xref: /dragonfly/sys/kern/subr_alist.c (revision 3f5e28f4)
1 /*
2  * ALIST.C -	Bitmap allocator/deallocator, using a radix tree with hinting.
3  *		Unlimited-size allocations, power-of-2 only, power-of-2
4  *		aligned results only.
5  *
6  * Copyright (c) 2007 The DragonFly Project.  All rights reserved.
7  *
8  * This code is derived from software contributed to The DragonFly Project
9  * by Matthew Dillon <dillon@backplane.com>
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  *
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in
19  *    the documentation and/or other materials provided with the
20  *    distribution.
21  * 3. Neither the name of The DragonFly Project nor the names of its
22  *    contributors may be used to endorse or promote products derived
23  *    from this software without specific, prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
28  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
29  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
30  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
31  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
32  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
33  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
34  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
35  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  * $DragonFly: src/sys/kern/subr_alist.c,v 1.2 2007/04/19 03:16:33 dillon Exp $
39  */
40 /*
41  * This module has been adapted from the BLIST module, which was written
42  * by Matthew Dillon many years ago.
43  *
44  * This module implements a general power-of-2 bitmap allocator/deallocator.
45  * All allocations must be in powers of 2 and will return similarly aligned
46  * results.  The module does not try to interpret the meaning of a 'block'
47  * other then to return ALIST_BLOCK_NONE on an allocation failure.
48  *
49  * A maximum of 2 billion blocks is supported so, for example, if one block
50  * represented 64 bytes a maximally sized ALIST would represent
51  * 128 gigabytes.
52  *
53  * A radix tree is used to maintain the bitmap and layed out in a manner
54  * similar to the blist code.  Meta nodes use a radix of 16 and 2 bits per
55  * block while leaf nodes use a radix of 32 and 1 bit per block (stored in
56  * a 32 bit bitmap field).  Both meta and leaf nodes have a hint field.
57  * This field gives us a hint as to the largest free contiguous range of
58  * blocks under the node.  It may contain a value that is too high, but
59  * will never contain a value that is too low.  When the radix tree is
60  * searched, allocation failures in subtrees update the hint.
61  *
62  * The radix tree is layed out recursively using a linear array.  Each meta
63  * node is immediately followed (layed out sequentially in memory) by
64  * ALIST_META_RADIX lower level nodes.  This is a recursive structure but one
65  * that can be easily scanned through a very simple 'skip' calculation.  In
66  * order to support large radixes, portions of the tree may reside outside our
67  * memory allocation.  We handle this with an early-terminate optimization
68  * in the meta-node.  The memory allocation is only large enough to cover
69  * the number of blocks requested at creation time even if it must be
70  * encompassed in larger root-node radix.
71  *
72  * This code can be compiled stand-alone for debugging.
73  */
74 
75 #ifdef _KERNEL
76 
77 #include <sys/param.h>
78 #include <sys/systm.h>
79 #include <sys/lock.h>
80 #include <sys/kernel.h>
81 #include <sys/alist.h>
82 #include <sys/malloc.h>
83 #include <vm/vm.h>
84 #include <vm/vm_object.h>
85 #include <vm/vm_kern.h>
86 #include <vm/vm_extern.h>
87 #include <vm/vm_page.h>
88 
89 #else
90 
91 #ifndef ALIST_NO_DEBUG
92 #define ALIST_DEBUG
93 #endif
94 
95 #include <sys/types.h>
96 #include <stdio.h>
97 #include <assert.h>
98 #include <string.h>
99 #include <stdlib.h>
100 #include <stdarg.h>
101 
102 #define kmalloc(a,b,c)	malloc(a)
103 #define kfree(a,b)	free(a)
104 #define kprintf		printf
105 #define KKASSERT(exp)	assert(exp)
106 struct malloc_type;
107 
108 typedef unsigned int u_daddr_t;
109 
110 #include <sys/alist.h>
111 
112 void panic(const char *ctl, ...);
113 
114 #endif
115 
116 /*
117  * static support functions
118  */
119 
120 static daddr_t alst_leaf_alloc(almeta_t *scan, daddr_t blk, int count);
121 static daddr_t alst_meta_alloc(almeta_t *scan, daddr_t blk,
122 				daddr_t count, daddr_t radix, int skip);
123 static void alst_leaf_free(almeta_t *scan, daddr_t relblk, int count);
124 static void alst_meta_free(almeta_t *scan, daddr_t freeBlk, daddr_t count,
125 					daddr_t radix, int skip, daddr_t blk);
126 static daddr_t	alst_radix_init(almeta_t *scan, daddr_t radix,
127 						int skip, daddr_t count);
128 #ifndef _KERNEL
129 static void	alst_radix_print(almeta_t *scan, daddr_t blk,
130 					daddr_t radix, int skip, int tab);
131 #endif
132 
133 /*
134  * alist_create() - create a alist capable of handling up to the specified
135  *		    number of blocks
136  *
137  *	blocks must be greater then 0
138  *
139  *	The smallest alist consists of a single leaf node capable of
140  *	managing ALIST_BMAP_RADIX blocks.
141  */
142 
143 alist_t
144 alist_create(daddr_t blocks, struct malloc_type *mtype)
145 {
146 	alist_t bl;
147 	int radix;
148 	int skip = 0;
149 
150 	/*
151 	 * Calculate radix and skip field used for scanning.
152 	 */
153 	radix = ALIST_BMAP_RADIX;
154 
155 	while (radix < blocks) {
156 		radix *= ALIST_META_RADIX;
157 		skip = (skip + 1) * ALIST_META_RADIX;
158 	}
159 
160 	bl = kmalloc(sizeof(struct alist), mtype, M_WAITOK);
161 
162 	bzero(bl, sizeof(*bl));
163 
164 	bl->bl_blocks = blocks;
165 	bl->bl_radix = radix;
166 	bl->bl_skip = skip;
167 	bl->bl_rootblks = 1 +
168 	    alst_radix_init(NULL, bl->bl_radix, bl->bl_skip, blocks);
169 	bl->bl_root = kmalloc(sizeof(almeta_t) * bl->bl_rootblks, mtype, M_WAITOK);
170 
171 #if defined(ALIST_DEBUG)
172 	kprintf(
173 		"ALIST representing %d blocks (%d MB of swap)"
174 		", requiring %dK of ram\n",
175 		bl->bl_blocks,
176 		bl->bl_blocks * 4 / 1024,
177 		(bl->bl_rootblks * sizeof(almeta_t) + 1023) / 1024
178 	);
179 	kprintf("ALIST raw radix tree contains %d records\n", bl->bl_rootblks);
180 #endif
181 	alst_radix_init(bl->bl_root, bl->bl_radix, bl->bl_skip, blocks);
182 
183 	return(bl);
184 }
185 
186 void
187 alist_destroy(alist_t bl, struct malloc_type *mtype)
188 {
189 	kfree(bl->bl_root, mtype);
190 	kfree(bl, mtype);
191 }
192 
193 /*
194  * alist_alloc() - reserve space in the block bitmap.  Return the base
195  *		   of a contiguous region or ALIST_BLOCK_NONE if space
196  *		   could not be allocated.
197  */
198 
199 daddr_t
200 alist_alloc(alist_t bl, daddr_t count)
201 {
202 	daddr_t blk = ALIST_BLOCK_NONE;
203 
204 	KKASSERT((count | (count - 1)) == (count << 1) - 1);
205 
206 	if (bl && count < bl->bl_radix) {
207 		if (bl->bl_radix == ALIST_BMAP_RADIX)
208 			blk = alst_leaf_alloc(bl->bl_root, 0, count);
209 		else
210 			blk = alst_meta_alloc(bl->bl_root, 0, count, bl->bl_radix, bl->bl_skip);
211 		if (blk != ALIST_BLOCK_NONE)
212 			bl->bl_free -= count;
213 	}
214 	return(blk);
215 }
216 
217 /*
218  * alist_free() -	free up space in the block bitmap.  Return the base
219  *		     	of a contiguous region.  Panic if an inconsistancy is
220  *			found.
221  */
222 
223 void
224 alist_free(alist_t bl, daddr_t blkno, daddr_t count)
225 {
226 	if (bl) {
227 		KKASSERT(blkno + count <= bl->bl_blocks);
228 		if (bl->bl_radix == ALIST_BMAP_RADIX)
229 			alst_leaf_free(bl->bl_root, blkno, count);
230 		else
231 			alst_meta_free(bl->bl_root, blkno, count, bl->bl_radix, bl->bl_skip, 0);
232 		bl->bl_free += count;
233 	}
234 }
235 
236 #ifdef ALIST_DEBUG
237 
238 /*
239  * alist_print()    - dump radix tree
240  */
241 
242 void
243 alist_print(alist_t bl)
244 {
245 	kprintf("ALIST {\n");
246 	alst_radix_print(bl->bl_root, 0, bl->bl_radix, bl->bl_skip, 4);
247 	kprintf("}\n");
248 }
249 
250 #endif
251 
252 /************************************************************************
253  *			  ALLOCATION SUPPORT FUNCTIONS			*
254  ************************************************************************
255  *
256  *	These support functions do all the actual work.  They may seem
257  *	rather longish, but that's because I've commented them up.  The
258  *	actual code is straight forward.
259  *
260  */
261 
262 /*
263  * alist_leaf_alloc() -	allocate at a leaf in the radix tree (a bitmap).
264  *
265  *	This is the core of the allocator and is optimized for the 1 block
266  *	and the ALIST_BMAP_RADIX block allocation cases.  Other cases are
267  *	somewhat slower.  The 1 block allocation case is log2 and extremely
268  *	quick.
269  */
270 
271 static daddr_t
272 alst_leaf_alloc(
273 	almeta_t *scan,
274 	daddr_t blk,
275 	int count
276 ) {
277 	u_daddr_t orig = scan->bm_bitmap;
278 
279 	/*
280 	 * Optimize bitmap all-allocated case.  Also, count = 1
281 	 * case assumes at least 1 bit is free in the bitmap, so
282 	 * we have to take care of this case here.
283 	 */
284 	if (orig == 0) {
285 		scan->bm_bighint = 0;
286 		return(ALIST_BLOCK_NONE);
287 	}
288 
289 	/*
290 	 * Optimized code to allocate one bit out of the bitmap
291 	 */
292 	if (count == 1) {
293 		u_daddr_t mask;
294 		int j = ALIST_BMAP_RADIX/2;
295 		int r = 0;
296 
297 		mask = (u_daddr_t)-1 >> (ALIST_BMAP_RADIX/2);
298 
299 		while (j) {
300 			if ((orig & mask) == 0) {
301 			    r += j;
302 			    orig >>= j;
303 			}
304 			j >>= 1;
305 			mask >>= j;
306 		}
307 		scan->bm_bitmap &= ~(1 << r);
308 		return(blk + r);
309 	}
310 
311 	/*
312 	 * non-optimized code to allocate N bits out of the bitmap.
313 	 * The more bits, the faster the code runs.  It will run
314 	 * the slowest allocating 2 bits, but since there aren't any
315 	 * memory ops in the core loop (or shouldn't be, anyway),
316 	 * you probably won't notice the difference.
317 	 *
318 	 * Similar to the blist case, the alist code also requires
319 	 * allocations to be power-of-2 sized and aligned to the
320 	 * size of the allocation, which simplifies the algorithm.
321 	 */
322 	{
323 		int j;
324 		int n = ALIST_BMAP_RADIX - count;
325 		u_daddr_t mask;
326 
327 		mask = (u_daddr_t)-1 >> n;
328 
329 		for (j = 0; j <= n; j += count) {
330 			if ((orig & mask) == mask) {
331 				scan->bm_bitmap &= ~mask;
332 				return(blk + j);
333 			}
334 			mask = mask << count;
335 		}
336 	}
337 
338 	/*
339 	 * We couldn't allocate count in this subtree, update bighint.
340 	 */
341 	scan->bm_bighint = count - 1;
342 	return(ALIST_BLOCK_NONE);
343 }
344 
345 /*
346  * alist_meta_alloc() -	allocate at a meta in the radix tree.
347  *
348  *	Attempt to allocate at a meta node.  If we can't, we update
349  *	bighint and return a failure.  Updating bighint optimize future
350  *	calls that hit this node.  We have to check for our collapse cases
351  *	and we have a few optimizations strewn in as well.
352  */
353 
354 static daddr_t
355 alst_meta_alloc(
356 	almeta_t *scan,
357 	daddr_t blk,
358 	daddr_t count,
359 	daddr_t radix,
360 	int skip
361 ) {
362 	int i;
363 	u_daddr_t mask;
364 	u_daddr_t pmask;
365 	int next_skip = ((u_int)skip / ALIST_META_RADIX);
366 
367 	/*
368 	 * ALL-ALLOCATED special case
369 	 */
370 	if (scan->bm_bitmap == 0)  {
371 		scan->bm_bighint = 0;
372 		return(ALIST_BLOCK_NONE);
373 	}
374 
375 	radix /= ALIST_META_RADIX;
376 
377 	/*
378 	 * Radix now represents each bitmap entry for this meta node.  If
379 	 * the number of blocks being allocated can be fully represented,
380 	 * we allocate directly out of this meta node.
381 	 *
382 	 * Meta node bitmaps use 2 bits per block.
383 	 *
384 	 *	00	ALL-ALLOCATED
385 	 *	01	PARTIALLY-FREE/PARTIALLY-ALLOCATED
386 	 *	10	(RESERVED)
387 	 *	11	ALL-FREE
388 	 */
389 	if (count >= radix) {
390 		int n = count / radix * 2;	/* number of bits */
391 		int j;
392 
393 		mask = (u_daddr_t)-1 >> (ALIST_BMAP_RADIX - n);
394 		for (j = 0; j < ALIST_META_RADIX; j += n / 2) {
395 			if ((scan->bm_bitmap & mask) == mask) {
396 				scan->bm_bitmap &= ~mask;
397 				return(blk + j * radix);
398 			}
399 			mask <<= n;
400 		}
401 		if (scan->bm_bighint >= count)
402 			scan->bm_bighint = count >> 1;
403 		return(ALIST_BLOCK_NONE);
404 	}
405 
406 	/*
407 	 * If not we have to recurse.
408 	 */
409 	mask = 0x00000003;
410 	pmask = 0x00000001;
411 	for (i = 1; i <= skip; i += next_skip) {
412 		if (scan[i].bm_bighint == (daddr_t)-1) {
413 			/*
414 			 * Terminator
415 			 */
416 			break;
417 		}
418 		if ((scan->bm_bitmap & mask) == mask) {
419 			scan[i].bm_bitmap = (u_daddr_t)-1;
420 			scan[i].bm_bighint = radix;
421 		}
422 
423 		if (count <= scan[i].bm_bighint) {
424 			/*
425 			 * count fits in object
426 			 */
427 			daddr_t r;
428 			if (next_skip == 1) {
429 				r = alst_leaf_alloc(&scan[i], blk, count);
430 			} else {
431 				r = alst_meta_alloc(&scan[i], blk, count, radix, next_skip - 1);
432 			}
433 			if (r != ALIST_BLOCK_NONE) {
434 				if (scan[i].bm_bitmap == 0) {
435 					scan->bm_bitmap &= ~mask;
436 				} else {
437 					scan->bm_bitmap &= ~mask;
438 					scan->bm_bitmap |= pmask;
439 				}
440 				return(r);
441 			}
442 		} else if (count > radix) {
443 			/*
444 			 * count does not fit in object even if it were
445 			 * completely free.
446 			 */
447 			break;
448 		}
449 		blk += radix;
450 		mask <<= 2;
451 		pmask <<= 2;
452 	}
453 
454 	/*
455 	 * We couldn't allocate count in this subtree, update bighint.
456 	 */
457 	if (scan->bm_bighint >= count)
458 		scan->bm_bighint = count >> 1;
459 	return(ALIST_BLOCK_NONE);
460 }
461 
462 /*
463  * BLST_LEAF_FREE() -	free allocated block from leaf bitmap
464  *
465  */
466 static void
467 alst_leaf_free(
468 	almeta_t *scan,
469 	daddr_t blk,
470 	int count
471 ) {
472 	/*
473 	 * free some data in this bitmap
474 	 *
475 	 * e.g.
476 	 *	0000111111111110000
477 	 *          \_________/\__/
478 	 *		v        n
479 	 */
480 	int n = blk & (ALIST_BMAP_RADIX - 1);
481 	u_daddr_t mask;
482 
483 	mask = ((u_daddr_t)-1 << n) &
484 	    ((u_daddr_t)-1 >> (ALIST_BMAP_RADIX - count - n));
485 
486 	if (scan->bm_bitmap & mask)
487 		panic("alst_radix_free: freeing free block");
488 	scan->bm_bitmap |= mask;
489 
490 	/*
491 	 * We could probably do a better job here.  We are required to make
492 	 * bighint at least as large as the biggest contiguous block of
493 	 * data.  If we just shoehorn it, a little extra overhead will
494 	 * be incured on the next allocation (but only that one typically).
495 	 */
496 	scan->bm_bighint = ALIST_BMAP_RADIX;
497 }
498 
499 /*
500  * BLST_META_FREE() - free allocated blocks from radix tree meta info
501  *
502  *	This support routine frees a range of blocks from the bitmap.
503  *	The range must be entirely enclosed by this radix node.  If a
504  *	meta node, we break the range down recursively to free blocks
505  *	in subnodes (which means that this code can free an arbitrary
506  *	range whereas the allocation code cannot allocate an arbitrary
507  *	range).
508  */
509 
510 static void
511 alst_meta_free(
512 	almeta_t *scan,
513 	daddr_t freeBlk,
514 	daddr_t count,
515 	daddr_t radix,
516 	int skip,
517 	daddr_t blk
518 ) {
519 	int next_skip = ((u_int)skip / ALIST_META_RADIX);
520 	u_daddr_t mask;
521 	u_daddr_t pmask;
522 	int i;
523 
524 	/*
525 	 * Break the free down into its components.  Because it is so easy
526 	 * to implement, frees are not limited to power-of-2 sizes.
527 	 *
528 	 * Each block in a meta-node bitmap takes two bits.
529 	 */
530 	radix /= ALIST_META_RADIX;
531 
532 	i = (freeBlk - blk) / radix;
533 	blk += i * radix;
534 	mask = 0x00000003 << (i * 2);
535 	pmask = 0x00000001 << (i * 2);
536 
537 	i = i * next_skip + 1;
538 
539 	while (i <= skip && blk < freeBlk + count) {
540 		daddr_t v;
541 
542 		v = blk + radix - freeBlk;
543 		if (v > count)
544 			v = count;
545 
546 		if (scan->bm_bighint == (daddr_t)-1)
547 			panic("alst_meta_free: freeing unexpected range");
548 
549 		if (freeBlk == blk && count >= radix) {
550 			/*
551 			 * All-free case, no need to update sub-tree
552 			 */
553 			scan->bm_bitmap |= mask;
554 			scan->bm_bighint = radix * ALIST_META_RADIX;/*XXX*/
555 		} else {
556 			/*
557 			 * Recursion case
558 			 */
559 			if (next_skip == 1)
560 				alst_leaf_free(&scan[i], freeBlk, v);
561 			else
562 				alst_meta_free(&scan[i], freeBlk, v, radix, next_skip - 1, blk);
563 			if (scan[i].bm_bitmap == (u_daddr_t)-1)
564 				scan->bm_bitmap |= mask;
565 			else
566 				scan->bm_bitmap |= pmask;
567 			if (scan->bm_bighint < scan[i].bm_bighint)
568 			    scan->bm_bighint = scan[i].bm_bighint;
569 		}
570 		mask <<= 2;
571 		pmask <<= 2;
572 		count -= v;
573 		freeBlk += v;
574 		blk += radix;
575 		i += next_skip;
576 	}
577 }
578 
579 /*
580  * BLST_RADIX_INIT() - initialize radix tree
581  *
582  *	Initialize our meta structures and bitmaps and calculate the exact
583  *	amount of space required to manage 'count' blocks - this space may
584  *	be considerably less then the calculated radix due to the large
585  *	RADIX values we use.
586  */
587 
588 static daddr_t
589 alst_radix_init(almeta_t *scan, daddr_t radix, int skip, daddr_t count)
590 {
591 	int i;
592 	int next_skip;
593 	daddr_t memindex = 0;
594 	u_daddr_t mask;
595 	u_daddr_t pmask;
596 
597 	/*
598 	 * Leaf node
599 	 */
600 	if (radix == ALIST_BMAP_RADIX) {
601 		if (scan) {
602 			scan->bm_bighint = 0;
603 			scan->bm_bitmap = 0;
604 		}
605 		return(memindex);
606 	}
607 
608 	/*
609 	 * Meta node.  If allocating the entire object we can special
610 	 * case it.  However, we need to figure out how much memory
611 	 * is required to manage 'count' blocks, so we continue on anyway.
612 	 */
613 
614 	if (scan) {
615 		scan->bm_bighint = 0;
616 		scan->bm_bitmap = 0;
617 	}
618 
619 	radix /= ALIST_META_RADIX;
620 	next_skip = ((u_int)skip / ALIST_META_RADIX);
621 	mask = 0x00000003;
622 	pmask = 0x00000001;
623 
624 	for (i = 1; i <= skip; i += next_skip) {
625 		if (count >= radix) {
626 			/*
627 			 * Allocate the entire object
628 			 */
629 			memindex = i + alst_radix_init(
630 			    ((scan) ? &scan[i] : NULL),
631 			    radix,
632 			    next_skip - 1,
633 			    radix
634 			);
635 			count -= radix;
636 			/* already marked as wholely allocated */
637 		} else if (count > 0) {
638 			/*
639 			 * Allocate a partial object
640 			 */
641 			memindex = i + alst_radix_init(
642 			    ((scan) ? &scan[i] : NULL),
643 			    radix,
644 			    next_skip - 1,
645 			    count
646 			);
647 			count = 0;
648 
649 			/*
650 			 * Mark as partially allocated
651 			 */
652 			if (scan)
653 				scan->bm_bitmap |= pmask;
654 		} else {
655 			/*
656 			 * Add terminator and break out
657 			 */
658 			if (scan)
659 				scan[i].bm_bighint = (daddr_t)-1;
660 			/* already marked as wholely allocated */
661 			break;
662 		}
663 		mask <<= 2;
664 		pmask <<= 2;
665 	}
666 	if (memindex < i)
667 		memindex = i;
668 	return(memindex);
669 }
670 
671 #ifdef ALIST_DEBUG
672 
673 static void
674 alst_radix_print(almeta_t *scan, daddr_t blk, daddr_t radix, int skip, int tab)
675 {
676 	int i;
677 	int next_skip;
678 	int lastState = 0;
679 	u_daddr_t mask;
680 
681 	if (radix == ALIST_BMAP_RADIX) {
682 		kprintf(
683 		    "%*.*s(%04x,%d): bitmap %08x big=%d\n",
684 		    tab, tab, "",
685 		    blk, radix,
686 		    scan->bm_bitmap,
687 		    scan->bm_bighint
688 		);
689 		return;
690 	}
691 
692 	if (scan->bm_bitmap == 0) {
693 		kprintf(
694 		    "%*.*s(%04x,%d) ALL ALLOCATED\n",
695 		    tab, tab, "",
696 		    blk,
697 		    radix
698 		);
699 		return;
700 	}
701 	if (scan->bm_bitmap == (u_daddr_t)-1) {
702 		kprintf(
703 		    "%*.*s(%04x,%d) ALL FREE\n",
704 		    tab, tab, "",
705 		    blk,
706 		    radix
707 		);
708 		return;
709 	}
710 
711 	kprintf(
712 	    "%*.*s(%04x,%d): subtree (%d) bitmap=%08x big=%d {\n",
713 	    tab, tab, "",
714 	    blk, radix,
715 	    radix,
716 	    scan->bm_bitmap,
717 	    scan->bm_bighint
718 	);
719 
720 	radix /= ALIST_META_RADIX;
721 	next_skip = ((u_int)skip / ALIST_META_RADIX);
722 	tab += 4;
723 	mask = 0x00000003;
724 
725 	for (i = 1; i <= skip; i += next_skip) {
726 		if (scan[i].bm_bighint == (daddr_t)-1) {
727 			kprintf(
728 			    "%*.*s(%04x,%d): Terminator\n",
729 			    tab, tab, "",
730 			    blk, radix
731 			);
732 			lastState = 0;
733 			break;
734 		}
735 		if ((scan->bm_bitmap & mask) == mask) {
736 			kprintf(
737 			    "%*.*s(%04x,%d): ALL FREE\n",
738 			    tab, tab, "",
739 			    blk, radix
740 			);
741 		} else if ((scan->bm_bitmap & mask) == 0) {
742 			kprintf(
743 			    "%*.*s(%04x,%d): ALL ALLOCATED\n",
744 			    tab, tab, "",
745 			    blk, radix
746 			);
747 		} else {
748 			alst_radix_print(
749 			    &scan[i],
750 			    blk,
751 			    radix,
752 			    next_skip - 1,
753 			    tab
754 			);
755 		}
756 		blk += radix;
757 		mask <<= 2;
758 	}
759 	tab -= 4;
760 
761 	kprintf(
762 	    "%*.*s}\n",
763 	    tab, tab, ""
764 	);
765 }
766 
767 #endif
768 
769 #ifdef ALIST_DEBUG
770 
771 int
772 main(int ac, char **av)
773 {
774 	int size = 1024;
775 	int i;
776 	alist_t bl;
777 
778 	for (i = 1; i < ac; ++i) {
779 		const char *ptr = av[i];
780 		if (*ptr != '-') {
781 			size = strtol(ptr, NULL, 0);
782 			continue;
783 		}
784 		ptr += 2;
785 		fprintf(stderr, "Bad option: %s\n", ptr - 2);
786 		exit(1);
787 	}
788 	bl = alist_create(size, NULL);
789 	alist_free(bl, 0, size);
790 
791 	for (;;) {
792 		char buf[1024];
793 		daddr_t da = 0;
794 		daddr_t count = 0;
795 
796 
797 		kprintf("%d/%d/%d> ", bl->bl_free, size, bl->bl_radix);
798 		fflush(stdout);
799 		if (fgets(buf, sizeof(buf), stdin) == NULL)
800 			break;
801 		switch(buf[0]) {
802 		case 'p':
803 			alist_print(bl);
804 			break;
805 		case 'a':
806 			if (sscanf(buf + 1, "%d", &count) == 1) {
807 				daddr_t blk = alist_alloc(bl, count);
808 				kprintf("    R=%04x\n", blk);
809 			} else {
810 				kprintf("?\n");
811 			}
812 			break;
813 		case 'f':
814 			if (sscanf(buf + 1, "%x %d", &da, &count) == 2) {
815 				alist_free(bl, da, count);
816 			} else {
817 				kprintf("?\n");
818 			}
819 			break;
820 		case '?':
821 		case 'h':
822 			puts(
823 			    "p          -print\n"
824 			    "a %d       -allocate\n"
825 			    "f %x %d    -free\n"
826 			    "h/?        -help"
827 			);
828 			break;
829 		default:
830 			kprintf("?\n");
831 			break;
832 		}
833 	}
834 	return(0);
835 }
836 
837 void
838 panic(const char *ctl, ...)
839 {
840 	__va_list va;
841 
842 	__va_start(va, ctl);
843 	vfprintf(stderr, ctl, va);
844 	fprintf(stderr, "\n");
845 	__va_end(va);
846 	exit(1);
847 }
848 
849 #endif
850 
851