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300 lines
7.7 KiB
C
300 lines
7.7 KiB
C
/* Functions for memory limit warnings.
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Copyright (C) 1990, 1992, 2001-2011 Free Software Foundation, Inc.
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This file is part of GNU Emacs.
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GNU Emacs is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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GNU Emacs is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
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#include <config.h>
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#include <setjmp.h>
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#include "lisp.h"
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#include "mem-limits.h"
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/*
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Level number of warnings already issued.
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0 -- no warnings issued.
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1 -- 75% warning already issued.
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2 -- 85% warning already issued.
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3 -- 95% warning issued; keep warning frequently.
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*/
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enum warnlevel { not_warned, warned_75, warned_85, warned_95 };
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static enum warnlevel warnlevel;
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typedef POINTER_TYPE *POINTER;
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/* Function to call to issue a warning;
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0 means don't issue them. */
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static void (*warn_function) (const char *);
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/* Start of data space; can be changed by calling malloc_init. */
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static POINTER data_space_start;
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/* Number of bytes of writable memory we can expect to be able to get. */
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static unsigned long lim_data;
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#if defined (HAVE_GETRLIMIT) && defined (RLIMIT_AS)
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static void
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get_lim_data (void)
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{
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struct rlimit rlimit;
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getrlimit (RLIMIT_AS, &rlimit);
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if (rlimit.rlim_cur == RLIM_INFINITY)
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lim_data = -1;
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else
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lim_data = rlimit.rlim_cur;
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}
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#else /* not HAVE_GETRLIMIT */
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#ifdef USG
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static void
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get_lim_data (void)
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{
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extern long ulimit ();
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lim_data = -1;
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/* Use the ulimit call, if we seem to have it. */
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#if !defined (ULIMIT_BREAK_VALUE) || defined (GNU_LINUX)
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lim_data = ulimit (3, 0);
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#endif
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/* If that didn't work, just use the macro's value. */
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#ifdef ULIMIT_BREAK_VALUE
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if (lim_data == -1)
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lim_data = ULIMIT_BREAK_VALUE;
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#endif
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lim_data -= (long) data_space_start;
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}
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#else /* not USG */
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#ifdef WINDOWSNT
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static void
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get_lim_data (void)
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{
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extern unsigned long reserved_heap_size;
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lim_data = reserved_heap_size;
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}
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#else
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#if !defined (BSD4_2) && !defined (CYGWIN)
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#ifdef MSDOS
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void
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get_lim_data (void)
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{
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_go32_dpmi_meminfo info;
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unsigned long lim1, lim2;
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_go32_dpmi_get_free_memory_information (&info);
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/* DPMI server of Windows NT and its descendants reports in
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info.available_memory a much lower amount that is really
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available, which causes bogus "past 95% of memory limit"
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warnings. Try to overcome that via circumstantial evidence. */
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lim1 = info.available_memory;
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lim2 = info.available_physical_pages;
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/* DPMI Spec: "Fields that are unavailable will hold -1." */
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if ((long)lim1 == -1L)
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lim1 = 0;
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if ((long)lim2 == -1L)
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lim2 = 0;
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else
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lim2 *= 4096;
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/* Surely, the available memory is at least what we have physically
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available, right? */
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if (lim1 >= lim2)
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lim_data = lim1;
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else
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lim_data = lim2;
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/* Don't believe they will give us more that 0.5 GB. */
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if (lim_data > 512U * 1024U * 1024U)
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lim_data = 512U * 1024U * 1024U;
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}
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unsigned long
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ret_lim_data (void)
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{
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get_lim_data ();
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return lim_data;
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}
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#else /* not MSDOS */
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static void
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get_lim_data (void)
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{
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lim_data = vlimit (LIM_DATA, -1);
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}
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#endif /* not MSDOS */
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#else /* BSD4_2 || CYGWIN */
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static void
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get_lim_data (void)
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{
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struct rlimit XXrlimit;
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getrlimit (RLIMIT_DATA, &XXrlimit);
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#ifdef RLIM_INFINITY
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lim_data = XXrlimit.rlim_cur & RLIM_INFINITY; /* soft limit */
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#else
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lim_data = XXrlimit.rlim_cur; /* soft limit */
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#endif
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}
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#endif /* BSD4_2 */
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#endif /* not WINDOWSNT */
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#endif /* not USG */
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#endif /* not HAVE_GETRLIMIT */
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/* Verify amount of memory available, complaining if we're near the end. */
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static void
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check_memory_limits (void)
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{
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#ifdef REL_ALLOC
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extern POINTER (*real_morecore) (SIZE);
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#endif
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extern POINTER (*__morecore) (SIZE);
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register POINTER cp;
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unsigned long five_percent;
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unsigned long data_size;
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enum warnlevel new_warnlevel;
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if (lim_data == 0)
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get_lim_data ();
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five_percent = lim_data / 20;
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/* Find current end of memory and issue warning if getting near max */
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#ifdef REL_ALLOC
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if (real_morecore)
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cp = (char *) (*real_morecore) (0);
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else
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#endif
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cp = (char *) (*__morecore) (0);
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data_size = (char *) cp - (char *) data_space_start;
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if (!warn_function)
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return;
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/* What level of warning does current memory usage demand? */
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new_warnlevel
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= (data_size > five_percent * 19) ? warned_95
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: (data_size > five_percent * 17) ? warned_85
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: (data_size > five_percent * 15) ? warned_75
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: not_warned;
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/* If we have gone up a level, give the appropriate warning. */
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if (new_warnlevel > warnlevel || new_warnlevel == warned_95)
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{
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warnlevel = new_warnlevel;
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switch (warnlevel)
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{
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case warned_75:
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(*warn_function) ("Warning: past 75% of memory limit");
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break;
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case warned_85:
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(*warn_function) ("Warning: past 85% of memory limit");
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break;
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case warned_95:
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(*warn_function) ("Warning: past 95% of memory limit");
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}
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}
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/* Handle going down in usage levels, with some hysteresis. */
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else
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{
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/* If we go down below 70% full, issue another 75% warning
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when we go up again. */
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if (data_size < five_percent * 14)
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warnlevel = not_warned;
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/* If we go down below 80% full, issue another 85% warning
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when we go up again. */
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else if (warnlevel > warned_75 && data_size < five_percent * 16)
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warnlevel = warned_75;
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/* If we go down below 90% full, issue another 95% warning
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when we go up again. */
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else if (warnlevel > warned_85 && data_size < five_percent * 18)
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warnlevel = warned_85;
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}
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if (EXCEEDS_LISP_PTR (cp))
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(*warn_function) ("Warning: memory in use exceeds lisp pointer size");
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}
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#if !defined(CANNOT_DUMP) || !defined(SYSTEM_MALLOC)
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/* Some systems that cannot dump also cannot implement these. */
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/*
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* Return the address of the start of the data segment prior to
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* doing an unexec. After unexec the return value is undefined.
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* See crt0.c for further information and definition of data_start.
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*
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* Apparently, on BSD systems this is etext at startup. On
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* USG systems (swapping) this is highly mmu dependent and
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* is also dependent on whether or not the program is running
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* with shared text. Generally there is a (possibly large)
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* gap between end of text and start of data with shared text.
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*
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*/
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char *
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start_of_data (void)
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{
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#ifdef BSD_SYSTEM
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extern char etext;
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return (POINTER)(&etext);
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#elif defined DATA_START
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return ((POINTER) DATA_START);
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#elif defined ORDINARY_LINK
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/*
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* This is a hack. Since we're not linking crt0.c or pre_crt0.c,
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* data_start isn't defined. We take the address of environ, which
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* is known to live at or near the start of the system crt0.c, and
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* we don't sweat the handful of bytes that might lose.
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*/
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extern char **environ;
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return ((POINTER) &environ);
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#else
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extern int data_start;
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return ((POINTER) &data_start);
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#endif
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}
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#endif /* (not CANNOT_DUMP or not SYSTEM_MALLOC) */
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/* Enable memory usage warnings.
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START says where the end of pure storage is.
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WARNFUN specifies the function to call to issue a warning. */
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void
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memory_warnings (POINTER start, void (*warnfun) (const char *))
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{
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extern void (* __after_morecore_hook) (void); /* From gmalloc.c */
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if (start)
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data_space_start = start;
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else
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data_space_start = start_of_data ();
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warn_function = warnfun;
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__after_morecore_hook = check_memory_limits;
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/* Force data limit to be recalculated on each run. */
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lim_data = 0;
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}
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