xref: /titanic_41/usr/src/lib/libast/common/vmalloc/vmbest.c (revision 8e50dcc9f00b393d43e6aa42b820bcbf1d3e1ce4)
1 /***********************************************************************
2 *                                                                      *
3 *               This software is part of the ast package               *
4 *           Copyright (c) 1985-2007 AT&T Knowledge Ventures            *
5 *                      and is licensed under the                       *
6 *                  Common Public License, Version 1.0                  *
7 *                      by AT&T Knowledge Ventures                      *
8 *                                                                      *
9 *                A copy of the License is available at                 *
10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
12 *                                                                      *
13 *              Information and Software Systems Research               *
14 *                            AT&T Research                             *
15 *                           Florham Park NJ                            *
16 *                                                                      *
17 *                 Glenn Fowler <gsf@research.att.com>                  *
18 *                  David Korn <dgk@research.att.com>                   *
19 *                   Phong Vo <kpv@research.att.com>                    *
20 *                                                                      *
21 ***********************************************************************/
22 #if defined(_UWIN) && defined(_BLD_ast)
23 
24 void _STUB_vmbest(){}
25 
26 #else
27 
28 #include	"vmhdr.h"
29 
30 /*	Best-fit allocation method. This is based on a best-fit strategy
31 **	using a splay tree for storage of lists of free blocks of the same
32 **	size. Recent free blocks may be cached for fast reuse.
33 **
34 **	Written by Kiem-Phong Vo, kpv@research.att.com, 01/16/94.
35 */
36 
37 #ifdef DEBUG
38 static int	N_free;		/* # of free calls			*/
39 static int	N_alloc;	/* # of alloc calls			*/
40 static int	N_resize;	/* # of resize calls			*/
41 static int	N_wild;		/* # allocated from the wild block	*/
42 static int	N_last;		/* # allocated from last free block	*/
43 static int	N_reclaim;	/* # of bestreclaim calls		*/
44 
45 #undef	VM_TRUST		/* always check for locking, etc.s	*/
46 #define	VM_TRUST	0
47 #endif /*DEBUG*/
48 
49 #define COMPACT		8	/* factor to decide when to compact	*/
50 
51 /* Check to see if a block is in the free tree */
52 #if __STD_C
53 static int vmintree(Block_t* node, Block_t* b)
54 #else
55 static int vmintree(node,b)
56 Block_t*	node;
57 Block_t*	b;
58 #endif
59 {	Block_t*	t;
60 
61 	for(t = node; t; t = LINK(t))
62 		if(t == b)
63 			return 1;
64 	if(LEFT(node) && vmintree(LEFT(node),b))
65 		return 1;
66 	if(RIGHT(node) && vmintree(RIGHT(node),b))
67 		return 1;
68 	return 0;
69 }
70 
71 #if __STD_C
72 static int vmonlist(Block_t* list, Block_t* b)
73 #else
74 static int vmonlist(list,b)
75 Block_t*	list;
76 Block_t*	b;
77 #endif
78 {
79 	for(; list; list = LINK(list))
80 		if(list == b)
81 			return 1;
82 	return 0;
83 }
84 
85 /* Check to see if a block is known to be free */
86 #if __STD_C
87 static int vmisfree(Vmdata_t* vd, Block_t* b)
88 #else
89 static int vmisfree(vd,b)
90 Vmdata_t*	vd;
91 Block_t*	b;
92 #endif
93 {
94 	if(SIZE(b) & (BUSY|JUNK|PFREE))
95 		return 0;
96 
97 	if(b == vd->wild)
98 		return 1;
99 
100 	if(SIZE(b) < MAXTINY)
101 		return vmonlist(TINY(vd)[INDEX(SIZE(b))], b);
102 
103 	if(vd->root)
104 		return vmintree(vd->root, b);
105 
106 	return 0;
107 }
108 
109 /* Check to see if a block is known to be junked */
110 #if __STD_C
111 static int vmisjunk(Vmdata_t* vd, Block_t* b)
112 #else
113 static int vmisjunk(vd,b)
114 Vmdata_t*	vd;
115 Block_t*	b;
116 #endif
117 {
118 	Block_t*	t;
119 
120 	if((SIZE(b)&BUSY) == 0 || (SIZE(b)&JUNK) == 0)
121 		return 0;
122 
123 	if(b == vd->free) /* recently freed */
124 		return 1;
125 
126 	/* check the list that b is supposed to be in */
127 	for(t = CACHE(vd)[C_INDEX(SIZE(b))]; t; t = LINK(t))
128 		if(t == b)
129 			return 1;
130 
131 	/* on occasions, b may be put onto the catch-all list */
132 	if(C_INDEX(SIZE(b)) < S_CACHE)
133 		for(t = CACHE(vd)[S_CACHE]; t; t = LINK(t))
134 			if(t == b)
135 				return 1;
136 
137 	return 0;
138 }
139 
140 /* check to see if the free tree is in good shape */
141 #if __STD_C
142 static int vmchktree(Block_t* node)
143 #else
144 static int vmchktree(node)
145 Block_t*	node;
146 #endif
147 {	Block_t*	t;
148 
149 	if(SIZE(node) & BITS)
150 		{ /**/ASSERT(0); return -1; }
151 
152 	for(t = LINK(node); t; t = LINK(t))
153 		if(SIZE(t) != SIZE(node))
154 			{ /**/ASSERT(0); return -1; }
155 
156 	if((t = LEFT(node)) )
157 	{	if(SIZE(t) >= SIZE(node) )
158 			{ /**/ASSERT(0); return -1; }
159 		else	return vmchktree(t);
160 	}
161 	if((t = RIGHT(node)) )
162 	{	if(SIZE(t) <= SIZE(node) )
163 			{ /**/ASSERT(0); return -1; }
164 		else	return vmchktree(t);
165 	}
166 
167 	return 0;
168 }
169 
170 #if __STD_C
171 int _vmbestcheck(Vmdata_t* vd, Block_t* freeb)
172 #else
173 int _vmbestcheck(vd, freeb)
174 Vmdata_t*	vd;
175 Block_t*	freeb; /* known to be free but not on any free list */
176 #endif
177 {
178 	reg Seg_t	*seg;
179 	reg Block_t	*b, *endb, *nextb;
180 	int		rv = 0;
181 
182 	if(!CHECK())
183 		return 0;
184 
185 	/* make sure the free tree is still in shape */
186 	if(vd->root && vmchktree(vd->root) < 0 )
187 		{ rv = -1; /**/ASSERT(0); }
188 
189 	for(seg = vd->seg; seg && rv == 0; seg = seg->next)
190 	{	b = SEGBLOCK(seg);
191 		endb = (Block_t*)(seg->baddr - sizeof(Head_t));
192 		for(; b < endb && rv == 0; b = nextb)
193 		{	nextb = (Block_t*)((Vmuchar_t*)DATA(b) + (SIZE(b)&~BITS) );
194 
195 			if(!ISBUSY(SIZE(b)) ) /* a completely free block */
196 			{	/* there should be no marked bits of any type */
197 				if(SIZE(b) & (BUSY|JUNK|PFREE) )
198 					{ rv = -1; /**/ASSERT(0); }
199 
200 				/* next block must be busy and marked PFREE */
201 				if(!ISBUSY(SIZE(nextb)) || !ISPFREE(SIZE(nextb)) )
202 					{ rv = -1; /**/ASSERT(0); }
203 
204 				/* must have a self-reference pointer */
205 				if(*SELF(b) != b)
206 					{ rv = -1; /**/ASSERT(0); }
207 
208 				/* segment pointer should be well-defined */
209 				if(!TINIEST(b) && SEG(b) != seg)
210 					{ rv = -1; /**/ASSERT(0); }
211 
212 				/* must be on a free list */
213 				if(b != freeb && !vmisfree(vd, b) )
214 					{ rv = -1; /**/ASSERT(0); }
215 			}
216 			else
217 			{	/* segment pointer should be well-defined */
218 				if(SEG(b) != seg)
219 					{ rv = -1; /**/ASSERT(0); }
220 
221 				/* next block should not be marked PFREE */
222 				if(ISPFREE(SIZE(nextb)) )
223 					{ rv = -1; /**/ASSERT(0); }
224 
225 				/* if PFREE, last block should be free */
226 				if(ISPFREE(SIZE(b)) && LAST(b) != freeb &&
227 				   !vmisfree(vd, LAST(b)) )
228 					{ rv = -1; /**/ASSERT(0); }
229 
230 				/* if free but unreclaimed, should be junk */
231 				if(ISJUNK(SIZE(b)) && !vmisjunk(vd, b))
232 					{ rv = -1; /**/ASSERT(0); }
233 			}
234 		}
235 	}
236 
237 	return rv;
238 }
239 
240 /* Tree rotation functions */
241 #define RROTATE(x,y)	(LEFT(x) = RIGHT(y), RIGHT(y) = (x), (x) = (y))
242 #define LROTATE(x,y)	(RIGHT(x) = LEFT(y), LEFT(y) = (x), (x) = (y))
243 #define RLINK(s,x)	((s) = LEFT(s) = (x))
244 #define LLINK(s,x)	((s) = RIGHT(s) = (x))
245 
246 /* Find and delete a suitable element in the free tree. */
247 #if __STD_C
248 static Block_t* bestsearch(Vmdata_t* vd, reg size_t size, Block_t* wanted)
249 #else
250 static Block_t* bestsearch(vd, size, wanted)
251 Vmdata_t*	vd;
252 reg size_t	size;
253 Block_t*	wanted;
254 #endif
255 {
256 	reg size_t	s;
257 	reg Block_t	*t, *root, *l, *r;
258 	Block_t		link;
259 
260 	/* extracting a tiniest block from its list */
261 	if((root = wanted) && size == TINYSIZE)
262 	{	reg Seg_t*	seg;
263 
264 		l = TLEFT(root);
265 		if((r = LINK(root)) )
266 			TLEFT(r) = l;
267 		if(l)
268 			LINK(l) = r;
269 		else	TINY(vd)[0] = r;
270 
271 		seg = vd->seg;
272 		if(!seg->next)
273 			SEG(root) = seg;
274 		else for(;; seg = seg->next)
275 		{	if((Vmuchar_t*)root > (Vmuchar_t*)seg->addr &&
276 			   (Vmuchar_t*)root < seg->baddr)
277 			{	SEG(root) = seg;
278 				break;
279 			}
280 		}
281 
282 		return root;
283 	}
284 
285 	/**/ASSERT(!vd->root || vmchktree(vd->root) == 0);
286 
287 	/* find the right one to delete */
288 	l = r = &link;
289 	if((root = vd->root) ) do
290 	{	/**/ ASSERT(!ISBITS(size) && !ISBITS(SIZE(root)));
291 		if(size == (s = SIZE(root)) )
292 			break;
293 		if(size < s)
294 		{	if((t = LEFT(root)) )
295 			{	if(size <= (s = SIZE(t)) )
296 				{	RROTATE(root,t);
297 					if(size == s)
298 						break;
299 					t = LEFT(root);
300 				}
301 				else
302 				{	LLINK(l,t);
303 					t = RIGHT(t);
304 				}
305 			}
306 			RLINK(r,root);
307 		}
308 		else
309 		{	if((t = RIGHT(root)) )
310 			{	if(size >= (s = SIZE(t)) )
311 				{	LROTATE(root,t);
312 					if(size == s)
313 						break;
314 					t = RIGHT(root);
315 				}
316 				else
317 				{	RLINK(r,t);
318 					t = LEFT(t);
319 				}
320 			}
321 			LLINK(l,root);
322 		}
323 		/**/ ASSERT(root != t);
324 	} while((root = t) );
325 
326 	if(root)	/* found it, now isolate it */
327 	{	RIGHT(l) = LEFT(root);
328 		LEFT(r) = RIGHT(root);
329 	}
330 	else		/* nothing exactly fit	*/
331 	{	LEFT(r) = NIL(Block_t*);
332 		RIGHT(l) = NIL(Block_t*);
333 
334 		/* grab the least one from the right tree */
335 		if((root = LEFT(&link)) )
336 		{	while((t = LEFT(root)) )
337 				RROTATE(root,t);
338 			LEFT(&link) = RIGHT(root);
339 		}
340 	}
341 
342 	if(root && (r = LINK(root)) )
343 	{	/* head of a link list, use next one for root */
344 		LEFT(r) = RIGHT(&link);
345 		RIGHT(r) = LEFT(&link);
346 	}
347 	else if(!(r = LEFT(&link)) )
348 		r = RIGHT(&link);
349 	else /* graft left tree to right tree */
350 	{	while((t = LEFT(r)) )
351 			RROTATE(r,t);
352 		LEFT(r) = RIGHT(&link);
353 	}
354 	vd->root = r; /**/ASSERT(!r || !ISBITS(SIZE(r)));
355 
356 	/**/ASSERT(!vd->root || vmchktree(vd->root) == 0);
357 	/**/ASSERT(!wanted || wanted == root);
358 
359 	return root;
360 }
361 
362 /* Reclaim all delayed free blocks into the free tree */
363 #if __STD_C
364 static int bestreclaim(reg Vmdata_t* vd, Block_t* wanted, int c)
365 #else
366 static int bestreclaim(vd, wanted, c)
367 reg Vmdata_t*	vd;
368 Block_t*	wanted;
369 int		c;
370 #endif
371 {
372 	reg size_t	size, s;
373 	reg Block_t	*fp, *np, *t, *list;
374 	reg int		n, saw_wanted;
375 	reg Seg_t	*seg;
376 
377 	/**/COUNT(N_reclaim);
378 	/**/ASSERT(_vmbestcheck(vd, NIL(Block_t*)) == 0);
379 
380 	if((fp = vd->free) )
381 	{	LINK(fp) = CACHE(vd)[S_CACHE]; CACHE(vd)[S_CACHE] = fp;
382 		vd->free = NIL(Block_t*);
383 	}
384 
385 	saw_wanted = wanted ? 0 : 1;
386 	for(n = S_CACHE; n >= c; --n)
387 	{	list = CACHE(vd)[n]; CACHE(vd)[n] = NIL(Block_t*);
388 		while((fp = list) )
389 		{	/* Note that below here we allow ISJUNK blocks to be
390 			** forward-merged even though they are not removed from
391 			** the list immediately. In this way, the list is
392 			** scanned only once. It works because the LINK and SIZE
393 			** fields are not destroyed during the merging. This can
394 			** be seen by observing that a tiniest block has a 2-word
395 			** header and a 2-word body. Merging a tiniest block
396 			** (1seg) and the next block (2seg) looks like this:
397 			**	1seg  size  link  left  2seg size link left ....
398 			**	1seg  size  link  left  rite xxxx xxxx .... self
399 			** After the merge, the 2seg word is replaced by the RIGHT
400 			** pointer of the new block and somewhere beyond the
401 			** two xxxx fields, the SELF pointer will replace some
402 			** other word. The important part is that the two xxxx
403 			** fields are kept intact.
404 			*/
405 			list = LINK(list); /**/ASSERT(!vmonlist(list,fp));
406 
407 			size = SIZE(fp);
408 			if(!ISJUNK(size))	/* already done */
409 				continue;
410 
411 			if(_Vmassert & VM_region)
412 			{	/* see if this address is from region */
413 				for(seg = vd->seg; seg; seg = seg->next)
414 					if(fp >= SEGBLOCK(seg) && fp < (Block_t*)seg->baddr )
415 						break;
416 				if(!seg) /* must be a bug in application code! */
417 				{	/**/ ASSERT(seg != NIL(Seg_t*));
418 					continue;
419 				}
420 			}
421 
422 			if(ISPFREE(size))	/* backward merge */
423 			{	fp = LAST(fp);
424 				s = SIZE(fp); /**/ASSERT(!(s&BITS));
425 				REMOVE(vd,fp,INDEX(s),t,bestsearch);
426 				size = (size&~BITS) + s + sizeof(Head_t);
427 			}
428 			else	size &= ~BITS;
429 
430 			for(;;)	/* forward merge */
431 			{	np = (Block_t*)((Vmuchar_t*)fp+size+sizeof(Head_t));
432 				s = SIZE(np);	/**/ASSERT(s > 0);
433 				if(!ISBUSY(s))
434 				{	/**/ASSERT((s&BITS) == 0);
435 					if(np == vd->wild)
436 						vd->wild = NIL(Block_t*);
437 					else	REMOVE(vd,np,INDEX(s),t,bestsearch);
438 				}
439 				else if(ISJUNK(s))
440 				{	/* reclaim any touched junk list */
441 					if((int)C_INDEX(s) < c)
442 						c = C_INDEX(s);
443 					SIZE(np) = 0;
444 					CLRBITS(s);
445 				}
446 				else	break;
447 				size += s + sizeof(Head_t);
448 			}
449 			SIZE(fp) = size;
450 
451 			/* tell next block that this one is free */
452 			np = NEXT(fp);	/**/ASSERT(ISBUSY(SIZE(np)));
453 					/**/ASSERT(!ISJUNK(SIZE(np)));
454 			SETPFREE(SIZE(np));
455 			*(SELF(fp)) = fp;
456 
457 			if(fp == wanted) /* to be consumed soon */
458 			{	/**/ASSERT(!saw_wanted); /* should be seen just once */
459 				saw_wanted = 1;
460 				continue;
461 			}
462 
463 			/* wilderness preservation */
464 			if(np->body.data >= vd->seg->baddr)
465 			{	vd->wild = fp;
466 				continue;
467 			}
468 
469 			/* tiny block goes to tiny list */
470 			if(size < MAXTINY)
471 			{	s = INDEX(size);
472 				np = LINK(fp) = TINY(vd)[s];
473 				if(s == 0)	/* TINIEST block */
474 				{	if(np)
475 						TLEFT(np) = fp;
476 					TLEFT(fp) = NIL(Block_t*);
477 				}
478 				else
479 				{	if(np)
480 						LEFT(np)  = fp;
481 					LEFT(fp) = NIL(Block_t*);
482 					SETLINK(fp);
483 				}
484 				TINY(vd)[s] = fp;
485 				continue;
486 			}
487 
488 			LEFT(fp) = RIGHT(fp) = LINK(fp) = NIL(Block_t*);
489 			if(!(np = vd->root) )	/* inserting into an empty tree	*/
490 			{	vd->root = fp;
491 				continue;
492 			}
493 
494 			size = SIZE(fp);
495 			while(1)	/* leaf insertion */
496 			{	/**/ASSERT(np != fp);
497 				if((s = SIZE(np)) > size)
498 				{	if((t = LEFT(np)) )
499 					{	/**/ ASSERT(np != t);
500 						np = t;
501 					}
502 					else
503 					{	LEFT(np) = fp;
504 						break;
505 					}
506 				}
507 				else if(s < size)
508 				{	if((t = RIGHT(np)) )
509 					{	/**/ ASSERT(np != t);
510 						np = t;
511 					}
512 					else
513 					{	RIGHT(np) = fp;
514 						break;
515 					}
516 				}
517 				else /* s == size */
518 				{	if((t = LINK(np)) )
519 					{	LINK(fp) = t;
520 						LEFT(t) = fp;
521 					}
522 					LINK(np) = fp;
523 					LEFT(fp) = np;
524 					SETLINK(fp);
525 					break;
526 				}
527 			}
528 		}
529 	}
530 
531 	/**/ASSERT(!wanted || saw_wanted == 1);
532 	/**/ASSERT(_vmbestcheck(vd, wanted) == 0);
533 	return saw_wanted;
534 }
535 
536 #if __STD_C
537 static int bestcompact(Vmalloc_t* vm)
538 #else
539 static int bestcompact(vm)
540 Vmalloc_t*	vm;
541 #endif
542 {
543 	reg Seg_t	*seg, *next;
544 	reg Block_t	*bp, *t;
545 	reg size_t	size, segsize, round;
546 	reg int		local;
547 	reg Vmdata_t*	vd = vm->data;
548 
549 	if(!(local = vd->mode&VM_TRUST) )
550 	{	GETLOCAL(vd,local);
551 		if(ISLOCK(vd,local))
552 			return -1;
553 		SETLOCK(vd,local);
554 	}
555 
556 	bestreclaim(vd,NIL(Block_t*),0);
557 
558 	for(seg = vd->seg; seg; seg = next)
559 	{	next = seg->next;
560 
561 		bp = BLOCK(seg->baddr);
562 		if(!ISPFREE(SIZE(bp)) )
563 			continue;
564 
565 		bp = LAST(bp);	/**/ASSERT(vmisfree(vd,bp));
566 		size = SIZE(bp);
567 		if(bp == vd->wild)
568 		{	/* During large block allocations, _Vmextend might
569 			** have been enlarged the rounding factor. Reducing
570 			** it a bit help avoiding getting large raw memory.
571 			*/
572 			if((round = vm->disc->round) == 0)
573 				round = _Vmpagesize;
574 			if(size > COMPACT*vd->incr && vd->incr > round)
575 				vd->incr /= 2;
576 
577 			/* for the bottom segment, we don't necessarily want
578 			** to return raw memory too early. vd->pool has an
579 			** approximation of the average size of recently freed
580 			** blocks. If this is large, the application is managing
581 			** large blocks so we throttle back memory chopping
582 			** to avoid thrashing the underlying memory system.
583 			*/
584 			if(size <= COMPACT*vd->incr || size <= COMPACT*vd->pool)
585 				continue;
586 
587 			vd->wild = NIL(Block_t*);
588 			vd->pool = 0;
589 		}
590 		else	REMOVE(vd,bp,INDEX(size),t,bestsearch);
591 		CLRPFREE(SIZE(NEXT(bp)));
592 
593 		if(size < (segsize = seg->size))
594 			size += sizeof(Head_t);
595 
596 		if((size = (*_Vmtruncate)(vm,seg,size,0)) > 0)
597 		{	if(size >= segsize) /* entire segment deleted */
598 				continue;
599 			/**/ASSERT(SEG(BLOCK(seg->baddr)) == seg);
600 
601 			if((size = (seg->baddr - ((Vmuchar_t*)bp) - sizeof(Head_t))) > 0)
602 				SIZE(bp) = size - sizeof(Head_t);
603 			else	bp = NIL(Block_t*);
604 		}
605 
606 		if(bp)
607 		{	/**/ ASSERT(SIZE(bp) >= BODYSIZE);
608 			/**/ ASSERT(SEGWILD(bp));
609 			/**/ ASSERT(!vd->root || !vmintree(vd->root,bp));
610 			SIZE(bp) |= BUSY|JUNK;
611 			LINK(bp) = CACHE(vd)[C_INDEX(SIZE(bp))];
612 			CACHE(vd)[C_INDEX(SIZE(bp))] = bp;
613 		}
614 	}
615 
616 	if(!local && _Vmtrace && (vd->mode&VM_TRACE) && VMETHOD(vd) == VM_MTBEST)
617 		(*_Vmtrace)(vm, (Vmuchar_t*)0, (Vmuchar_t*)0, 0, 0);
618 
619 	CLRLOCK(vd,local); /**/ASSERT(_vmbestcheck(vd, NIL(Block_t*)) == 0);
620 
621 	return 0;
622 }
623 
624 #if __STD_C
625 static Void_t* bestalloc(Vmalloc_t* vm, reg size_t size )
626 #else
627 static Void_t* bestalloc(vm,size)
628 Vmalloc_t*	vm;	/* region allocating from	*/
629 reg size_t	size;	/* desired block size		*/
630 #endif
631 {
632 	reg Vmdata_t*	vd = vm->data;
633 	reg size_t	s;
634 	reg int		n;
635 	reg Block_t	*tp, *np;
636 	reg int		local;
637 	size_t		orgsize = 0;
638 
639 	if(!(_Vmassert & VM_init))
640 	{	char	*chk = getenv("VMCHECK");
641 		_Vmassert = VM_init|VM_primary|VM_secondary;
642 		if(chk)
643 		{	int	set = 1;
644 			for(;; set ? (_Vmassert |= n) : (_Vmassert &= ~n))
645 			{
646 				switch (*chk++)
647 				{
648 				case 0:
649 					break;
650 				case '-':
651 				case '!':
652 					set = 0;
653 					n = 0;
654 					continue;
655 				case '+':
656 					set = 1;
657 					n = 0;
658 					continue;
659 				case '1':
660 					n = VM_check;
661 					continue;
662 				case '2':
663 					n = VM_abort;
664 					continue;
665 				case '3':
666 					n = VM_check|VM_abort;
667 					continue;
668 				case 'a':
669 				case 'A':
670 					n = VM_abort;
671 					continue;
672 				case 'c':
673 				case 'C':
674 					n = VM_check;
675 					continue;
676 				case 'p':
677 				case 'P':
678 					n = VM_primary;
679 					continue;
680 				case 'r':
681 				case 'R':
682 					n = VM_region;
683 					continue;
684 				case 's':
685 				case 'S':
686 					n = VM_secondary;
687 					continue;
688 				default:
689 					n = 0;
690 					continue;
691 				}
692 				break;
693 			}
694 		}
695 	}
696 	/**/COUNT(N_alloc);
697 
698 	if(!(local = vd->mode&VM_TRUST))
699 	{	GETLOCAL(vd,local);	/**/ASSERT(!ISLOCK(vd,local));
700 		if(ISLOCK(vd,local) )
701 			return NIL(Void_t*);
702 		SETLOCK(vd,local);
703 		orgsize = size;
704 	}
705 
706 	/**/ASSERT(_vmbestcheck(vd, NIL(Block_t*)) == 0);
707 	/**/ ASSERT(HEADSIZE == sizeof(Head_t));
708 	/**/ ASSERT(BODYSIZE == sizeof(Body_t));
709 	/**/ ASSERT((ALIGN%(BITS+1)) == 0 );
710 	/**/ ASSERT((sizeof(Head_t)%ALIGN) == 0 );
711 	/**/ ASSERT((sizeof(Body_t)%ALIGN) == 0 );
712 	/**/ ASSERT((BODYSIZE%ALIGN) == 0 );
713 	/**/ ASSERT(sizeof(Block_t) == (sizeof(Body_t)+sizeof(Head_t)) );
714 
715 	/* for ANSI requirement that malloc(0) returns non-NULL pointer */
716 	size = size <= BODYSIZE ? BODYSIZE : ROUND(size,ALIGN);
717 
718 	if((tp = vd->free) )	/* reuse last free piece if appropriate */
719 	{	/**/ASSERT(ISBUSY(SIZE(tp)) );
720 		/**/ASSERT(ISJUNK(SIZE(tp)) );
721 		/**/COUNT(N_last);
722 
723 		vd->free = NIL(Block_t*);
724 		if((s = SIZE(tp)) >= size && s < (size << 1) )
725 		{	if(s >= size + (sizeof(Head_t)+BODYSIZE) )
726 			{	SIZE(tp) = size;
727 				np = NEXT(tp);
728 				SEG(np) = SEG(tp);
729 				SIZE(np) = ((s&~BITS) - (size+sizeof(Head_t)))|JUNK|BUSY;
730 				vd->free = np;
731 				SIZE(tp) |= s&BITS;
732 			}
733 			CLRJUNK(SIZE(tp));
734 			goto done;
735 		}
736 
737 		LINK(tp) = CACHE(vd)[S_CACHE];
738 		CACHE(vd)[S_CACHE] = tp;
739 	}
740 
741 	for(;;)
742 	{	for(n = S_CACHE; n >= 0; --n)	/* best-fit except for coalescing */
743 		{	bestreclaim(vd,NIL(Block_t*),n);
744 			if(vd->root && (tp = bestsearch(vd,size,NIL(Block_t*))) )
745 				goto got_block;
746 		}
747 
748 		/**/ASSERT(!vd->free);
749 		if((tp = vd->wild) && SIZE(tp) >= size)
750 		{	/**/COUNT(N_wild);
751 			vd->wild = NIL(Block_t*);
752 			goto got_block;
753 		}
754 
755 		KPVCOMPACT(vm,bestcompact);
756 		if((tp = (*_Vmextend)(vm,size,bestsearch)) )
757 			goto got_block;
758 		else if(vd->mode&VM_AGAIN)
759 			vd->mode &= ~VM_AGAIN;
760 		else
761 		{	CLRLOCK(vd,local);
762 			return NIL(Void_t*);
763 		}
764 	}
765 
766 got_block:
767 	/**/ ASSERT(!ISBITS(SIZE(tp)));
768 	/**/ ASSERT(SIZE(tp) >= size);
769 	/**/ ASSERT((SIZE(tp)%ALIGN) == 0);
770 	/**/ ASSERT(!vd->free);
771 
772 	/* tell next block that we are no longer a free block */
773 	CLRPFREE(SIZE(NEXT(tp)));	/**/ ASSERT(ISBUSY(SIZE(NEXT(tp))));
774 
775 	if((s = SIZE(tp)-size) >= (sizeof(Head_t)+BODYSIZE) )
776 	{	SIZE(tp) = size;
777 
778 		np = NEXT(tp);
779 		SEG(np) = SEG(tp);
780 		SIZE(np) = (s - sizeof(Head_t)) | BUSY|JUNK;
781 
782 		if(VMWILD(vd,np))
783 		{	SIZE(np) &= ~BITS;
784 			*SELF(np) = np; /**/ASSERT(ISBUSY(SIZE(NEXT(np))));
785 			SETPFREE(SIZE(NEXT(np)));
786 			vd->wild = np;
787 		}
788 		else	vd->free = np;
789 	}
790 
791 	SETBUSY(SIZE(tp));
792 
793 done:
794 	if(!local && (vd->mode&VM_TRACE) && _Vmtrace && VMETHOD(vd) == VM_MTBEST)
795 		(*_Vmtrace)(vm,NIL(Vmuchar_t*),(Vmuchar_t*)DATA(tp),orgsize,0);
796 
797 	/**/ASSERT(_vmbestcheck(vd, NIL(Block_t*)) == 0);
798 	CLRLOCK(vd,local);
799 	ANNOUNCE(local, vm, VM_ALLOC, DATA(tp), vm->disc);
800 
801 	return DATA(tp);
802 }
803 
804 #if __STD_C
805 static long bestaddr(Vmalloc_t* vm, Void_t* addr )
806 #else
807 static long bestaddr(vm, addr)
808 Vmalloc_t*	vm;	/* region allocating from	*/
809 Void_t*		addr;	/* address to check		*/
810 #endif
811 {
812 	reg Seg_t*	seg;
813 	reg Block_t	*b, *endb;
814 	reg long	offset;
815 	reg Vmdata_t*	vd = vm->data;
816 	reg int		local;
817 
818 	if(!(local = vd->mode&VM_TRUST) )
819 	{	GETLOCAL(vd,local); /**/ASSERT(!ISLOCK(vd,local));
820 		if(ISLOCK(vd,local))
821 			return -1L;
822 		SETLOCK(vd,local);
823 	}
824 
825 	offset = -1L; b = endb = NIL(Block_t*);
826 	for(seg = vd->seg; seg; seg = seg->next)
827 	{	b = SEGBLOCK(seg);
828 		endb = (Block_t*)(seg->baddr - sizeof(Head_t));
829 		if((Vmuchar_t*)addr > (Vmuchar_t*)b &&
830 		   (Vmuchar_t*)addr < (Vmuchar_t*)endb)
831 			break;
832 	}
833 
834 	if(local && !(vd->mode&VM_TRUST) ) /* from bestfree or bestresize */
835 	{	b = BLOCK(addr);
836 		if(seg && SEG(b) == seg && ISBUSY(SIZE(b)) && !ISJUNK(SIZE(b)) )
837 			offset = 0;
838 		if(offset != 0 && vm->disc->exceptf)
839 			(void)(*vm->disc->exceptf)(vm,VM_BADADDR,addr,vm->disc);
840 	}
841 	else if(seg)
842 	{	while(b < endb)
843 		{	reg Vmuchar_t*	data = (Vmuchar_t*)DATA(b);
844 			reg size_t	size = SIZE(b)&~BITS;
845 
846 			if((Vmuchar_t*)addr >= data && (Vmuchar_t*)addr < data+size)
847 			{	if(ISJUNK(SIZE(b)) || !ISBUSY(SIZE(b)))
848 					offset = -1L;
849 				else	offset = (Vmuchar_t*)addr - data;
850 				goto done;
851 			}
852 
853 			b = (Block_t*)((Vmuchar_t*)DATA(b) + size);
854 		}
855 	}
856 
857 done:
858 	CLRLOCK(vd,local);
859 	return offset;
860 }
861 
862 #if __STD_C
863 static int bestfree(Vmalloc_t* vm, Void_t* data )
864 #else
865 static int bestfree(vm, data )
866 Vmalloc_t*	vm;
867 Void_t*		data;
868 #endif
869 {
870 	reg Vmdata_t*	vd = vm->data;
871 	reg Block_t	*bp;
872 	reg size_t	s;
873 	reg int		local;
874 
875 #ifdef DEBUG
876 	if((local = (int)data) >= 0 && local <= 0xf)
877 	{	int	vmassert = _Vmassert;
878 		_Vmassert = local ? local : vmassert ? vmassert : (VM_check|VM_abort);
879 		_vmbestcheck(vd, NIL(Block_t*));
880 		_Vmassert = local ? local : vmassert;
881 		return 0;
882 	}
883 #endif
884 
885 	if(!data) /* ANSI-ism */
886 		return 0;
887 
888 	/**/COUNT(N_free);
889 
890 	if(!(local = vd->mode&VM_TRUST) )
891 	{	GETLOCAL(vd,local);	/**/ASSERT(!ISLOCK(vd,local));
892 		if(ISLOCK(vd,local) )
893 			return -1;
894 		if(KPVADDR(vm,data,bestaddr) != 0 )
895 			return -1;
896 		SETLOCK(vd,local);
897 	}
898 
899 	/**/ASSERT(_vmbestcheck(vd, NIL(Block_t*)) == 0);
900 	bp = BLOCK(data); s = SIZE(bp);
901 
902 	/* Keep an approximate average free block size.
903 	** This is used in bestcompact() to decide when to release
904 	** raw memory back to the underlying memory system.
905 	*/
906 	vd->pool = (vd->pool + (s&~BITS))/2;
907 
908 	if(ISBUSY(s) && !ISJUNK(s))
909 	{	SETJUNK(SIZE(bp));
910 	        if(s < MAXCACHE)
911 	        {       /**/ASSERT(!vmonlist(CACHE(vd)[INDEX(s)], bp) );
912 	                LINK(bp) = CACHE(vd)[INDEX(s)];
913 	                CACHE(vd)[INDEX(s)] = bp;
914 	        }
915 	        else if(!vd->free)
916 	                vd->free = bp;
917 	        else
918 	        {       /**/ASSERT(!vmonlist(CACHE(vd)[S_CACHE], bp) );
919 	                LINK(bp) = CACHE(vd)[S_CACHE];
920 	                CACHE(vd)[S_CACHE] = bp;
921 	        }
922 
923 		/* coalesce on freeing large blocks to avoid fragmentation */
924 		if(SIZE(bp) >= 2*vd->incr)
925 		{	bestreclaim(vd,NIL(Block_t*),0);
926 			if(vd->wild && SIZE(vd->wild) >= COMPACT*vd->incr)
927 				KPVCOMPACT(vm,bestcompact);
928 		}
929 	}
930 
931 	if(!local && _Vmtrace && (vd->mode&VM_TRACE) && VMETHOD(vd) == VM_MTBEST )
932 		(*_Vmtrace)(vm,(Vmuchar_t*)data,NIL(Vmuchar_t*), (s&~BITS), 0);
933 
934 	/**/ASSERT(_vmbestcheck(vd, NIL(Block_t*)) == 0);
935 	CLRLOCK(vd,local);
936 	ANNOUNCE(local, vm, VM_FREE, data, vm->disc);
937 
938 	return 0;
939 }
940 
941 #if __STD_C
942 static Void_t* bestresize(Vmalloc_t* vm, Void_t* data, reg size_t size, int type)
943 #else
944 static Void_t* bestresize(vm,data,size,type)
945 Vmalloc_t*	vm;		/* region allocating from	*/
946 Void_t*		data;		/* old block of data		*/
947 reg size_t	size;		/* new size			*/
948 int		type;		/* !=0 to move, <0 for not copy */
949 #endif
950 {
951 	reg Block_t	*rp, *np, *t;
952 	int		local;
953 	size_t		s, bs, oldsize = 0, orgsize = 0;
954 	Void_t		*oldd, *orgdata = NIL(Void_t*);
955 	Vmdata_t	*vd = vm->data;
956 
957 	/**/COUNT(N_resize);
958 
959 	if(!data)
960 	{	if((data = bestalloc(vm,size)) )
961 		{	oldsize = 0;
962 			size = size <= BODYSIZE ? BODYSIZE : ROUND(size,ALIGN);
963 		}
964 		goto done;
965 	}
966 	if(size == 0)
967 	{	(void)bestfree(vm,data);
968 		return NIL(Void_t*);
969 	}
970 
971 	if(!(local = vd->mode&VM_TRUST) )
972 	{	GETLOCAL(vd,local); /**/ASSERT(!ISLOCK(vd,local));
973 		if(ISLOCK(vd,local) )
974 			return NIL(Void_t*);
975 		if(!local && KPVADDR(vm,data,bestaddr) != 0 )
976 			return NIL(Void_t*);
977 		SETLOCK(vd,local);
978 
979 		orgdata = data;	/* for tracing */
980 		orgsize = size;
981 	}
982 
983 	/**/ASSERT(_vmbestcheck(vd, NIL(Block_t*)) == 0);
984 	size = size <= BODYSIZE ? BODYSIZE : ROUND(size,ALIGN);
985 	rp = BLOCK(data);	/**/ASSERT(ISBUSY(SIZE(rp)) && !ISJUNK(SIZE(rp)));
986 	oldsize = SIZE(rp); CLRBITS(oldsize);
987 	if(oldsize < size)
988 	{	np = (Block_t*)((Vmuchar_t*)rp + oldsize + sizeof(Head_t));
989 		do	/* forward merge as much as possible */
990 		{	s = SIZE(np); /**/ASSERT(!ISPFREE(s));
991 			if(np == vd->free)
992 			{	vd->free = NIL(Block_t*);
993 				CLRBITS(s);
994 			}
995 			else if(ISJUNK(s) )
996 			{	if(!bestreclaim(vd,np,C_INDEX(s)) )
997 					/**/ASSERT(0); /* oops: did not see np! */
998 				s = SIZE(np); /**/ASSERT(s%ALIGN == 0);
999 			}
1000 			else if(!ISBUSY(s) )
1001 			{	if(np == vd->wild)
1002 					vd->wild = NIL(Block_t*);
1003 				else	REMOVE(vd,np,INDEX(s),t,bestsearch);
1004 			}
1005 			else	break;
1006 
1007 			SIZE(rp) += (s += sizeof(Head_t)); /**/ASSERT((s%ALIGN) == 0);
1008 			np = (Block_t*)((Vmuchar_t*)np + s);
1009 			CLRPFREE(SIZE(np));
1010 		} while(SIZE(rp) < size);
1011 
1012 		if(SIZE(rp) < size && size > vd->incr && SEGWILD(rp) )
1013 		{	reg Seg_t*	seg;
1014 
1015 			s = (size - SIZE(rp)) + sizeof(Head_t); s = ROUND(s,vd->incr);
1016 			seg = SEG(rp);
1017 			if((*vm->disc->memoryf)(vm,seg->addr,seg->extent,seg->extent+s,
1018 				      vm->disc) == seg->addr )
1019 			{	SIZE(rp) += s;
1020 				seg->extent += s;
1021 				seg->size += s;
1022 				seg->baddr += s;
1023 				s  = (SIZE(rp)&~BITS) + sizeof(Head_t);
1024 				np = (Block_t*)((Vmuchar_t*)rp + s);
1025 				SEG(np) = seg;
1026 				SIZE(np) = BUSY;
1027 			}
1028 		}
1029 	}
1030 
1031 	if((s = SIZE(rp)) >= (size + (BODYSIZE+sizeof(Head_t))) )
1032 	{	SIZE(rp) = size;
1033 		np = NEXT(rp);
1034 		SEG(np) = SEG(rp);
1035 		SIZE(np) = (((s&~BITS)-size) - sizeof(Head_t))|BUSY|JUNK;
1036 		CPYBITS(SIZE(rp),s);
1037 		rp = np;
1038 		goto do_free;
1039 	}
1040 	else if((bs = s&~BITS) < size)
1041 	{	if(!(type&(VM_RSMOVE|VM_RSCOPY)) )
1042 			data = NIL(Void_t*); /* old data is not moveable */
1043 		else
1044 		{	oldd = data;
1045 			if((data = KPVALLOC(vm,size,bestalloc)) )
1046 			{	if(type&VM_RSCOPY)
1047 					memcpy(data, oldd, bs);
1048 
1049 			do_free: /* reclaim these right away */
1050 				SETJUNK(SIZE(rp));
1051 				LINK(rp) = CACHE(vd)[S_CACHE];
1052 				CACHE(vd)[S_CACHE] = rp;
1053 				bestreclaim(vd, NIL(Block_t*), S_CACHE);
1054 			}
1055 		}
1056 	}
1057 
1058 	if(!local && _Vmtrace && data && (vd->mode&VM_TRACE) && VMETHOD(vd) == VM_MTBEST)
1059 		(*_Vmtrace)(vm, (Vmuchar_t*)orgdata, (Vmuchar_t*)data, orgsize, 0);
1060 
1061 	/**/ASSERT(_vmbestcheck(vd, NIL(Block_t*)) == 0);
1062 	CLRLOCK(vd,local);
1063 	ANNOUNCE(local, vm, VM_RESIZE, data, vm->disc);
1064 
1065 done:	if(data && (type&VM_RSZERO) && (size = SIZE(BLOCK(data))&~BITS) > oldsize )
1066 		memset((Void_t*)((Vmuchar_t*)data + oldsize), 0, size-oldsize);
1067 
1068 	return data;
1069 }
1070 
1071 #if __STD_C
1072 static long bestsize(Vmalloc_t* vm, Void_t* addr )
1073 #else
1074 static long bestsize(vm, addr)
1075 Vmalloc_t*	vm;	/* region allocating from	*/
1076 Void_t*		addr;	/* address to check		*/
1077 #endif
1078 {
1079 	reg Seg_t*	seg;
1080 	reg Block_t	*b, *endb;
1081 	reg long	size;
1082 	reg Vmdata_t*	vd = vm->data;
1083 
1084 	if(!(vd->mode&VM_TRUST) )
1085 	{	if(ISLOCK(vd,0))
1086 			return -1L;
1087 		SETLOCK(vd,0);
1088 	}
1089 
1090 	size = -1L;
1091 	for(seg = vd->seg; seg; seg = seg->next)
1092 	{	b = SEGBLOCK(seg);
1093 		endb = (Block_t*)(seg->baddr - sizeof(Head_t));
1094 		if((Vmuchar_t*)addr <= (Vmuchar_t*)b ||
1095 		   (Vmuchar_t*)addr >= (Vmuchar_t*)endb)
1096 			continue;
1097 		while(b < endb)
1098 		{	if(addr == DATA(b))
1099 			{	if(!ISBUSY(SIZE(b)) || ISJUNK(SIZE(b)) )
1100 					size = -1L;
1101 				else	size = (long)SIZE(b)&~BITS;
1102 				goto done;
1103 			}
1104 			else if((Vmuchar_t*)addr <= (Vmuchar_t*)b)
1105 				break;
1106 
1107 			b = (Block_t*)((Vmuchar_t*)DATA(b) + (SIZE(b)&~BITS) );
1108 		}
1109 	}
1110 
1111 done:
1112 	CLRLOCK(vd,0);
1113 	return size;
1114 }
1115 
1116 #if __STD_C
1117 static Void_t* bestalign(Vmalloc_t* vm, size_t size, size_t align)
1118 #else
1119 static Void_t* bestalign(vm, size, align)
1120 Vmalloc_t*	vm;
1121 size_t		size;
1122 size_t		align;
1123 #endif
1124 {
1125 	reg Vmuchar_t	*data;
1126 	reg Block_t	*tp, *np;
1127 	reg Seg_t*	seg;
1128 	reg int		local;
1129 	reg size_t	s, extra, orgsize = 0, orgalign = 0;
1130 	reg Vmdata_t*	vd = vm->data;
1131 
1132 	if(size <= 0 || align <= 0)
1133 		return NIL(Void_t*);
1134 
1135 	if(!(local = vd->mode&VM_TRUST) )
1136 	{	GETLOCAL(vd,local); /**/ASSERT(!ISLOCK(vd,local));
1137 		if(ISLOCK(vd,local) )
1138 			return NIL(Void_t*);
1139 		SETLOCK(vd,local);
1140 		orgsize = size;
1141 		orgalign = align;
1142 	}
1143 
1144 	/**/ASSERT(_vmbestcheck(vd, NIL(Block_t*)) == 0);
1145 	size = size <= BODYSIZE ? BODYSIZE : ROUND(size,ALIGN);
1146 	align = MULTIPLE(align,ALIGN);
1147 
1148 	/* hack so that dbalign() can store header data */
1149 	if(VMETHOD(vd) != VM_MTDEBUG)
1150 		extra = 0;
1151 	else
1152 	{	extra = DB_HEAD;
1153 		while(align < extra || (align - extra) < sizeof(Block_t))
1154 			align *= 2;
1155 	}
1156 
1157 	/* reclaim all free blocks now to avoid fragmentation */
1158 	bestreclaim(vd,NIL(Block_t*),0);
1159 
1160 	s = size + 2*(align+sizeof(Head_t)+extra);
1161 	if(!(data = (Vmuchar_t*)KPVALLOC(vm,s,bestalloc)) )
1162 		goto done;
1163 
1164 	tp = BLOCK(data);
1165 	seg = SEG(tp);
1166 
1167 	/* get an aligned address that we can live with */
1168 	if((s = (size_t)((VLONG(data)+extra)%align)) != 0)
1169 		data += align-s; /**/ASSERT(((VLONG(data)+extra)%align) == 0);
1170 
1171 	if((np = BLOCK(data)) != tp ) /* need to free left part */
1172 	{	if(((Vmuchar_t*)np - (Vmuchar_t*)tp) < (ssize_t)(sizeof(Block_t)+extra) )
1173 		{	data += align;
1174 			np = BLOCK(data);
1175 		} /**/ASSERT(((VLONG(data)+extra)%align) == 0);
1176 
1177 		s  = (Vmuchar_t*)np - (Vmuchar_t*)tp;
1178 		SIZE(np) = ((SIZE(tp)&~BITS) - s)|BUSY;
1179 		SEG(np) = seg;
1180 
1181 		SIZE(tp) = (s - sizeof(Head_t)) | (SIZE(tp)&BITS) | JUNK;
1182 		/**/ ASSERT(SIZE(tp) >= sizeof(Body_t) );
1183 		LINK(tp) = CACHE(vd)[C_INDEX(SIZE(tp))];
1184 		CACHE(vd)[C_INDEX(SIZE(tp))] = tp;
1185 	}
1186 
1187 	/* free left-over if too big */
1188 	if((s = SIZE(np) - size) >= sizeof(Block_t))
1189 	{	SIZE(np) = size;
1190 
1191 		tp = NEXT(np);
1192 		SIZE(tp) = ((s & ~BITS) - sizeof(Head_t)) | BUSY | JUNK;
1193 		SEG(tp) = seg;
1194 		LINK(tp) = CACHE(vd)[C_INDEX(SIZE(tp))];
1195 		CACHE(vd)[C_INDEX(SIZE(tp))] = tp;
1196 
1197 		SIZE(np) |= s&BITS;
1198 	}
1199 
1200 	bestreclaim(vd,NIL(Block_t*),0); /* coalesce all free blocks */
1201 
1202 	if(!local && !(vd->mode&VM_TRUST) && _Vmtrace && (vd->mode&VM_TRACE) )
1203 		(*_Vmtrace)(vm,NIL(Vmuchar_t*),data,orgsize,orgalign);
1204 
1205 done:
1206 	/**/ASSERT(_vmbestcheck(vd, NIL(Block_t*)) == 0);
1207 	CLRLOCK(vd,local);
1208 	ANNOUNCE(local, vm, VM_ALLOC, (Void_t*)data, vm->disc);
1209 
1210 	return (Void_t*)data;
1211 }
1212 
1213 
1214 #if _mem_win32
1215 #if _PACKAGE_ast
1216 #include		<ast_windows.h>
1217 #else
1218 #include		<windows.h>
1219 #endif
1220 #endif /* _lib_win32 */
1221 
1222 #if _mem_mmap_anon
1223 #include		<sys/mman.h>
1224 #ifndef MAP_ANON
1225 #define	MAP_ANON	MAP_ANONYMOUS
1226 #endif
1227 #endif /* _mem_mmap_anon */
1228 
1229 #if _mem_mmap_zero
1230 #include		<sys/fcntl.h>
1231 #include		<sys/mman.h>
1232 typedef struct _mmapdisc_s
1233 {	Vmdisc_t	disc;
1234 	int		fd;
1235 	off_t		offset;
1236 } Mmapdisc_t;
1237 
1238 #ifndef OPEN_MAX
1239 #define	OPEN_MAX	64
1240 #endif
1241 #define OPEN_PRIVATE	(3*OPEN_MAX/4)
1242 #endif /* _mem_mmap_zero */
1243 
1244 /* failure mode of mmap, sbrk and brk */
1245 #ifndef MAP_FAILED
1246 #define MAP_FAILED	((Void_t*)(-1))
1247 #endif
1248 #define BRK_FAILED	((Void_t*)(-1))
1249 
1250 /* A discipline to get raw memory using sbrk/VirtualAlloc/mmap */
1251 #if __STD_C
1252 static Void_t* sbrkmem(Vmalloc_t* vm, Void_t* caddr,
1253 			size_t csize, size_t nsize, Vmdisc_t* disc)
1254 #else
1255 static Void_t* sbrkmem(vm, caddr, csize, nsize, disc)
1256 Vmalloc_t*	vm;	/* region doing allocation from		*/
1257 Void_t*		caddr;	/* current address			*/
1258 size_t		csize;	/* current size				*/
1259 size_t		nsize;	/* new size				*/
1260 Vmdisc_t*	disc;	/* discipline structure			*/
1261 #endif
1262 {
1263 #undef _done_sbrkmem
1264 
1265 #if !defined(_done_sbrkmem) && defined(_mem_win32)
1266 #define _done_sbrkmem	1
1267 	NOTUSED(vm);
1268 	NOTUSED(disc);
1269 	if(csize == 0)
1270 		return (Void_t*)VirtualAlloc(0,nsize,MEM_COMMIT,PAGE_READWRITE);
1271 	else if(nsize == 0)
1272 		return VirtualFree((LPVOID)caddr,0,MEM_RELEASE) ? caddr : NIL(Void_t*);
1273 	else	return NIL(Void_t*);
1274 #endif /* MUST_WIN32 */
1275 
1276 #if !defined(_done_sbrkmem) && (_mem_sbrk || _mem_mmap_zero || _mem_mmap_anon)
1277 #define _done_sbrkmem	1
1278 	Vmuchar_t	*addr;
1279 #if _mem_mmap_zero
1280 	Mmapdisc_t	*mmdc = (Mmapdisc_t*)disc;
1281 #else
1282 	NOTUSED(disc);
1283 #endif
1284 	NOTUSED(vm);
1285 
1286 	if(csize == 0) /* allocating new memory */
1287 	{
1288 #if ( _mem_sbrk || _mem_mmap_anon || _mem_mmap_zero )
1289 #define ALTERNATES	VM_primary
1290 #endif
1291 #if _mem_sbrk	/* try using sbrk() and brk() */
1292 #if ALTERNATES
1293 		if (_Vmassert & ALTERNATES)
1294 #undef	ALTERNATES
1295 #define ALTERNATES	VM_secondary
1296 #endif
1297 		{
1298 			addr = (Vmuchar_t*)sbrk(0); /* old break value */
1299 			if(addr && addr != (Vmuchar_t*)BRK_FAILED )
1300 				if(brk(addr+nsize) == 0 )
1301 					return addr;
1302 		}
1303 #endif /* _mem_sbrk */
1304 
1305 #if _mem_mmap_anon /* anonymous mmap */
1306 #if ALTERNATES
1307 		if (_Vmassert & ALTERNATES)
1308 #undef	ALTERNATES
1309 #define ALTERNATES	VM_secondary
1310 #endif
1311 		{
1312 			addr = (Vmuchar_t*)mmap(0, nsize, PROT_READ|PROT_WRITE,
1313                                         	MAP_ANON|MAP_PRIVATE, -1, 0);
1314 			if(addr && addr != (Vmuchar_t*)MAP_FAILED)
1315 				return addr;
1316 		}
1317 #endif /* _mem_mmap_anon */
1318 
1319 #if _mem_mmap_zero /* mmap from /dev/zero */
1320 #if ALTERNATES
1321 		if (_Vmassert & ALTERNATES)
1322 #undef	ALTERNATES
1323 #define ALTERNATES	VM_secondary
1324 #endif
1325 		{
1326 			if(mmdc->fd < 0)
1327 			{	int	fd;
1328 				if(mmdc->fd != -1)
1329 					return NIL(Void_t*);
1330 				if((fd = open("/dev/zero", O_RDONLY)) < 0 )
1331 				{	mmdc->fd = -2;
1332 					return NIL(Void_t*);
1333 				}
1334 				if(fd >= OPEN_PRIVATE || (mmdc->fd = dup2(fd,OPEN_PRIVATE)) < 0 )
1335 					mmdc->fd = fd;
1336 				else	close(fd);
1337 #ifdef FD_CLOEXEC
1338 				fcntl(mmdc->fd, F_SETFD, FD_CLOEXEC);
1339 #endif
1340 			}
1341 			addr = (Vmuchar_t*)mmap(0, nsize, PROT_READ|PROT_WRITE,
1342 						MAP_PRIVATE, mmdc->fd, mmdc->offset);
1343 			if(addr && addr != (Vmuchar_t*)MAP_FAILED)
1344 			{	mmdc->offset += nsize;
1345 				return addr;
1346 			}
1347 		}
1348 #endif /* _mem_mmap_zero */
1349 
1350 		return NIL(Void_t*);
1351 	}
1352 	else
1353 	{	addr = caddr; /* in case !_mem_sbrk */
1354 #if ( _mem_sbrk || _mem_mmap_anon || _mem_mmap_zero )
1355 #undef	ALTERNATES
1356 #define ALTERNATES	VM_primary
1357 #endif
1358 #if _mem_sbrk
1359 #if ALTERNATES
1360 		if (_Vmassert & ALTERNATES)
1361 #undef	ALTERNATES
1362 #define ALTERNATES	VM_secondary
1363 #endif
1364 		{
1365 			addr = (Vmuchar_t*)sbrk(0);
1366 			if(!addr || addr == (Vmuchar_t*)BRK_FAILED)
1367 				addr = caddr;
1368 			else if(((Vmuchar_t*)caddr+csize) == addr) /* in sbrk-space */
1369 			{	if(nsize > csize)
1370 					addr += nsize-csize;
1371 				else	addr -= csize-nsize;
1372 				return brk(addr) == 0 ? caddr : NIL(Void_t*);
1373 			}
1374 		}
1375 #endif /* _mem_sbrk */
1376 
1377 #if _mem_mmap_zero || _mem_mmap_anon
1378 #if ALTERNATES
1379 		if (_Vmassert & ALTERNATES)
1380 #undef	ALTERNATES
1381 #define ALTERNATES	VM_secondary
1382 #endif
1383 		{
1384 			if(((Vmuchar_t*)caddr+csize) > addr) /* in mmap-space */
1385 				if(nsize == 0 && munmap(caddr,csize) == 0)
1386 					return caddr;
1387 		}
1388 #endif /* _mem_mmap_zero || _mem_mmap_anon */
1389 
1390 		return NIL(Void_t*);
1391 	}
1392 #endif /*_done_sbrkmem*/
1393 
1394 #if !_done_sbrkmem /* use native malloc/free as a last resource */
1395 	/**/ASSERT(_std_malloc); /* _std_malloc should be well-defined */
1396 	NOTUSED(vm);
1397 	NOTUSED(disc);
1398 	if(csize == 0)
1399 		return (Void_t*)malloc(nsize);
1400 	else if(nsize == 0)
1401 	{	free(caddr);
1402 		return caddr;
1403 	}
1404 	else	return NIL(Void_t*);
1405 #endif /* _done_sbrkmem */
1406 }
1407 
1408 #if _mem_mmap_zero
1409 static Mmapdisc_t _Vmdcsbrk = { { sbrkmem, NIL(Vmexcept_f), 64*1024 }, -1, 0 };
1410 #else
1411 static Vmdisc_t _Vmdcsbrk = { sbrkmem, NIL(Vmexcept_f), 0 };
1412 #endif
1413 
1414 static Vmethod_t _Vmbest =
1415 {
1416 	bestalloc,
1417 	bestresize,
1418 	bestfree,
1419 	bestaddr,
1420 	bestsize,
1421 	bestcompact,
1422 	bestalign,
1423 	VM_MTBEST
1424 };
1425 
1426 /* The heap region */
1427 static Vmdata_t	_Vmdata =
1428 {
1429 	VM_MTBEST|VM_TRUST,		/* mode		*/
1430 	0,				/* incr		*/
1431 	0,				/* pool		*/
1432 	NIL(Seg_t*),			/* seg		*/
1433 	NIL(Block_t*),			/* free		*/
1434 	NIL(Block_t*),			/* wild		*/
1435 	NIL(Block_t*),			/* root		*/
1436 };
1437 Vmalloc_t _Vmheap =
1438 {
1439 	{ bestalloc,
1440 	  bestresize,
1441 	  bestfree,
1442 	  bestaddr,
1443 	  bestsize,
1444 	  bestcompact,
1445 	  bestalign,
1446 	  VM_MTBEST
1447 	},
1448 	NIL(char*),			/* file		*/
1449 	0,				/* line		*/
1450 	0,				/* func		*/
1451 	(Vmdisc_t*)(&_Vmdcsbrk),	/* disc		*/
1452 	&_Vmdata,			/* data		*/
1453 	NIL(Vmalloc_t*)			/* next		*/
1454 };
1455 
1456 __DEFINE__(Vmalloc_t*, Vmheap, &_Vmheap);
1457 __DEFINE__(Vmalloc_t*, Vmregion, &_Vmheap);
1458 __DEFINE__(Vmethod_t*, Vmbest, &_Vmbest);
1459 __DEFINE__(Vmdisc_t*,  Vmdcsbrk, (Vmdisc_t*)(&_Vmdcsbrk) );
1460 
1461 #ifdef NoF
1462 NoF(vmbest)
1463 #endif
1464 
1465 #endif
1466