guile/libguile/gc-malloc.c

/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2002 Free Software Foundation, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this software; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307 USA
 *
 * As a special exception, the Free Software Foundation gives permission
 * for additional uses of the text contained in its release of GUILE.
 *
 * The exception is that, if you link the GUILE library with other files
 * to produce an executable, this does not by itself cause the
 * resulting executable to be covered by the GNU General Public License.
 * Your use of that executable is in no way restricted on account of
 * linking the GUILE library code into it.
 *
 * This exception does not however invalidate any other reasons why
 * the executable file might be covered by the GNU General Public License.
 *
 * This exception applies only to the code released by the
 * Free Software Foundation under the name GUILE.  If you copy
 * code from other Free Software Foundation releases into a copy of
 * GUILE, as the General Public License permits, the exception does
 * not apply to the code that you add in this way.  To avoid misleading
 * anyone as to the status of such modified files, you must delete
 * this exception notice from them.
 *
 * If you write modifications of your own for GUILE, it is your choice
 * whether to permit this exception to apply to your modifications.
 * If you do not wish that, delete this exception notice.  */



#if HAVE_CONFIG_H
#  include <config.h>
#endif

#include <stdio.h>
#include <errno.h>
#include <string.h>

#ifdef __ia64__
#include <ucontext.h>
extern unsigned long * __libc_ia64_register_backing_store_base;
#endif

#include "libguile/_scm.h"
#include "libguile/eval.h"
#include "libguile/stime.h"
#include "libguile/stackchk.h"
#include "libguile/struct.h"
#include "libguile/smob.h"
#include "libguile/unif.h"
#include "libguile/async.h"
#include "libguile/ports.h"
#include "libguile/root.h"
#include "libguile/strings.h"
#include "libguile/vectors.h"
#include "libguile/weaks.h"
#include "libguile/hashtab.h"
#include "libguile/tags.h"

#include "libguile/validate.h"
#include "libguile/deprecation.h"
#include "libguile/gc.h"

#include "libguile/private-gc.h"

#ifdef GUILE_DEBUG_MALLOC
#include "libguile/debug-malloc.h"
#endif

#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

/*
  INIT_MALLOC_LIMIT is the initial amount of malloc usage which will
  trigger a GC.
  
  After startup (at the guile> prompt), we have approximately 100k of
  alloced memory, which won't go away on GC. Let's set the init such
  that we get a nice yield on the next allocation:
*/
#define SCM_DEFAULT_INIT_MALLOC_LIMIT 200*1024
#define SCM_DEFAULT_MALLOC_MINYIELD 40

/* #define DEBUGINFO */

static int scm_i_minyield_malloc;

void
scm_gc_init_malloc (void)
{
  scm_mtrigger = scm_getenv_int ("GUILE_INIT_MALLOC_LIMIT",
				 SCM_DEFAULT_INIT_MALLOC_LIMIT);
  scm_i_minyield_malloc =  scm_getenv_int ("GUILE_MIN_YIELD_MALLOC",
					   SCM_DEFAULT_MALLOC_MINYIELD);

  if (scm_i_minyield_malloc >= 100)
    scm_i_minyield_malloc = 99;
  if (scm_i_minyield_malloc < 1)
    scm_i_minyield_malloc = 1;

  if (scm_mtrigger < 0)
    scm_mtrigger = SCM_DEFAULT_INIT_MALLOC_LIMIT;
}



/* Function for non-cell memory management.
 */

void *
scm_realloc (void *mem, size_t size)
{
  void *ptr;

  SCM_SYSCALL (ptr = realloc (mem, size));
  if (ptr)
    return ptr;

  scm_rec_mutex_lock (&scm_i_sweep_mutex);
  
  scm_i_sweep_all_segments ("realloc");
  
  SCM_SYSCALL (ptr = realloc (mem, size));
  if (ptr)
    { 
      scm_rec_mutex_unlock (&scm_i_sweep_mutex);
      return ptr;
    }

  scm_igc ("realloc");
  scm_i_sweep_all_segments ("realloc");
  
  scm_rec_mutex_unlock (&scm_i_sweep_mutex);
  
  SCM_SYSCALL (ptr = realloc (mem, size));
  if (ptr)
    return ptr;

  scm_memory_error ("realloc");
}

void *
scm_malloc (size_t sz)
{
  return scm_realloc (NULL, sz);
}

/*
  Hmm. Should we use the C convention for arguments (i.e. N_ELTS,
  SIZEOF_ELT)? --hwn
 */
void *
scm_calloc (size_t sz)
{
  void * ptr;

  /*
    By default, try to use calloc, as it is likely more efficient than
    calling memset by hand.
   */
  SCM_SYSCALL (ptr = calloc (sz, 1));
  if (ptr)
    return ptr;
  
  ptr = scm_realloc (NULL, sz);
  memset (ptr, 0x0, sz);
  return ptr;
}


char *
scm_strndup (const char *str, size_t n)
{
  char *dst = scm_malloc (n + 1);
  memcpy (dst, str, n);
  dst[n] = 0;
  return dst;
}

char *
scm_strdup (const char *str)
{
  return scm_strndup (str, strlen (str));
}

void
scm_gc_register_collectable_memory (void *mem, size_t size, const char *what)
{
  scm_mallocated += size;

  /*
    we could finish the full sweep (without mark) here, but in
    practice this turns out to be ineffective.
   */

  /*
    A program that uses a lot of malloced collectable memory (vectors,
    strings), will use a lot of memory off the cell-heap; it needs to
    do GC more often (before cells are exhausted), otherwise swapping
    and malloc management will tie it down.
   */
  if (scm_mallocated > scm_mtrigger)
    {
      unsigned long prev_alloced;
      float yield;
      
      scm_rec_mutex_lock (&scm_i_sweep_mutex);
      
      prev_alloced  = scm_mallocated;
      scm_igc (what);
      scm_i_sweep_all_segments ("mtrigger");

      yield = (((float) prev_alloced - (float) scm_mallocated)
	       / (float) prev_alloced);
      
      scm_gc_malloc_yield_percentage = (int) (100  * yield);

#ifdef DEBUGINFO
      fprintf (stderr,  "prev %lud , now %lud, yield %4.2lf, want %d",
	       prev_alloced,
	       scm_mallocated,
	       100.0 * yield,
	       scm_i_minyield_malloc);
#endif
      
      if (yield < scm_i_minyield_malloc /  100.0)
	{
	  /*
	    We make the trigger a little larger, even; If you have a
	    program that builds up a lot of data in strings, then the
	    desired yield will never be satisfied.

	    Instead of getting bogged down, we let the mtrigger grow
	    strongly with it.
	   */
	  float no_overflow_trigger = scm_mallocated * 110.0;

	  no_overflow_trigger /= (float)  (100.0 - scm_i_minyield_malloc);
	  scm_mtrigger =  (unsigned long) no_overflow_trigger;
	  
#ifdef DEBUGINFO
	  fprintf (stderr, "Mtrigger sweep: ineffective. New trigger %d\n",
		   scm_mtrigger);
#endif
	}
      
      scm_rec_mutex_unlock (&scm_i_sweep_mutex);
    }
  
#ifdef GUILE_DEBUG_MALLOC
  if (mem)
    scm_malloc_register (mem, what);
#endif
}

void
scm_gc_unregister_collectable_memory (void *mem, size_t size, const char *what)
{
  scm_mallocated -= size;
  scm_gc_malloc_collected += size;
  
#ifdef GUILE_DEBUG_MALLOC
  if (mem)
    scm_malloc_unregister (mem);
#endif
}

void *
scm_gc_malloc (size_t size, const char *what)
{
  /*
    The straightforward implementation below has the problem
     that it might call the GC twice, once in scm_malloc and then
     again in scm_gc_register_collectable_memory.  We don't really
     want the second GC since it will not find new garbage.


     Note: this is a theoretical peeve. In reality, malloc() never
     returns NULL. Usually, memory is overcommitted, and when you try
     to write it the program is killed with signal 11. --hwn
  */

  void *ptr = scm_malloc (size);
  scm_gc_register_collectable_memory (ptr, size, what);
  return ptr;
}

void *
scm_gc_calloc (size_t size, const char *what)
{
  void *ptr = scm_gc_malloc (size, what);
  memset (ptr, 0x0, size);
  return ptr;
}


void *
scm_gc_realloc (void *mem, size_t old_size, size_t new_size, const char *what)
{
  /* XXX - see scm_gc_malloc. */

  void *ptr = scm_realloc (mem, new_size);
  scm_gc_unregister_collectable_memory (mem, old_size, what);
  scm_gc_register_collectable_memory (ptr, new_size, what);
  return ptr;
}

void
scm_gc_free (void *mem, size_t size, const char *what)
{
  scm_gc_unregister_collectable_memory (mem, size, what);
  free (mem);
}

char *
scm_gc_strndup (const char *str, size_t n, const char *what)
{
  char *dst = scm_gc_malloc (n+1, what);
  memcpy (dst, str, n);
  dst[n] = 0;
  return dst;
}

char *
scm_gc_strdup (const char *str, const char *what)
{
  return scm_gc_strndup (str, strlen (str), what);
}

#if SCM_ENABLE_DEPRECATED == 1

/* {Deprecated front end to malloc}
 *
 * scm_must_malloc, scm_must_realloc, scm_must_free, scm_done_malloc,
 * scm_done_free
 *
 * These functions provide services comparable to malloc, realloc, and
 * free.  They should be used when allocating memory that will be under
 * control of the garbage collector, i.e., if the memory may be freed
 * during garbage collection.
 *
 * They are deprecated because they weren't really used the way
 * outlined above, and making sure to return the right amount from
 * smob free routines was sometimes difficult when dealing with nested
 * data structures.  We basically want everybody to review their code
 * and use the more symmetrical scm_gc_malloc/scm_gc_free functions
 * instead.  In some cases, where scm_must_malloc has been used
 * incorrectly (i.e. for non-GC-able memory), use scm_malloc/free.
 */

void *
scm_must_malloc (size_t size, const char *what)
{
  scm_c_issue_deprecation_warning
    ("scm_must_malloc is deprecated.  "
     "Use scm_gc_malloc and scm_gc_free instead.");

  return scm_gc_malloc (size, what);
}

void *
scm_must_realloc (void *where,
		  size_t old_size,
		  size_t size,
		  const char *what)
{
  scm_c_issue_deprecation_warning
    ("scm_must_realloc is deprecated.  "
     "Use scm_gc_realloc and scm_gc_free instead.");

  return scm_gc_realloc (where, old_size, size, what);
}

char *
scm_must_strndup (const char *str, size_t length)
{
  scm_c_issue_deprecation_warning
    ("scm_must_strndup is deprecated.  "
     "Use scm_gc_strndup and scm_gc_free instead.");

  return scm_gc_strndup (str, length, "string");
}

char *
scm_must_strdup (const char *str)
{
  scm_c_issue_deprecation_warning
    ("scm_must_strdup is deprecated.  "
     "Use scm_gc_strdup and scm_gc_free instead.");

  return scm_gc_strdup (str, "string");
}

void
scm_must_free (void *obj)
#define FUNC_NAME "scm_must_free"
{
  scm_c_issue_deprecation_warning
    ("scm_must_free is deprecated.  "
     "Use scm_gc_malloc and scm_gc_free instead.");

#ifdef GUILE_DEBUG_MALLOC
  scm_malloc_unregister (obj);
#endif
  if (obj)
    free (obj);
  else
    {
      fprintf (stderr,"freeing NULL pointer");
      abort ();
    }
}
#undef FUNC_NAME


void
scm_done_malloc (long size)
{
  scm_c_issue_deprecation_warning
    ("scm_done_malloc is deprecated.  "
     "Use scm_gc_register_collectable_memory instead.");

  scm_gc_register_collectable_memory (NULL, size, "foreign mallocs");
}

void
scm_done_free (long size)
{
  scm_c_issue_deprecation_warning
    ("scm_done_free is deprecated.  "
     "Use scm_gc_unregister_collectable_memory instead.");

  scm_gc_unregister_collectable_memory (NULL, size, "foreign mallocs");
}

#endif /* SCM_ENABLE_DEPRECATED == 1 */