1 /* Licensed under LGPLv2.1+ - see LICENSE file for details */
11 #include <ccan/build_assert/build_assert.h>
12 #include <ccan/likely/likely.h>
13 #include <ccan/alignof/alignof.h>
14 #include <ccan/short_types/short_types.h>
15 #include <ccan/compiler/compiler.h>
19 Inspired by (and parts taken from) Andrew Tridgell's alloc_mmap:
20 http://samba.org/~tridge/junkcode/alloc_mmap/
22 Copyright (C) Andrew Tridgell 2007
24 This library is free software; you can redistribute it and/or
25 modify it under the terms of the GNU Lesser General Public
26 License as published by the Free Software Foundation; either
27 version 2 of the License, or (at your option) any later version.
29 This library is distributed in the hope that it will be useful,
30 but WITHOUT ANY WARRANTY; without even the implied warranty of
31 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
32 Lesser General Public License for more details.
34 You should have received a copy of the GNU Lesser General Public
35 License along with this library; if not, write to the Free Software
36 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
39 /* We divide the pool into this many large pages (nearest power of 2) */
40 #define MAX_LARGE_PAGES (256UL)
42 /* 32 small pages == 1 large page. */
43 #define BITS_FROM_SMALL_TO_LARGE_PAGE 5
45 #define MAX_SMALL_PAGES (MAX_LARGE_PAGES << BITS_FROM_SMALL_TO_LARGE_PAGE)
47 /* Smallest pool size for this scheme: 128-byte small pages. That's
48 * 9/13% overhead for 32/64 bit. */
49 #define MIN_USEFUL_SIZE (MAX_SMALL_PAGES * 128)
51 /* Every 4 buckets, we jump up a power of 2. ...8 10 12 14 16 20 24 28 32... */
52 #define INTER_BUCKET_SPACE 4
54 #define SMALL_PAGES_PER_LARGE_PAGE (1 << BITS_FROM_SMALL_TO_LARGE_PAGE)
56 /* FIXME: Figure this out properly. */
57 #define MAX_SIZE (1 << 30)
59 /* How few object to fit in a page before using a larger one? (8) */
60 #define MAX_PAGE_OBJECT_ORDER 3
62 #define BITS_PER_LONG (sizeof(long) * CHAR_BIT)
65 u32 elements_per_page;
71 /* Bitmap of which pages are large. */
72 unsigned long pagesize[MAX_LARGE_PAGES / BITS_PER_LONG];
74 /* List of unused small/large pages. */
78 /* List of huge allocs. */
81 /* This is less defined: we have two buckets for each power of 2 */
82 struct bucket_state bs[1];
86 unsigned long next, prev;
87 unsigned long off, len;
92 /* FIXME: We can just count all-0 and all-1 used[] elements. */
93 unsigned elements_used : 25;
95 unsigned long used[1]; /* One bit per element. */
99 * Every 4 buckets, the size doubles.
100 * Between buckets, sizes increase linearly.
102 * eg. bucket 40 = 2^10 = 1024
103 * bucket 41 = 2^10 + 2^10*4 = 1024 + 256
104 * bucket 42 = 2^10 + 2^10*4 = 1024 + 512
105 * bucket 43 = 2^10 + 2^10*4 = 1024 + 768
106 * bucket 45 = 2^11 = 2048
108 * Care is taken to handle low numbered buckets, at cost of overflow.
110 static unsigned long bucket_to_size(unsigned int bucket)
112 unsigned long base = 1UL << (bucket / INTER_BUCKET_SPACE);
113 return base + ((bucket % INTER_BUCKET_SPACE)
114 << (bucket / INTER_BUCKET_SPACE))
115 / INTER_BUCKET_SPACE;
120 * fls(size/2) == 3. 1 << 3 == 8, so we're 2 too large, out of a possible
121 * 8 too large. That's 1/4 of the way to the next power of 2 == 1 bucket.
123 * We make sure we round up. Note that this fails on 32 bit at size
124 * 1879048193 (around bucket 120).
126 static unsigned int size_to_bucket(unsigned long size)
128 unsigned int base = afls(size/2);
129 unsigned long overshoot;
131 overshoot = size - (1UL << base);
132 return base * INTER_BUCKET_SPACE
133 + ((overshoot * INTER_BUCKET_SPACE + (1UL << base)-1) >> base);
136 static unsigned int small_page_bits(unsigned long poolsize)
138 return afls(poolsize / MAX_SMALL_PAGES - 1);
141 static struct page_header *from_pgnum(struct header *head,
145 return (struct page_header *)((char *)head + (pgnum << sp_bits));
148 static u16 to_pgnum(struct header *head, void *p, unsigned sp_bits)
150 return ((char *)p - (char *)head) >> sp_bits;
153 static size_t used_size(unsigned int num_elements)
155 return align_up(num_elements, BITS_PER_LONG) / CHAR_BIT;
159 * We always align the first entry to the lower power of 2.
160 * eg. the 12-byte bucket gets 8-byte aligned. The 4096-byte bucket
161 * gets 4096-byte aligned.
163 static unsigned long page_header_size(unsigned int align_bits,
164 unsigned long num_elements)
168 size = sizeof(struct page_header)
169 - sizeof(((struct page_header *)0)->used)
170 + used_size(num_elements);
171 return align_up(size, 1UL << align_bits);
174 static void add_to_list(struct header *head,
175 u16 *list, struct page_header *ph, unsigned sp_bits)
177 unsigned long h = *list, offset = to_pgnum(head, ph, sp_bits);
181 struct page_header *prev = from_pgnum(head, h, sp_bits);
182 assert(prev->prev == 0);
189 static void del_from_list(struct header *head,
190 u16 *list, struct page_header *ph, unsigned sp_bits)
196 struct page_header *prev = from_pgnum(head, ph->prev, sp_bits);
197 prev->next = ph->next;
200 struct page_header *next = from_pgnum(head, ph->next, sp_bits);
201 next->prev = ph->prev;
205 static u16 pop_from_list(struct header *head,
207 unsigned int sp_bits)
210 struct page_header *ph = from_pgnum(head, h, sp_bits);
215 from_pgnum(head, *list, sp_bits)->prev = 0;
220 static void add_to_huge_list(struct header *head, struct huge_alloc *ha)
222 unsigned long h = head->huge;
223 unsigned long offset = (char *)ha - (char *)head;
227 struct huge_alloc *prev = (void *)((char *)head + h);
228 assert(prev->prev == 0);
235 static void del_from_huge(struct header *head, struct huge_alloc *ha)
239 head->huge = ha->next;
241 struct huge_alloc *prev = (void *)((char *)head + ha->prev);
242 prev->next = ha->next;
245 struct huge_alloc *next = (void *)((char *)head + ha->next);
246 next->prev = ha->prev;
250 static void add_small_page_to_freelist(struct header *head,
251 struct page_header *ph,
252 unsigned int sp_bits)
254 add_to_list(head, &head->small_free_list, ph, sp_bits);
257 static void add_large_page_to_freelist(struct header *head,
258 struct page_header *ph,
259 unsigned int sp_bits)
261 add_to_list(head, &head->large_free_list, ph, sp_bits);
264 static void add_to_bucket_list(struct header *head,
265 struct bucket_state *bs,
266 struct page_header *ph,
267 unsigned int sp_bits)
269 add_to_list(head, &bs->page_list, ph, sp_bits);
272 static void del_from_bucket_list(struct header *head,
273 struct bucket_state *bs,
274 struct page_header *ph,
275 unsigned int sp_bits)
277 del_from_list(head, &bs->page_list, ph, sp_bits);
280 static void del_from_bucket_full_list(struct header *head,
281 struct bucket_state *bs,
282 struct page_header *ph,
283 unsigned int sp_bits)
285 del_from_list(head, &bs->full_list, ph, sp_bits);
288 static void add_to_bucket_full_list(struct header *head,
289 struct bucket_state *bs,
290 struct page_header *ph,
291 unsigned int sp_bits)
293 add_to_list(head, &bs->full_list, ph, sp_bits);
296 static void clear_bit(unsigned long bitmap[], unsigned int off)
298 bitmap[off / BITS_PER_LONG] &= ~(1UL << (off % BITS_PER_LONG));
301 static bool test_bit(const unsigned long bitmap[], unsigned int off)
303 return bitmap[off / BITS_PER_LONG] & (1UL << (off % BITS_PER_LONG));
306 static void set_bit(unsigned long bitmap[], unsigned int off)
308 bitmap[off / BITS_PER_LONG] |= (1UL << (off % BITS_PER_LONG));
311 /* There must be a bit to be found. */
312 static unsigned int find_free_bit(const unsigned long bitmap[])
316 for (i = 0; bitmap[i] == -1UL; i++);
317 return (i*BITS_PER_LONG) + affsl(~bitmap[i]) - 1;
320 /* How many elements can we fit in a page? */
321 static unsigned long elements_per_page(unsigned long align_bits,
325 unsigned long num, overhead;
327 /* First approximation: no extra room for bitmap. */
328 overhead = align_up(sizeof(struct page_header), 1UL << align_bits);
329 num = (psize - overhead) / esize;
331 while (page_header_size(align_bits, num) + esize * num > psize)
336 static bool large_page_bucket(unsigned int bucket, unsigned int sp_bits)
338 unsigned long max_smallsize;
340 /* Note: this doesn't take into account page header. */
341 max_smallsize = (1UL << sp_bits) >> MAX_PAGE_OBJECT_ORDER;
343 return bucket_to_size(bucket) > max_smallsize;
346 static unsigned int max_bucket(unsigned int lp_bits)
348 return (lp_bits - MAX_PAGE_OBJECT_ORDER) * INTER_BUCKET_SPACE;
351 void alloc_init(void *pool, unsigned long poolsize)
353 struct header *head = pool;
354 struct page_header *ph;
355 unsigned int lp_bits, sp_bits, num_buckets;
356 unsigned long header_size, i;
358 if (poolsize < MIN_USEFUL_SIZE) {
359 tiny_alloc_init(pool, poolsize);
363 /* We rely on page numbers fitting in 16 bit. */
364 BUILD_ASSERT(MAX_SMALL_PAGES < 65536);
366 sp_bits = small_page_bits(poolsize);
367 lp_bits = sp_bits + BITS_FROM_SMALL_TO_LARGE_PAGE;
369 num_buckets = max_bucket(lp_bits);
372 header_size = sizeof(*head) + sizeof(head->bs) * (num_buckets-1);
374 memset(head, 0, header_size);
375 for (i = 0; i < num_buckets; i++) {
376 unsigned long pagesize;
378 if (large_page_bucket(i, sp_bits))
379 pagesize = 1UL << lp_bits;
381 pagesize = 1UL << sp_bits;
383 head->bs[i].elements_per_page
384 = elements_per_page(i / INTER_BUCKET_SPACE,
389 /* They start as all large pages. */
390 memset(head->pagesize, 0xFF, sizeof(head->pagesize));
391 /* FIXME: small pages for last bit? */
393 /* Split first page into small pages. */
394 assert(header_size < (1UL << lp_bits));
395 clear_bit(head->pagesize, 0);
397 /* Skip over page(s) used by header, add rest to free list */
398 for (i = align_up(header_size, (1UL << sp_bits)) >> sp_bits;
399 i < SMALL_PAGES_PER_LARGE_PAGE;
401 ph = from_pgnum(head, i, sp_bits);
402 ph->elements_used = 0;
403 add_small_page_to_freelist(head, ph, sp_bits);
406 /* Add the rest of the pages as large pages. */
407 i = SMALL_PAGES_PER_LARGE_PAGE;
408 while ((i << sp_bits) + (1UL << lp_bits) <= poolsize) {
409 assert(i < MAX_SMALL_PAGES);
410 ph = from_pgnum(head, i, sp_bits);
411 ph->elements_used = 0;
412 add_large_page_to_freelist(head, ph, sp_bits);
413 i += SMALL_PAGES_PER_LARGE_PAGE;
417 /* A large page worth of small pages are free: delete them from free list. */
418 static void del_large_from_small_free_list(struct header *head,
419 struct page_header *ph,
420 unsigned int sp_bits)
424 for (i = 0; i < SMALL_PAGES_PER_LARGE_PAGE; i++) {
425 del_from_list(head, &head->small_free_list,
426 (struct page_header *)((char *)ph
432 static bool all_empty(struct header *head,
438 for (i = 0; i < SMALL_PAGES_PER_LARGE_PAGE; i++) {
439 struct page_header *ph = from_pgnum(head, pgnum + i, sp_bits);
440 if (ph->elements_used)
446 static void recombine_small_pages(struct header *head, unsigned long poolsize,
447 unsigned int sp_bits)
450 unsigned int lp_bits = sp_bits + BITS_FROM_SMALL_TO_LARGE_PAGE;
452 /* Look for small pages to coalesce, after first large page. */
453 for (i = SMALL_PAGES_PER_LARGE_PAGE;
454 i < (poolsize >> lp_bits) << BITS_FROM_SMALL_TO_LARGE_PAGE;
455 i += SMALL_PAGES_PER_LARGE_PAGE) {
456 /* Already a large page? */
457 if (test_bit(head->pagesize, i / SMALL_PAGES_PER_LARGE_PAGE))
459 if (all_empty(head, i, sp_bits)) {
460 struct page_header *ph = from_pgnum(head, i, sp_bits);
461 set_bit(head->pagesize,
462 i / SMALL_PAGES_PER_LARGE_PAGE);
463 del_large_from_small_free_list(head, ph, sp_bits);
464 add_large_page_to_freelist(head, ph, sp_bits);
469 static u16 get_large_page(struct header *head, unsigned long poolsize,
470 unsigned int sp_bits)
474 page = pop_from_list(head, &head->large_free_list, sp_bits);
478 recombine_small_pages(head, poolsize, sp_bits);
480 return pop_from_list(head, &head->large_free_list, sp_bits);
483 /* Returns small page. */
484 static unsigned long break_up_large_page(struct header *head,
485 unsigned int sp_bits,
490 clear_bit(head->pagesize, lpage >> BITS_FROM_SMALL_TO_LARGE_PAGE);
492 for (i = 1; i < SMALL_PAGES_PER_LARGE_PAGE; i++) {
493 struct page_header *ph = from_pgnum(head, lpage + i, sp_bits);
494 /* Initialize this: huge_alloc reads it. */
495 ph->elements_used = 0;
496 add_small_page_to_freelist(head, ph, sp_bits);
502 static u16 get_small_page(struct header *head, unsigned long poolsize,
503 unsigned int sp_bits)
507 ret = pop_from_list(head, &head->small_free_list, sp_bits);
510 ret = get_large_page(head, poolsize, sp_bits);
512 ret = break_up_large_page(head, sp_bits, ret);
516 static bool huge_allocated(struct header *head, unsigned long offset)
519 struct huge_alloc *ha;
521 for (i = head->huge; i; i = ha->next) {
522 ha = (void *)((char *)head + i);
523 if (ha->off <= offset && ha->off + ha->len > offset)
529 /* They want something really big. Aim for contiguous pages (slow). */
530 static COLD void *huge_alloc(void *pool, unsigned long poolsize,
531 unsigned long size, unsigned long align)
533 struct header *head = pool;
534 struct huge_alloc *ha;
535 unsigned long i, sp_bits, lp_bits, num, header_size;
537 sp_bits = small_page_bits(poolsize);
538 lp_bits = sp_bits + BITS_FROM_SMALL_TO_LARGE_PAGE;
540 /* Allocate tracking structure optimistically. */
541 ha = alloc_get(pool, poolsize, sizeof(*ha), ALIGNOF(*ha));
545 /* First search for contiguous small pages... */
546 header_size = sizeof(*head) + sizeof(head->bs) * (max_bucket(lp_bits)-1);
549 for (i = (header_size + (1UL << sp_bits) - 1) >> sp_bits;
550 i << sp_bits < poolsize;
552 struct page_header *pg;
553 unsigned long off = (i << sp_bits);
555 /* Skip over large pages. */
556 if (test_bit(head->pagesize, i >> BITS_FROM_SMALL_TO_LARGE_PAGE)) {
557 i += (1UL << BITS_FROM_SMALL_TO_LARGE_PAGE)-1;
561 /* Does this page meet alignment requirements? */
562 if (!num && off % align != 0)
565 /* FIXME: This makes us O(n^2). */
566 if (huge_allocated(head, off)) {
571 pg = (struct page_header *)((char *)head + off);
572 if (pg->elements_used) {
578 if (num << sp_bits >= size) {
581 /* Remove from free list. */
582 for (pgnum = i; pgnum > i - num; pgnum--) {
583 pg = from_pgnum(head, pgnum, sp_bits);
585 &head->small_free_list,
588 ha->off = (i - num + 1) << sp_bits;
589 ha->len = num << sp_bits;
594 /* Now search for large pages... */
595 recombine_small_pages(head, poolsize, sp_bits);
598 for (i = (header_size + (1UL << lp_bits) - 1) >> lp_bits;
599 (i << lp_bits) < poolsize; i++) {
600 struct page_header *pg;
601 unsigned long off = (i << lp_bits);
603 /* Ignore small pages. */
604 if (!test_bit(head->pagesize, i))
607 /* Does this page meet alignment requirements? */
608 if (!num && off % align != 0)
611 /* FIXME: This makes us O(n^2). */
612 if (huge_allocated(head, off)) {
617 pg = (struct page_header *)((char *)head + off);
618 if (pg->elements_used) {
624 if (num << lp_bits >= size) {
627 /* Remove from free list. */
628 for (pgnum = i; pgnum > i - num; pgnum--) {
629 pg = from_pgnum(head, pgnum, lp_bits);
631 &head->large_free_list,
634 ha->off = (i - num + 1) << lp_bits;
635 ha->len = num << lp_bits;
640 /* Unable to satisfy: free huge alloc structure. */
641 alloc_free(pool, poolsize, ha);
645 add_to_huge_list(pool, ha);
646 return (char *)pool + ha->off;
650 huge_free(struct header *head, unsigned long poolsize, void *free)
652 unsigned long i, off, pgnum, free_off = (char *)free - (char *)head;
653 unsigned int sp_bits, lp_bits;
654 struct huge_alloc *ha;
656 for (i = head->huge; i; i = ha->next) {
657 ha = (void *)((char *)head + i);
658 if (free_off == ha->off)
663 /* Free up all the pages, delete and free ha */
664 sp_bits = small_page_bits(poolsize);
665 lp_bits = sp_bits + BITS_FROM_SMALL_TO_LARGE_PAGE;
666 pgnum = free_off >> sp_bits;
668 if (test_bit(head->pagesize, pgnum >> BITS_FROM_SMALL_TO_LARGE_PAGE)) {
670 off < ha->off + ha->len;
671 off += 1UL << lp_bits) {
672 add_large_page_to_freelist(head,
673 (void *)((char *)head + off),
678 off < ha->off + ha->len;
679 off += 1UL << sp_bits) {
680 add_small_page_to_freelist(head,
681 (void *)((char *)head + off),
685 del_from_huge(head, ha);
686 alloc_free(head, poolsize, ha);
689 static COLD unsigned long huge_size(struct header *head, void *p)
691 unsigned long i, off = (char *)p - (char *)head;
692 struct huge_alloc *ha;
694 for (i = head->huge; i; i = ha->next) {
695 ha = (void *)((char *)head + i);
696 if (off == ha->off) {
703 void *alloc_get(void *pool, unsigned long poolsize,
704 unsigned long size, unsigned long align)
706 struct header *head = pool;
709 struct bucket_state *bs;
710 struct page_header *ph;
711 unsigned int sp_bits;
713 if (poolsize < MIN_USEFUL_SIZE) {
714 return tiny_alloc_get(pool, poolsize, size, align);
717 size = align_up(size, align);
720 bucket = size_to_bucket(size);
722 sp_bits = small_page_bits(poolsize);
724 if (bucket >= max_bucket(sp_bits + BITS_FROM_SMALL_TO_LARGE_PAGE)) {
725 return huge_alloc(pool, poolsize, size, align);
728 bs = &head->bs[bucket];
730 if (!bs->page_list) {
731 if (large_page_bucket(bucket, sp_bits))
732 bs->page_list = get_large_page(head, poolsize,
735 bs->page_list = get_small_page(head, poolsize,
737 /* FIXME: Try large-aligned alloc? Header stuffing? */
738 if (unlikely(!bs->page_list))
740 ph = from_pgnum(head, bs->page_list, sp_bits);
742 ph->elements_used = 0;
744 memset(ph->used, 0, used_size(bs->elements_per_page));
747 ph = from_pgnum(head, bs->page_list, sp_bits);
749 i = find_free_bit(ph->used);
750 set_bit(ph->used, i);
753 /* check if this page is now full */
754 if (unlikely(ph->elements_used == bs->elements_per_page)) {
755 del_from_bucket_list(head, bs, ph, sp_bits);
756 add_to_bucket_full_list(head, bs, ph, sp_bits);
759 return (char *)ph + page_header_size(ph->bucket / INTER_BUCKET_SPACE,
760 bs->elements_per_page)
761 + i * bucket_to_size(bucket);
764 void alloc_free(void *pool, unsigned long poolsize, void *free)
766 struct header *head = pool;
767 struct bucket_state *bs;
768 unsigned int sp_bits;
769 unsigned long i, pgnum, pgoffset, offset = (char *)free - (char *)pool;
771 struct page_header *ph;
773 if (poolsize < MIN_USEFUL_SIZE) {
774 tiny_alloc_free(pool, poolsize, free);
778 /* Get page header. */
779 sp_bits = small_page_bits(poolsize);
780 pgnum = offset >> sp_bits;
782 /* Big page? Round down further. */
783 if (test_bit(head->pagesize, pgnum >> BITS_FROM_SMALL_TO_LARGE_PAGE)) {
785 pgnum &= ~(SMALL_PAGES_PER_LARGE_PAGE - 1);
789 /* Step back to page header. */
790 ph = from_pgnum(head, pgnum, sp_bits);
791 if ((void *)ph == free) {
792 huge_free(head, poolsize, free);
796 bs = &head->bs[ph->bucket];
797 pgoffset = offset - (pgnum << sp_bits)
798 - page_header_size(ph->bucket / INTER_BUCKET_SPACE,
799 bs->elements_per_page);
801 if (unlikely(ph->elements_used == bs->elements_per_page)) {
802 del_from_bucket_full_list(head, bs, ph, sp_bits);
803 add_to_bucket_list(head, bs, ph, sp_bits);
806 /* Which element are we? */
807 i = pgoffset / bucket_to_size(ph->bucket);
808 clear_bit(ph->used, i);
811 if (unlikely(ph->elements_used == 0)) {
812 bs = &head->bs[ph->bucket];
813 del_from_bucket_list(head, bs, ph, sp_bits);
815 add_small_page_to_freelist(head, ph, sp_bits);
817 add_large_page_to_freelist(head, ph, sp_bits);
821 unsigned long alloc_size(void *pool, unsigned long poolsize, void *p)
823 struct header *head = pool;
824 unsigned int pgnum, sp_bits;
825 unsigned long offset = (char *)p - (char *)pool;
826 struct page_header *ph;
828 if (poolsize < MIN_USEFUL_SIZE)
829 return tiny_alloc_size(pool, poolsize, p);
831 /* Get page header. */
832 sp_bits = small_page_bits(poolsize);
833 pgnum = offset >> sp_bits;
835 /* Big page? Round down further. */
836 if (test_bit(head->pagesize, pgnum >> BITS_FROM_SMALL_TO_LARGE_PAGE))
837 pgnum &= ~(SMALL_PAGES_PER_LARGE_PAGE - 1);
839 /* Step back to page header. */
840 ph = from_pgnum(head, pgnum, sp_bits);
842 return huge_size(head, p);
844 return bucket_to_size(ph->bucket);
847 /* Useful for gdb breakpoints. */
848 static bool check_fail(void)
853 static unsigned long count_bits(const unsigned long bitmap[],
856 unsigned long i, count = 0;
858 while (limit >= BITS_PER_LONG) {
859 count += popcount(bitmap[0]);
861 limit -= BITS_PER_LONG;
864 for (i = 0; i < limit; i++)
865 if (test_bit(bitmap, i))
870 static bool out_of_bounds(unsigned long pgnum,
871 unsigned int sp_bits,
872 unsigned long pagesize,
873 unsigned long poolsize)
875 if (((pgnum << sp_bits) >> sp_bits) != pgnum)
878 if ((pgnum << sp_bits) > poolsize)
881 return ((pgnum << sp_bits) + pagesize > poolsize);
884 static bool check_bucket(struct header *head,
885 unsigned long poolsize,
886 unsigned long pages[],
887 struct bucket_state *bs,
891 struct page_header *ph;
892 unsigned long taken, i, prev, pagesize, sp_bits, lp_bits;
894 sp_bits = small_page_bits(poolsize);
895 lp_bits = sp_bits + BITS_FROM_SMALL_TO_LARGE_PAGE;
897 lp_bucket = large_page_bucket(bindex, sp_bits);
899 pagesize = 1UL << (lp_bucket ? lp_bits : sp_bits);
901 /* This many elements fit? */
902 taken = page_header_size(bindex / INTER_BUCKET_SPACE,
903 bs->elements_per_page);
904 taken += bucket_to_size(bindex) * bs->elements_per_page;
905 if (taken > pagesize)
908 /* One more wouldn't fit? */
909 taken = page_header_size(bindex / INTER_BUCKET_SPACE,
910 bs->elements_per_page + 1);
911 taken += bucket_to_size(bindex) * (bs->elements_per_page + 1);
912 if (taken <= pagesize)
915 /* Walk used list. */
917 for (i = bs->page_list; i; i = ph->next) {
919 if (out_of_bounds(i, sp_bits, pagesize, poolsize))
921 /* Wrong size page? */
922 if (!!test_bit(head->pagesize, i >> BITS_FROM_SMALL_TO_LARGE_PAGE)
925 /* Large page not on boundary? */
926 if (lp_bucket && (i % SMALL_PAGES_PER_LARGE_PAGE) != 0)
928 ph = from_pgnum(head, i, sp_bits);
929 /* Linked list corrupt? */
930 if (ph->prev != prev)
932 /* Already seen this page? */
933 if (test_bit(pages, i))
937 if (ph->elements_used == 0)
939 if (ph->elements_used >= bs->elements_per_page)
941 /* Used bits don't agree? */
942 if (ph->elements_used != count_bits(ph->used,
943 bs->elements_per_page))
946 if (ph->bucket != bindex)
951 /* Walk full list. */
953 for (i = bs->full_list; i; i = ph->next) {
955 if (out_of_bounds(i, sp_bits, pagesize, poolsize))
957 /* Wrong size page? */
958 if (!!test_bit(head->pagesize, i >> BITS_FROM_SMALL_TO_LARGE_PAGE)
960 /* Large page not on boundary? */
961 if (lp_bucket && (i % SMALL_PAGES_PER_LARGE_PAGE) != 0)
963 ph = from_pgnum(head, i, sp_bits);
964 /* Linked list corrupt? */
965 if (ph->prev != prev)
967 /* Already seen this page? */
968 if (test_bit(pages, i))
972 if (ph->elements_used != bs->elements_per_page)
974 /* Used bits don't agree? */
975 if (ph->elements_used != count_bits(ph->used,
976 bs->elements_per_page))
979 if (ph->bucket != bindex)
986 bool alloc_check(void *pool, unsigned long poolsize)
988 struct header *head = pool;
989 unsigned long prev, i, lp_bits, sp_bits, header_size, num_buckets;
990 struct page_header *ph;
991 struct huge_alloc *ha;
992 unsigned long pages[MAX_SMALL_PAGES / BITS_PER_LONG] = { 0 };
994 if (poolsize < MIN_USEFUL_SIZE)
995 return tiny_alloc_check(pool, poolsize);
997 sp_bits = small_page_bits(poolsize);
998 lp_bits = sp_bits + BITS_FROM_SMALL_TO_LARGE_PAGE;
1000 num_buckets = max_bucket(lp_bits);
1002 header_size = sizeof(*head) + sizeof(head->bs) * (num_buckets-1);
1004 /* First, set all bits taken by header. */
1005 for (i = 0; i < header_size; i += (1UL << sp_bits))
1006 set_bit(pages, i >> sp_bits);
1008 /* Check small page free list. */
1010 for (i = head->small_free_list; i; i = ph->next) {
1012 if (out_of_bounds(i, sp_bits, 1UL << sp_bits, poolsize))
1013 return check_fail();
1015 if (test_bit(head->pagesize, i >> BITS_FROM_SMALL_TO_LARGE_PAGE))
1016 return check_fail();
1017 ph = from_pgnum(head, i, sp_bits);
1018 /* Linked list corrupt? */
1019 if (ph->prev != prev)
1020 return check_fail();
1021 /* Already seen this page? */
1022 if (test_bit(pages, i))
1023 return check_fail();
1028 /* Check large page free list. */
1030 for (i = head->large_free_list; i; i = ph->next) {
1032 if (out_of_bounds(i, sp_bits, 1UL << lp_bits, poolsize))
1033 return check_fail();
1034 /* Not large page? */
1035 if (!test_bit(head->pagesize, i >> BITS_FROM_SMALL_TO_LARGE_PAGE))
1036 return check_fail();
1037 /* Not page boundary? */
1038 if ((i % SMALL_PAGES_PER_LARGE_PAGE) != 0)
1039 return check_fail();
1040 ph = from_pgnum(head, i, sp_bits);
1041 /* Linked list corrupt? */
1042 if (ph->prev != prev)
1043 return check_fail();
1044 /* Already seen this page? */
1045 if (test_bit(pages, i))
1046 return check_fail();
1051 /* Check the buckets. */
1052 for (i = 0; i < max_bucket(lp_bits); i++) {
1053 struct bucket_state *bs = &head->bs[i];
1055 if (!check_bucket(head, poolsize, pages, bs, i))
1059 /* Check the huge alloc list. */
1061 for (i = head->huge; i; i = ha->next) {
1062 unsigned long pgbits, j;
1065 if (i >= poolsize || i + sizeof(*ha) > poolsize)
1066 return check_fail();
1067 ha = (void *)((char *)head + i);
1069 /* Check contents of ha. */
1070 if (ha->off > poolsize || ha->off + ha->len > poolsize)
1071 return check_fail();
1073 /* Large or small page? */
1074 pgbits = test_bit(head->pagesize, ha->off >> lp_bits)
1075 ? lp_bits : sp_bits;
1077 /* Not page boundary? */
1078 if ((ha->off % (1UL << pgbits)) != 0)
1079 return check_fail();
1081 /* Not page length? */
1082 if ((ha->len % (1UL << pgbits)) != 0)
1083 return check_fail();
1085 /* Linked list corrupt? */
1086 if (ha->prev != prev)
1087 return check_fail();
1089 for (j = ha->off; j < ha->off + ha->len; j += (1UL<<sp_bits)) {
1090 /* Already seen this page? */
1091 if (test_bit(pages, j >> sp_bits))
1092 return check_fail();
1093 set_bit(pages, j >> sp_bits);
1099 /* Make sure every page accounted for. */
1100 for (i = 0; i < poolsize >> sp_bits; i++) {
1101 if (!test_bit(pages, i))
1102 return check_fail();
1103 if (test_bit(head->pagesize,
1104 i >> BITS_FROM_SMALL_TO_LARGE_PAGE)) {
1105 /* Large page, skip rest. */
1106 i += SMALL_PAGES_PER_LARGE_PAGE - 1;
1113 static unsigned long print_overhead(FILE *out, const char *desc,
1114 unsigned long bytes,
1115 unsigned long poolsize)
1117 fprintf(out, "Overhead (%s): %lu bytes (%.3g%%)\n",
1118 desc, bytes, 100.0 * bytes / poolsize);
1122 static unsigned long count_list(struct header *head,
1124 unsigned int sp_bits,
1125 unsigned long *total_elems)
1127 struct page_header *p;
1128 unsigned long ret = 0;
1131 p = from_pgnum(head, pgnum, sp_bits);
1133 (*total_elems) += p->elements_used;
1140 static unsigned long visualize_bucket(FILE *out, struct header *head,
1141 unsigned int bucket,
1142 unsigned long poolsize,
1143 unsigned int sp_bits)
1145 unsigned long num_full, num_partial, num_pages, page_size,
1146 elems, hdr_min, hdr_size, elems_per_page, overhead = 0;
1148 elems_per_page = head->bs[bucket].elements_per_page;
1150 /* If we used byte-based bitmaps, we could get pg hdr to: */
1151 hdr_min = sizeof(struct page_header)
1152 - sizeof(((struct page_header *)0)->used)
1153 + align_up(elems_per_page, CHAR_BIT) / CHAR_BIT;
1154 hdr_size = page_header_size(bucket / INTER_BUCKET_SPACE,
1158 num_full = count_list(head, head->bs[bucket].full_list, sp_bits,
1160 num_partial = count_list(head, head->bs[bucket].page_list, sp_bits,
1162 num_pages = num_full + num_partial;
1166 fprintf(out, "Bucket %u (%lu bytes):"
1167 " %lu full, %lu partial = %lu elements\n",
1168 bucket, bucket_to_size(bucket), num_full, num_partial, elems);
1169 /* Strict requirement of page header size. */
1170 overhead += print_overhead(out, "page headers",
1171 hdr_min * num_pages, poolsize);
1172 /* Gap between minimal page header and actual start. */
1173 overhead += print_overhead(out, "page post-header alignments",
1174 (hdr_size - hdr_min) * num_pages, poolsize);
1175 /* Between last element and end of page. */
1176 page_size = (1UL << sp_bits);
1177 if (large_page_bucket(bucket, sp_bits))
1178 page_size <<= BITS_FROM_SMALL_TO_LARGE_PAGE;
1180 overhead += print_overhead(out, "page tails",
1181 (page_size - (hdr_size
1183 * bucket_to_size(bucket))))
1184 * num_pages, poolsize);
1188 void alloc_visualize(FILE *out, void *pool, unsigned long poolsize)
1190 struct header *head = pool;
1191 unsigned long i, lp_bits, sp_bits, header_size, num_buckets, count,
1194 fprintf(out, "Pool %p size %lu: (%s allocator)\n", pool, poolsize,
1195 poolsize < MIN_USEFUL_SIZE ? "tiny" : "standard");
1197 if (poolsize < MIN_USEFUL_SIZE) {
1198 tiny_alloc_visualize(out, pool, poolsize);
1202 sp_bits = small_page_bits(poolsize);
1203 lp_bits = sp_bits + BITS_FROM_SMALL_TO_LARGE_PAGE;
1205 num_buckets = max_bucket(lp_bits);
1206 header_size = sizeof(*head) + sizeof(head->bs) * (num_buckets-1);
1208 fprintf(out, "Large page size %lu, small page size %lu.\n",
1209 1UL << lp_bits, 1UL << sp_bits);
1210 overhead += print_overhead(out, "unused pool tail",
1211 poolsize % (1UL << lp_bits), poolsize);
1212 fprintf(out, "Main header %lu bytes (%lu small pages).\n",
1213 header_size, align_up(header_size, 1UL << sp_bits) >> sp_bits);
1214 overhead += print_overhead(out, "partial header page",
1215 align_up(header_size, 1UL << sp_bits)
1216 - header_size, poolsize);
1217 /* Total large pages. */
1218 i = count_bits(head->pagesize, poolsize >> lp_bits);
1220 count = i - count_list(head, head->large_free_list, sp_bits, NULL);
1221 fprintf(out, "%lu/%lu large pages used (%.3g%%)\n",
1222 count, i, count ? 100.0 * count / i : 0.0);
1224 /* Total small pages. */
1225 i = ((poolsize >> lp_bits) - i) << BITS_FROM_SMALL_TO_LARGE_PAGE;
1227 count = i - count_list(head, head->small_free_list, sp_bits, NULL);
1228 fprintf(out, "%lu/%lu small pages used (%.3g%%)\n",
1229 count, i, count ? 100.0 * count / i : 0.0);
1231 /* Summary of each bucket. */
1232 fprintf(out, "%lu buckets:\n", num_buckets);
1233 for (i = 0; i < num_buckets; i++)
1234 overhead += visualize_bucket(out, head, i, poolsize, sp_bits);
1236 print_overhead(out, "total", overhead, poolsize);