/* Functions for memory limit warnings.
Copyright (C) 1990, 1992, 2001-2012 Free Software Foundation, Inc.
This file is part of GNU Emacs.
GNU Emacs 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 3 of the License, or
(at your option) any later version.
GNU Emacs 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 GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
#include <setjmp.h>
#include "lisp.h"
#include "mem-limits.h"
/*
Level number of warnings already issued.
0 -- no warnings issued.
1 -- 75% warning already issued.
2 -- 85% warning already issued.
3 -- 95% warning issued; keep warning frequently.
*/
enum warnlevel { not_warned, warned_75, warned_85, warned_95 };
static enum warnlevel warnlevel;
typedef void *POINTER;
/* Function to call to issue a warning;
0 means don't issue them. */
static void (*warn_function) (const char *);
/* Start of data space; can be changed by calling malloc_init. */
static POINTER data_space_start;
/* Number of bytes of writable memory we can expect to be able to get. */
static unsigned long lim_data;
#if defined (HAVE_GETRLIMIT) && defined (RLIMIT_AS)
static void
get_lim_data (void)
{
struct rlimit rlimit;
getrlimit (RLIMIT_AS, &rlimit);
if (rlimit.rlim_cur == RLIM_INFINITY)
lim_data = -1;
else
lim_data = rlimit.rlim_cur;
}
#else /* not HAVE_GETRLIMIT */
#ifdef USG
static void
get_lim_data (void)
{
extern long ulimit ();
lim_data = -1;
/* Use the ulimit call, if we seem to have it. */
#if !defined (ULIMIT_BREAK_VALUE) || defined (GNU_LINUX)
lim_data = ulimit (3, 0);
#endif
/* If that didn't work, just use the macro's value. */
#ifdef ULIMIT_BREAK_VALUE
if (lim_data == -1)
lim_data = ULIMIT_BREAK_VALUE;
#endif
lim_data -= (long) data_space_start;
}
#else /* not USG */
#ifdef WINDOWSNT
static void
get_lim_data (void)
{
extern unsigned long reserved_heap_size;
lim_data = reserved_heap_size;
}
#else
#if !defined (BSD4_2) && !defined (CYGWIN)
#ifdef MSDOS
void
get_lim_data (void)
{
_go32_dpmi_meminfo info;
unsigned long lim1, lim2;
_go32_dpmi_get_free_memory_information (&info);
/* DPMI server of Windows NT and its descendants reports in
info.available_memory a much lower amount that is really
available, which causes bogus "past 95% of memory limit"
warnings. Try to overcome that via circumstantial evidence. */
lim1 = info.available_memory;
lim2 = info.available_physical_pages;
/* DPMI Spec: "Fields that are unavailable will hold -1." */
if ((long)lim1 == -1L)
lim1 = 0;
if ((long)lim2 == -1L)
lim2 = 0;
else
lim2 *= 4096;
/* Surely, the available memory is at least what we have physically
available, right? */
if (lim1 >= lim2)
lim_data = lim1;
else
lim_data = lim2;
/* Don't believe they will give us more that 0.5 GB. */
if (lim_data > 512U * 1024U * 1024U)
lim_data = 512U * 1024U * 1024U;
}
unsigned long
ret_lim_data (void)
{
get_lim_data ();
return lim_data;
}
#else /* not MSDOS */
static void
get_lim_data (void)
{
lim_data = vlimit (LIM_DATA, -1);
}
#endif /* not MSDOS */
#else /* BSD4_2 || CYGWIN */
static void
get_lim_data (void)
{
struct rlimit XXrlimit;
getrlimit (RLIMIT_DATA, &XXrlimit);
#ifdef RLIM_INFINITY
lim_data = XXrlimit.rlim_cur & RLIM_INFINITY; /* soft limit */
#else
lim_data = XXrlimit.rlim_cur; /* soft limit */
#endif
}
#endif /* BSD4_2 */
#endif /* not WINDOWSNT */
#endif /* not USG */
#endif /* not HAVE_GETRLIMIT */
/* Verify amount of memory available, complaining if we're near the end. */
static void
check_memory_limits (void)
{
#ifdef REL_ALLOC
extern POINTER (*real_morecore) (long);
#endif
extern POINTER (*__morecore) (long);
register POINTER cp;
unsigned long five_percent;
unsigned long data_size;
enum warnlevel new_warnlevel;
if (lim_data == 0)
get_lim_data ();
five_percent = lim_data / 20;
/* Find current end of memory and issue warning if getting near max */
#ifdef REL_ALLOC
if (real_morecore)
cp = (char *) (*real_morecore) (0);
else
#endif
cp = (char *) (*__morecore) (0);
data_size = (char *) cp - (char *) data_space_start;
if (!warn_function)
return;
/* What level of warning does current memory usage demand? */
new_warnlevel
= (data_size > five_percent * 19) ? warned_95
: (data_size > five_percent * 17) ? warned_85
: (data_size > five_percent * 15) ? warned_75
: not_warned;
/* If we have gone up a level, give the appropriate warning. */
if (new_warnlevel > warnlevel || new_warnlevel == warned_95)
{
warnlevel = new_warnlevel;
switch (warnlevel)
{
case warned_75:
(*warn_function) ("Warning: past 75% of memory limit");
break;
case warned_85:
(*warn_function) ("Warning: past 85% of memory limit");
break;
case warned_95:
(*warn_function) ("Warning: past 95% of memory limit");
}
}
/* Handle going down in usage levels, with some hysteresis. */
else
{
/* If we go down below 70% full, issue another 75% warning
when we go up again. */
if (data_size < five_percent * 14)
warnlevel = not_warned;
/* If we go down below 80% full, issue another 85% warning
when we go up again. */
else if (warnlevel > warned_75 && data_size < five_percent * 16)
warnlevel = warned_75;
/* If we go down below 90% full, issue another 95% warning
when we go up again. */
else if (warnlevel > warned_85 && data_size < five_percent * 18)
warnlevel = warned_85;
}
if (EXCEEDS_LISP_PTR (cp))
(*warn_function) ("Warning: memory in use exceeds lisp pointer size");
}
#if !defined (CANNOT_DUMP) || !defined (SYSTEM_MALLOC)
/* Some systems that cannot dump also cannot implement these. */
/*
* Return the address of the start of the data segment prior to
* doing an unexec. After unexec the return value is undefined.
* See crt0.c for further information and definition of data_start.
*
* Apparently, on BSD systems this is etext at startup. On
* USG systems (swapping) this is highly mmu dependent and
* is also dependent on whether or not the program is running
* with shared text. Generally there is a (possibly large)
* gap between end of text and start of data with shared text.
*
*/
char *
start_of_data (void)
{
#ifdef BSD_SYSTEM
extern char etext;
return (POINTER)(&etext);
#elif defined DATA_START
return ((POINTER) DATA_START);
#elif defined ORDINARY_LINK
/*
* This is a hack. Since we're not linking crt0.c or pre_crt0.c,
* data_start isn't defined. We take the address of environ, which
* is known to live at or near the start of the system crt0.c, and
* we don't sweat the handful of bytes that might lose.
*/
extern char **environ;
return ((POINTER) &environ);
#else
extern int data_start;
return ((POINTER) &data_start);
#endif
}
#endif /* (not CANNOT_DUMP or not SYSTEM_MALLOC) */
/* Enable memory usage warnings.
START says where the end of pure storage is.
WARNFUN specifies the function to call to issue a warning. */
void
memory_warnings (POINTER start, void (*warnfun) (const char *))
{
extern void (* __after_morecore_hook) (void); /* From gmalloc.c */
if (start)
data_space_start = start;
else
data_space_start = start_of_data ();
warn_function = warnfun;
__after_morecore_hook = check_memory_limits;
/* Force data limit to be recalculated on each run. */
lim_data = 0;
}