diff --git a/sys/kern/subr_blist.c b/sys/kern/subr_blist.c new file mode 100644 index 000000000000..91047fd1a177 --- /dev/null +++ b/sys/kern/subr_blist.c @@ -0,0 +1,1098 @@ +/*- + * 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 then to return + * SWAPBLK_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 then 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 layed out recursively using a + * linear array. Each meta node is immediately followed (layed 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 then + * 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 +__FBSDID("$FreeBSD: src/sys/kern/subr_blist.c,v 1.17 2004/06/04 04:03:25 alc Exp $"); + +#ifdef _KERNEL + +#include +#include +#include +#include +#include +#include +#include +#include + +#else + +#ifndef BLIST_NO_DEBUG +#define BLIST_DEBUG +#endif + +#define SWAPBLK_NONE ((daddr_t)-1) + +#include +#include +#include +#include +#include + +#define malloc(a,b,c) calloc(a, 1) +#define free(a,b) free(a) + +typedef unsigned int u_daddr_t; + +#include + +void panic(const char *ctl, ...); + +#endif + +/* + * static support functions + */ + +static daddr_t blst_leaf_alloc(blmeta_t *scan, daddr_t blk, int count); +static daddr_t blst_meta_alloc(blmeta_t *scan, daddr_t blk, + daddr_t count, daddr_t radix, int skip); +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, + daddr_t radix, int skip, daddr_t blk); +static void blst_copy(blmeta_t *scan, daddr_t blk, daddr_t radix, + daddr_t skip, blist_t dest, daddr_t count); +static int blst_leaf_fill(blmeta_t *scan, daddr_t blk, int count); +static int blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr_t count, + daddr_t radix, int skip, daddr_t blk); +static daddr_t blst_radix_init(blmeta_t *scan, daddr_t radix, + int skip, daddr_t count); +#ifndef _KERNEL +static void blst_radix_print(blmeta_t *scan, daddr_t blk, + daddr_t radix, int skip, int tab); +#endif + +#ifdef _KERNEL +static MALLOC_DEFINE(M_SWAP, "SWAP", "Swap space"); +#endif + +/* + * blist_create() - create a blist capable of handling up to the specified + * number of blocks + * + * blocks must be greater then 0 + * + * The smallest blist consists of a single leaf node capable of + * managing BLIST_BMAP_RADIX blocks. + */ + +blist_t +blist_create(daddr_t blocks) +{ + blist_t bl; + int radix; + int skip = 0; + + /* + * Calculate radix and skip field used for scanning. + */ + radix = BLIST_BMAP_RADIX; + + while (radix < blocks) { + radix *= BLIST_META_RADIX; + skip = (skip + 1) * BLIST_META_RADIX; + } + + bl = malloc(sizeof(struct blist), M_SWAP, M_WAITOK | M_ZERO); + + 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 = malloc(sizeof(blmeta_t) * bl->bl_rootblks, M_SWAP, M_WAITOK); + +#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)(bl->bl_rootblks * sizeof(blmeta_t) + 1023) / 1024 + ); + printf("BLIST raw radix tree contains %lld records\n", + (long long)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) +{ + free(bl->bl_root, M_SWAP); + 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, daddr_t count) +{ + daddr_t blk = SWAPBLK_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 != SWAPBLK_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 inconsistancy is + * found. + */ + +void +blist_free(blist_t bl, daddr_t blkno, daddr_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. + */ + +int +blist_fill(blist_t bl, daddr_t blkno, daddr_t count) +{ + int 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, daddr_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 daddr_t +blst_leaf_alloc( + blmeta_t *scan, + daddr_t blk, + int count +) { + u_daddr_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(SWAPBLK_NONE); + } + if (count == 1) { + /* + * Optimized code to allocate one bit out of the bitmap + */ + u_daddr_t mask; + int j = BLIST_BMAP_RADIX/2; + int r = 0; + + mask = (u_daddr_t)-1 >> (BLIST_BMAP_RADIX/2); + + while (j) { + if ((orig & mask) == 0) { + r += j; + orig >>= j; + } + j >>= 1; + mask >>= j; + } + scan->u.bmu_bitmap &= ~(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; + u_daddr_t mask; + + mask = (u_daddr_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(SWAPBLK_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 daddr_t +blst_meta_alloc( + blmeta_t *scan, + daddr_t blk, + daddr_t count, + daddr_t radix, + int skip +) { + int i; + int next_skip = ((u_int)skip / BLIST_META_RADIX); + + if (scan->u.bmu_avail == 0) { + /* + * ALL-ALLOCATED special case + */ + scan->bm_bighint = count; + return(SWAPBLK_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 == (daddr_t)-1) + break; + if (next_skip == 1) { + scan[i].u.bmu_bitmap = (u_daddr_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 (count <= scan[i].bm_bighint) { + /* + * count fits in object + */ + daddr_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 != SWAPBLK_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 (scan[i].bm_bighint == (daddr_t)-1) { + /* + * Terminator + */ + break; + } 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(SWAPBLK_NONE); +} + +/* + * BLST_LEAF_FREE() - free allocated block from leaf bitmap + * + */ + +static void +blst_leaf_free( + blmeta_t *scan, + daddr_t blk, + int count +) { + /* + * free some data in this bitmap + * + * e.g. + * 0000111111111110000 + * \_________/\__/ + * v n + */ + int n = blk & (BLIST_BMAP_RADIX - 1); + u_daddr_t mask; + + mask = ((u_daddr_t)-1 << n) & + ((u_daddr_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, + daddr_t freeBlk, + daddr_t count, + daddr_t radix, + int skip, + daddr_t blk +) { + int i; + int next_skip = ((u_int)skip / BLIST_META_RADIX); + +#if 0 + printf("FREE (%llx,%lld) FROM (%llx,%lld)\n", + (long long)freeBlk, (long long)count, + (long long)blk, (long long)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 == (daddr_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 (%lld) %lld/%lld", + (long long)count, (long long)scan->u.bmu_avail, + (long long)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) { + daddr_t v; + + v = blk + radix - freeBlk; + if (v > count) + v = count; + + if (scan->bm_bighint == (daddr_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, + daddr_t blk, + daddr_t radix, + daddr_t skip, + blist_t dest, + daddr_t count +) { + int next_skip; + int i; + + /* + * Leaf node + */ + + if (radix == BLIST_BMAP_RADIX) { + u_daddr_t v = scan->u.bmu_bitmap; + + if (v == (u_daddr_t)-1) { + blist_free(dest, blk, count); + } else if (v != 0) { + int i; + + for (i = 0; i < BLIST_BMAP_RADIX && i < count; ++i) { + if (v & (1 << i)) + blist_free(dest, blk + i, 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 = ((u_int)skip / BLIST_META_RADIX); + + for (i = 1; count && i <= skip; i += next_skip) { + if (scan[i].bm_bighint == (daddr_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, daddr_t blk, int count) +{ + int n = blk & (BLIST_BMAP_RADIX - 1); + int nblks; + u_daddr_t mask, bitmap; + + mask = ((u_daddr_t)-1 << n) & + ((u_daddr_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 int +blst_meta_fill( + blmeta_t *scan, + daddr_t allocBlk, + daddr_t count, + daddr_t radix, + int skip, + daddr_t blk +) { + int i; + int next_skip = ((u_int)skip / BLIST_META_RADIX); + int 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 (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 == (daddr_t)-1) + break; + if (next_skip == 1) { + scan[i].u.bmu_bitmap = (u_daddr_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; + } + + if (count > radix) + panic("blist_meta_fill: allocation too large"); + + i = (allocBlk - blk) / radix; + blk += i * radix; + i = i * next_skip + 1; + + while (i <= skip && blk < allocBlk + count) { + daddr_t v; + + v = blk + radix - allocBlk; + if (v > count) + v = count; + + if (scan->bm_bighint == (daddr_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 then the calculated radix due to the large + * RADIX values we use. + */ + +static daddr_t +blst_radix_init(blmeta_t *scan, daddr_t radix, int skip, daddr_t count) +{ + int i; + int next_skip; + daddr_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 = ((u_int)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 = (daddr_t)-1; + break; + } + } + if (memindex < i) + memindex = i; + return(memindex); +} + +#ifdef BLIST_DEBUG + +static void +blst_radix_print(blmeta_t *scan, daddr_t blk, daddr_t radix, int skip, int tab) +{ + int i; + int next_skip; + int lastState = 0; + + if (radix == BLIST_BMAP_RADIX) { + printf( + "%*.*s(%08llx,%lld): bitmap %08llx big=%lld\n", + tab, tab, "", + (long long)blk, (long long)radix, + (long long)scan->u.bmu_bitmap, + (long long)scan->bm_bighint + ); + return; + } + + if (scan->u.bmu_avail == 0) { + printf( + "%*.*s(%08llx,%lld) ALL ALLOCATED\n", + tab, tab, "", + (long long)blk, + (long long)radix + ); + return; + } + if (scan->u.bmu_avail == radix) { + printf( + "%*.*s(%08llx,%lld) ALL FREE\n", + tab, tab, "", + (long long)blk, + (long long)radix + ); + return; + } + + printf( + "%*.*s(%08llx,%lld): subtree (%lld/%lld) big=%lld {\n", + tab, tab, "", + (long long)blk, (long long)radix, + (long long)scan->u.bmu_avail, + (long long)radix, + (long long)scan->bm_bighint + ); + + radix /= BLIST_META_RADIX; + next_skip = ((u_int)skip / BLIST_META_RADIX); + tab += 4; + + for (i = 1; i <= skip; i += next_skip) { + if (scan[i].bm_bighint == (daddr_t)-1) { + printf( + "%*.*s(%08llx,%lld): Terminator\n", + tab, tab, "", + (long long)blk, (long long)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) +{ + int 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]; + daddr_t da = 0; + daddr_t count = 0; + + + printf("%lld/%lld/%lld> ", (long long)bl->bl_free, + (long long)size, (long long)bl->bl_radix); + fflush(stdout); + if (fgets(buf, sizeof(buf), stdin) == NULL) + break; + switch(buf[0]) { + case 'r': + if (sscanf(buf + 1, "%lld", &count) == 1) { + blist_resize(&bl, count, 1); + } else { + printf("?\n"); + } + case 'p': + blist_print(bl); + break; + case 'a': + if (sscanf(buf + 1, "%lld", &count) == 1) { + daddr_t blk = blist_alloc(bl, count); + printf(" R=%08llx\n", (long long)blk); + } else { + printf("?\n"); + } + break; + case 'f': + if (sscanf(buf + 1, "%llx %lld", + (long long *)&da, (long long *)&count) == 2) { + blist_free(bl, da, count); + } else { + printf("?\n"); + } + break; + case 'l': + if (sscanf(buf + 1, "%llx %lld", + (long long *)&da, (long long *)&count) == 2) { + printf(" n=%d\n", + 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 + diff --git a/sys/sys/blist.h b/sys/sys/blist.h new file mode 100644 index 000000000000..132ec236e640 --- /dev/null +++ b/sys/sys/blist.h @@ -0,0 +1,103 @@ +/*- + * 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. + */ + +/* + * Implements bitmap resource lists. + * + * Usage: + * blist = blist_create(blocks) + * (void) blist_destroy(blist) + * blkno = blist_alloc(blist, count) + * (void) blist_free(blist, blkno, count) + * nblks = blist_fill(blist, blkno, count) + * (void) blist_resize(&blist, count, freeextra) + * + * + * Notes: + * on creation, the entire list is marked reserved. You should + * first blist_free() the sections you want to make available + * for allocation before doing general blist_alloc()/free() + * ops. + * + * SWAPBLK_NONE is returned on failure. This module is typically + * capable of managing up to (2^31) blocks per blist, though + * the memory utilization would be insane if you actually did + * that. Managing something like 512MB worth of 4K blocks + * eats around 32 KBytes of memory. + * + * $FreeBSD: src/sys/sys/blist.h,v 1.9 2005/01/07 02:29:23 imp Exp $ + */ + +#ifndef _SYS_BLIST_H_ +#define _SYS_BLIST_H_ + +typedef u_int32_t u_daddr_t; /* unsigned disk address */ + +/* + * note: currently use SWAPBLK_NONE as an absolute value rather then + * a flag bit. + */ + +#define SWAPBLK_MASK ((daddr_t)((u_daddr_t)-1 >> 1)) /* mask */ +#define SWAPBLK_NONE ((daddr_t)((u_daddr_t)SWAPBLK_MASK + 1))/* flag */ + +/* + * blmeta and bl_bitmap_t MUST be a power of 2 in size. + */ + +typedef struct blmeta { + union { + daddr_t bmu_avail; /* space available under us */ + u_daddr_t bmu_bitmap; /* bitmap if we are a leaf */ + } u; + daddr_t bm_bighint; /* biggest contiguous block hint*/ +} blmeta_t; + +typedef struct blist { + daddr_t bl_blocks; /* area of coverage */ + daddr_t bl_radix; /* coverage radix */ + daddr_t bl_skip; /* starting skip */ + daddr_t bl_free; /* number of free blocks */ + blmeta_t *bl_root; /* root of radix tree */ + daddr_t bl_rootblks; /* daddr_t blks allocated for tree */ +} *blist_t; + +#define BLIST_META_RADIX 16 +#define BLIST_BMAP_RADIX (sizeof(u_daddr_t)*8) + +#define BLIST_MAX_ALLOC BLIST_BMAP_RADIX + +extern blist_t blist_create(daddr_t blocks); +extern void blist_destroy(blist_t blist); +extern daddr_t blist_alloc(blist_t blist, daddr_t count); +extern void blist_free(blist_t blist, daddr_t blkno, daddr_t count); +extern int blist_fill(blist_t bl, daddr_t blkno, daddr_t count); +extern void blist_print(blist_t blist); +extern void blist_resize(blist_t *pblist, daddr_t count, int freenew); + +#endif /* _SYS_BLIST_H_ */ +