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Index: sys/kern/subr_blist.c
===================================================================
--- sys/kern/subr_blist.c
+++ sys/kern/subr_blist.c
@@ -36,15 +36,14 @@
*
* A radix tree controls access to pieces of the bitmap, and includes
* auxiliary information at each interior node about the availabilty of
- * contiguous free blocks in the subtree rooted at that node. Two radix
- * constants are involved: one for the size of the bitmaps contained in the
- * leaf nodes (BLIST_BMAP_RADIX), and one for the number of descendents of
- * each of the meta (interior) nodes (BLIST_META_RADIX). Each subtree is
- * associated with a range of blocks. The root of any subtree stores a
- * hint field that defines an upper bound on the size of the largest
- * allocation that can begin in the associated block range. A hint is an
- * upper bound on a potential allocation, but not necessarily a tight upper
- * bound.
+ * contiguous free blocks in the subtree rooted at that node. A radix
+ * constant defines the size of the bitmaps contained in a leaf node
+ * and the number of descendents of each of the meta (interior) nodes.
+ * Each subtree is associated with a range of blocks. The root of any
+ * subtree stores a hint field that defines an upper bound on the size
+ * of the largest allocation that can begin in the associated block
+ * range. A hint is an upper bound on a potential allocation, but not
+ * necessarily a tight upper bound.
*
* The bitmap field in each node directs the search for available blocks.
* For a leaf node, a bit is set if the corresponding block is free. For a
@@ -64,13 +63,13 @@
*
* LAYOUT: The radix tree is laid out recursively using a linear array.
* Each meta node is immediately followed (laid out sequentially in
- * memory) by BLIST_META_RADIX lower level nodes. This is a recursive
+ * memory) by BLIST_RADIX lower-level nodes. This is a recursive
* structure but one that can be easily scanned through a very simple
* 'skip' calculation. The memory allocation is only large enough to
* cover the number of blocks requested at creation time. Nodes that
* represent blocks beyond that limit, nodes that would never be read
* or written, are not allocated, so that the last of the
- * BLIST_META_RADIX lower level nodes of a some nodes may not be
+ * BLIST_RADIX lower-level nodes of a some nodes may not be
* allocated.
*
* NOTE: the allocator cannot currently allocate more than
@@ -152,24 +151,19 @@
static MALLOC_DEFINE(M_SWAP, "SWAP", "Swap space");
#endif
-_Static_assert(BLIST_BMAP_RADIX % BLIST_META_RADIX == 0,
- "radix divisibility error");
-#define BLIST_BMAP_MASK (BLIST_BMAP_RADIX - 1)
-#define BLIST_META_MASK (BLIST_META_RADIX - 1)
+#define BLIST_MASK (BLIST_RADIX - 1)
/*
* For a subtree that can represent the state of up to 'radix' blocks, the
- * number of leaf nodes of the subtree is L=radix/BLIST_BMAP_RADIX. If 'm'
- * is short for BLIST_META_RADIX, then for a tree of height h with L=m**h
+ * number of leaf nodes of the subtree is L=radix/BLIST_RADIX. If 'm'
+ * is short for BLIST_RADIX, then for a tree of height h with L=m**h
* leaf nodes, the total number of tree nodes is 1 + m + m**2 + ... + m**h,
* or, equivalently, (m**(h+1)-1)/(m-1). This quantity is called 'skip'
* in the 'meta' functions that process subtrees. Since integer division
* discards remainders, we can express this computation as
* skip = (m * m**h) / (m - 1)
- * skip = (m * (radix / BLIST_BMAP_RADIX)) / (m - 1)
- * and since m divides BLIST_BMAP_RADIX, we can simplify further to
- * skip = (radix / (BLIST_BMAP_RADIX / m)) / (m - 1)
- * skip = radix / ((BLIST_BMAP_RADIX / m) * (m - 1))
+ * skip = (m * (radix / m)) / (m - 1)
+ * skip = radix / (m - 1)
* so that simple integer division by a constant can safely be used for the
* calculation.
*/
@@ -177,8 +171,7 @@
radix_to_skip(daddr_t radix)
{
- return (radix /
- ((BLIST_BMAP_RADIX / BLIST_META_RADIX) * BLIST_META_MASK));
+ return (radix / BLIST_MASK);
}
/*
@@ -189,7 +182,7 @@
{
return (((u_daddr_t)-1 << n) &
- ((u_daddr_t)-1 >> (BLIST_BMAP_RADIX - (n + count))));
+ ((u_daddr_t)-1 >> (BLIST_RADIX - (n + count))));
}
/*
@@ -201,7 +194,7 @@
int hi, lo, mid;
lo = 0;
- hi = BLIST_BMAP_RADIX;
+ hi = BLIST_RADIX;
while (lo + 1 < hi) {
mid = (lo + hi) >> 1;
if (mask & bitrange(0, mid))
@@ -238,7 +231,7 @@
* flags - malloc flags
*
* The smallest blist consists of a single leaf node capable of
- * managing BLIST_BMAP_RADIX blocks.
+ * managing BLIST_RADIX blocks.
*/
blist_t
blist_create(daddr_t blocks, int flags)
@@ -252,11 +245,9 @@
* Calculate the radix and node count used for scanning.
*/
nodes = 1;
- radix = BLIST_BMAP_RADIX;
- while (radix <= blocks) {
- nodes += 1 + (blocks - 1) / radix;
- radix *= BLIST_META_RADIX;
- }
+ radix = 1;
+ for (radix = 1; radix <= blocks / BLIST_RADIX; radix *= BLIST_RADIX)
+ nodes += 1 + (blocks - 1) / radix / BLIST_RADIX;
bl = malloc(offsetof(struct blist, bl_root[nodes]), M_SWAP, flags |
M_ZERO);
@@ -549,19 +540,12 @@
init_gap_stats(stats);
nodes = 0;
- i = bl->bl_radix;
- while (i < bl->bl_radix + bl->bl_blocks) {
+ radix = bl->bl_radix;
+ for (i = 0; i < bl->bl_blocks; ) {
/*
- * Find max size subtree starting at i.
- */
- radix = BLIST_BMAP_RADIX;
- while (((i / radix) & BLIST_META_MASK) == 0)
- radix *= BLIST_META_RADIX;
-
- /*
* Check for skippable subtrees starting at i.
*/
- while (radix > BLIST_BMAP_RADIX) {
+ while (radix != 1) {
if (bl->bl_root[nodes].bm_bitmap == 0) {
if (gap_stats_counting(stats))
update_gap_stats(stats, i);
@@ -572,9 +556,9 @@
* Skip subtree root.
*/
nodes++;
- radix /= BLIST_META_RADIX;
+ radix /= BLIST_RADIX;
}
- if (radix == BLIST_BMAP_RADIX) {
+ if (radix == 1) {
/*
* Scan leaf.
*/
@@ -588,8 +572,15 @@
diff ^= bitrange(digit, 1);
}
}
- nodes += radix_to_skip(radix);
- i += radix;
+ nodes += radix_to_skip(radix * BLIST_RADIX);
+ i += radix * BLIST_RADIX;
+
+ /*
+ * Find max size subtree starting at i.
+ */
+ radix = 1;
+ while (((i / BLIST_RADIX / radix) & BLIST_MASK) == 0)
+ radix *= BLIST_RADIX;
}
update_gap_stats(stats, i);
dump_gap_stats(stats, s);
@@ -623,13 +614,13 @@
daddr_t blk;
int avail, digit;
- start += BLIST_BMAP_RADIX;
- for (blk = start; blk - start < maxcount; blk += BLIST_BMAP_RADIX) {
+ start += BLIST_RADIX;
+ for (blk = start; blk - start < maxcount; blk += BLIST_RADIX) {
/* Skip meta-nodes, as long as they promise more free blocks. */
- radix = BLIST_BMAP_RADIX;
+ radix = BLIST_RADIX;
while (((++scan)->bm_bitmap & 1) == 1 &&
- ((blk / radix) & BLIST_META_MASK) == 0)
- radix *= BLIST_META_RADIX;
+ ((blk / radix) & BLIST_MASK) == 0)
+ radix *= BLIST_RADIX;
if (~scan->bm_bitmap != 0) {
/*
* Either there is no next leaf with any free blocks,
@@ -647,39 +638,38 @@
return (avail);
}
maxcount = imin(avail, maxcount);
- if (maxcount % BLIST_BMAP_RADIX == 0) {
+ if (maxcount % BLIST_RADIX == 0) {
/*
* There was no next leaf. Back scan up to
* last leaf.
*/
- --scan;
- while (radix != BLIST_BMAP_RADIX) {
- radix /= BLIST_META_RADIX;
+ do {
+ radix /= BLIST_RADIX;
--scan;
- }
- blk -= BLIST_BMAP_RADIX;
+ } while (radix != 1);
+ blk -= BLIST_RADIX;
}
}
}
/*
* 'scan' is the last leaf that provides blocks. Clear from 1 to
- * BLIST_BMAP_RADIX bits to represent the allocation of those last
+ * BLIST_RADIX bits to represent the allocation of those last
* blocks.
*/
- if (maxcount % BLIST_BMAP_RADIX != 0)
- scan->bm_bitmap &= ~bitrange(0, maxcount % BLIST_BMAP_RADIX);
+ if (maxcount % BLIST_RADIX != 0)
+ scan->bm_bitmap &= ~bitrange(0, maxcount % BLIST_RADIX);
else
scan->bm_bitmap = 0;
for (;;) {
/* Back up over meta-nodes, clearing bits if necessary. */
- blk -= BLIST_BMAP_RADIX;
- radix = BLIST_BMAP_RADIX;
- while ((digit = ((blk / radix) & BLIST_META_MASK)) == 0) {
+ blk -= BLIST_RADIX;
+ radix = BLIST_RADIX;
+ while ((digit = ((blk / radix) & BLIST_MASK)) == 0) {
if ((scan--)->bm_bitmap == 0)
scan->bm_bitmap ^= 1;
- radix *= BLIST_META_RADIX;
+ radix *= BLIST_RADIX;
}
if ((scan--)->bm_bitmap == 0)
scan[-digit * radix_to_skip(radix)].bm_bitmap ^=
@@ -734,17 +724,17 @@
}
/* Discard any candidates that appear before blk. */
- if ((blk & BLIST_BMAP_MASK) != 0) {
- if ((~mask & bitrange(0, blk & BLIST_BMAP_MASK)) != 0) {
+ if ((blk & BLIST_MASK) != 0) {
+ if ((~mask & bitrange(0, blk & BLIST_MASK)) != 0) {
/* Grow bighint in case all discarded bits are set. */
- bighint += blk & BLIST_BMAP_MASK;
- mask |= bitrange(0, blk & BLIST_BMAP_MASK);
+ bighint += blk & BLIST_MASK;
+ mask |= bitrange(0, blk & BLIST_MASK);
if (~mask == 0) {
scan->bm_bighint = bighint;
return (SWAPBLK_NONE);
}
}
- blk -= blk & BLIST_BMAP_MASK;
+ blk -= blk & BLIST_MASK;
}
/*
@@ -763,17 +753,17 @@
hi = lo + maxcount;
*count = hi - lo;
mask = ~bitrange(lo, *count);
- } else if (maxcount <= BLIST_BMAP_RADIX - lo) {
+ } else if (maxcount <= BLIST_RADIX - lo) {
/* All the blocks we can use are available here. */
hi = lo + maxcount;
*count = maxcount;
mask = ~bitrange(lo, *count);
- if (hi == BLIST_BMAP_RADIX)
+ if (hi == BLIST_RADIX)
scan->bm_bighint = bighint;
} else {
/* Check next leaf for some of the blocks we want or need. */
- count1 = *count - (BLIST_BMAP_RADIX - lo);
- maxcount -= BLIST_BMAP_RADIX - lo;
+ count1 = *count - (BLIST_RADIX - lo);
+ maxcount -= BLIST_RADIX - lo;
hi = blst_next_leaf_alloc(scan, blk, count1, maxcount);
if (hi < count1)
/*
@@ -785,7 +775,7 @@
* this leaf.
*/
return (SWAPBLK_NONE);
- *count = BLIST_BMAP_RADIX - lo + hi;
+ *count = BLIST_RADIX - lo + hi;
scan->bm_bighint = bighint;
}
@@ -811,16 +801,15 @@
bool scan_from_start;
int digit;
- if (radix == BLIST_BMAP_RADIX)
+ if (radix == 1)
return (blst_leaf_alloc(scan, cursor, count, maxcount));
- blk = cursor & -radix;
+ blk = cursor & -(radix * BLIST_RADIX);
scan_from_start = (cursor == blk);
- radix /= BLIST_META_RADIX;
skip = radix_to_skip(radix);
mask = scan->bm_bitmap;
/* Discard any candidates that appear before cursor. */
- digit = (cursor / radix) & BLIST_META_MASK;
+ digit = (cursor / radix) & BLIST_MASK;
mask &= (u_daddr_t)-1 << digit;
if (mask == 0)
return (SWAPBLK_NONE);
@@ -846,7 +835,7 @@
* The allocation might fit beginning in the i'th subtree.
*/
r = blst_meta_alloc(&scan[i], cursor + digit * radix,
- count, maxcount, radix);
+ count, maxcount, radix / BLIST_RADIX);
if (r != SWAPBLK_NONE) {
if (scan[i].bm_bitmap == 0)
scan->bm_bitmap ^= bitrange(digit, 1);
@@ -860,7 +849,7 @@
* We couldn't allocate count in this subtree. If the whole tree was
* scanned, and the last tree node is allocated, update bighint.
*/
- if (scan_from_start && !(digit == BLIST_META_RADIX - 1 &&
+ if (scan_from_start && !(digit == BLIST_RADIX - 1 &&
scan[i].bm_bighint == BLIST_MAX_ALLOC))
scan->bm_bighint = *count - 1;
@@ -882,7 +871,7 @@
* \_________/\__/
* count n
*/
- mask = bitrange(blk & BLIST_BMAP_MASK, count);
+ mask = bitrange(blk & BLIST_MASK, count);
KASSERT((scan->bm_bitmap & mask) == 0,
("freeing free block: %jx, size %d, mask %jx",
(uintmax_t)blk, count, (uintmax_t)scan->bm_bitmap & mask));
@@ -913,20 +902,26 @@
*/
scan->bm_bighint = BLIST_MAX_ALLOC;
- if (radix == BLIST_BMAP_RADIX)
+ if (radix == 1)
return (blst_leaf_free(scan, freeBlk, count));
- endBlk = ummin(freeBlk + count, (freeBlk + radix) & -radix);
- radix /= BLIST_META_RADIX;
+ endBlk = freeBlk + count;
+ blk = (freeBlk + radix * BLIST_RADIX) & -(radix * BLIST_RADIX);
+ /*
+ * blk is first block past the end of the range of this meta node,
+ * or 0 in case of overflow.
+ */
+ if (blk != 0)
+ endBlk = ummin(endBlk, blk);
skip = radix_to_skip(radix);
blk = freeBlk & -radix;
- digit = (blk / radix) & BLIST_META_MASK;
- endDigit = 1 + (((endBlk - 1) / radix) & BLIST_META_MASK);
+ digit = (blk / radix) & BLIST_MASK;
+ endDigit = 1 + (((endBlk - 1) / radix) & BLIST_MASK);
scan->bm_bitmap |= bitrange(digit, endDigit - digit);
for (i = 1 + digit * skip; blk < endBlk; i += skip) {
blk += radix;
count = ummin(blk, endBlk) - freeBlk;
- blst_meta_free(&scan[i], freeBlk, count, radix);
+ blst_meta_free(&scan[i], freeBlk, count, radix / BLIST_RADIX);
freeBlk = blk;
}
}
@@ -947,7 +942,7 @@
* Leaf node
*/
- if (radix == BLIST_BMAP_RADIX) {
+ if (radix == 1) {
u_daddr_t v = scan->bm_bitmap;
if (v == (u_daddr_t)-1) {
@@ -975,14 +970,14 @@
}
endBlk = blk + count;
- radix /= BLIST_META_RADIX;
skip = radix_to_skip(radix);
for (i = 1; blk < endBlk; i += skip) {
blk += radix;
count = radix;
if (blk >= endBlk)
count -= blk - endBlk;
- blst_copy(&scan[i], blk - radix, radix, dest, count);
+ blst_copy(&scan[i], blk - radix,
+ radix / BLIST_RADIX, dest, count);
}
}
@@ -999,7 +994,7 @@
daddr_t nblks;
u_daddr_t mask;
- mask = bitrange(blk & BLIST_BMAP_MASK, count);
+ mask = bitrange(blk & BLIST_MASK, count);
/* Count the number of blocks that we are allocating. */
nblks = bitcount64(scan->bm_bitmap & mask);
@@ -1022,20 +1017,27 @@
daddr_t blk, endBlk, i, nblks, skip;
int digit;
- if (radix == BLIST_BMAP_RADIX)
+ if (radix == 1)
return (blst_leaf_fill(scan, allocBlk, count));
- endBlk = ummin(allocBlk + count, (allocBlk + radix) & -radix);
- radix /= BLIST_META_RADIX;
+ endBlk = allocBlk + count;
+ blk = (allocBlk + radix * BLIST_RADIX) & -(radix * BLIST_RADIX);
+ /*
+ * blk is first block past the end of the range of this meta node,
+ * or 0 in case of overflow.
+ */
+ if (blk != 0)
+ endBlk = ummin(endBlk, blk);
skip = radix_to_skip(radix);
blk = allocBlk & -radix;
nblks = 0;
while (blk < endBlk) {
- digit = (blk / radix) & BLIST_META_MASK;
+ digit = (blk / radix) & BLIST_MASK;
i = 1 + digit * skip;
blk += radix;
count = ummin(blk, endBlk) - allocBlk;
- nblks += blst_meta_fill(&scan[i], allocBlk, count, radix);
+ nblks += blst_meta_fill(&scan[i], allocBlk, count,
+ radix / BLIST_RADIX);
if (scan[i].bm_bitmap == 0)
scan->bm_bitmap &= ~((u_daddr_t)1 << digit);
allocBlk = blk;
@@ -1052,12 +1054,12 @@
u_daddr_t mask;
int digit;
- if (radix == BLIST_BMAP_RADIX) {
+ if (radix == 1) {
printf(
"%*.*s(%08llx,%lld): bitmap %0*llx big=%lld\n",
tab, tab, "",
- (long long)blk, (long long)radix,
- 1 + (BLIST_BMAP_RADIX - 1) / 4,
+ (long long)blk, (long long)BLIST_RADIX,
+ (int)(1 + (BLIST_RADIX - 1) / 4),
(long long)scan->bm_bitmap,
(long long)scan->bm_bighint
);
@@ -1067,14 +1069,13 @@
printf(
"%*.*s(%08llx): subtree (%lld/%lld) bitmap %0*llx big=%lld {\n",
tab, tab, "",
- (long long)blk, (long long)radix,
- (long long)radix,
- 1 + (BLIST_META_RADIX - 1) / 4,
+ (long long)blk, (long long)radix * BLIST_RADIX,
+ (long long)radix * BLIST_RADIX,
+ (int)(1 + (BLIST_RADIX - 1) / 4),
(long long)scan->bm_bitmap,
(long long)scan->bm_bighint
);
- radix /= BLIST_META_RADIX;
skip = radix_to_skip(radix);
tab += 4;
@@ -1083,7 +1084,7 @@
do {
digit = bitpos(mask);
blst_radix_print(&scan[1 + digit * skip], blk + digit * radix,
- radix, tab);
+ radix / BLIST_RADIX, tab);
} while ((mask ^= bitrange(digit, 1)) != 0);
tab -= 4;
@@ -1100,7 +1101,7 @@
int
main(int ac, char **av)
{
- int size = BLIST_META_RADIX * BLIST_BMAP_RADIX;
+ daddr_t size = BLIST_RADIX * BLIST_RADIX;
int i;
blist_t bl;
struct sbuf *s;
@@ -1108,7 +1109,7 @@
for (i = 1; i < ac; ++i) {
const char *ptr = av[i];
if (*ptr != '-') {
- size = strtol(ptr, NULL, 0);
+ size = strtoll(ptr, NULL, 0);
continue;
}
ptr += 2;
@@ -1116,6 +1117,10 @@
exit(1);
}
bl = blist_create(size, M_WAITOK);
+ if (bl == NULL) {
+ fprintf(stderr, "blist_create failed\n");
+ exit(1);
+ }
blist_free(bl, 0, size);
for (;;) {
@@ -1124,7 +1129,7 @@
int count = 0, maxcount = 0;
printf("%lld/%lld/%lld> ", (long long)blist_avail(bl),
- (long long)size, (long long)bl->bl_radix);
+ (long long)size, (long long)bl->bl_radix * BLIST_RADIX);
fflush(stdout);
if (fgets(buf, sizeof(buf), stdin) == NULL)
break;
Index: sys/sys/blist.h
===================================================================
--- sys/sys/blist.h
+++ sys/sys/blist.h
@@ -85,10 +85,9 @@
blmeta_t bl_root[1]; /* root of radix tree */
} *blist_t;
-#define BLIST_BMAP_RADIX (sizeof(u_daddr_t)*8)
-#define BLIST_META_RADIX BLIST_BMAP_RADIX
+#define BLIST_RADIX (sizeof(u_daddr_t)*8)
-#define BLIST_MAX_ALLOC BLIST_BMAP_RADIX
+#define BLIST_MAX_ALLOC BLIST_RADIX
struct sbuf;
Index: sys/vm/swap_pager.c
===================================================================
--- sys/vm/swap_pager.c
+++ sys/vm/swap_pager.c
@@ -2328,7 +2328,6 @@
{
struct swdevt *sp, *tsp;
daddr_t dvbase;
- u_long mblocks;
/*
* nblks is in DEV_BSIZE'd chunks, convert to PAGE_SIZE'd chunks.
@@ -2339,19 +2338,8 @@
nblks &= ~(ctodb(1) - 1);
nblks = dbtoc(nblks);
- /*
- * If we go beyond this, we get overflows in the radix
- * tree bitmap code.
- */
- mblocks = 0x40000000 / BLIST_META_RADIX;
- if (nblks > mblocks) {
- printf(
- "WARNING: reducing swap size to maximum of %luMB per unit\n",
- mblocks / 1024 / 1024 * PAGE_SIZE);
- nblks = mblocks;
- }
-
sp = malloc(sizeof *sp, M_VMPGDATA, M_WAITOK | M_ZERO);
+ sp->sw_blist = blist_create(nblks, M_WAITOK);
sp->sw_vp = vp;
sp->sw_id = id;
sp->sw_dev = dev;
@@ -2361,7 +2349,6 @@
sp->sw_close = close;
sp->sw_flags = flags;
- sp->sw_blist = blist_create(nblks, M_WAITOK);
/*
* Do not free the first blocks in order to avoid overwriting
* any bsd label at the front of the partition

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