1 /* Functions for memory limit warnings.
2 Copyright (C) 1990, 1992, 2001-2014 Free Software Foundation, Inc.
4 This file is part of GNU Emacs.
6 GNU Emacs is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 GNU Emacs is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
20 #include <unistd.h> /* for 'environ', on AIX */
28 /* Some systems need this before <sys/resource.h>. */
29 #include <sys/types.h>
31 #ifdef HAVE_SYS_RESOURCE_H
32 # include <sys/time.h>
33 # include <sys/resource.h>
35 # if HAVE_SYS_VLIMIT_H
36 # include <sys/vlimit.h> /* Obsolete, says glibc */
40 /* Start of data. It is OK if this is approximate; it's used only as
43 # define data_start ((char *) DATA_START)
45 extern char data_start
[];
46 # ifndef HAVE_DATA_START
47 /* Initialize to nonzero, so that it's put into data and not bss.
48 Link this file's object code first, so that this symbol is near the
50 char data_start
[1] = { 1 };
55 Level number of warnings already issued.
56 0 -- no warnings issued.
57 1 -- 75% warning already issued.
58 2 -- 85% warning already issued.
59 3 -- 95% warning issued; keep warning frequently.
61 enum warnlevel
{ not_warned
, warned_75
, warned_85
, warned_95
};
62 static enum warnlevel warnlevel
;
64 /* Function to call to issue a warning;
65 0 means don't issue them. */
66 static void (*warn_function
) (const char *);
68 /* Start of data space; can be changed by calling memory_warnings. */
69 static char *data_space_start
;
71 /* Number of bytes of writable memory we can expect to be able to get. */
72 static size_t lim_data
;
77 # define RLIMIT_AS RLIMIT_DATA
83 /* Set LIM_DATA to the minimum of the maximum object size and the
84 maximum address space. Don't bother to check for values like
85 RLIM_INFINITY since in practice they are not much less than SIZE_MAX. */
88 = (getrlimit (RLIMIT_AS
, &rlimit
) == 0 && rlimit
.rlim_cur
<= SIZE_MAX
93 #elif defined WINDOWSNT
100 extern size_t reserved_heap_size
;
101 lim_data
= reserved_heap_size
;
109 _go32_dpmi_meminfo info
;
110 unsigned long lim1
, lim2
;
112 _go32_dpmi_get_free_memory_information (&info
);
113 /* DPMI server of Windows NT and its descendants reports in
114 info.available_memory a much lower amount that is really
115 available, which causes bogus "past 95% of memory limit"
116 warnings. Try to overcome that via circumstantial evidence. */
117 lim1
= info
.available_memory
;
118 lim2
= info
.available_physical_pages
;
119 /* DPMI Spec: "Fields that are unavailable will hold -1." */
120 if ((long)lim1
== -1L)
122 if ((long)lim2
== -1L)
126 /* Surely, the available memory is at least what we have physically
132 /* Don't believe they will give us more that 0.5 GB. */
133 if (lim_data
> 512U * 1024U * 1024U)
134 lim_data
= 512U * 1024U * 1024U;
144 # error "get_lim_data not implemented on this machine"
147 /* Verify amount of memory available, complaining if we're near the end. */
150 check_memory_limits (void)
153 extern void *(*real_morecore
) (ptrdiff_t);
155 void *(*real_morecore
) (ptrdiff_t) = 0;
157 extern void *(*__morecore
) (ptrdiff_t);
162 enum warnlevel new_warnlevel
;
166 five_percent
= lim_data
/ 20;
168 /* Find current end of memory and issue warning if getting near max */
169 cp
= (real_morecore
? real_morecore
: __morecore
) (0);
170 data_size
= cp
- data_space_start
;
175 /* What level of warning does current memory usage demand? */
177 = (data_size
> five_percent
* 19) ? warned_95
178 : (data_size
> five_percent
* 17) ? warned_85
179 : (data_size
> five_percent
* 15) ? warned_75
182 /* If we have gone up a level, give the appropriate warning. */
183 if (new_warnlevel
> warnlevel
|| new_warnlevel
== warned_95
)
185 warnlevel
= new_warnlevel
;
189 (*warn_function
) ("Warning: past 75% of memory limit");
193 (*warn_function
) ("Warning: past 85% of memory limit");
197 (*warn_function
) ("Warning: past 95% of memory limit");
200 /* Handle going down in usage levels, with some hysteresis. */
203 /* If we go down below 70% full, issue another 75% warning
204 when we go up again. */
205 if (data_size
< five_percent
* 14)
206 warnlevel
= not_warned
;
207 /* If we go down below 80% full, issue another 85% warning
208 when we go up again. */
209 else if (warnlevel
> warned_75
&& data_size
< five_percent
* 16)
210 warnlevel
= warned_75
;
211 /* If we go down below 90% full, issue another 95% warning
212 when we go up again. */
213 else if (warnlevel
> warned_85
&& data_size
< five_percent
* 18)
214 warnlevel
= warned_85
;
218 /* Enable memory usage warnings.
219 START says where the end of pure storage is.
220 WARNFUN specifies the function to call to issue a warning. */
223 memory_warnings (void *start
, void (*warnfun
) (const char *))
225 extern void (* __after_morecore_hook
) (void); /* From gmalloc.c */
227 data_space_start
= start
? start
: data_start
;
229 warn_function
= warnfun
;
230 __after_morecore_hook
= check_memory_limits
;
232 /* Force data limit to be recalculated on each run. */