Allocation: Low-level

Functions
static void *	_tm_os_alloc_ (long size)
	Allocate memory from the OS.
static void *	_tm_os_free_ (void *ptr, long size)
	Return memory back to the OS.
static __inline void *	_tm_os_alloc (long size)
	Allocate memory from OS.
static __inline void *	_tm_os_free (void *ptr, long size)
	Return block to the OS.
Variables
size_t	tm_os_alloc_total = 0
	Total bytes currently allocated from OS.

---

Function Documentation

static __inline void* _tm_os_alloc

(

long

size

)

[static]

Allocate memory from OS.

• Check soft memory limit.
• Update stats and timers.

Definition at line 125 of file os.c.

References _tm_os_alloc_(), tm_data::n, tm, tm_assert_test, tm_B, tm_msg(), tm_os_alloc_max, tm_os_alloc_total, tm_print_stats(), tm_time_stat_begin(), tm_time_stat_end(), and tm_data::ts_os_alloc.

Referenced by _tm_os_alloc_aligned().

{
  void *ptr;

#if tm_TIME_STAT
  tm_time_stat_begin(&tm.ts_os_alloc);
#endif

  /* Soft memory limit? */
  if ( tm_os_alloc_total + size > tm_os_alloc_max ) {
    ptr = 0;
  } else {
    ptr = _tm_os_alloc_(size);
  }

#if tm_TIME_STAT
  tm_time_stat_end(&tm.ts_os_alloc);
#endif

  if ( ptr == 0 || ptr == (void*) -1L ) {
    ptr = 0;
    tm_msg("A 0 %lu\n", (unsigned long) size);
  } else
  if ( size > 0 ) {
    tm_msg("A a %p[%lu] #%lu\n", ptr, (unsigned long) size, (unsigned long) tm.n[tm_B]);

    tm_os_alloc_total += size;
  } else if ( size < 0 ) {
    tm_assert_test(size > 0);
  }
#if 0 
  else {
    tm_msg("A z\n");
  }
#endif

#if 0
  if ( tm.n[tm_B] > 16 ) {
    tm_print_stats();
  }
#endif

  // fprintf(stderr, "  _tm_os_alloc(%lu) => %p\n", (unsigned long) size, (void*) ptr);
  
  return ptr;
}

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static void* _tm_os_alloc_

(

long

size

)

[static]

Allocate memory from the OS.

• If tm_USE_MMAP is true, use mmap().
• If tm_USE_SBRK is true, use sbrk().

Definition at line 27 of file os.c.

References tm_data::mmap_fd, tm_data::os_alloc_expected, tm_data::os_alloc_last, tm_data::os_alloc_last_size, tm, tm_abort(), tm_assert_test, and tm_warn.

Referenced by _tm_os_alloc().

{
  void *ptr;

  tm_assert_test(size > 0);

#if tm_USE_MMAP
#ifdef MAP_ANONYMOUS
  tm.mmap_fd = -1;
#endif

  ptr = mmap((void*) 0,
             (size_t) size,
             PROT_READ | PROT_WRITE,
#ifdef MAP_ANONYMOUS
             MAP_ANONYMOUS |
#endif
             MAP_PRIVATE,
             tm.mmap_fd,
             (off_t) 0
             );

  if ( ptr == MAP_FAILED ) {
    perror("tm: mmap() failed");
    ptr = 0;
    tm_abort();
  }
#endif /* tm_USE_MMAP */

#if tm_USE_SBRK
  ptr = sbrk(size);

  tm.os_alloc_last = ptr;
  tm.os_alloc_last_size = size;

  if ( tm.os_alloc_expected ) {
    tm_warn(ptr == tm.os_alloc_expected, "ptr = %p, expected = %p", ptr, tm.os_alloc_expected);
  }
  if ( size > 0 ) {
    tm.os_alloc_expected = (char *)ptr + size;
  }
#endif /* tm_USE_SBRK */

#if 0
  fprintf(stderr, "  _tm_os_alloc_(%lu) => %p\n", (unsigned long) size, (void*) ptr);
#endif

  return ptr;
}

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static __inline void* _tm_os_free	(	void *	ptr,
		long	size
	)			[static]

Return block to the OS.

• Update stats and timers.

Definition at line 179 of file os.c.

References _tm_os_free_(), _tm_page_mark_unused_range(), tm_data::n, tm, tm_B, tm_msg(), tm_os_alloc_total, tm_ptr_is_aligned_to_page, tm_time_stat_begin(), tm_time_stat_end(), and tm_data::ts_os_free.

Referenced by _tm_os_alloc_aligned(), and _tm_os_free_aligned().

{
  void *result = 0;

#if tm_TIME_STAT
  tm_time_stat_begin(&tm.ts_os_free);
#endif

  result = _tm_os_free_(ptr, size);

#if tm_TIME_STAT
  tm_time_stat_end(&tm.ts_os_free);
#endif

  /* Mark freed pages as unused. */
  if ( tm_ptr_is_aligned_to_page(ptr) ) {
    _tm_page_mark_unused_range(ptr, size);
  }

  tm_msg("A d %p[%lu] #%lu\n", ptr, (unsigned long) size, (unsigned long) tm.n[tm_B]);

  tm_os_alloc_total -= size;

  return result;
}

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static void* _tm_os_free_	(	void *	ptr,
		long	size
	)			[static]

Return memory back to the OS.

• If tm_USE_MMAP is true, use munmap().
• If tm_USE_SBRK is true, use sbrk(- size) only if the block was the last block requested from sbrk(). Note: other callers to sbrk() may exist.

Definition at line 87 of file os.c.

References tm_data::os_alloc_expected, tm_data::os_alloc_last, tm_data::os_alloc_last_size, tm, and tm_assert_test.

Referenced by _tm_os_free().

{
#if 0
  fprintf(stderr, "  _tm_os_free_(%p, %lu)\n", (void*) ptr, (unsigned long) size);
#endif

  tm_assert_test(ptr != 0);
  tm_assert_test(size > 0);

#if tm_USE_MMAP
  munmap(ptr, size);

  /*! Return next allocation ptr as "unknown" (0). */
  return 0;
#endif /* tm_USE_MMAP */

#if tm_USE_SBRK
  if ( ptr == tm.os_alloc_last &&
       size == tm.os_alloc_last_size &&
       ptr == sbrk(0) ) {
    ptr = sbrk(- size);

    tm.os_alloc_expected -= size;
  }

  /*! Return next allocation ptr expected (non-0). */
  return ptr;
#endif /* tm_USE_SBRK */
}

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---

Variable Documentation

size_t tm_os_alloc_total = 0

Total bytes currently allocated from OS.

Definition at line 12 of file os.c.

Referenced by _tm_os_alloc(), and _tm_os_free().