1 /*
2 * ircd-ratbox: A slightly useful ircd.
3 * balloc.c: A block allocator.
4 *
5 * Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
6 * Copyright (C) 1996-2002 Hybrid Development Team
7 * Copyright (C) 2002-2012 ircd-ratbox development team
8 *
9 * Below are the orignal headers from the old blalloc.c
10 *
11 * File: blalloc.c
12 * Owner: Wohali (Joan Touzet)
13 *
14 * Modified 2001/11/29 for mmap() support by Aaron Sethman <androsyn@ratbox.org>
15 *
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License as published by
18 * the Free Software Foundation; either version 2 of the License, or
19 * (at your option) any later version.
20 *
21 * This program is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24 * GNU General Public License for more details.
25 *
26 * You should have received a copy of the GNU General Public License
27 * along with this program; if not, write to the Free Software
28 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
29 * USA
30 *
31 * $Id: balloc.c 27377 2012-03-16 06:29:42Z dubkat $
32 */
33
34 /*
35 * About the block allocator
36 *
37 * Basically we have three ways of getting memory off of the operating
38 * system. Below are this list of methods and the order of preference.
39 *
40 * 1. mmap() anonymous pages with the MMAP_ANON flag.
41 * 2. mmap() via the /dev/zero trick.
42 * 3. HeapCreate/HeapAlloc (on win32)
43 * 4. malloc()
44 *
45 * The advantages of 1 and 2 are this. We can munmap() the pages which will
46 * return the pages back to the operating system, thus reducing the size
47 * of the process as the memory is unused. malloc() on many systems just keeps
48 * a heap of memory to itself, which never gets given back to the OS, except on
49 * exit. This of course is bad, if say we have an event that causes us to allocate
50 * say, 200MB of memory, while our normal memory consumption would be 15MB. In the
51 * malloc() case, the amount of memory allocated to our process never goes down, as
52 * malloc() has it locked up in its heap. With the mmap() method, we can munmap()
53 * the block and return it back to the OS, thus causing our memory consumption to go
54 * down after we no longer need it.
55 *
56 *
57 *
58 */
59 #include <libratbox_config.h>
60 #include <ratbox_lib.h>
61
62 #ifndef NOBALLOC
63 #ifdef HAVE_MMAP /* We've got mmap() that is good */
64 #include <sys/mman.h>
65 /* HP-UX sucks */
66 #ifdef MAP_ANONYMOUS
67 #ifndef MAP_ANON
68 #define MAP_ANON MAP_ANONYMOUS
69 #endif
70 #endif
71 #endif
72 #endif
73
74 static uintptr_t offset_pad;
75
76 /* status information for an allocated block in heap */
77 struct rb_heap_block
78 {
79 size_t alloc_size;
80 rb_dlink_node node;
81 unsigned long free_count;
82 void *elems; /* Points to allocated memory */
83 };
84 typedef struct rb_heap_block rb_heap_block;
85
86 /* information for the root node of the heap */
87 struct rb_bh
88 {
89 rb_dlink_node hlist;
90 size_t elemSize; /* Size of each element to be stored */
91 unsigned long elemsPerBlock; /* Number of elements per block */
92 rb_dlink_list block_list;
93 rb_dlink_list free_list;
94 char *desc;
95 };
96
97 #ifndef NOBALLOC
98 static int newblock(rb_bh *bh);
99 static void rb_bh_gc_event(void *unused);
100 #endif /* !NOBALLOC */
101 static rb_dlink_list *heap_lists;
102
103 #if defined(WIN32)
104 static HANDLE block_heap;
105 #endif
106
107 #define rb_bh_fail(x) _rb_bh_fail(x, __FILE__, __LINE__)
108
109 static void
_rb_bh_fail(const char * reason,const char * file,int line)110 _rb_bh_fail(const char *reason, const char *file, int line)
111 {
112 rb_lib_log("rb_heap_blockheap failure: %s (%s:%d)", reason, file, line);
113 abort();
114 }
115
116 #ifndef NOBALLOC
117 /*
118 * static inline void free_block(void *ptr, size_t size)
119 *
120 * Inputs: The block and its size
121 * Output: None
122 * Side Effects: Returns memory for the block back to the OS
123 */
124 static inline void
free_block(void * ptr,size_t size)125 free_block(void *ptr, size_t size)
126 {
127 #ifdef HAVE_MMAP
128 munmap(ptr, size);
129 #else
130 #ifdef _WIN32
131 HeapFree(block_heap, 0, ptr);
132 #else
133 free(ptr);
134 #endif
135 #endif
136 }
137 #endif /* !NOBALLOC */
138
139 /*
140 * void rb_init_bh(void)
141 *
142 * Inputs: None
143 * Outputs: None
144 * Side Effects: Initializes the block heap
145 */
146
147 void
rb_init_bh(void)148 rb_init_bh(void)
149 {
150 heap_lists = rb_malloc(sizeof(rb_dlink_list));
151 offset_pad = sizeof(void *);
152 /* XXX if you get SIGBUS when trying to use a long long..here is where you need to
153 * fix your shit
154 */
155 #ifdef __sparc__
156 if((offset_pad % __alignof__(long long)) != 0)
157 {
158 offset_pad += __alignof__(long long);
159 offset_pad &= ~(__alignof__(long long) - 1);
160 }
161 #endif
162
163 #ifndef NOBALLOC
164 #ifdef _WIN32
165 block_heap = HeapCreate(HEAP_NO_SERIALIZE, 0, 0);
166 #endif
167 rb_event_addish("rb_bh_gc_event", rb_bh_gc_event, NULL, 300);
168 #endif /* !NOBALLOC */
169 }
170
171 #ifndef NOBALLOC
172 /*
173 * static inline void *get_block(size_t size)
174 *
175 * Input: Size of block to allocate
176 * Output: Pointer to new block
177 * Side Effects: None
178 */
179 static inline void *
get_block(size_t size)180 get_block(size_t size)
181 {
182 void *ptr;
183 #ifdef HAVE_MMAP
184 #ifdef MAP_ANON
185 ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
186 #else
187 int zero_fd;
188 zero_fd = open("/dev/zero", O_RDWR);
189 if(zero_fd < 0)
190 rb_bh_fail("Failed opening /dev/zero");
191 ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, zero_fd, 0);
192 close(zero_fd);
193 #endif /* MAP_ANON */
194 if(ptr == MAP_FAILED)
195 ptr = NULL;
196 #else
197 #ifdef _WIN32
198 ptr = HeapAlloc(block_heap, 0, size);
199 #else
200 ptr = malloc(size);
201 #endif
202 #endif
203 return (ptr);
204 }
205
206
207 static void
rb_bh_gc_event(void * unused)208 rb_bh_gc_event(void *unused)
209 {
210 rb_dlink_node *ptr;
211 RB_DLINK_FOREACH(ptr, heap_lists->head)
212 {
213 rb_bh_gc(ptr->data);
214 }
215 }
216
217 /* ************************************************************************ */
218 /* FUNCTION DOCUMENTATION: */
219 /* newblock */
220 /* Description: */
221 /* Allocates a new block for addition to a blockheap */
222 /* Parameters: */
223 /* bh (IN): Pointer to parent blockheap. */
224 /* Returns: */
225 /* 0 if successful, 1 if not */
226 /* ************************************************************************ */
227
228 static int
newblock(rb_bh * bh)229 newblock(rb_bh *bh)
230 {
231 rb_heap_block *b;
232 unsigned long i;
233 uintptr_t offset;
234 rb_dlink_node *node;
235 /* Setup the initial data structure. */
236 b = rb_malloc(sizeof(rb_heap_block));
237
238 b->alloc_size = bh->elemsPerBlock * bh->elemSize;
239
240 b->elems = get_block(b->alloc_size);
241 if(rb_unlikely(b->elems == NULL))
242 {
243 return (1);
244 }
245 offset = (uintptr_t)b->elems;
246 /* Setup our blocks now */
247 for(i = 0; i < bh->elemsPerBlock; i++, offset += bh->elemSize)
248 {
249 *((void **)offset) = b;
250 node = (void *)(offset + offset_pad);
251 rb_dlinkAdd((void *)offset, node, &bh->free_list);
252 }
253 rb_dlinkAdd(b, &b->node, &bh->block_list);
254 b->free_count = bh->elemsPerBlock;
255 return (0);
256 }
257 #endif /* !NOBALLOC */
258
259 /* ************************************************************************ */
260 /* FUNCTION DOCUMENTATION: */
261 /* rb_bh_create */
262 /* Description: */
263 /* Creates a new blockheap from which smaller blocks can be allocated. */
264 /* Intended to be used instead of multiple calls to malloc() when */
265 /* performance is an issue. */
266 /* Parameters: */
267 /* elemsize (IN): Size of the basic element to be stored */
268 /* elemsperblock (IN): Number of elements to be stored in a single block */
269 /* of memory. When the blockheap runs out of free memory, it will */
270 /* allocate elemsize * elemsperblock more. */
271 /* Returns: */
272 /* Pointer to new rb_bh, or NULL if unsuccessful */
273 /* ************************************************************************ */
274 rb_bh *
rb_bh_create(size_t elemsize,int elemsperblock,const char * desc)275 rb_bh_create(size_t elemsize, int elemsperblock, const char *desc)
276 {
277 rb_bh *bh;
278 lrb_assert(elemsize > 0 && elemsperblock > 0);
279 lrb_assert(elemsize >= sizeof(rb_dlink_node));
280
281 /* Catch idiotic requests up front */
282 if((elemsize == 0) || (elemsperblock <= 0))
283 {
284 rb_bh_fail("Attempting to rb_bh_create idiotic sizes");
285 }
286
287 if(elemsize < sizeof(rb_dlink_node))
288 rb_bh_fail("Attempt to rb_bh_create smaller than sizeof(rb_dlink_node)");
289
290 /* Allocate our new rb_bh */
291 bh = rb_malloc(sizeof(rb_bh));
292 #ifndef NOBALLOC
293 elemsize += offset_pad;
294 if((elemsize % sizeof(void *)) != 0)
295 {
296 /* Pad to even pointer boundary */
297 elemsize += sizeof(void *);
298 elemsize &= ~(sizeof(void *) - 1);
299 }
300 #endif
301
302 bh->elemSize = elemsize;
303 bh->elemsPerBlock = elemsperblock;
304 if(desc != NULL)
305 bh->desc = rb_strdup(desc);
306
307 #ifndef NOBALLOC
308 /* Be sure our malloc was successful */
309 if(newblock(bh))
310 {
311 if(bh != NULL)
312 free(bh);
313 rb_lib_log("newblock() failed");
314 rb_outofmemory(); /* die.. out of memory */
315 }
316 #endif /* !NOBALLOC */
317
318 if(bh == NULL)
319 {
320 rb_bh_fail("bh == NULL when it shouldn't be");
321 }
322 rb_dlinkAdd(bh, &bh->hlist, heap_lists);
323 return (bh);
324 }
325
326 /* ************************************************************************ */
327 /* FUNCTION DOCUMENTATION: */
328 /* rb_bh_alloc */
329 /* Description: */
330 /* Returns a pointer to a struct within our rb_bh that's free for */
331 /* the taking. */
332 /* Parameters: */
333 /* bh (IN): Pointer to the Blockheap. */
334 /* Returns: */
335 /* Pointer to a structure (void *), or NULL if unsuccessful. */
336 /* ************************************************************************ */
337
338 void *
rb_bh_alloc(rb_bh * bh)339 rb_bh_alloc(rb_bh *bh)
340 {
341 #ifndef NOBALLOC
342 rb_dlink_node *new_node;
343 rb_heap_block **block;
344 void *ptr;
345 #endif
346 lrb_assert(bh != NULL);
347 if(rb_unlikely(bh == NULL))
348 {
349 rb_bh_fail("Cannot allocate if bh == NULL");
350 }
351
352 #ifdef NOBALLOC
353 return (rb_malloc(bh->elemSize));
354 #else
355 if(bh->free_list.head == NULL)
356 {
357 /* Allocate new block and assign */
358 /* newblock returns 1 if unsuccessful, 0 if not */
359
360 if(rb_unlikely(newblock(bh)))
361 {
362 rb_lib_log("newblock() failed");
363 rb_outofmemory(); /* Well that didn't work either...bail */
364 }
365 if(bh->free_list.head == NULL)
366 {
367 rb_lib_log("out of memory after newblock()...");
368 rb_outofmemory();
369 }
370 }
371
372 new_node = bh->free_list.head;
373 block = (rb_heap_block **) new_node->data;
374 ptr = (void *)((uintptr_t)new_node->data + (uintptr_t)offset_pad);
375 rb_dlinkDelete(new_node, &bh->free_list);
376 (*block)->free_count--;
377 memset(ptr, 0, bh->elemSize - offset_pad);
378 return (ptr);
379 #endif
380 }
381
382
383 /* ************************************************************************ */
384 /* FUNCTION DOCUMENTATION: */
385 /* rb_bh_free */
386 /* Description: */
387 /* Returns an element to the free pool, does not free() */
388 /* Parameters: */
389 /* bh (IN): Pointer to rb_bh containing element */
390 /* ptr (in): Pointer to element to be "freed" */
391 /* Returns: */
392 /* 0 if successful, 1 if element not contained within rb_bh. */
393 /* ************************************************************************ */
394 int
rb_bh_free(rb_bh * bh,void * ptr)395 rb_bh_free(rb_bh *bh, void *ptr)
396 {
397 #ifndef NOBALLOC
398 rb_heap_block *block;
399 void *data;
400 #endif
401 lrb_assert(bh != NULL);
402 lrb_assert(ptr != NULL);
403
404 if(rb_unlikely(bh == NULL))
405 {
406 rb_lib_log("balloc.c:rb_bhFree() bh == NULL");
407 return (1);
408 }
409
410 if(rb_unlikely(ptr == NULL))
411 {
412 rb_lib_log("balloc.rb_bhFree() ptr == NULL");
413 return (1);
414 }
415
416 #ifdef NOBALLOC
417 rb_free(ptr);
418 #else
419 data = (void *)((uintptr_t)ptr - (uintptr_t)offset_pad);
420 block = *(rb_heap_block **) data;
421 /* XXX */
422 if(rb_unlikely
423 (!((uintptr_t)ptr >= (uintptr_t)block->elems
424 && (uintptr_t)ptr < (uintptr_t)block->elems + (uintptr_t)block->alloc_size)))
425 {
426 rb_bh_fail("rb_bh_free() bogus pointer");
427 }
428 block->free_count++;
429
430 rb_dlinkAdd(data, (rb_dlink_node *)ptr, &bh->free_list);
431 #endif /* !NOBALLOC */
432 return (0);
433 }
434
435
436 /* ************************************************************************ */
437 /* FUNCTION DOCUMENTATION: */
438 /* rb_bhDestroy */
439 /* Description: */
440 /* Completely free()s a rb_bh. Use for cleanup. */
441 /* Parameters: */
442 /* bh (IN): Pointer to the rb_bh to be destroyed. */
443 /* Returns: */
444 /* 0 if successful, 1 if bh == NULL */
445 /* ************************************************************************ */
446 int
rb_bh_destroy(rb_bh * bh)447 rb_bh_destroy(rb_bh *bh)
448 {
449 #ifndef NOBALLOC
450 rb_dlink_node *ptr, *next;
451 rb_heap_block *b;
452 #endif
453 if(bh == NULL)
454 return (1);
455
456 #ifndef NOBALLOC
457 RB_DLINK_FOREACH_SAFE(ptr, next, bh->block_list.head)
458 {
459 b = ptr->data;
460 free_block(b->elems, b->alloc_size);
461 rb_free(b);
462 }
463 #endif /* !NOBALLOC */
464
465 rb_dlinkDelete(&bh->hlist, heap_lists);
466 rb_free(bh->desc);
467 rb_free(bh);
468
469 return (0);
470 }
471
472 void
rb_bh_usage(rb_bh * bh,size_t * bused,size_t * bfree,size_t * bmemusage,const char ** desc)473 rb_bh_usage(rb_bh *bh, size_t *bused, size_t *bfree, size_t *bmemusage, const char **desc)
474 {
475 #ifndef NOBALLOC
476 size_t used, freem, memusage;
477
478 if(bh == NULL)
479 {
480 return;
481 }
482
483 freem = rb_dlink_list_length(&bh->free_list);
484 used = (rb_dlink_list_length(&bh->block_list) * bh->elemsPerBlock) - freem;
485 memusage = used * bh->elemSize;
486 if(bused != NULL)
487 *bused = used;
488 if(bfree != NULL)
489 *bfree = freem;
490 if(bmemusage != NULL)
491 *bmemusage = memusage;
492 if(desc != NULL)
493 *desc = bh->desc;
494 #else
495 static char *noballoc = "no blockheap";
496 *bused = 0;
497 *bfree = 0;
498 *bmemusage = 0;
499 *desc = noballoc;
500 #endif
501 }
502
503 void
rb_bh_usage_all(rb_bh_usage_cb * cb,void * data)504 rb_bh_usage_all(rb_bh_usage_cb *cb, void *data)
505 {
506 rb_dlink_node *ptr;
507 rb_bh *bh;
508 size_t used, freem, memusage, heapalloc;
509 static const char *unnamed = "(unnamed_heap)";
510 const char *desc = unnamed;
511
512 if(cb == NULL)
513 return;
514
515 RB_DLINK_FOREACH(ptr, heap_lists->head)
516 {
517 bh = (rb_bh *)ptr->data;
518 freem = rb_dlink_list_length(&bh->free_list);
519 used = (rb_dlink_list_length(&bh->block_list) * bh->elemsPerBlock) - freem;
520 memusage = used * bh->elemSize;
521 heapalloc = (freem + used) * bh->elemSize;
522 if(bh->desc != NULL)
523 desc = bh->desc;
524 cb(used, freem, memusage, heapalloc, desc, data);
525 }
526 return;
527 }
528
529 void
rb_bh_total_usage(size_t * total_alloc,size_t * total_used)530 rb_bh_total_usage(size_t *total_alloc, size_t *total_used)
531 {
532 rb_dlink_node *ptr;
533 size_t total_memory = 0, used_memory = 0, used, freem;
534 rb_bh *bh;
535
536 RB_DLINK_FOREACH(ptr, heap_lists->head)
537 {
538 bh = (rb_bh *)ptr->data;
539 freem = rb_dlink_list_length(&bh->free_list);
540 used = (rb_dlink_list_length(&bh->block_list) * bh->elemsPerBlock) - freem;
541 used_memory += used * bh->elemSize;
542 total_memory += (freem + used) * bh->elemSize;
543 }
544
545 if(total_alloc != NULL)
546 *total_alloc = total_memory;
547 if(total_used != NULL)
548 *total_used = used_memory;
549 }
550
551 #ifndef NOBALLOC
552 int
rb_bh_gc(rb_bh * bh)553 rb_bh_gc(rb_bh *bh)
554 {
555 rb_heap_block *b;
556 rb_dlink_node *ptr, *next;
557 unsigned long i;
558 uintptr_t offset;
559
560 if(bh == NULL)
561 {
562 /* somebody is smoking some craq..(probably lee, but don't tell him that) */
563 return (1);
564 }
565
566 if((rb_dlink_list_length(&bh->free_list) < bh->elemsPerBlock)
567 || rb_dlink_list_length(&bh->block_list) == 1)
568 {
569 /* There couldn't possibly be an entire free block. Return. */
570 return (0);
571 }
572
573 RB_DLINK_FOREACH_SAFE(ptr, next, bh->block_list.head)
574 {
575 b = ptr->data;
576 if(rb_dlink_list_length(&bh->block_list) == 1)
577 return (0);
578
579 if(b->free_count == bh->elemsPerBlock)
580 {
581 /* i'm seriously going to hell for this.. */
582
583 offset = (uintptr_t)b->elems;
584 for(i = 0; i < bh->elemsPerBlock; i++, offset += (uintptr_t)bh->elemSize)
585 {
586 rb_dlinkDelete((rb_dlink_node *)(offset + offset_pad),
587 &bh->free_list);
588 }
589 rb_dlinkDelete(&b->node, &bh->block_list);
590 free_block(b->elems, b->alloc_size);
591 rb_free(b);
592 }
593
594 }
595 return (0);
596 }
597 #endif /* !NOBALLOC */
598