freebsd-dev/sys/kern/subr_blist.c

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1998 Matthew Dillon. All Rights Reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* BLIST.C - Bitmap allocator/deallocator, using a radix tree with hinting
*
* This module implements a general bitmap allocator/deallocator. The
* allocator eats around 2 bits per 'block'. The module does not
* try to interpret the meaning of a 'block' other than to return
* SWAPBLK_NONE on an allocation failure.
*
Modify blst_leaf_alloc to take only the cursor argument. Modify blst_leaf_alloc to find allocations that cross the boundary between one leaf node and the next when those two leaves descend from the same meta node. Update the hint field for leaves so that it represents a bound on how large an allocation can begin in that leaf, where it currently represents a bound on how large an allocation can be found within the boundaries of the leaf. The first phase of blst_leaf_alloc currently shrinks sequences of consecutive 1-bits in mask until each has been shrunken by count-1 bits, so that any bits remaining show where an allocation can begin, or until all the bits have disappeared, in which case the allocation fails. This change amends that so that the high-order bit is copied, as if, when the last block was free, it was followed by an endless stream of free blocks. It also amends the early stopping condition, so that the shrinking of 1-sequences stops early when there are none, or there is only one unbounded one remaining. The search for the first set bit is unchanged, and the code path thereafter is mostly unchanged unless the first set bit is in a position that makes some of those copied sign bits matter. In that case, we look for a next leaf, and at what blocks it can provide, to see if a cross-boundary allocation is possible. The hint is updated on a successful allocation that clears the last bit, but it not updated on a failed allocation that leaves the last bit set. So, as long as the last block is free, the hint value for the leaf is large. As long as the last block is free, and there's a next leaf, a large allocation can begin here, perhaps. A stricter rule than this would mean that allocations and frees in one leaf could require hint updates to the preceding leaf, and this change seeks to leave the freeing code unmodified. Define BLIST_BMAP_MASK, and use it for bit masking in blst_leaf_free and blist_leaf_fill, as well as in blst_leaf_alloc. Correct a panic message in blst_leaf_free. Submitted by: Doug Moore <dougm@rice.edu> Reviewed by: markj (an earlier version) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D11819
2017-09-16 18:12:15 +00:00
* 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. 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.
*
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* 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
* meta node, a bit is set if the corresponding subtree contains a free
* block somewhere within it. The search at a meta node considers only
* children of that node that represent a range that includes a free block.
*
* The hinting greatly increases code efficiency for allocations while
* the general radix structure optimizes both allocations and frees. The
* radix tree should be able to operate well no matter how much
* fragmentation there is and no matter how large a bitmap is used.
*
* The blist code wires all necessary memory at creation time. Neither
* allocations nor frees require interaction with the memory subsystem.
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* The non-blocking nature of allocations and frees is required by swap
* code (vm/swap_pager.c).
*
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* 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_RADIX lower-level nodes. This is a recursive
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* 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_RADIX lower-level nodes of a some nodes may not be allocated.
*
* NOTE: the allocator cannot currently allocate more than
* BLIST_RADIX blocks per call. It will panic with 'allocation too
* large' if you try. This is an area that could use improvement. The
* radix is large enough that this restriction does not effect the swap
* system, though. Currently only the allocation code is affected by
* this algorithmic unfeature. The freeing code can handle arbitrary
* ranges.
*
* This code can be compiled stand-alone for debugging.
*/
2003-06-11 00:56:59 +00:00
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#ifdef _KERNEL
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/kernel.h>
#include <sys/blist.h>
#include <sys/malloc.h>
#include <sys/sbuf.h>
#include <sys/proc.h>
#include <sys/mutex.h>
#else
#ifndef BLIST_NO_DEBUG
#define BLIST_DEBUG
#endif
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#include <sys/errno.h>
#include <sys/types.h>
#include <sys/malloc.h>
#include <sys/sbuf.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdbool.h>
#define bitcount64(x) __bitcount64((uint64_t)(x))
#define malloc(a,b,c) calloc(a, 1)
#define free(a,b) free(a)
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#define ummin(a,b) ((a) < (b) ? (a) : (b))
#define imin(a,b) ((a) < (b) ? (a) : (b))
#define KASSERT(a,b) assert(a)
#include <sys/blist.h>
#endif
/*
* static support functions
*/
static daddr_t blst_leaf_alloc(blmeta_t *scan, daddr_t blk,
int *count, int maxcount);
static daddr_t blst_meta_alloc(blmeta_t *scan, daddr_t cursor, int *count,
int maxcount, u_daddr_t radix);
static void blst_leaf_free(blmeta_t *scan, daddr_t relblk, int count);
static void blst_meta_free(blmeta_t *scan, daddr_t freeBlk, daddr_t count,
u_daddr_t radix);
static void blst_copy(blmeta_t *scan, daddr_t blk, daddr_t radix,
blist_t dest, daddr_t count);
static daddr_t blst_leaf_fill(blmeta_t *scan, daddr_t blk, int count);
static daddr_t blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr_t count,
u_daddr_t radix);
#ifndef _KERNEL
static void blst_radix_print(blmeta_t *scan, daddr_t blk, daddr_t radix,
int tab);
#endif
#ifdef _KERNEL
static MALLOC_DEFINE(M_SWAP, "SWAP", "Swap space");
#endif
#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_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 / m)) / (m - 1)
* skip = radix / (m - 1)
* so that simple integer division by a constant can safely be used for the
* calculation.
*/
static inline daddr_t
radix_to_skip(daddr_t radix)
{
return (radix / BLIST_MASK);
}
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/*
* Provide a mask with count bits set, starting as position n.
*/
static inline u_daddr_t
bitrange(int n, int count)
{
return (((u_daddr_t)-1 << n) &
((u_daddr_t)-1 >> (BLIST_RADIX - (n + count))));
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}
/*
* Find the first bit set in a u_daddr_t.
*/
static inline int
generic_bitpos(u_daddr_t mask)
{
int hi, lo, mid;
lo = 0;
hi = BLIST_RADIX;
while (lo + 1 < hi) {
mid = (lo + hi) >> 1;
if (mask & bitrange(0, mid))
hi = mid;
else
lo = mid;
}
return (lo);
}
static inline int
bitpos(u_daddr_t mask)
{
switch (sizeof(mask)) {
#ifdef HAVE_INLINE_FFSLL
case sizeof(long long):
return (ffsll(mask) - 1);
#endif
#ifdef HAVE_INLINE_FFS
case sizeof(int):
return (ffs(mask) - 1);
#endif
default:
return (generic_bitpos(mask));
}
}
/*
* blist_create() - create a blist capable of handling up to the specified
* number of blocks
*
* blocks - must be greater than 0
* flags - malloc flags
*
* The smallest blist consists of a single leaf node capable of
* managing BLIST_RADIX blocks.
*/
blist_t
blist_create(daddr_t blocks, int flags)
{
blist_t bl;
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u_daddr_t nodes, radix;
KASSERT(blocks > 0, ("invalid block count"));
/*
* Calculate the radix and node count used for scanning.
*/
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nodes = 1;
for (radix = 1; (blocks - 1) / BLIST_RADIX / radix > 0;
radix *= BLIST_RADIX)
nodes += 1 + (blocks - 1) / BLIST_RADIX / radix;
/*
* Include a sentinel node to ensure that cross-leaf scans stay within
* the bounds of the allocation.
*/
if (blocks % BLIST_RADIX == 0)
nodes++;
bl = malloc(offsetof(struct blist, bl_root[nodes]), M_SWAP, flags |
M_ZERO);
if (bl == NULL)
return (NULL);
bl->bl_blocks = blocks;
bl->bl_radix = radix;
#if defined(BLIST_DEBUG)
printf(
"BLIST representing %lld blocks (%lld MB of swap)"
", requiring %lldK of ram\n",
(long long)bl->bl_blocks,
(long long)bl->bl_blocks * 4 / 1024,
(long long)(nodes * sizeof(blmeta_t) + 1023) / 1024
);
printf("BLIST raw radix tree contains %lld records\n",
(long long)nodes);
#endif
return (bl);
}
void
blist_destroy(blist_t bl)
{
free(bl, M_SWAP);
}
/*
* blist_alloc() - reserve space in the block bitmap. Return the base
* of a contiguous region or SWAPBLK_NONE if space could
* not be allocated.
*/
daddr_t
blist_alloc(blist_t bl, int *count, int maxcount)
{
daddr_t blk, cursor;
KASSERT(*count <= maxcount,
("invalid parameters %d > %d", *count, maxcount));
KASSERT(*count <= BLIST_MAX_ALLOC,
("minimum allocation too large: %d", *count));
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/*
* This loop iterates at most twice. An allocation failure in the
* first iteration leads to a second iteration only if the cursor was
* non-zero. When the cursor is zero, an allocation failure will
* stop further iterations.
*/
for (cursor = bl->bl_cursor;; cursor = 0) {
blk = blst_meta_alloc(bl->bl_root, cursor, count, maxcount,
bl->bl_radix);
if (blk != SWAPBLK_NONE) {
bl->bl_avail -= *count;
bl->bl_cursor = blk + *count;
if (bl->bl_cursor == bl->bl_blocks)
bl->bl_cursor = 0;
return (blk);
}
if (cursor == 0)
return (SWAPBLK_NONE);
}
}
/*
* blist_avail() - return the number of free blocks.
*/
daddr_t
blist_avail(blist_t bl)
{
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return (bl->bl_avail);
}
/*
* blist_free() - free up space in the block bitmap. Return the base
* of a contiguous region.
*/
void
blist_free(blist_t bl, daddr_t blkno, daddr_t count)
{
KASSERT(blkno >= 0 && blkno + count <= bl->bl_blocks,
("freeing invalid range: blkno %jx, count %d, blocks %jd",
(uintmax_t)blkno, (int)count, (uintmax_t)bl->bl_blocks));
blst_meta_free(bl->bl_root, blkno, count, bl->bl_radix);
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bl->bl_avail += count;
}
/*
* blist_fill() - mark a region in the block bitmap as off-limits
* to the allocator (i.e. allocate it), ignoring any
* existing allocations. Return the number of blocks
* actually filled that were free before the call.
*/
daddr_t
blist_fill(blist_t bl, daddr_t blkno, daddr_t count)
{
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daddr_t filled;
KASSERT(blkno >= 0 && blkno + count <= bl->bl_blocks,
("filling invalid range: blkno %jx, count %d, blocks %jd",
(uintmax_t)blkno, (int)count, (uintmax_t)bl->bl_blocks));
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filled = blst_meta_fill(bl->bl_root, blkno, count, bl->bl_radix);
bl->bl_avail -= filled;
return (filled);
}
/*
* blist_resize() - resize an existing radix tree to handle the
* specified number of blocks. This will reallocate
* the tree and transfer the previous bitmap to the new
* one. When extending the tree you can specify whether
* the new blocks are to left allocated or freed.
*/
void
blist_resize(blist_t *pbl, daddr_t count, int freenew, int flags)
{
blist_t newbl = blist_create(count, flags);
blist_t save = *pbl;
*pbl = newbl;
if (count > save->bl_blocks)
count = save->bl_blocks;
blst_copy(save->bl_root, 0, save->bl_radix, newbl, count);
/*
* If resizing upwards, should we free the new space or not?
*/
if (freenew && count < newbl->bl_blocks) {
blist_free(newbl, count, newbl->bl_blocks - count);
}
blist_destroy(save);
}
#ifdef BLIST_DEBUG
/*
* blist_print() - dump radix tree
*/
void
blist_print(blist_t bl)
{
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printf("BLIST avail = %jd, cursor = %08jx {\n",
(uintmax_t)bl->bl_avail, (uintmax_t)bl->bl_cursor);
if (bl->bl_root->bm_bitmap != 0)
blst_radix_print(bl->bl_root, 0, bl->bl_radix, 4);
printf("}\n");
}
#endif
static const u_daddr_t fib[] = {
1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584,
4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393, 196418, 317811,
514229, 832040, 1346269, 2178309, 3524578,
};
/*
* Use 'gap' to describe a maximal range of unallocated blocks/bits.
*/
struct gap_stats {
daddr_t start; /* current gap start, or SWAPBLK_NONE */
daddr_t num; /* number of gaps observed */
daddr_t max; /* largest gap size */
daddr_t avg; /* average gap size */
daddr_t err; /* sum - num * avg */
daddr_t histo[nitems(fib)]; /* # gaps in each size range */
int max_bucket; /* last histo elt with nonzero val */
};
/*
* gap_stats_counting() - is the state 'counting 1 bits'?
* or 'skipping 0 bits'?
*/
static inline bool
gap_stats_counting(const struct gap_stats *stats)
{
return (stats->start != SWAPBLK_NONE);
}
/*
* init_gap_stats() - initialize stats on gap sizes
*/
static inline void
init_gap_stats(struct gap_stats *stats)
{
bzero(stats, sizeof(*stats));
stats->start = SWAPBLK_NONE;
}
/*
* update_gap_stats() - update stats on gap sizes
*/
static void
update_gap_stats(struct gap_stats *stats, daddr_t posn)
{
daddr_t size;
int hi, lo, mid;
if (!gap_stats_counting(stats)) {
stats->start = posn;
return;
}
size = posn - stats->start;
stats->start = SWAPBLK_NONE;
if (size > stats->max)
stats->max = size;
/*
* Find the fibonacci range that contains size,
* expecting to find it in an early range.
*/
lo = 0;
hi = 1;
while (hi < nitems(fib) && fib[hi] <= size) {
lo = hi;
hi *= 2;
}
if (hi >= nitems(fib))
hi = nitems(fib);
while (lo + 1 != hi) {
mid = (lo + hi) >> 1;
if (fib[mid] <= size)
lo = mid;
else
hi = mid;
}
stats->histo[lo]++;
if (lo > stats->max_bucket)
stats->max_bucket = lo;
stats->err += size - stats->avg;
stats->num++;
stats->avg += stats->err / stats->num;
stats->err %= stats->num;
}
/*
* dump_gap_stats() - print stats on gap sizes
*/
static inline void
dump_gap_stats(const struct gap_stats *stats, struct sbuf *s)
{
int i;
sbuf_printf(s, "number of maximal free ranges: %jd\n",
(intmax_t)stats->num);
sbuf_printf(s, "largest free range: %jd\n", (intmax_t)stats->max);
sbuf_printf(s, "average maximal free range size: %jd\n",
(intmax_t)stats->avg);
sbuf_printf(s, "number of maximal free ranges of different sizes:\n");
sbuf_printf(s, " count | size range\n");
sbuf_printf(s, " ----- | ----------\n");
for (i = 0; i < stats->max_bucket; i++) {
if (stats->histo[i] != 0) {
sbuf_printf(s, "%20jd | ",
(intmax_t)stats->histo[i]);
if (fib[i] != fib[i + 1] - 1)
sbuf_printf(s, "%jd to %jd\n", (intmax_t)fib[i],
(intmax_t)fib[i + 1] - 1);
else
sbuf_printf(s, "%jd\n", (intmax_t)fib[i]);
}
}
sbuf_printf(s, "%20jd | ", (intmax_t)stats->histo[i]);
if (stats->histo[i] > 1)
sbuf_printf(s, "%jd to %jd\n", (intmax_t)fib[i],
(intmax_t)stats->max);
else
sbuf_printf(s, "%jd\n", (intmax_t)stats->max);
}
/*
* blist_stats() - dump radix tree stats
*/
void
blist_stats(blist_t bl, struct sbuf *s)
{
struct gap_stats gstats;
struct gap_stats *stats = &gstats;
daddr_t i, nodes, radix;
u_daddr_t diff, mask;
int digit;
init_gap_stats(stats);
nodes = 0;
radix = bl->bl_radix;
for (i = 0; i < bl->bl_blocks; ) {
/*
* Check for skippable subtrees starting at i.
*/
while (radix != 1) {
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if (bl->bl_root[nodes].bm_bitmap == 0) {
if (gap_stats_counting(stats))
update_gap_stats(stats, i);
break;
}
/*
* Skip subtree root.
*/
nodes++;
radix /= BLIST_RADIX;
}
if (radix == 1) {
/*
* Scan leaf.
*/
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mask = bl->bl_root[nodes].bm_bitmap;
diff = mask ^ (mask << 1);
if (gap_stats_counting(stats))
diff ^= 1;
while (diff != 0) {
digit = bitpos(diff);
update_gap_stats(stats, i + digit);
diff ^= bitrange(digit, 1);
}
}
nodes += radix_to_skip(radix * BLIST_RADIX);
i += radix * BLIST_RADIX;
/*
* Find max size subtree starting at i.
*/
for (radix = 1;
((i / BLIST_RADIX / radix) & BLIST_MASK) == 0;
radix *= BLIST_RADIX)
;
}
update_gap_stats(stats, i);
dump_gap_stats(stats, s);
}
/************************************************************************
* ALLOCATION SUPPORT FUNCTIONS *
************************************************************************
*
* These support functions do all the actual work. They may seem
* rather longish, but that's because I've commented them up. The
* actual code is straight forward.
*
*/
/*
* BLST_NEXT_LEAF_ALLOC() - allocate the blocks starting with the next leaf.
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*
* 'scan' is a leaf node, and its first block is at address 'start'. The
* next leaf node could be adjacent, or several nodes away if the least
* common ancestor of 'scan' and its neighbor is several levels up. Use
* addresses to determine how many meta-nodes lie between the leaves. If
* sequence of leaves starting with the next one has enough initial bits
* set, clear them and clear the bits in the meta nodes on the path up to
* the least common ancestor to mark any subtrees made completely empty.
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*/
static int
blst_next_leaf_alloc(blmeta_t *scan, daddr_t start, int count, int maxcount)
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{
u_daddr_t radix;
daddr_t blk;
int avail, digit;
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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_RADIX;
while (((++scan)->bm_bitmap & 1) == 1 &&
((blk / radix) & BLIST_MASK) == 0)
radix *= BLIST_RADIX;
if (~scan->bm_bitmap != 0) {
/*
* Either there is no next leaf with any free blocks,
* or we've reached the next leaf and found that some
* of its blocks are not free. In the first case,
* bitpos() returns zero here.
*/
avail = blk - start + bitpos(~scan->bm_bitmap);
if (avail < count || avail == 0) {
/*
* There isn't a next leaf with enough free
* blocks at its beginning to bother
* allocating.
*/
return (avail);
}
maxcount = imin(avail, maxcount);
if (maxcount % BLIST_RADIX == 0) {
/*
* There was no next leaf. Back scan up to
* last leaf.
*/
do {
radix /= BLIST_RADIX;
--scan;
} while (radix != 1);
blk -= BLIST_RADIX;
}
}
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}
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/*
* 'scan' is the last leaf that provides blocks. Clear from 1 to
* BLIST_RADIX bits to represent the allocation of those last blocks.
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*/
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_RADIX;
for (radix = BLIST_RADIX;
(digit = ((blk / radix) & BLIST_MASK)) == 0;
radix *= BLIST_RADIX) {
if ((scan--)->bm_bitmap == 0)
scan->bm_bitmap ^= 1;
}
if ((scan--)->bm_bitmap == 0)
scan[-digit * radix_to_skip(radix)].bm_bitmap ^=
(u_daddr_t)1 << digit;
if (blk == start)
break;
/* Clear all the bits of this leaf. */
scan->bm_bitmap = 0;
}
return (maxcount);
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}
/*
* BLST_LEAF_ALLOC() - allocate at a leaf in the radix tree (a bitmap).
*
* This function is the core of the allocator. Its execution time is
* proportional to log(count), plus height of the tree if the allocation
* crosses a leaf boundary.
*/
static daddr_t
blst_leaf_alloc(blmeta_t *scan, daddr_t blk, int *count, int maxcount)
{
u_daddr_t mask;
int bighint, count1, hi, lo, num_shifts;
count1 = *count - 1;
num_shifts = fls(count1);
mask = ~scan->bm_bitmap;
while ((mask & (mask + 1)) != 0 && num_shifts > 0) {
/*
* If bit i is 0 in mask, then bits in [i, i + (count1 >>
* num_shifts)] are 1 in scan->bm_bitmap. Reduce num_shifts to
* 0, while preserving this invariant. The updates to mask
* leave fewer bits 0, but each bit that remains 0 represents a
* longer string of consecutive 1-bits in scan->bm_bitmap. If
* more updates to mask cannot set more bits, because mask is
* partitioned with all 1 bits following all 0 bits, the loop
* terminates immediately.
*/
num_shifts--;
mask |= mask >> ((count1 >> num_shifts) + 1) / 2;
}
bighint = count1 >> num_shifts;
if (~mask == 0) {
/*
* Update bighint. There is no allocation bigger than
* count1 >> num_shifts starting in this leaf.
*/
scan->bm_bighint = bighint;
return (SWAPBLK_NONE);
}
Modify blst_leaf_alloc to take only the cursor argument. Modify blst_leaf_alloc to find allocations that cross the boundary between one leaf node and the next when those two leaves descend from the same meta node. Update the hint field for leaves so that it represents a bound on how large an allocation can begin in that leaf, where it currently represents a bound on how large an allocation can be found within the boundaries of the leaf. The first phase of blst_leaf_alloc currently shrinks sequences of consecutive 1-bits in mask until each has been shrunken by count-1 bits, so that any bits remaining show where an allocation can begin, or until all the bits have disappeared, in which case the allocation fails. This change amends that so that the high-order bit is copied, as if, when the last block was free, it was followed by an endless stream of free blocks. It also amends the early stopping condition, so that the shrinking of 1-sequences stops early when there are none, or there is only one unbounded one remaining. The search for the first set bit is unchanged, and the code path thereafter is mostly unchanged unless the first set bit is in a position that makes some of those copied sign bits matter. In that case, we look for a next leaf, and at what blocks it can provide, to see if a cross-boundary allocation is possible. The hint is updated on a successful allocation that clears the last bit, but it not updated on a failed allocation that leaves the last bit set. So, as long as the last block is free, the hint value for the leaf is large. As long as the last block is free, and there's a next leaf, a large allocation can begin here, perhaps. A stricter rule than this would mean that allocations and frees in one leaf could require hint updates to the preceding leaf, and this change seeks to leave the freeing code unmodified. Define BLIST_BMAP_MASK, and use it for bit masking in blst_leaf_free and blist_leaf_fill, as well as in blst_leaf_alloc. Correct a panic message in blst_leaf_free. Submitted by: Doug Moore <dougm@rice.edu> Reviewed by: markj (an earlier version) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D11819
2017-09-16 18:12:15 +00:00
/* Discard any candidates that appear before blk. */
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_MASK;
mask |= bitrange(0, blk & BLIST_MASK);
if (~mask == 0) {
scan->bm_bighint = bighint;
return (SWAPBLK_NONE);
}
}
blk -= blk & BLIST_MASK;
}
/*
* The least significant set bit in mask marks the start of the first
* available range of sufficient size. Find its position.
*/
lo = bitpos(~mask);
/*
* Find how much space is available starting at that position.
*/
if ((mask & (mask + 1)) != 0) {
/* Count the 1 bits starting at position lo. */
hi = bitpos(mask & (mask + 1)) + count1;
if (maxcount < hi - lo)
hi = lo + maxcount;
*count = hi - lo;
mask = ~bitrange(lo, *count);
} 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_RADIX)
scan->bm_bighint = bighint;
} else {
/* Check next leaf for some of the blocks we want or need. */
count1 = *count - (BLIST_RADIX - lo);
maxcount -= BLIST_RADIX - lo;
hi = blst_next_leaf_alloc(scan, blk, count1, maxcount);
if (hi < count1)
Modify blst_leaf_alloc to take only the cursor argument. Modify blst_leaf_alloc to find allocations that cross the boundary between one leaf node and the next when those two leaves descend from the same meta node. Update the hint field for leaves so that it represents a bound on how large an allocation can begin in that leaf, where it currently represents a bound on how large an allocation can be found within the boundaries of the leaf. The first phase of blst_leaf_alloc currently shrinks sequences of consecutive 1-bits in mask until each has been shrunken by count-1 bits, so that any bits remaining show where an allocation can begin, or until all the bits have disappeared, in which case the allocation fails. This change amends that so that the high-order bit is copied, as if, when the last block was free, it was followed by an endless stream of free blocks. It also amends the early stopping condition, so that the shrinking of 1-sequences stops early when there are none, or there is only one unbounded one remaining. The search for the first set bit is unchanged, and the code path thereafter is mostly unchanged unless the first set bit is in a position that makes some of those copied sign bits matter. In that case, we look for a next leaf, and at what blocks it can provide, to see if a cross-boundary allocation is possible. The hint is updated on a successful allocation that clears the last bit, but it not updated on a failed allocation that leaves the last bit set. So, as long as the last block is free, the hint value for the leaf is large. As long as the last block is free, and there's a next leaf, a large allocation can begin here, perhaps. A stricter rule than this would mean that allocations and frees in one leaf could require hint updates to the preceding leaf, and this change seeks to leave the freeing code unmodified. Define BLIST_BMAP_MASK, and use it for bit masking in blst_leaf_free and blist_leaf_fill, as well as in blst_leaf_alloc. Correct a panic message in blst_leaf_free. Submitted by: Doug Moore <dougm@rice.edu> Reviewed by: markj (an earlier version) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D11819
2017-09-16 18:12:15 +00:00
/*
* The next leaf cannot supply enough blocks to reach
* the minimum required allocation. The hint cannot be
* updated, because the same allocation request could
* be satisfied later, by this leaf, if the state of
* the next leaf changes, and without any changes to
* this leaf.
Modify blst_leaf_alloc to take only the cursor argument. Modify blst_leaf_alloc to find allocations that cross the boundary between one leaf node and the next when those two leaves descend from the same meta node. Update the hint field for leaves so that it represents a bound on how large an allocation can begin in that leaf, where it currently represents a bound on how large an allocation can be found within the boundaries of the leaf. The first phase of blst_leaf_alloc currently shrinks sequences of consecutive 1-bits in mask until each has been shrunken by count-1 bits, so that any bits remaining show where an allocation can begin, or until all the bits have disappeared, in which case the allocation fails. This change amends that so that the high-order bit is copied, as if, when the last block was free, it was followed by an endless stream of free blocks. It also amends the early stopping condition, so that the shrinking of 1-sequences stops early when there are none, or there is only one unbounded one remaining. The search for the first set bit is unchanged, and the code path thereafter is mostly unchanged unless the first set bit is in a position that makes some of those copied sign bits matter. In that case, we look for a next leaf, and at what blocks it can provide, to see if a cross-boundary allocation is possible. The hint is updated on a successful allocation that clears the last bit, but it not updated on a failed allocation that leaves the last bit set. So, as long as the last block is free, the hint value for the leaf is large. As long as the last block is free, and there's a next leaf, a large allocation can begin here, perhaps. A stricter rule than this would mean that allocations and frees in one leaf could require hint updates to the preceding leaf, and this change seeks to leave the freeing code unmodified. Define BLIST_BMAP_MASK, and use it for bit masking in blst_leaf_free and blist_leaf_fill, as well as in blst_leaf_alloc. Correct a panic message in blst_leaf_free. Submitted by: Doug Moore <dougm@rice.edu> Reviewed by: markj (an earlier version) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D11819
2017-09-16 18:12:15 +00:00
*/
return (SWAPBLK_NONE);
*count = BLIST_RADIX - lo + hi;
scan->bm_bighint = bighint;
Modify blst_leaf_alloc to take only the cursor argument. Modify blst_leaf_alloc to find allocations that cross the boundary between one leaf node and the next when those two leaves descend from the same meta node. Update the hint field for leaves so that it represents a bound on how large an allocation can begin in that leaf, where it currently represents a bound on how large an allocation can be found within the boundaries of the leaf. The first phase of blst_leaf_alloc currently shrinks sequences of consecutive 1-bits in mask until each has been shrunken by count-1 bits, so that any bits remaining show where an allocation can begin, or until all the bits have disappeared, in which case the allocation fails. This change amends that so that the high-order bit is copied, as if, when the last block was free, it was followed by an endless stream of free blocks. It also amends the early stopping condition, so that the shrinking of 1-sequences stops early when there are none, or there is only one unbounded one remaining. The search for the first set bit is unchanged, and the code path thereafter is mostly unchanged unless the first set bit is in a position that makes some of those copied sign bits matter. In that case, we look for a next leaf, and at what blocks it can provide, to see if a cross-boundary allocation is possible. The hint is updated on a successful allocation that clears the last bit, but it not updated on a failed allocation that leaves the last bit set. So, as long as the last block is free, the hint value for the leaf is large. As long as the last block is free, and there's a next leaf, a large allocation can begin here, perhaps. A stricter rule than this would mean that allocations and frees in one leaf could require hint updates to the preceding leaf, and this change seeks to leave the freeing code unmodified. Define BLIST_BMAP_MASK, and use it for bit masking in blst_leaf_free and blist_leaf_fill, as well as in blst_leaf_alloc. Correct a panic message in blst_leaf_free. Submitted by: Doug Moore <dougm@rice.edu> Reviewed by: markj (an earlier version) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D11819
2017-09-16 18:12:15 +00:00
}
/* Clear the allocated bits from this leaf. */
scan->bm_bitmap &= mask;
return (blk + lo);
}
/*
* blist_meta_alloc() - allocate at a meta in the radix tree.
*
* Attempt to allocate at a meta node. If we can't, we update
* bighint and return a failure. Updating bighint optimize future
* calls that hit this node. We have to check for our collapse cases
* and we have a few optimizations strewn in as well.
*/
static daddr_t
blst_meta_alloc(blmeta_t *scan, daddr_t cursor, int *count,
int maxcount, u_daddr_t radix)
{
2018-11-13 18:40:01 +00:00
daddr_t blk, i, r, skip;
u_daddr_t mask;
bool scan_from_start;
2018-11-13 18:40:01 +00:00
int digit;
if (radix == 1)
return (blst_leaf_alloc(scan, cursor, count, maxcount));
blk = cursor & -(radix * BLIST_RADIX);
2018-11-13 18:40:01 +00:00
scan_from_start = (cursor == blk);
skip = radix_to_skip(radix);
2018-11-13 18:40:01 +00:00
mask = scan->bm_bitmap;
/* Discard any candidates that appear before cursor. */
digit = (cursor / radix) & BLIST_MASK;
2018-11-13 18:40:01 +00:00
mask &= (u_daddr_t)-1 << digit;
if (mask == 0)
return (SWAPBLK_NONE);
/*
2018-11-13 18:40:01 +00:00
* If the first try is for a block that includes the cursor, pre-undo
* the digit * radix offset in the first call; otherwise, ignore the
* cursor entirely.
*/
2018-11-13 18:40:01 +00:00
if (((mask >> digit) & 1) == 1)
cursor -= digit * radix;
else
cursor = blk;
2018-11-13 18:40:01 +00:00
/*
* Examine the nonempty subtree associated with each bit set in mask.
*/
do {
digit = bitpos(mask);
2018-11-13 18:40:01 +00:00
i = 1 + digit * skip;
if (*count <= scan[i].bm_bighint) {
/*
Modify blst_leaf_alloc to take only the cursor argument. Modify blst_leaf_alloc to find allocations that cross the boundary between one leaf node and the next when those two leaves descend from the same meta node. Update the hint field for leaves so that it represents a bound on how large an allocation can begin in that leaf, where it currently represents a bound on how large an allocation can be found within the boundaries of the leaf. The first phase of blst_leaf_alloc currently shrinks sequences of consecutive 1-bits in mask until each has been shrunken by count-1 bits, so that any bits remaining show where an allocation can begin, or until all the bits have disappeared, in which case the allocation fails. This change amends that so that the high-order bit is copied, as if, when the last block was free, it was followed by an endless stream of free blocks. It also amends the early stopping condition, so that the shrinking of 1-sequences stops early when there are none, or there is only one unbounded one remaining. The search for the first set bit is unchanged, and the code path thereafter is mostly unchanged unless the first set bit is in a position that makes some of those copied sign bits matter. In that case, we look for a next leaf, and at what blocks it can provide, to see if a cross-boundary allocation is possible. The hint is updated on a successful allocation that clears the last bit, but it not updated on a failed allocation that leaves the last bit set. So, as long as the last block is free, the hint value for the leaf is large. As long as the last block is free, and there's a next leaf, a large allocation can begin here, perhaps. A stricter rule than this would mean that allocations and frees in one leaf could require hint updates to the preceding leaf, and this change seeks to leave the freeing code unmodified. Define BLIST_BMAP_MASK, and use it for bit masking in blst_leaf_free and blist_leaf_fill, as well as in blst_leaf_alloc. Correct a panic message in blst_leaf_free. Submitted by: Doug Moore <dougm@rice.edu> Reviewed by: markj (an earlier version) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D11819
2017-09-16 18:12:15 +00:00
* The allocation might fit beginning in the i'th subtree.
*/
2018-11-13 18:40:01 +00:00
r = blst_meta_alloc(&scan[i], cursor + digit * radix,
count, maxcount, radix / BLIST_RADIX);
if (r != SWAPBLK_NONE) {
2018-11-13 18:40:01 +00:00
if (scan[i].bm_bitmap == 0)
scan->bm_bitmap ^= bitrange(digit, 1);
return (r);
}
}
2018-11-13 18:40:01 +00:00
cursor = blk;
} while ((mask ^= bitrange(digit, 1)) != 0);
/*
2018-11-13 18:40:01 +00:00
* 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_RADIX - 1 &&
2018-11-13 18:40:01 +00:00
scan[i].bm_bighint == BLIST_MAX_ALLOC))
scan->bm_bighint = *count - 1;
return (SWAPBLK_NONE);
}
/*
* BLST_LEAF_FREE() - free allocated block from leaf bitmap
*
*/
static void
blst_leaf_free(blmeta_t *scan, daddr_t blk, int count)
{
Modify blst_leaf_alloc to take only the cursor argument. Modify blst_leaf_alloc to find allocations that cross the boundary between one leaf node and the next when those two leaves descend from the same meta node. Update the hint field for leaves so that it represents a bound on how large an allocation can begin in that leaf, where it currently represents a bound on how large an allocation can be found within the boundaries of the leaf. The first phase of blst_leaf_alloc currently shrinks sequences of consecutive 1-bits in mask until each has been shrunken by count-1 bits, so that any bits remaining show where an allocation can begin, or until all the bits have disappeared, in which case the allocation fails. This change amends that so that the high-order bit is copied, as if, when the last block was free, it was followed by an endless stream of free blocks. It also amends the early stopping condition, so that the shrinking of 1-sequences stops early when there are none, or there is only one unbounded one remaining. The search for the first set bit is unchanged, and the code path thereafter is mostly unchanged unless the first set bit is in a position that makes some of those copied sign bits matter. In that case, we look for a next leaf, and at what blocks it can provide, to see if a cross-boundary allocation is possible. The hint is updated on a successful allocation that clears the last bit, but it not updated on a failed allocation that leaves the last bit set. So, as long as the last block is free, the hint value for the leaf is large. As long as the last block is free, and there's a next leaf, a large allocation can begin here, perhaps. A stricter rule than this would mean that allocations and frees in one leaf could require hint updates to the preceding leaf, and this change seeks to leave the freeing code unmodified. Define BLIST_BMAP_MASK, and use it for bit masking in blst_leaf_free and blist_leaf_fill, as well as in blst_leaf_alloc. Correct a panic message in blst_leaf_free. Submitted by: Doug Moore <dougm@rice.edu> Reviewed by: markj (an earlier version) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D11819
2017-09-16 18:12:15 +00:00
u_daddr_t mask;
/*
* free some data in this bitmap
Modify blst_leaf_alloc to take only the cursor argument. Modify blst_leaf_alloc to find allocations that cross the boundary between one leaf node and the next when those two leaves descend from the same meta node. Update the hint field for leaves so that it represents a bound on how large an allocation can begin in that leaf, where it currently represents a bound on how large an allocation can be found within the boundaries of the leaf. The first phase of blst_leaf_alloc currently shrinks sequences of consecutive 1-bits in mask until each has been shrunken by count-1 bits, so that any bits remaining show where an allocation can begin, or until all the bits have disappeared, in which case the allocation fails. This change amends that so that the high-order bit is copied, as if, when the last block was free, it was followed by an endless stream of free blocks. It also amends the early stopping condition, so that the shrinking of 1-sequences stops early when there are none, or there is only one unbounded one remaining. The search for the first set bit is unchanged, and the code path thereafter is mostly unchanged unless the first set bit is in a position that makes some of those copied sign bits matter. In that case, we look for a next leaf, and at what blocks it can provide, to see if a cross-boundary allocation is possible. The hint is updated on a successful allocation that clears the last bit, but it not updated on a failed allocation that leaves the last bit set. So, as long as the last block is free, the hint value for the leaf is large. As long as the last block is free, and there's a next leaf, a large allocation can begin here, perhaps. A stricter rule than this would mean that allocations and frees in one leaf could require hint updates to the preceding leaf, and this change seeks to leave the freeing code unmodified. Define BLIST_BMAP_MASK, and use it for bit masking in blst_leaf_free and blist_leaf_fill, as well as in blst_leaf_alloc. Correct a panic message in blst_leaf_free. Submitted by: Doug Moore <dougm@rice.edu> Reviewed by: markj (an earlier version) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D11819
2017-09-16 18:12:15 +00:00
* mask=0000111111111110000
* \_________/\__/
Modify blst_leaf_alloc to take only the cursor argument. Modify blst_leaf_alloc to find allocations that cross the boundary between one leaf node and the next when those two leaves descend from the same meta node. Update the hint field for leaves so that it represents a bound on how large an allocation can begin in that leaf, where it currently represents a bound on how large an allocation can be found within the boundaries of the leaf. The first phase of blst_leaf_alloc currently shrinks sequences of consecutive 1-bits in mask until each has been shrunken by count-1 bits, so that any bits remaining show where an allocation can begin, or until all the bits have disappeared, in which case the allocation fails. This change amends that so that the high-order bit is copied, as if, when the last block was free, it was followed by an endless stream of free blocks. It also amends the early stopping condition, so that the shrinking of 1-sequences stops early when there are none, or there is only one unbounded one remaining. The search for the first set bit is unchanged, and the code path thereafter is mostly unchanged unless the first set bit is in a position that makes some of those copied sign bits matter. In that case, we look for a next leaf, and at what blocks it can provide, to see if a cross-boundary allocation is possible. The hint is updated on a successful allocation that clears the last bit, but it not updated on a failed allocation that leaves the last bit set. So, as long as the last block is free, the hint value for the leaf is large. As long as the last block is free, and there's a next leaf, a large allocation can begin here, perhaps. A stricter rule than this would mean that allocations and frees in one leaf could require hint updates to the preceding leaf, and this change seeks to leave the freeing code unmodified. Define BLIST_BMAP_MASK, and use it for bit masking in blst_leaf_free and blist_leaf_fill, as well as in blst_leaf_alloc. Correct a panic message in blst_leaf_free. Submitted by: Doug Moore <dougm@rice.edu> Reviewed by: markj (an earlier version) MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D11819
2017-09-16 18:12:15 +00:00
* count n
*/
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));
2018-11-13 18:40:01 +00:00
scan->bm_bitmap |= mask;
}
/*
* BLST_META_FREE() - free allocated blocks from radix tree meta info
*
* This support routine frees a range of blocks from the bitmap.
* The range must be entirely enclosed by this radix node. If a
* meta node, we break the range down recursively to free blocks
* in subnodes (which means that this code can free an arbitrary
* range whereas the allocation code cannot allocate an arbitrary
* range).
*/
static void
blst_meta_free(blmeta_t *scan, daddr_t freeBlk, daddr_t count, u_daddr_t radix)
{
2018-11-13 18:40:01 +00:00
daddr_t blk, endBlk, i, skip;
int digit, endDigit;
/*
2018-11-13 18:40:01 +00:00
* We could probably do a better job here. We are required to make
* bighint at least as large as the biggest allocable block of data.
* If we just shoehorn it, a little extra overhead will be incurred
* on the next allocation (but only that one typically).
*/
2018-11-13 18:40:01 +00:00
scan->bm_bighint = BLIST_MAX_ALLOC;
if (radix == 1)
2018-11-13 18:40:01 +00:00
return (blst_leaf_free(scan, freeBlk, count));
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);
2018-11-13 18:40:01 +00:00
skip = radix_to_skip(radix);
blk = freeBlk & -radix;
digit = (blk / radix) & BLIST_MASK;
endDigit = 1 + (((endBlk - 1) / radix) & BLIST_MASK);
2018-11-13 18:40:01 +00:00
scan->bm_bitmap |= bitrange(digit, endDigit - digit);
for (i = 1 + digit * skip; blk < endBlk; i += skip) {
blk += radix;
2018-11-13 18:40:01 +00:00
count = ummin(blk, endBlk) - freeBlk;
blst_meta_free(&scan[i], freeBlk, count, radix / BLIST_RADIX);
2018-11-13 18:40:01 +00:00
freeBlk = blk;
}
}
/*
2018-11-13 18:40:01 +00:00
* BLST_COPY() - copy one radix tree to another
*
* Locates free space in the source tree and frees it in the destination
* tree. The space may not already be free in the destination.
*/
static void
blst_copy(blmeta_t *scan, daddr_t blk, daddr_t radix, blist_t dest,
daddr_t count)
{
2018-11-13 18:40:01 +00:00
daddr_t endBlk, i, skip;
/*
* Leaf node
*/
if (radix == 1) {
2018-11-13 18:40:01 +00:00
u_daddr_t v = scan->bm_bitmap;
if (v == (u_daddr_t)-1) {
blist_free(dest, blk, count);
} else if (v != 0) {
int i;
2018-11-13 18:40:01 +00:00
for (i = 0; i < count; ++i) {
if (v & ((u_daddr_t)1 << i))
blist_free(dest, blk + i, 1);
}
}
return;
}
/*
* Meta node
*/
2018-11-13 18:40:01 +00:00
if (scan->bm_bitmap == 0) {
/*
* Source all allocated, leave dest allocated
*/
return;
}
2018-11-13 18:40:01 +00:00
endBlk = blk + count;
skip = radix_to_skip(radix);
for (i = 1; blk < endBlk; i += skip) {
blk += radix;
2018-11-13 18:40:01 +00:00
count = radix;
if (blk >= endBlk)
count -= blk - endBlk;
blst_copy(&scan[i], blk - radix,
radix / BLIST_RADIX, dest, count);
}
}
/*
* BLST_LEAF_FILL() - allocate specific blocks in leaf bitmap
*
* This routine allocates all blocks in the specified range
* regardless of any existing allocations in that range. Returns
* the number of blocks allocated by the call.
*/
static daddr_t
blst_leaf_fill(blmeta_t *scan, daddr_t blk, int count)
{
daddr_t nblks;
u_daddr_t mask;
mask = bitrange(blk & BLIST_MASK, count);
/* Count the number of blocks that we are allocating. */
2018-11-13 18:40:01 +00:00
nblks = bitcount64(scan->bm_bitmap & mask);
2018-11-13 18:40:01 +00:00
scan->bm_bitmap &= ~mask;
return (nblks);
}
/*
* BLIST_META_FILL() - allocate specific blocks at a meta node
*
* This routine allocates the specified range of blocks,
* regardless of any existing allocations in the range. The
* range must be within the extent of this node. Returns the
* number of blocks allocated by the call.
*/
static daddr_t
blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr_t count, u_daddr_t radix)
{
2018-11-13 18:40:01 +00:00
daddr_t blk, endBlk, i, nblks, skip;
int digit;
if (radix == 1)
return (blst_leaf_fill(scan, allocBlk, count));
2018-11-13 18:40:01 +00:00
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;
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while (blk < endBlk) {
digit = (blk / radix) & BLIST_MASK;
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i = 1 + digit * skip;
blk += radix;
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count = ummin(blk, endBlk) - allocBlk;
nblks += blst_meta_fill(&scan[i], allocBlk, count,
radix / BLIST_RADIX);
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if (scan[i].bm_bitmap == 0)
scan->bm_bitmap &= ~((u_daddr_t)1 << digit);
allocBlk = blk;
}
return (nblks);
}
#ifdef BLIST_DEBUG
static void
blst_radix_print(blmeta_t *scan, daddr_t blk, daddr_t radix, int tab)
{
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daddr_t skip;
u_daddr_t mask;
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int digit;
if (radix == 1) {
printf(
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"%*.*s(%08llx,%lld): bitmap %0*llx big=%lld\n",
tab, tab, "",
(long long)blk, (long long)BLIST_RADIX,
(int)(1 + (BLIST_RADIX - 1) / 4),
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(long long)scan->bm_bitmap,
(long long)scan->bm_bighint
);
return;
}
printf(
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"%*.*s(%08llx): subtree (%lld/%lld) bitmap %0*llx big=%lld {\n",
tab, tab, "",
(long long)blk, (long long)radix * BLIST_RADIX,
(long long)radix * BLIST_RADIX,
(int)(1 + (BLIST_RADIX - 1) / 4),
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(long long)scan->bm_bitmap,
(long long)scan->bm_bighint
);
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skip = radix_to_skip(radix);
tab += 4;
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mask = scan->bm_bitmap;
/* Examine the nonempty subtree associated with each bit set in mask */
do {
digit = bitpos(mask);
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blst_radix_print(&scan[1 + digit * skip], blk + digit * radix,
radix / BLIST_RADIX, tab);
} while ((mask ^= bitrange(digit, 1)) != 0);
tab -= 4;
printf(
"%*.*s}\n",
tab, tab, ""
);
}
#endif
#ifdef BLIST_DEBUG
int
main(int ac, char **av)
{
daddr_t size = BLIST_RADIX * BLIST_RADIX;
int i;
blist_t bl;
struct sbuf *s;
for (i = 1; i < ac; ++i) {
const char *ptr = av[i];
if (*ptr != '-') {
size = strtoll(ptr, NULL, 0);
continue;
}
ptr += 2;
fprintf(stderr, "Bad option: %s\n", ptr - 2);
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 (;;) {
char buf[1024];
long long da = 0;
int count = 0, maxcount = 0;
printf("%lld/%lld/%lld> ", (long long)blist_avail(bl),
(long long)size, (long long)bl->bl_radix * BLIST_RADIX);
fflush(stdout);
if (fgets(buf, sizeof(buf), stdin) == NULL)
break;
switch(buf[0]) {
case 'r':
if (sscanf(buf + 1, "%d", &count) == 1) {
blist_resize(&bl, count, 1, M_WAITOK);
} else {
printf("?\n");
}
case 'p':
blist_print(bl);
break;
case 's':
s = sbuf_new_auto();
blist_stats(bl, s);
sbuf_finish(s);
printf("%s", sbuf_data(s));
sbuf_delete(s);
break;
case 'a':
if (sscanf(buf + 1, "%d%d", &count, &maxcount) == 2) {
daddr_t blk = blist_alloc(bl, &count, maxcount);
printf(" R=%08llx, c=%08d\n",
(long long)blk, count);
} else {
printf("?\n");
}
break;
case 'f':
if (sscanf(buf + 1, "%llx %d", &da, &count) == 2) {
blist_free(bl, da, count);
} else {
printf("?\n");
}
break;
case 'l':
if (sscanf(buf + 1, "%llx %d", &da, &count) == 2) {
printf(" n=%jd\n",
(intmax_t)blist_fill(bl, da, count));
} else {
printf("?\n");
}
break;
case '?':
case 'h':
puts(
"p -print\n"
"s -stats\n"
"a %d %d -allocate\n"
"f %x %d -free\n"
"l %x %d -fill\n"
"r %d -resize\n"
"h/? -help\n"
"q -quit"
);
break;
case 'q':
break;
default:
printf("?\n");
break;
}
if (buf[0] == 'q')
break;
}
return (0);
}
#endif