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dcfdbac7 JB |
1 | /* Block-relocating memory allocator. |
2 | Copyright (C) 1990 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 1, or (at your option) | |
9 | 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; see the file COPYING. If not, write to | |
18 | the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
19 | ||
20 | /* NOTES: | |
21 | ||
22 | Only relocate the blocs neccessary for SIZE in r_alloc_sbrk, | |
23 | rather than all of them. This means allowing for a possible | |
24 | hole between the first bloc and the end of malloc storage. */ | |
25 | ||
26 | #include "config.h" | |
27 | #include "lisp.h" /* Needed for xterm.h */ | |
28 | #undef NULL | |
29 | #include "mem_limits.h" | |
30 | #include "xterm.h" /* Needed for BLOCK_INPUT */ | |
31 | ||
32 | #define NIL ((POINTER) 0) | |
33 | ||
34 | \f | |
35 | /* System call to set the break value. */ | |
36 | extern POINTER sbrk (); | |
37 | ||
38 | /* The break value, as seen by malloc (). */ | |
39 | static POINTER virtual_break_value; | |
40 | ||
41 | /* The break value, viewed by the relocatable blocs. */ | |
42 | static POINTER break_value; | |
43 | ||
44 | /* The REAL (i.e., page aligned) break value of the process. */ | |
45 | static POINTER page_break_value; | |
46 | ||
47 | /* Macros for rounding. Note that rounding to any value is possible | |
48 | by changing the definition of PAGE. */ | |
49 | #define PAGE (getpagesize ()) | |
50 | #define ALIGNED(addr) (((unsigned int) (addr) & (PAGE - 1)) == 0) | |
51 | #define ROUNDUP(size) (((unsigned int) (size) + PAGE) & ~(PAGE - 1)) | |
52 | #define ROUND_TO_PAGE(addr) (addr & (~(PAGE - 1))) | |
53 | #define EXCEEDS_ELISP_PTR(ptr) ((unsigned int) (ptr) >> VALBITS) | |
54 | \f | |
55 | /* Level of warnings issued. */ | |
56 | static int warnlevel; | |
57 | ||
58 | /* Function to call to issue a warning; | |
59 | 0 means don't issue them. */ | |
60 | static void (*warnfunction) (); | |
61 | ||
62 | static void | |
63 | check_memory_limits (address) | |
64 | POINTER address; | |
65 | { | |
66 | SIZE data_size = address - data_space_start; | |
67 | ||
68 | switch (warnlevel) | |
69 | { | |
70 | case 0: | |
71 | if (data_size > (lim_data / 4) * 3) | |
72 | { | |
73 | warnlevel++; | |
74 | (*warnfunction) ("Warning: past 75% of memory limit"); | |
75 | } | |
76 | break; | |
77 | ||
78 | case 1: | |
79 | if (data_size > (lim_data / 20) * 17) | |
80 | { | |
81 | warnlevel++; | |
82 | (*warnfunction) ("Warning: past 85% of memory limit"); | |
83 | } | |
84 | break; | |
85 | ||
86 | case 2: | |
87 | if (data_size > (lim_data / 20) * 19) | |
88 | { | |
89 | warnlevel++; | |
90 | (*warnfunction) ("Warning: past 95% of memory limit"); | |
91 | } | |
92 | break; | |
93 | ||
94 | default: | |
95 | (*warnfunction) ("Warning: past acceptable memory limits"); | |
96 | break; | |
97 | } | |
98 | ||
99 | if (EXCEEDS_ELISP_PTR (address)) | |
265a9e55 | 100 | memory_full (); |
dcfdbac7 JB |
101 | } |
102 | \f | |
103 | /* Obtain SIZE bytes of space. If enough space is not presently available | |
104 | in our process reserve, (i.e., (page_break_value - break_value)), | |
105 | this means getting more page-aligned space from the system. */ | |
106 | ||
107 | static void | |
108 | obtain (size) | |
109 | SIZE size; | |
110 | { | |
111 | SIZE already_available = page_break_value - break_value; | |
112 | ||
113 | if (already_available < size) | |
114 | { | |
115 | SIZE get = ROUNDUP (size); | |
116 | ||
117 | if (warnfunction) | |
118 | check_memory_limits (page_break_value); | |
119 | ||
120 | if (((int) sbrk (get)) < 0) | |
121 | abort (); | |
122 | ||
123 | page_break_value += get; | |
124 | } | |
125 | ||
126 | break_value += size; | |
127 | } | |
128 | ||
129 | /* Obtain SIZE bytes of space and return a pointer to the new area. */ | |
130 | ||
131 | static POINTER | |
132 | get_more_space (size) | |
133 | SIZE size; | |
134 | { | |
135 | POINTER ptr = break_value; | |
136 | obtain (size); | |
137 | return ptr; | |
138 | } | |
139 | ||
140 | /* Note that SIZE bytes of space have been relinquished by the process. | |
141 | If SIZE is more than a page, return the space the system. */ | |
142 | ||
143 | static void | |
144 | relinquish (size) | |
145 | SIZE size; | |
146 | { | |
147 | SIZE page_part = ROUND_TO_PAGE (size); | |
148 | ||
149 | if (page_part) | |
150 | { | |
151 | if (((int) (sbrk (- page_part))) < 0) | |
152 | abort (); | |
153 | ||
154 | page_break_value -= page_part; | |
155 | } | |
156 | ||
157 | break_value -= size; | |
158 | bzero (break_value, (size - page_part)); | |
159 | } | |
160 | \f | |
161 | typedef struct bp | |
162 | { | |
163 | struct bp *next; | |
164 | struct bp *prev; | |
165 | POINTER *variable; | |
166 | POINTER data; | |
167 | SIZE size; | |
168 | } *bloc_ptr; | |
169 | ||
170 | #define NIL_BLOC ((bloc_ptr) 0) | |
171 | #define BLOC_PTR_SIZE (sizeof (struct bp)) | |
172 | ||
173 | /* Head and tail of the list of relocatable blocs. */ | |
174 | static bloc_ptr first_bloc, last_bloc; | |
175 | ||
176 | /* Declared in dispnew.c, this version dosen't fuck up if regions overlap. */ | |
177 | extern void safe_bcopy (); | |
178 | ||
179 | /* Find the bloc reference by the address in PTR. Returns a pointer | |
180 | to that block. */ | |
181 | ||
182 | static bloc_ptr | |
183 | find_bloc (ptr) | |
184 | POINTER *ptr; | |
185 | { | |
186 | register bloc_ptr p = first_bloc; | |
187 | ||
188 | while (p != NIL_BLOC) | |
189 | { | |
190 | if (p->variable == ptr && p->data == *ptr) | |
191 | return p; | |
192 | ||
193 | p = p->next; | |
194 | } | |
195 | ||
196 | return p; | |
197 | } | |
198 | ||
199 | /* Allocate a bloc of SIZE bytes and append it to the chain of blocs. | |
200 | Returns a pointer to the new bloc. */ | |
201 | ||
202 | static bloc_ptr | |
203 | get_bloc (size) | |
204 | SIZE size; | |
205 | { | |
206 | register bloc_ptr new_bloc = (bloc_ptr) malloc (BLOC_PTR_SIZE); | |
207 | ||
208 | new_bloc->data = get_more_space (size); | |
209 | new_bloc->size = size; | |
210 | new_bloc->next = NIL_BLOC; | |
211 | new_bloc->variable = NIL; | |
212 | ||
213 | if (first_bloc) | |
214 | { | |
215 | new_bloc->prev = last_bloc; | |
216 | last_bloc->next = new_bloc; | |
217 | last_bloc = new_bloc; | |
218 | } | |
219 | else | |
220 | { | |
221 | first_bloc = last_bloc = new_bloc; | |
222 | new_bloc->prev = NIL_BLOC; | |
223 | } | |
224 | ||
225 | return new_bloc; | |
226 | } | |
227 | ||
228 | /* Relocate all blocs from BLOC on upward in the list to the zone | |
229 | indicated by ADDRESS. Direction of relocation is determined by | |
230 | the position of ADDRESS relative to BLOC->data. | |
231 | ||
232 | Note that ordering of blocs is not affected by this function. */ | |
233 | ||
234 | static void | |
235 | relocate_some_blocs (bloc, address) | |
236 | bloc_ptr bloc; | |
237 | POINTER address; | |
238 | { | |
239 | register bloc_ptr b; | |
240 | POINTER data_zone = bloc->data; | |
241 | register SIZE data_zone_size = 0; | |
242 | register SIZE offset = bloc->data - address; | |
243 | POINTER new_data_zone = data_zone - offset; | |
244 | ||
245 | for (b = bloc; b != NIL_BLOC; b = b->next) | |
246 | { | |
247 | data_zone_size += b->size; | |
248 | b->data -= offset; | |
249 | *b->variable = b->data; | |
250 | } | |
251 | ||
252 | safe_bcopy (data_zone, new_data_zone, data_zone_size); | |
253 | } | |
254 | ||
255 | /* Free BLOC from the chain of blocs, relocating any blocs above it | |
256 | and returning BLOC->size bytes to the free area. */ | |
257 | ||
258 | static void | |
259 | free_bloc (bloc) | |
260 | bloc_ptr bloc; | |
261 | { | |
262 | if (bloc == first_bloc && bloc == last_bloc) | |
263 | { | |
264 | first_bloc = last_bloc = NIL_BLOC; | |
265 | } | |
266 | else if (bloc == last_bloc) | |
267 | { | |
268 | last_bloc = bloc->prev; | |
269 | last_bloc->next = NIL_BLOC; | |
270 | } | |
271 | else if (bloc == first_bloc) | |
272 | { | |
273 | first_bloc = bloc->next; | |
274 | first_bloc->prev = NIL_BLOC; | |
275 | relocate_some_blocs (bloc->next, bloc->data); | |
276 | } | |
277 | else | |
278 | { | |
279 | bloc->next->prev = bloc->prev; | |
280 | bloc->prev->next = bloc->next; | |
281 | relocate_some_blocs (bloc->next, bloc->data); | |
282 | } | |
283 | ||
284 | relinquish (bloc->size); | |
285 | free (bloc); | |
286 | } | |
287 | \f | |
288 | static int use_relocatable_buffers; | |
289 | ||
290 | /* Obtain SIZE bytes of storage from the free pool, or the system, | |
291 | as neccessary. If relocatable blocs are in use, this means | |
292 | relocating them. */ | |
293 | ||
294 | POINTER | |
295 | r_alloc_sbrk (size) | |
296 | long size; | |
297 | { | |
298 | POINTER ptr; | |
299 | ||
300 | if (! use_relocatable_buffers) | |
301 | return sbrk (size); | |
302 | ||
303 | if (size > 0) | |
304 | { | |
305 | obtain (size); | |
306 | if (first_bloc) | |
307 | { | |
308 | relocate_some_blocs (first_bloc, first_bloc->data + size); | |
309 | bzero (virtual_break_value, size); | |
310 | } | |
311 | } | |
312 | else if (size < 0) | |
313 | { | |
314 | if (first_bloc) | |
315 | relocate_some_blocs (first_bloc, first_bloc->data + size); | |
316 | relinquish (- size); | |
317 | } | |
318 | ||
319 | ptr = virtual_break_value; | |
320 | virtual_break_value += size; | |
321 | return ptr; | |
322 | } | |
323 | ||
324 | /* Allocate a relocatable bloc of storage of size SIZE. A pointer to | |
325 | the data is returned in *PTR. PTR is thus the address of some variable | |
326 | which will use the data area. */ | |
327 | ||
328 | POINTER | |
329 | r_alloc (ptr, size) | |
330 | POINTER *ptr; | |
331 | SIZE size; | |
332 | { | |
333 | register bloc_ptr new_bloc; | |
334 | ||
335 | BLOCK_INPUT; | |
336 | new_bloc = get_bloc (size); | |
337 | new_bloc->variable = ptr; | |
338 | *ptr = new_bloc->data; | |
339 | UNBLOCK_INPUT; | |
340 | ||
341 | return *ptr; | |
342 | } | |
343 | ||
344 | /* Free a bloc of relocatable storage whose data is pointed to by PTR. */ | |
345 | ||
346 | void | |
347 | r_alloc_free (ptr) | |
348 | register POINTER *ptr; | |
349 | { | |
350 | register bloc_ptr dead_bloc; | |
351 | ||
352 | BLOCK_INPUT; | |
353 | dead_bloc = find_bloc (ptr); | |
354 | if (dead_bloc == NIL_BLOC) | |
355 | abort (); | |
356 | ||
357 | free_bloc (dead_bloc); | |
358 | UNBLOCK_INPUT; | |
359 | } | |
360 | ||
361 | /* Given a pointer at address PTR to relocatable data, resize it | |
362 | to SIZE. This is done by obtaining a new block and freeing the | |
363 | old, unless SIZE is less than or equal to the current bloc size, | |
364 | in which case nothing happens and the current value is returned. | |
365 | ||
366 | The contents of PTR is changed to reflect the new bloc, and this | |
367 | value is returned. */ | |
368 | ||
369 | POINTER | |
370 | r_re_alloc (ptr, size) | |
371 | POINTER *ptr; | |
372 | SIZE size; | |
373 | { | |
374 | register bloc_ptr old_bloc, new_bloc; | |
375 | ||
376 | BLOCK_INPUT; | |
377 | old_bloc = find_bloc (ptr); | |
378 | if (old_bloc == NIL_BLOC) | |
379 | abort (); | |
380 | ||
381 | if (size <= old_bloc->size) | |
382 | return *ptr; | |
383 | ||
384 | new_bloc = get_bloc (size); | |
385 | new_bloc->variable = ptr; | |
386 | safe_bcopy (old_bloc->data, new_bloc->data, old_bloc->size); | |
387 | *ptr = new_bloc->data; | |
388 | ||
389 | free_bloc (old_bloc); | |
390 | UNBLOCK_INPUT; | |
391 | ||
392 | return *ptr; | |
393 | } | |
394 | \f | |
395 | /* The hook `malloc' uses for the function which gets more space | |
396 | from the system. */ | |
397 | extern POINTER (*__morecore) (); | |
398 | ||
399 | /* Intialize various things for memory allocation. */ | |
400 | ||
401 | void | |
402 | malloc_init (start, warn_func) | |
403 | POINTER start; | |
404 | void (*warn_func) (); | |
405 | { | |
406 | static int malloc_initialized = 0; | |
407 | ||
408 | if (start) | |
409 | data_space_start = start; | |
410 | ||
411 | if (malloc_initialized) | |
412 | return; | |
413 | ||
414 | malloc_initialized = 1; | |
415 | __morecore = r_alloc_sbrk; | |
416 | virtual_break_value = break_value = sbrk (0); | |
417 | page_break_value = (POINTER) ROUNDUP (break_value); | |
418 | bzero (break_value, (page_break_value - break_value)); | |
419 | use_relocatable_buffers = 1; | |
420 | ||
421 | lim_data = 0; | |
422 | warnlevel = 0; | |
423 | warnfunction = warn_func; | |
424 | ||
425 | get_lim_data (); | |
426 | } |