xref: /netbsd-src/external/bsd/openldap/dist/servers/slapd/sl_malloc.c (revision b7b7574d3bf8eeb51a1fa3977b59142ec6434a55)
1 /*	$NetBSD: sl_malloc.c,v 1.1.1.4 2014/05/28 09:58:47 tron Exp $	*/
2 
3 /* sl_malloc.c - malloc routines using a per-thread slab */
4 /* $OpenLDAP$ */
5 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
6  *
7  * Copyright 2003-2014 The OpenLDAP Foundation.
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted only as authorized by the OpenLDAP
12  * Public License.
13  *
14  * A copy of this license is available in the file LICENSE in the
15  * top-level directory of the distribution or, alternatively, at
16  * <http://www.OpenLDAP.org/license.html>.
17  */
18 
19 #include "portable.h"
20 
21 #include <stdio.h>
22 #include <ac/string.h>
23 
24 #include "slap.h"
25 
26 #ifdef USE_VALGRIND
27 /* Get debugging help from Valgrind */
28 #include <valgrind/memcheck.h>
29 #define	VGMEMP_MARK(m,s)	VALGRIND_MAKE_MEM_NOACCESS(m,s)
30 #define VGMEMP_CREATE(h,r,z)	VALGRIND_CREATE_MEMPOOL(h,r,z)
31 #define VGMEMP_TRIM(h,a,s)	VALGRIND_MEMPOOL_TRIM(h,a,s)
32 #define VGMEMP_ALLOC(h,a,s)	VALGRIND_MEMPOOL_ALLOC(h,a,s)
33 #define VGMEMP_CHANGE(h,a,b,s)	VALGRIND_MEMPOOL_CHANGE(h,a,b,s)
34 #else
35 #define	VGMEMP_MARK(m,s)
36 #define VGMEMP_CREATE(h,r,z)
37 #define VGMEMP_TRIM(h,a,s)
38 #define VGMEMP_ALLOC(h,a,s)
39 #define VGMEMP_CHANGE(h,a,b,s)
40 #endif
41 
42 /*
43  * This allocator returns temporary memory from a slab in a given memory
44  * context, aligned on a 2-int boundary.  It cannot be used for data
45  * which will outlive the task allocating it.
46  *
47  * A new memory context attaches to the creator's thread context, if any.
48  * Threads cannot use other threads' memory contexts; there are no locks.
49  *
50  * The caller of slap_sl_malloc, usually a thread pool task, must
51  * slap_sl_free the memory before finishing: New tasks reuse the context
52  * and normally reset it, reclaiming memory left over from last task.
53  *
54  * The allocator helps memory fragmentation, speed and memory leaks.
55  * It is not (yet) reliable as a garbage collector:
56  *
57  * It falls back to context NULL - plain ber_memalloc() - when the
58  * context's slab is full.  A reset does not reclaim such memory.
59  * Conversely, free/realloc of data not from the given context assumes
60  * context NULL.  The data must not belong to another memory context.
61  *
62  * Code which has lost track of the current memory context can try
63  * slap_sl_context() or ch_malloc.c:ch_free/ch_realloc().
64  *
65  * Allocations cannot yet return failure.  Like ch_malloc, they succeed
66  * or abort slapd.  This will change, do fix code which assumes success.
67  */
68 
69 /*
70  * The stack-based allocator stores (ber_len_t)sizeof(head+block) at
71  * allocated blocks' head - and in freed blocks also at the tail, marked
72  * by ORing *next* block's head with 1.  Freed blocks are only reclaimed
73  * from the last block forward.  This is fast, but when a block is never
74  * freed, older blocks will not be reclaimed until the slab is reset...
75  */
76 
77 #ifdef SLAP_NO_SL_MALLOC /* Useful with memory debuggers like Valgrind */
78 enum { No_sl_malloc = 1 };
79 #else
80 enum { No_sl_malloc = 0 };
81 #endif
82 
83 #define SLAP_SLAB_SOBLOCK 64
84 
85 struct slab_object {
86     void *so_ptr;
87 	int so_blockhead;
88     LDAP_LIST_ENTRY(slab_object) so_link;
89 };
90 
91 struct slab_heap {
92     void *sh_base;
93     void *sh_last;
94     void *sh_end;
95 	int sh_stack;
96 	int sh_maxorder;
97     unsigned char **sh_map;
98     LDAP_LIST_HEAD(sh_freelist, slab_object) *sh_free;
99 	LDAP_LIST_HEAD(sh_so, slab_object) sh_sopool;
100 };
101 
102 enum {
103 	Align = sizeof(ber_len_t) > 2*sizeof(int)
104 		? sizeof(ber_len_t) : 2*sizeof(int),
105 	Align_log2 = 1 + (Align>2) + (Align>4) + (Align>8) + (Align>16),
106 	order_start = Align_log2 - 1,
107 	pad = Align - 1
108 };
109 
110 static struct slab_object * slap_replenish_sopool(struct slab_heap* sh);
111 #ifdef SLAPD_UNUSED
112 static void print_slheap(int level, void *ctx);
113 #endif
114 
115 /* Keep memory context in a thread-local var, or in a global when no threads */
116 #ifdef NO_THREADS
117 static struct slab_heap *slheap;
118 # define SET_MEMCTX(thrctx, memctx, sfree)	((void) (slheap = (memctx)))
119 # define GET_MEMCTX(thrctx, memctxp)		(*(memctxp) = slheap)
120 #else
121 # define memctx_key ((void *) slap_sl_mem_init)
122 # define SET_MEMCTX(thrctx, memctx, kfree) \
123 	ldap_pvt_thread_pool_setkey(thrctx,memctx_key, memctx,kfree, NULL,NULL)
124 # define GET_MEMCTX(thrctx, memctxp) \
125 	((void) (*(memctxp) = NULL), \
126 	 (void) ldap_pvt_thread_pool_getkey(thrctx,memctx_key, memctxp,NULL), \
127 	 *(memctxp))
128 #endif /* NO_THREADS */
129 
130 
131 /* Destroy the context, or if key==NULL clean it up for reuse. */
132 void
133 slap_sl_mem_destroy(
134 	void *key,
135 	void *data
136 )
137 {
138 	struct slab_heap *sh = data;
139 	struct slab_object *so;
140 	int i;
141 
142 	if (!sh->sh_stack) {
143 		for (i = 0; i <= sh->sh_maxorder - order_start; i++) {
144 			so = LDAP_LIST_FIRST(&sh->sh_free[i]);
145 			while (so) {
146 				struct slab_object *so_tmp = so;
147 				so = LDAP_LIST_NEXT(so, so_link);
148 				LDAP_LIST_INSERT_HEAD(&sh->sh_sopool, so_tmp, so_link);
149 			}
150 			ch_free(sh->sh_map[i]);
151 		}
152 		ch_free(sh->sh_free);
153 		ch_free(sh->sh_map);
154 
155 		so = LDAP_LIST_FIRST(&sh->sh_sopool);
156 		while (so) {
157 			struct slab_object *so_tmp = so;
158 			so = LDAP_LIST_NEXT(so, so_link);
159 			if (!so_tmp->so_blockhead) {
160 				LDAP_LIST_REMOVE(so_tmp, so_link);
161 			}
162 		}
163 		so = LDAP_LIST_FIRST(&sh->sh_sopool);
164 		while (so) {
165 			struct slab_object *so_tmp = so;
166 			so = LDAP_LIST_NEXT(so, so_link);
167 			ch_free(so_tmp);
168 		}
169 	}
170 
171 	if (key != NULL) {
172 		ber_memfree_x(sh->sh_base, NULL);
173 		ber_memfree_x(sh, NULL);
174 	}
175 }
176 
177 BerMemoryFunctions slap_sl_mfuncs =
178 	{ slap_sl_malloc, slap_sl_calloc, slap_sl_realloc, slap_sl_free };
179 
180 void
181 slap_sl_mem_init()
182 {
183 	assert( Align == 1 << Align_log2 );
184 
185 	ber_set_option( NULL, LBER_OPT_MEMORY_FNS, &slap_sl_mfuncs );
186 }
187 
188 /* Create, reset or just return the memory context of the current thread. */
189 void *
190 slap_sl_mem_create(
191 	ber_len_t size,
192 	int stack,
193 	void *thrctx,
194 	int new
195 )
196 {
197 	void *memctx;
198 	struct slab_heap *sh;
199 	ber_len_t size_shift;
200 	struct slab_object *so;
201 	char *base, *newptr;
202 	enum { Base_offset = (unsigned) -sizeof(ber_len_t) % Align };
203 
204 	sh = GET_MEMCTX(thrctx, &memctx);
205 	if ( sh && !new )
206 		return sh;
207 
208 	/* Round up to doubleword boundary, then make room for initial
209 	 * padding, preserving expected available size for pool version */
210 	size = ((size + Align-1) & -Align) + Base_offset;
211 
212 	if (!sh) {
213 		sh = ch_malloc(sizeof(struct slab_heap));
214 		base = ch_malloc(size);
215 		SET_MEMCTX(thrctx, sh, slap_sl_mem_destroy);
216 		VGMEMP_MARK(base, size);
217 		VGMEMP_CREATE(sh, 0, 0);
218 	} else {
219 		slap_sl_mem_destroy(NULL, sh);
220 		base = sh->sh_base;
221 		if (size > (ber_len_t) ((char *) sh->sh_end - base)) {
222 			newptr = ch_realloc(base, size);
223 			if ( newptr == NULL ) return NULL;
224 			VGMEMP_CHANGE(sh, base, newptr, size);
225 			base = newptr;
226 		}
227 		VGMEMP_TRIM(sh, base, 0);
228 	}
229 	sh->sh_base = base;
230 	sh->sh_end = base + size;
231 
232 	/* Align (base + head of first block) == first returned block */
233 	base += Base_offset;
234 	size -= Base_offset;
235 
236 	sh->sh_stack = stack;
237 	if (stack) {
238 		sh->sh_last = base;
239 
240 	} else {
241 		int i, order = -1, order_end = -1;
242 
243 		size_shift = size - 1;
244 		do {
245 			order_end++;
246 		} while (size_shift >>= 1);
247 		order = order_end - order_start + 1;
248 		sh->sh_maxorder = order_end;
249 
250 		sh->sh_free = (struct sh_freelist *)
251 						ch_malloc(order * sizeof(struct sh_freelist));
252 		for (i = 0; i < order; i++) {
253 			LDAP_LIST_INIT(&sh->sh_free[i]);
254 		}
255 
256 		LDAP_LIST_INIT(&sh->sh_sopool);
257 
258 		if (LDAP_LIST_EMPTY(&sh->sh_sopool)) {
259 			slap_replenish_sopool(sh);
260 		}
261 		so = LDAP_LIST_FIRST(&sh->sh_sopool);
262 		LDAP_LIST_REMOVE(so, so_link);
263 		so->so_ptr = base;
264 
265 		LDAP_LIST_INSERT_HEAD(&sh->sh_free[order-1], so, so_link);
266 
267 		sh->sh_map = (unsigned char **)
268 					ch_malloc(order * sizeof(unsigned char *));
269 		for (i = 0; i < order; i++) {
270 			int shiftamt = order_start + 1 + i;
271 			int nummaps = size >> shiftamt;
272 			assert(nummaps);
273 			nummaps >>= 3;
274 			if (!nummaps) nummaps = 1;
275 			sh->sh_map[i] = (unsigned char *) ch_malloc(nummaps);
276 			memset(sh->sh_map[i], 0, nummaps);
277 		}
278 	}
279 
280 	return sh;
281 }
282 
283 /*
284  * Separate memory context from thread context.  Future users must
285  * know the context, since ch_free/slap_sl_context() cannot find it.
286  */
287 void
288 slap_sl_mem_detach(
289 	void *thrctx,
290 	void *memctx
291 )
292 {
293 	SET_MEMCTX(thrctx, NULL, 0);
294 }
295 
296 void *
297 slap_sl_malloc(
298     ber_len_t	size,
299     void *ctx
300 )
301 {
302 	struct slab_heap *sh = ctx;
303 	ber_len_t *ptr, *newptr;
304 
305 	/* ber_set_option calls us like this */
306 	if (No_sl_malloc || !ctx) {
307 		newptr = ber_memalloc_x( size, NULL );
308 		if ( newptr ) return newptr;
309 		Debug(LDAP_DEBUG_ANY, "slap_sl_malloc of %lu bytes failed\n",
310 			(unsigned long) size, 0, 0);
311 		assert( 0 );
312 		exit( EXIT_FAILURE );
313 	}
314 
315 	/* Add room for head, ensure room for tail when freed, and
316 	 * round up to doubleword boundary. */
317 	size = (size + sizeof(ber_len_t) + Align-1 + !size) & -Align;
318 
319 	if (sh->sh_stack) {
320 		if (size < (ber_len_t) ((char *) sh->sh_end - (char *) sh->sh_last)) {
321 			newptr = sh->sh_last;
322 			sh->sh_last = (char *) sh->sh_last + size;
323 			VGMEMP_ALLOC(sh, newptr, size);
324 			*newptr++ = size;
325 			return( (void *)newptr );
326 		}
327 
328 		size -= sizeof(ber_len_t);
329 
330 	} else {
331 		struct slab_object *so_new, *so_left, *so_right;
332 		ber_len_t size_shift;
333 		unsigned long diff;
334 		int i, j, order = -1;
335 
336 		size_shift = size - 1;
337 		do {
338 			order++;
339 		} while (size_shift >>= 1);
340 
341 		size -= sizeof(ber_len_t);
342 
343 		for (i = order; i <= sh->sh_maxorder &&
344 				LDAP_LIST_EMPTY(&sh->sh_free[i-order_start]); i++);
345 
346 		if (i == order) {
347 			so_new = LDAP_LIST_FIRST(&sh->sh_free[i-order_start]);
348 			LDAP_LIST_REMOVE(so_new, so_link);
349 			ptr = so_new->so_ptr;
350 			diff = (unsigned long)((char*)ptr -
351 					(char*)sh->sh_base) >> (order + 1);
352 			sh->sh_map[order-order_start][diff>>3] |= (1 << (diff & 0x7));
353 			*ptr++ = size;
354 			LDAP_LIST_INSERT_HEAD(&sh->sh_sopool, so_new, so_link);
355 			return((void*)ptr);
356 		} else if (i <= sh->sh_maxorder) {
357 			for (j = i; j > order; j--) {
358 				so_left = LDAP_LIST_FIRST(&sh->sh_free[j-order_start]);
359 				LDAP_LIST_REMOVE(so_left, so_link);
360 				if (LDAP_LIST_EMPTY(&sh->sh_sopool)) {
361 					slap_replenish_sopool(sh);
362 				}
363 				so_right = LDAP_LIST_FIRST(&sh->sh_sopool);
364 				LDAP_LIST_REMOVE(so_right, so_link);
365 				so_right->so_ptr = (void *)((char *)so_left->so_ptr + (1 << j));
366 				if (j == order + 1) {
367 					ptr = so_left->so_ptr;
368 					diff = (unsigned long)((char*)ptr -
369 							(char*)sh->sh_base) >> (order+1);
370 					sh->sh_map[order-order_start][diff>>3] |=
371 							(1 << (diff & 0x7));
372 					*ptr++ = size;
373 					LDAP_LIST_INSERT_HEAD(
374 							&sh->sh_free[j-1-order_start], so_right, so_link);
375 					LDAP_LIST_INSERT_HEAD(&sh->sh_sopool, so_left, so_link);
376 					return((void*)ptr);
377 				} else {
378 					LDAP_LIST_INSERT_HEAD(
379 							&sh->sh_free[j-1-order_start], so_right, so_link);
380 					LDAP_LIST_INSERT_HEAD(
381 							&sh->sh_free[j-1-order_start], so_left, so_link);
382 				}
383 			}
384 		}
385 		/* FIXME: missing return; guessing we failed... */
386 	}
387 
388 	Debug(LDAP_DEBUG_TRACE,
389 		"sl_malloc %lu: ch_malloc\n",
390 		(unsigned long) size, 0, 0);
391 	return ch_malloc(size);
392 }
393 
394 #define LIM_SQRT(t) /* some value < sqrt(max value of unsigned type t) */ \
395 	((0UL|(t)-1) >>31>>31 > 1 ? ((t)1 <<32) - 1 : \
396 	 (0UL|(t)-1) >>31 ? 65535U : (0UL|(t)-1) >>15 ? 255U : 15U)
397 
398 void *
399 slap_sl_calloc( ber_len_t n, ber_len_t size, void *ctx )
400 {
401 	void *newptr;
402 	ber_len_t total = n * size;
403 
404 	/* The sqrt test is a slight optimization: often avoids the division */
405 	if ((n | size) <= LIM_SQRT(ber_len_t) || n == 0 || total/n == size) {
406 		newptr = slap_sl_malloc( total, ctx );
407 		memset( newptr, 0, n*size );
408 	} else {
409 		Debug(LDAP_DEBUG_ANY, "slap_sl_calloc(%lu,%lu) out of range\n",
410 			(unsigned long) n, (unsigned long) size, 0);
411 		assert(0);
412 		exit(EXIT_FAILURE);
413 	}
414 	return newptr;
415 }
416 
417 void *
418 slap_sl_realloc(void *ptr, ber_len_t size, void *ctx)
419 {
420 	struct slab_heap *sh = ctx;
421 	ber_len_t oldsize, *p = (ber_len_t *) ptr, *nextp;
422 	void *newptr;
423 
424 	if (ptr == NULL)
425 		return slap_sl_malloc(size, ctx);
426 
427 	/* Not our memory? */
428 	if (No_sl_malloc || !sh || ptr < sh->sh_base || ptr >= sh->sh_end) {
429 		/* Like ch_realloc(), except not trying a new context */
430 		newptr = ber_memrealloc_x(ptr, size, NULL);
431 		if (newptr) {
432 			return newptr;
433 		}
434 		Debug(LDAP_DEBUG_ANY, "slap_sl_realloc of %lu bytes failed\n",
435 			(unsigned long) size, 0, 0);
436 		assert(0);
437 		exit( EXIT_FAILURE );
438 	}
439 
440 	if (size == 0) {
441 		slap_sl_free(ptr, ctx);
442 		return NULL;
443 	}
444 
445 	oldsize = p[-1];
446 
447 	if (sh->sh_stack) {
448 		/* Add room for head, round up to doubleword boundary */
449 		size = (size + sizeof(ber_len_t) + Align-1) & -Align;
450 
451 		p--;
452 
453 		/* Never shrink blocks */
454 		if (size <= oldsize) {
455 			return ptr;
456 		}
457 
458 		oldsize &= -2;
459 		nextp = (ber_len_t *) ((char *) p + oldsize);
460 
461 		/* If reallocing the last block, try to grow it */
462 		if (nextp == sh->sh_last) {
463 			if (size < (ber_len_t) ((char *) sh->sh_end - (char *) p)) {
464 				sh->sh_last = (char *) p + size;
465 				p[0] = (p[0] & 1) | size;
466 				return ptr;
467 			}
468 
469 		/* Nowhere to grow, need to alloc and copy */
470 		} else {
471 			/* Slight optimization of the final realloc variant */
472 			newptr = slap_sl_malloc(size-sizeof(ber_len_t), ctx);
473 			AC_MEMCPY(newptr, ptr, oldsize-sizeof(ber_len_t));
474 			/* Not last block, can just mark old region as free */
475 			nextp[-1] = oldsize;
476 			nextp[0] |= 1;
477 			return newptr;
478 		}
479 
480 		size -= sizeof(ber_len_t);
481 		oldsize -= sizeof(ber_len_t);
482 
483 	} else if (oldsize > size) {
484 		oldsize = size;
485 	}
486 
487 	newptr = slap_sl_malloc(size, ctx);
488 	AC_MEMCPY(newptr, ptr, oldsize);
489 	slap_sl_free(ptr, ctx);
490 	return newptr;
491 }
492 
493 void
494 slap_sl_free(void *ptr, void *ctx)
495 {
496 	struct slab_heap *sh = ctx;
497 	ber_len_t size;
498 	ber_len_t *p = ptr, *nextp, *tmpp;
499 
500 	if (!ptr)
501 		return;
502 
503 	if (No_sl_malloc || !sh || ptr < sh->sh_base || ptr >= sh->sh_end) {
504 		ber_memfree_x(ptr, NULL);
505 		return;
506 	}
507 
508 	size = *(--p);
509 
510 	if (sh->sh_stack) {
511 		size &= -2;
512 		nextp = (ber_len_t *) ((char *) p + size);
513 		if (sh->sh_last != nextp) {
514 			/* Mark it free: tail = size, head of next block |= 1 */
515 			nextp[-1] = size;
516 			nextp[0] |= 1;
517 			/* We can't tell Valgrind about it yet, because we
518 			 * still need read/write access to this block for
519 			 * when we eventually get to reclaim it.
520 			 */
521 		} else {
522 			/* Reclaim freed block(s) off tail */
523 			while (*p & 1) {
524 				p = (ber_len_t *) ((char *) p - p[-1]);
525 			}
526 			sh->sh_last = p;
527 			VGMEMP_TRIM(sh, sh->sh_base,
528 				(char *) sh->sh_last - (char *) sh->sh_base);
529 		}
530 
531 	} else {
532 		int size_shift, order_size;
533 		struct slab_object *so;
534 		unsigned long diff;
535 		int i, inserted = 0, order = -1;
536 
537 		size_shift = size + sizeof(ber_len_t) - 1;
538 		do {
539 			order++;
540 		} while (size_shift >>= 1);
541 
542 		for (i = order, tmpp = p; i <= sh->sh_maxorder; i++) {
543 			order_size = 1 << (i+1);
544 			diff = (unsigned long)((char*)tmpp - (char*)sh->sh_base) >> (i+1);
545 			sh->sh_map[i-order_start][diff>>3] &= (~(1 << (diff & 0x7)));
546 			if (diff == ((diff>>1)<<1)) {
547 				if (!(sh->sh_map[i-order_start][(diff+1)>>3] &
548 						(1<<((diff+1)&0x7)))) {
549 					so = LDAP_LIST_FIRST(&sh->sh_free[i-order_start]);
550 					while (so) {
551 						if ((char*)so->so_ptr == (char*)tmpp) {
552 							LDAP_LIST_REMOVE( so, so_link );
553 						} else if ((char*)so->so_ptr ==
554 								(char*)tmpp + order_size) {
555 							LDAP_LIST_REMOVE(so, so_link);
556 							break;
557 						}
558 						so = LDAP_LIST_NEXT(so, so_link);
559 					}
560 					if (so) {
561 						if (i < sh->sh_maxorder) {
562 							inserted = 1;
563 							so->so_ptr = tmpp;
564 							LDAP_LIST_INSERT_HEAD(&sh->sh_free[i-order_start+1],
565 									so, so_link);
566 						}
567 						continue;
568 					} else {
569 						if (LDAP_LIST_EMPTY(&sh->sh_sopool)) {
570 							slap_replenish_sopool(sh);
571 						}
572 						so = LDAP_LIST_FIRST(&sh->sh_sopool);
573 						LDAP_LIST_REMOVE(so, so_link);
574 						so->so_ptr = tmpp;
575 						LDAP_LIST_INSERT_HEAD(&sh->sh_free[i-order_start],
576 								so, so_link);
577 						break;
578 
579 						Debug(LDAP_DEBUG_TRACE, "slap_sl_free: "
580 							"free object not found while bit is clear.\n",
581 							0, 0, 0);
582 						assert(so != NULL);
583 
584 					}
585 				} else {
586 					if (!inserted) {
587 						if (LDAP_LIST_EMPTY(&sh->sh_sopool)) {
588 							slap_replenish_sopool(sh);
589 						}
590 						so = LDAP_LIST_FIRST(&sh->sh_sopool);
591 						LDAP_LIST_REMOVE(so, so_link);
592 						so->so_ptr = tmpp;
593 						LDAP_LIST_INSERT_HEAD(&sh->sh_free[i-order_start],
594 								so, so_link);
595 					}
596 					break;
597 				}
598 			} else {
599 				if (!(sh->sh_map[i-order_start][(diff-1)>>3] &
600 						(1<<((diff-1)&0x7)))) {
601 					so = LDAP_LIST_FIRST(&sh->sh_free[i-order_start]);
602 					while (so) {
603 						if ((char*)so->so_ptr == (char*)tmpp) {
604 							LDAP_LIST_REMOVE(so, so_link);
605 						} else if ((char*)tmpp == (char *)so->so_ptr + order_size) {
606 							LDAP_LIST_REMOVE(so, so_link);
607 							tmpp = so->so_ptr;
608 							break;
609 						}
610 						so = LDAP_LIST_NEXT(so, so_link);
611 					}
612 					if (so) {
613 						if (i < sh->sh_maxorder) {
614 							inserted = 1;
615 							LDAP_LIST_INSERT_HEAD(&sh->sh_free[i-order_start+1],									so, so_link);
616 							continue;
617 						}
618 					} else {
619 						if (LDAP_LIST_EMPTY(&sh->sh_sopool)) {
620 							slap_replenish_sopool(sh);
621 						}
622 						so = LDAP_LIST_FIRST(&sh->sh_sopool);
623 						LDAP_LIST_REMOVE(so, so_link);
624 						so->so_ptr = tmpp;
625 						LDAP_LIST_INSERT_HEAD(&sh->sh_free[i-order_start],
626 								so, so_link);
627 						break;
628 
629 						Debug(LDAP_DEBUG_TRACE, "slap_sl_free: "
630 							"free object not found while bit is clear.\n",
631 							0, 0, 0 );
632 						assert(so != NULL);
633 
634 					}
635 				} else {
636 					if ( !inserted ) {
637 						if (LDAP_LIST_EMPTY(&sh->sh_sopool)) {
638 							slap_replenish_sopool(sh);
639 						}
640 						so = LDAP_LIST_FIRST(&sh->sh_sopool);
641 						LDAP_LIST_REMOVE(so, so_link);
642 						so->so_ptr = tmpp;
643 						LDAP_LIST_INSERT_HEAD(&sh->sh_free[i-order_start],
644 								so, so_link);
645 					}
646 					break;
647 				}
648 			}
649 		}
650 	}
651 }
652 
653 /*
654  * Return the memory context of the current thread if the given block of
655  * memory belongs to it, otherwise return NULL.
656  */
657 void *
658 slap_sl_context( void *ptr )
659 {
660 	void *memctx;
661 	struct slab_heap *sh;
662 
663 	if ( slapMode & SLAP_TOOL_MODE ) return NULL;
664 
665 	sh = GET_MEMCTX(ldap_pvt_thread_pool_context(), &memctx);
666 	if (sh && ptr >= sh->sh_base && ptr <= sh->sh_end) {
667 		return sh;
668 	}
669 	return NULL;
670 }
671 
672 static struct slab_object *
673 slap_replenish_sopool(
674     struct slab_heap* sh
675 )
676 {
677     struct slab_object *so_block;
678     int i;
679 
680     so_block = (struct slab_object *)ch_malloc(
681                     SLAP_SLAB_SOBLOCK * sizeof(struct slab_object));
682 
683     if ( so_block == NULL ) {
684         return NULL;
685     }
686 
687     so_block[0].so_blockhead = 1;
688     LDAP_LIST_INSERT_HEAD(&sh->sh_sopool, &so_block[0], so_link);
689     for (i = 1; i < SLAP_SLAB_SOBLOCK; i++) {
690         so_block[i].so_blockhead = 0;
691         LDAP_LIST_INSERT_HEAD(&sh->sh_sopool, &so_block[i], so_link );
692     }
693 
694     return so_block;
695 }
696 
697 #ifdef SLAPD_UNUSED
698 static void
699 print_slheap(int level, void *ctx)
700 {
701 	struct slab_heap *sh = ctx;
702 	struct slab_object *so;
703 	int i, j, once = 0;
704 
705 	if (!ctx) {
706 		Debug(level, "NULL memctx\n", 0, 0, 0);
707 		return;
708 	}
709 
710 	Debug(level, "sh->sh_maxorder=%d\n", sh->sh_maxorder, 0, 0);
711 
712 	for (i = order_start; i <= sh->sh_maxorder; i++) {
713 		once = 0;
714 		Debug(level, "order=%d\n", i, 0, 0);
715 		for (j = 0; j < (1<<(sh->sh_maxorder-i))/8; j++) {
716 			Debug(level, "%02x ", sh->sh_map[i-order_start][j], 0, 0);
717 			once = 1;
718 		}
719 		if (!once) {
720 			Debug(level, "%02x ", sh->sh_map[i-order_start][0], 0, 0);
721 		}
722 		Debug(level, "\n", 0, 0, 0);
723 		Debug(level, "free list:\n", 0, 0, 0);
724 		so = LDAP_LIST_FIRST(&sh->sh_free[i-order_start]);
725 		while (so) {
726 			Debug(level, "%p\n", so->so_ptr, 0, 0);
727 			so = LDAP_LIST_NEXT(so, so_link);
728 		}
729 	}
730 }
731 #endif
732