| 1 | /* Functions for memory limit warnings. |
| 2 | Copyright (C) 1990, 1992, 2001-2014 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GNU Emacs. |
| 5 | |
| 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. |
| 10 | |
| 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. |
| 15 | |
| 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/>. */ |
| 18 | |
| 19 | #include <config.h> |
| 20 | #include <unistd.h> /* for 'environ', on AIX */ |
| 21 | #include "lisp.h" |
| 22 | |
| 23 | #ifdef MSDOS |
| 24 | #include <dpmi.h> |
| 25 | extern int etext; |
| 26 | #endif |
| 27 | |
| 28 | /* Some systems need this before <sys/resource.h>. */ |
| 29 | #include <sys/types.h> |
| 30 | |
| 31 | #ifdef HAVE_SYS_RESOURCE_H |
| 32 | # include <sys/time.h> |
| 33 | # include <sys/resource.h> |
| 34 | #else |
| 35 | # if HAVE_SYS_VLIMIT_H |
| 36 | # include <sys/vlimit.h> /* Obsolete, says glibc */ |
| 37 | # endif |
| 38 | #endif |
| 39 | |
| 40 | /* Start of data. It is OK if this is approximate; it's used only as |
| 41 | a heuristic. */ |
| 42 | #ifdef DATA_START |
| 43 | # define data_start ((char *) DATA_START) |
| 44 | #else |
| 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 |
| 49 | start of data. */ |
| 50 | char data_start[1] = { 1 }; |
| 51 | # endif |
| 52 | #endif |
| 53 | |
| 54 | /* |
| 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. |
| 60 | */ |
| 61 | enum warnlevel { not_warned, warned_75, warned_85, warned_95 }; |
| 62 | static enum warnlevel warnlevel; |
| 63 | |
| 64 | /* Function to call to issue a warning; |
| 65 | 0 means don't issue them. */ |
| 66 | static void (*warn_function) (const char *); |
| 67 | |
| 68 | /* Start of data space; can be changed by calling memory_warnings. */ |
| 69 | static char *data_space_start; |
| 70 | |
| 71 | /* Number of bytes of writable memory we can expect to be able to get. */ |
| 72 | static size_t lim_data; |
| 73 | \f |
| 74 | /* Return true if PTR cannot be represented as an Emacs Lisp object. */ |
| 75 | static bool |
| 76 | exceeds_lisp_ptr (void *ptr) |
| 77 | { |
| 78 | return (! USE_LSB_TAG |
| 79 | && VAL_MAX < UINTPTR_MAX |
| 80 | && ((uintptr_t) ptr & ~DATA_SEG_BITS) >> VALBITS != 0); |
| 81 | } |
| 82 | |
| 83 | #ifdef HAVE_GETRLIMIT |
| 84 | |
| 85 | # ifndef RLIMIT_AS |
| 86 | # define RLIMIT_AS RLIMIT_DATA |
| 87 | # endif |
| 88 | |
| 89 | static void |
| 90 | get_lim_data (void) |
| 91 | { |
| 92 | /* Set LIM_DATA to the minimum of the maximum object size and the |
| 93 | maximum address space. Don't bother to check for values like |
| 94 | RLIM_INFINITY since in practice they are not much less than SIZE_MAX. */ |
| 95 | struct rlimit rlimit; |
| 96 | lim_data |
| 97 | = (getrlimit (RLIMIT_AS, &rlimit) == 0 && rlimit.rlim_cur <= SIZE_MAX |
| 98 | ? rlimit.rlim_cur |
| 99 | : SIZE_MAX); |
| 100 | } |
| 101 | |
| 102 | #elif defined WINDOWSNT |
| 103 | |
| 104 | #include "w32heap.h" |
| 105 | |
| 106 | static void |
| 107 | get_lim_data (void) |
| 108 | { |
| 109 | extern size_t reserved_heap_size; |
| 110 | lim_data = reserved_heap_size; |
| 111 | } |
| 112 | |
| 113 | #elif defined MSDOS |
| 114 | |
| 115 | void |
| 116 | get_lim_data (void) |
| 117 | { |
| 118 | _go32_dpmi_meminfo info; |
| 119 | unsigned long lim1, lim2; |
| 120 | |
| 121 | _go32_dpmi_get_free_memory_information (&info); |
| 122 | /* DPMI server of Windows NT and its descendants reports in |
| 123 | info.available_memory a much lower amount that is really |
| 124 | available, which causes bogus "past 95% of memory limit" |
| 125 | warnings. Try to overcome that via circumstantial evidence. */ |
| 126 | lim1 = info.available_memory; |
| 127 | lim2 = info.available_physical_pages; |
| 128 | /* DPMI Spec: "Fields that are unavailable will hold -1." */ |
| 129 | if ((long)lim1 == -1L) |
| 130 | lim1 = 0; |
| 131 | if ((long)lim2 == -1L) |
| 132 | lim2 = 0; |
| 133 | else |
| 134 | lim2 *= 4096; |
| 135 | /* Surely, the available memory is at least what we have physically |
| 136 | available, right? */ |
| 137 | if (lim1 >= lim2) |
| 138 | lim_data = lim1; |
| 139 | else |
| 140 | lim_data = lim2; |
| 141 | /* Don't believe they will give us more that 0.5 GB. */ |
| 142 | if (lim_data > 512U * 1024U * 1024U) |
| 143 | lim_data = 512U * 1024U * 1024U; |
| 144 | } |
| 145 | |
| 146 | unsigned long |
| 147 | ret_lim_data (void) |
| 148 | { |
| 149 | get_lim_data (); |
| 150 | return lim_data; |
| 151 | } |
| 152 | #else |
| 153 | # error "get_lim_data not implemented on this machine" |
| 154 | #endif |
| 155 | \f |
| 156 | /* Verify amount of memory available, complaining if we're near the end. */ |
| 157 | |
| 158 | static void |
| 159 | check_memory_limits (void) |
| 160 | { |
| 161 | #ifdef REL_ALLOC |
| 162 | extern void *(*real_morecore) (ptrdiff_t); |
| 163 | #else |
| 164 | void *(*real_morecore) (ptrdiff_t) = 0; |
| 165 | #endif |
| 166 | extern void *(*__morecore) (ptrdiff_t); |
| 167 | |
| 168 | char *cp; |
| 169 | size_t five_percent; |
| 170 | size_t data_size; |
| 171 | enum warnlevel new_warnlevel; |
| 172 | |
| 173 | if (lim_data == 0) |
| 174 | get_lim_data (); |
| 175 | five_percent = lim_data / 20; |
| 176 | |
| 177 | /* Find current end of memory and issue warning if getting near max */ |
| 178 | cp = (real_morecore ? real_morecore : __morecore) (0); |
| 179 | data_size = cp - data_space_start; |
| 180 | |
| 181 | if (!warn_function) |
| 182 | return; |
| 183 | |
| 184 | /* What level of warning does current memory usage demand? */ |
| 185 | new_warnlevel |
| 186 | = (data_size > five_percent * 19) ? warned_95 |
| 187 | : (data_size > five_percent * 17) ? warned_85 |
| 188 | : (data_size > five_percent * 15) ? warned_75 |
| 189 | : not_warned; |
| 190 | |
| 191 | /* If we have gone up a level, give the appropriate warning. */ |
| 192 | if (new_warnlevel > warnlevel || new_warnlevel == warned_95) |
| 193 | { |
| 194 | warnlevel = new_warnlevel; |
| 195 | switch (warnlevel) |
| 196 | { |
| 197 | case warned_75: |
| 198 | (*warn_function) ("Warning: past 75% of memory limit"); |
| 199 | break; |
| 200 | |
| 201 | case warned_85: |
| 202 | (*warn_function) ("Warning: past 85% of memory limit"); |
| 203 | break; |
| 204 | |
| 205 | case warned_95: |
| 206 | (*warn_function) ("Warning: past 95% of memory limit"); |
| 207 | } |
| 208 | } |
| 209 | /* Handle going down in usage levels, with some hysteresis. */ |
| 210 | else |
| 211 | { |
| 212 | /* If we go down below 70% full, issue another 75% warning |
| 213 | when we go up again. */ |
| 214 | if (data_size < five_percent * 14) |
| 215 | warnlevel = not_warned; |
| 216 | /* If we go down below 80% full, issue another 85% warning |
| 217 | when we go up again. */ |
| 218 | else if (warnlevel > warned_75 && data_size < five_percent * 16) |
| 219 | warnlevel = warned_75; |
| 220 | /* If we go down below 90% full, issue another 95% warning |
| 221 | when we go up again. */ |
| 222 | else if (warnlevel > warned_85 && data_size < five_percent * 18) |
| 223 | warnlevel = warned_85; |
| 224 | } |
| 225 | |
| 226 | if (exceeds_lisp_ptr (cp)) |
| 227 | (*warn_function) ("Warning: memory in use exceeds lisp pointer size"); |
| 228 | } |
| 229 | \f |
| 230 | /* Enable memory usage warnings. |
| 231 | START says where the end of pure storage is. |
| 232 | WARNFUN specifies the function to call to issue a warning. */ |
| 233 | |
| 234 | void |
| 235 | memory_warnings (void *start, void (*warnfun) (const char *)) |
| 236 | { |
| 237 | extern void (* __after_morecore_hook) (void); /* From gmalloc.c */ |
| 238 | |
| 239 | data_space_start = start ? start : data_start; |
| 240 | |
| 241 | warn_function = warnfun; |
| 242 | __after_morecore_hook = check_memory_limits; |
| 243 | |
| 244 | /* Force data limit to be recalculated on each run. */ |
| 245 | lim_data = 0; |
| 246 | } |