytes; used: %zu\n", zmalloc_used_memory());
      ptr = zrealloc(ptr, 456);
      printf("Reallocated to 456 bytes; used: %zu\n", zmalloc_used_memory());
      zfree(ptr);
      printf("Freed pointer; used: %zu\n", zmalloc_used_memory());
      return 0;
  }
  #endif
  