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NetBSD/sys/kern/subr_blist.c

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/* $NetBSD: subr_blist.c,v 1.15 2022/05/31 08:43:16 andvar Exp $ */
/*-
* 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.
* 4. 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
* BLIST_NONE on an allocation failure.
*
* A radix tree is used to maintain the bitmap. Two radix constants are
* involved: One for the bitmaps contained in the leaf nodes (typically
* 32), and one for the meta nodes (typically 16). Both meta and leaf
* nodes have a hint field. This field gives us a hint as to the largest
* free contiguous range of blocks under the node. It may contain a
* value that is too high, but will never contain a value that is too
* low. When the radix tree is searched, allocation failures in subtrees
* update the hint.
*
* The radix tree also implements two collapsed states for meta nodes:
* the ALL-ALLOCATED state and the ALL-FREE state. If a meta node is
* in either of these two states, all information contained underneath
* the node is considered stale. These states are used to optimize
* allocation and freeing operations.
*
* 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.
*
* Unlike the rlist code, the blist code wires all necessary memory at
* creation time. Neither allocations nor frees require interaction with
* the memory subsystem. In contrast, the rlist code may allocate memory
* on an rlist_free() call. The non-blocking features of the blist code
* are used to great advantage in the swap code (vm/nswap_pager.c). The
* rlist code uses a little less overall memory than the blist code (but
* due to swap interleaving not all that much less), but the blist code
* scales much, much better.
*
* 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 structure but one that can be easily scanned through
* a very simple 'skip' calculation. In order to support large radixes,
* portions of the tree may reside outside our memory allocation. We
* handle this with an early-termination optimization (when bighint is
* set to -1) on the scan. The memory allocation is only large enough
* to cover the number of blocks requested at creation time even if it
* must be encompassed in larger root-node radix.
*
* NOTE: the allocator cannot currently allocate more than
* BLIST_BMAP_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 effected by
* this algorithmic unfeature. The freeing code can handle arbitrary
* ranges.
*
* This code can be compiled stand-alone for debugging.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_blist.c,v 1.15 2022/05/31 08:43:16 andvar Exp $");
#if 0
__FBSDID("$FreeBSD: src/sys/kern/subr_blist.c,v 1.17 2004/06/04 04:03:25 alc Exp $");
#endif
#ifdef _KERNEL
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/blist.h>
#include <sys/kmem.h>
#else
#ifndef BLIST_NO_DEBUG
#define BLIST_DEBUG
#endif
#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <inttypes.h>
#define KM_SLEEP 1
#define kmem_zalloc(a,b) calloc(1, (a))
#define kmem_alloc(a,b) malloc(a)
#define kmem_free(a,b) free(a)
#include "../sys/blist.h"
void panic(const char *ctl, ...) __printflike(1, 2);
#endif
/*
* blmeta and bl_bitmap_t MUST be a power of 2 in size.
*/
typedef struct blmeta {
union {
blist_blkno_t bmu_avail; /* space available under us */
blist_bitmap_t bmu_bitmap; /* bitmap if we are a leaf */
} u;
blist_blkno_t bm_bighint; /* biggest contiguous block hint*/
} blmeta_t;
struct blist {
blist_blkno_t bl_blocks; /* area of coverage */
blist_blkno_t bl_radix; /* coverage radix */
blist_blkno_t bl_skip; /* starting skip */
blist_blkno_t bl_free; /* number of free blocks */
blmeta_t *bl_root; /* root of radix tree */
blist_blkno_t bl_rootblks; /* blks allocated for tree */
};
#define BLIST_META_RADIX 16
/*
* static support functions
*/
static blist_blkno_t blst_leaf_alloc(blmeta_t *scan, blist_blkno_t blk,
int count);
static blist_blkno_t blst_meta_alloc(blmeta_t *scan, blist_blkno_t blk,
blist_blkno_t count, blist_blkno_t radix, blist_blkno_t skip);
static void blst_leaf_free(blmeta_t *scan, blist_blkno_t relblk, int count);
static void blst_meta_free(blmeta_t *scan, blist_blkno_t freeBlk,
blist_blkno_t count, blist_blkno_t radix, blist_blkno_t skip,
blist_blkno_t blk);
static void blst_copy(blmeta_t *scan, blist_blkno_t blk, blist_blkno_t radix,
blist_blkno_t skip, blist_t dest, blist_blkno_t count);
static int blst_leaf_fill(blmeta_t *scan, blist_blkno_t blk, int count);
static blist_blkno_t blst_meta_fill(blmeta_t *scan, blist_blkno_t allocBlk,
blist_blkno_t count, blist_blkno_t radix, blist_blkno_t skip,
blist_blkno_t blk);
static blist_blkno_t blst_radix_init(blmeta_t *scan, blist_blkno_t radix,
blist_blkno_t skip, blist_blkno_t count);
#ifndef _KERNEL
static void blst_radix_print(blmeta_t *scan, blist_blkno_t blk,
blist_blkno_t radix, blist_blkno_t skip, int tab);
#endif
/*
* blist_create() - create a blist capable of handling up to the specified
* number of blocks
*
* blocks must be greater than 0
*
* The smallest blist consists of a single leaf node capable of
* managing BLIST_BMAP_RADIX blocks.
*/
blist_t
blist_create(blist_blkno_t blocks)
{
blist_t bl;
blist_blkno_t radix;
blist_blkno_t skip = 0;
/*
* Calculate radix and skip field used for scanning.
*
* XXX check overflow
*/
radix = BLIST_BMAP_RADIX;
while (radix < blocks) {
radix *= BLIST_META_RADIX;
skip = (skip + 1) * BLIST_META_RADIX;
}
bl = kmem_zalloc(sizeof(struct blist), KM_SLEEP);
bl->bl_blocks = blocks;
bl->bl_radix = radix;
bl->bl_skip = skip;
bl->bl_rootblks = 1 +
blst_radix_init(NULL, bl->bl_radix, bl->bl_skip, blocks);
bl->bl_root = kmem_alloc(sizeof(blmeta_t) * bl->bl_rootblks, KM_SLEEP);
#if defined(BLIST_DEBUG)
printf(
"BLIST representing %" PRIu64 " blocks (%" PRIu64 " MB of swap)"
", requiring %" PRIu64 "K of ram\n",
(uint64_t)bl->bl_blocks,
(uint64_t)bl->bl_blocks * 4 / 1024,
((uint64_t)bl->bl_rootblks * sizeof(blmeta_t) + 1023) / 1024
);
printf("BLIST raw radix tree contains %" PRIu64 " records\n",
(uint64_t)bl->bl_rootblks);
#endif
blst_radix_init(bl->bl_root, bl->bl_radix, bl->bl_skip, blocks);
return(bl);
}
void
blist_destroy(blist_t bl)
{
kmem_free(bl->bl_root, sizeof(blmeta_t) * bl->bl_rootblks);
kmem_free(bl, sizeof(struct blist));
}
/*
* blist_alloc() - reserve space in the block bitmap. Return the base
* of a contiguous region or BLIST_NONE if space could
* not be allocated.
*/
blist_blkno_t
blist_alloc(blist_t bl, blist_blkno_t count)
{
blist_blkno_t blk = BLIST_NONE;
if (bl) {
if (bl->bl_radix == BLIST_BMAP_RADIX)
blk = blst_leaf_alloc(bl->bl_root, 0, count);
else
blk = blst_meta_alloc(bl->bl_root, 0, count, bl->bl_radix, bl->bl_skip);
if (blk != BLIST_NONE)
bl->bl_free -= count;
}
return(blk);
}
/*
* blist_free() - free up space in the block bitmap. Return the base
* of a contiguous region. Panic if an inconsistency is
* found.
*/
void
blist_free(blist_t bl, blist_blkno_t blkno, blist_blkno_t count)
{
if (bl) {
if (bl->bl_radix == BLIST_BMAP_RADIX)
blst_leaf_free(bl->bl_root, blkno, count);
else
blst_meta_free(bl->bl_root, blkno, count, bl->bl_radix, bl->bl_skip, 0);
bl->bl_free += 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.
*/
blist_blkno_t
blist_fill(blist_t bl, blist_blkno_t blkno, blist_blkno_t count)
{
blist_blkno_t filled;
if (bl) {
if (bl->bl_radix == BLIST_BMAP_RADIX)
filled = blst_leaf_fill(bl->bl_root, blkno, count);
else
filled = blst_meta_fill(bl->bl_root, blkno, count,
bl->bl_radix, bl->bl_skip, 0);
bl->bl_free -= filled;
return filled;
} else
return 0;
}
/*
* 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, blist_blkno_t count, int freenew)
{
blist_t newbl = blist_create(count);
blist_t save = *pbl;
*pbl = newbl;
if (count > save->bl_blocks)
count = save->bl_blocks;
blst_copy(save->bl_root, 0, save->bl_radix, save->bl_skip, 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)
{
printf("BLIST {\n");
blst_radix_print(bl->bl_root, 0, bl->bl_radix, bl->bl_skip, 4);
printf("}\n");
}
#endif
/************************************************************************
* 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.
*
*/
/*
* blist_leaf_alloc() - allocate at a leaf in the radix tree (a bitmap).
*
* This is the core of the allocator and is optimized for the 1 block
* and the BLIST_BMAP_RADIX block allocation cases. Other cases are
* somewhat slower. The 1 block allocation case is log2 and extremely
* quick.
*/
static blist_blkno_t
blst_leaf_alloc(
blmeta_t *scan,
blist_blkno_t blk,
int count
) {
blist_bitmap_t orig = scan->u.bmu_bitmap;
if (orig == 0) {
/*
* Optimize bitmap all-allocated case. Also, count = 1
* case assumes at least 1 bit is free in the bitmap, so
* we have to take care of this case here.
*/
scan->bm_bighint = 0;
return(BLIST_NONE);
}
if (count == 1) {
/*
* Optimized code to allocate one bit out of the bitmap
*/
blist_bitmap_t mask;
int j = BLIST_BMAP_RADIX/2;
int r = 0;
mask = (blist_bitmap_t)-1 >> (BLIST_BMAP_RADIX/2);
while (j) {
if ((orig & mask) == 0) {
r += j;
orig >>= j;
}
j >>= 1;
mask >>= j;
}
scan->u.bmu_bitmap &= ~((blist_bitmap_t)1 << r);
return(blk + r);
}
if (count <= BLIST_BMAP_RADIX) {
/*
* non-optimized code to allocate N bits out of the bitmap.
* The more bits, the faster the code runs. It will run
* the slowest allocating 2 bits, but since there aren't any
* memory ops in the core loop (or shouldn't be, anyway),
* you probably won't notice the difference.
*/
int j;
int n = BLIST_BMAP_RADIX - count;
blist_bitmap_t mask;
mask = (blist_bitmap_t)-1 >> n;
for (j = 0; j <= n; ++j) {
if ((orig & mask) == mask) {
scan->u.bmu_bitmap &= ~mask;
return(blk + j);
}
mask = (mask << 1);
}
}
/*
* We couldn't allocate count in this subtree, update bighint.
*/
scan->bm_bighint = count - 1;
return(BLIST_NONE);
}
/*
* 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 blist_blkno_t
blst_meta_alloc(
blmeta_t *scan,
blist_blkno_t blk,
blist_blkno_t count,
blist_blkno_t radix,
blist_blkno_t skip
) {
blist_blkno_t i;
blist_blkno_t next_skip = (skip / BLIST_META_RADIX);
if (scan->u.bmu_avail == 0) {
/*
* ALL-ALLOCATED special case
*/
scan->bm_bighint = count;
return(BLIST_NONE);
}
if (scan->u.bmu_avail == radix) {
radix /= BLIST_META_RADIX;
/*
* ALL-FREE special case, initialize uninitialize
* sublevel.
*/
for (i = 1; i <= skip; i += next_skip) {
if (scan[i].bm_bighint == (blist_blkno_t)-1)
break;
if (next_skip == 1) {
scan[i].u.bmu_bitmap = (blist_bitmap_t)-1;
scan[i].bm_bighint = BLIST_BMAP_RADIX;
} else {
scan[i].bm_bighint = radix;
scan[i].u.bmu_avail = radix;
}
}
} else {
radix /= BLIST_META_RADIX;
}
for (i = 1; i <= skip; i += next_skip) {
if (scan[i].bm_bighint == (blist_blkno_t)-1) {
/*
* Terminator
*/
break;
} else if (count <= scan[i].bm_bighint) {
/*
* count fits in object
*/
blist_blkno_t r;
if (next_skip == 1) {
r = blst_leaf_alloc(&scan[i], blk, count);
} else {
r = blst_meta_alloc(&scan[i], blk, count, radix, next_skip - 1);
}
if (r != BLIST_NONE) {
scan->u.bmu_avail -= count;
if (scan->bm_bighint > scan->u.bmu_avail)
scan->bm_bighint = scan->u.bmu_avail;
return(r);
}
} else if (count > radix) {
/*
* count does not fit in object even if it were
* complete free.
*/
panic("blist_meta_alloc: allocation too large");
}
blk += radix;
}
/*
* We couldn't allocate count in this subtree, update bighint.
*/
if (scan->bm_bighint >= count)
scan->bm_bighint = count - 1;
return(BLIST_NONE);
}
/*
* BLST_LEAF_FREE() - free allocated block from leaf bitmap
*
*/
static void
blst_leaf_free(
blmeta_t *scan,
blist_blkno_t blk,
int count
) {
/*
* free some data in this bitmap
*
* e.g.
* 0000111111111110000
* \_________/\__/
* v n
*/
int n = blk & (BLIST_BMAP_RADIX - 1);
blist_bitmap_t mask;
mask = ((blist_bitmap_t)-1 << n) &
((blist_bitmap_t)-1 >> (BLIST_BMAP_RADIX - count - n));
if (scan->u.bmu_bitmap & mask)
panic("blst_radix_free: freeing free block");
scan->u.bmu_bitmap |= mask;
/*
* We could probably do a better job here. We are required to make
* bighint at least as large as the biggest contiguous block of
* data. If we just shoehorn it, a little extra overhead will
* be incured on the next allocation (but only that one typically).
*/
scan->bm_bighint = BLIST_BMAP_RADIX;
}
/*
* 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,
blist_blkno_t freeBlk,
blist_blkno_t count,
blist_blkno_t radix,
blist_blkno_t skip,
blist_blkno_t blk
) {
blist_blkno_t i;
blist_blkno_t next_skip = (skip / BLIST_META_RADIX);
#if 0
printf("FREE (%" PRIx64 ",%" PRIu64
") FROM (%" PRIx64 ",%" PRIu64 ")\n",
(uint64_t)freeBlk, (uint64_t)count,
(uint64_t)blk, (uint64_t)radix
);
#endif
if (scan->u.bmu_avail == 0) {
/*
* ALL-ALLOCATED special case, with possible
* shortcut to ALL-FREE special case.
*/
scan->u.bmu_avail = count;
scan->bm_bighint = count;
if (count != radix) {
for (i = 1; i <= skip; i += next_skip) {
if (scan[i].bm_bighint == (blist_blkno_t)-1)
break;
scan[i].bm_bighint = 0;
if (next_skip == 1) {
scan[i].u.bmu_bitmap = 0;
} else {
scan[i].u.bmu_avail = 0;
}
}
/* fall through */
}
} else {
scan->u.bmu_avail += count;
/* scan->bm_bighint = radix; */
}
/*
* ALL-FREE special case.
*/
if (scan->u.bmu_avail == radix)
return;
if (scan->u.bmu_avail > radix)
panic("blst_meta_free: freeing already free blocks (%"
PRIu64 ") %" PRIu64 "/%" PRIu64,
(uint64_t)count,
(uint64_t)scan->u.bmu_avail,
(uint64_t)radix);
/*
* Break the free down into its components
*/
radix /= BLIST_META_RADIX;
i = (freeBlk - blk) / radix;
blk += i * radix;
i = i * next_skip + 1;
while (i <= skip && blk < freeBlk + count) {
blist_blkno_t v;
v = blk + radix - freeBlk;
if (v > count)
v = count;
if (scan->bm_bighint == (blist_blkno_t)-1)
panic("blst_meta_free: freeing unexpected range");
if (next_skip == 1) {
blst_leaf_free(&scan[i], freeBlk, v);
} else {
blst_meta_free(&scan[i], freeBlk, v, radix, next_skip - 1, blk);
}
if (scan->bm_bighint < scan[i].bm_bighint)
scan->bm_bighint = scan[i].bm_bighint;
count -= v;
freeBlk += v;
blk += radix;
i += next_skip;
}
}
/*
* BLIST_RADIX_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,
blist_blkno_t blk,
blist_blkno_t radix,
blist_blkno_t skip,
blist_t dest,
blist_blkno_t count
) {
blist_blkno_t next_skip;
blist_blkno_t i;
/*
* Leaf node
*/
if (radix == BLIST_BMAP_RADIX) {
blist_bitmap_t v = scan->u.bmu_bitmap;
if (v == (blist_bitmap_t)-1) {
blist_free(dest, blk, count);
} else if (v != 0) {
int j;
for (j = 0; j < BLIST_BMAP_RADIX && j < count; ++j) {
if (v & (1 << j))
blist_free(dest, blk + j, 1);
}
}
return;
}
/*
* Meta node
*/
if (scan->u.bmu_avail == 0) {
/*
* Source all allocated, leave dest allocated
*/
return;
}
if (scan->u.bmu_avail == radix) {
/*
* Source all free, free entire dest
*/
if (count < radix)
blist_free(dest, blk, count);
else
blist_free(dest, blk, radix);
return;
}
radix /= BLIST_META_RADIX;
next_skip = (skip / BLIST_META_RADIX);
for (i = 1; count && i <= skip; i += next_skip) {
if (scan[i].bm_bighint == (blist_blkno_t)-1)
break;
if (count >= radix) {
blst_copy(
&scan[i],
blk,
radix,
next_skip - 1,
dest,
radix
);
count -= radix;
} else {
if (count) {
blst_copy(
&scan[i],
blk,
radix,
next_skip - 1,
dest,
count
);
}
count = 0;
}
blk += radix;
}
}
/*
* 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 int
blst_leaf_fill(blmeta_t *scan, blist_blkno_t blk, int count)
{
int n = blk & (BLIST_BMAP_RADIX - 1);
int nblks;
blist_bitmap_t mask, bitmap;
mask = ((blist_bitmap_t)-1 << n) &
((blist_bitmap_t)-1 >> (BLIST_BMAP_RADIX - count - n));
/* Count the number of blocks we're about to allocate */
bitmap = scan->u.bmu_bitmap & mask;
for (nblks = 0; bitmap != 0; nblks++)
bitmap &= bitmap - 1;
scan->u.bmu_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 blist_blkno_t
blst_meta_fill(
blmeta_t *scan,
blist_blkno_t allocBlk,
blist_blkno_t count,
blist_blkno_t radix,
blist_blkno_t skip,
blist_blkno_t blk
) {
blist_blkno_t i;
blist_blkno_t next_skip = (skip / BLIST_META_RADIX);
blist_blkno_t nblks = 0;
if (count == radix || scan->u.bmu_avail == 0) {
/*
* ALL-ALLOCATED special case
*/
nblks = scan->u.bmu_avail;
scan->u.bmu_avail = 0;
scan->bm_bighint = count;
return nblks;
}
if (count > radix)
panic("blist_meta_fill: allocation too large");
if (scan->u.bmu_avail == radix) {
radix /= BLIST_META_RADIX;
/*
* ALL-FREE special case, initialize sublevel
*/
for (i = 1; i <= skip; i += next_skip) {
if (scan[i].bm_bighint == (blist_blkno_t)-1)
break;
if (next_skip == 1) {
scan[i].u.bmu_bitmap = (blist_bitmap_t)-1;
scan[i].bm_bighint = BLIST_BMAP_RADIX;
} else {
scan[i].bm_bighint = radix;
scan[i].u.bmu_avail = radix;
}
}
} else {
radix /= BLIST_META_RADIX;
}
i = (allocBlk - blk) / radix;
blk += i * radix;
i = i * next_skip + 1;
while (i <= skip && blk < allocBlk + count) {
blist_blkno_t v;
v = blk + radix - allocBlk;
if (v > count)
v = count;
if (scan->bm_bighint == (blist_blkno_t)-1)
panic("blst_meta_fill: filling unexpected range");
if (next_skip == 1) {
nblks += blst_leaf_fill(&scan[i], allocBlk, v);
} else {
nblks += blst_meta_fill(&scan[i], allocBlk, v,
radix, next_skip - 1, blk);
}
count -= v;
allocBlk += v;
blk += radix;
i += next_skip;
}
scan->u.bmu_avail -= nblks;
return nblks;
}
/*
* BLST_RADIX_INIT() - initialize radix tree
*
* Initialize our meta structures and bitmaps and calculate the exact
* amount of space required to manage 'count' blocks - this space may
* be considerably less than the calculated radix due to the large
* RADIX values we use.
*/
static blist_blkno_t
blst_radix_init(blmeta_t *scan, blist_blkno_t radix, blist_blkno_t skip,
blist_blkno_t count)
{
blist_blkno_t i;
blist_blkno_t next_skip;
blist_blkno_t memindex = 0;
/*
* Leaf node
*/
if (radix == BLIST_BMAP_RADIX) {
if (scan) {
scan->bm_bighint = 0;
scan->u.bmu_bitmap = 0;
}
return(memindex);
}
/*
* Meta node. If allocating the entire object we can special
* case it. However, we need to figure out how much memory
* is required to manage 'count' blocks, so we continue on anyway.
*/
if (scan) {
scan->bm_bighint = 0;
scan->u.bmu_avail = 0;
}
radix /= BLIST_META_RADIX;
next_skip = (skip / BLIST_META_RADIX);
for (i = 1; i <= skip; i += next_skip) {
if (count >= radix) {
/*
* Allocate the entire object
*/
memindex = i + blst_radix_init(
((scan) ? &scan[i] : NULL),
radix,
next_skip - 1,
radix
);
count -= radix;
} else if (count > 0) {
/*
* Allocate a partial object
*/
memindex = i + blst_radix_init(
((scan) ? &scan[i] : NULL),
radix,
next_skip - 1,
count
);
count = 0;
} else {
/*
* Add terminator and break out
*/
if (scan)
scan[i].bm_bighint = (blist_blkno_t)-1;
break;
}
}
if (memindex < i)
memindex = i;
return(memindex);
}
#ifdef BLIST_DEBUG
static void
blst_radix_print(blmeta_t *scan, blist_blkno_t blk, blist_blkno_t radix,
blist_blkno_t skip, int tab)
{
blist_blkno_t i;
blist_blkno_t next_skip;
int lastState = 0;
if (radix == BLIST_BMAP_RADIX) {
printf(
"%*.*s(%0*" PRIx64 ",%" PRIu64
"): bitmap %0*" PRIx64 " big=%" PRIu64 "\n",
tab, tab, "",
sizeof(blk) * 2,
(uint64_t)blk,
(uint64_t)radix,
sizeof(scan->u.bmu_bitmap) * 2,
(uint64_t)scan->u.bmu_bitmap,
(uint64_t)scan->bm_bighint
);
return;
}
if (scan->u.bmu_avail == 0) {
printf(
"%*.*s(%0*" PRIx64 ",%" PRIu64") ALL ALLOCATED\n",
tab, tab, "",
sizeof(blk) * 2,
(uint64_t)blk,
(uint64_t)radix
);
return;
}
if (scan->u.bmu_avail == radix) {
printf(
"%*.*s(%0*" PRIx64 ",%" PRIu64 ") ALL FREE\n",
tab, tab, "",
sizeof(blk) * 2,
(uint64_t)blk,
(uint64_t)radix
);
return;
}
printf(
"%*.*s(%0*" PRIx64 ",%" PRIu64 "): subtree (%" PRIu64 "/%"
PRIu64 ") big=%" PRIu64 " {\n",
tab, tab, "",
sizeof(blk) * 2,
(uint64_t)blk,
(uint64_t)radix,
(uint64_t)scan->u.bmu_avail,
(uint64_t)radix,
(uint64_t)scan->bm_bighint
);
radix /= BLIST_META_RADIX;
next_skip = (skip / BLIST_META_RADIX);
tab += 4;
for (i = 1; i <= skip; i += next_skip) {
if (scan[i].bm_bighint == (blist_blkno_t)-1) {
printf(
"%*.*s(%0*" PRIx64 ",%" PRIu64 "): Terminator\n",
tab, tab, "",
sizeof(blk) * 2,
(uint64_t)blk,
(uint64_t)radix
);
lastState = 0;
break;
}
blst_radix_print(
&scan[i],
blk,
radix,
next_skip - 1,
tab
);
blk += radix;
}
tab -= 4;
printf(
"%*.*s}\n",
tab, tab, ""
);
}
#endif
#ifdef BLIST_DEBUG
int
main(int ac, char **av)
{
blist_blkno_t size = 1024;
int i;
blist_t bl;
for (i = 1; i < ac; ++i) {
const char *ptr = av[i];
if (*ptr != '-') {
size = strtol(ptr, NULL, 0);
continue;
}
ptr += 2;
fprintf(stderr, "Bad option: %s\n", ptr - 2);
exit(1);
}
bl = blist_create(size);
blist_free(bl, 0, size);
for (;;) {
char buf[1024];
uint64_t da = 0;
uint64_t count = 0;
printf("%" PRIu64 "/%" PRIu64 "/%" PRIu64 "> ",
(uint64_t)bl->bl_free,
(uint64_t)size,
(uint64_t)bl->bl_radix);
fflush(stdout);
if (fgets(buf, sizeof(buf), stdin) == NULL)
break;
switch(buf[0]) {
case 'r':
if (sscanf(buf + 1, "%" SCNu64, &count) == 1) {
blist_resize(&bl, count, 1);
} else {
printf("?\n");
}
case 'p':
blist_print(bl);
break;
case 'a':
if (sscanf(buf + 1, "%" SCNu64, &count) == 1) {
blist_blkno_t blk = blist_alloc(bl, count);
printf(" R=%0*" PRIx64 "\n",
sizeof(blk) * 2,
(uint64_t)blk);
} else {
printf("?\n");
}
break;
case 'f':
if (sscanf(buf + 1, "%" SCNx64 " %" SCNu64,
&da, &count) == 2) {
blist_free(bl, da, count);
} else {
printf("?\n");
}
break;
case 'l':
if (sscanf(buf + 1, "%" SCNx64 " %" SCNu64,
&da, &count) == 2) {
printf(" n=%" PRIu64 "\n",
(uint64_t)blist_fill(bl, da, count));
} else {
printf("?\n");
}
break;
case '?':
case 'h':
puts(
"p -print\n"
"a %d -allocate\n"
"f %x %d -free\n"
"l %x %d -fill\n"
"r %d -resize\n"
"h/? -help"
);
break;
default:
printf("?\n");
break;
}
}
return(0);
}
void
panic(const char *ctl, ...)
{
va_list va;
va_start(va, ctl);
vfprintf(stderr, ctl, va);
fprintf(stderr, "\n");
va_end(va);
exit(1);
}
#endif
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