Index: head/sys/kern/subr_blist.c =================================================================== --- head/sys/kern/subr_blist.c (revision 320526) +++ head/sys/kern/subr_blist.c (revision 320527) @@ -1,1111 +1,1129 @@ /*- * 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. * * 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. * * The blist code wires all necessary memory at creation time. Neither * allocations nor frees require interaction with the memory subsystem. * The non-blocking features of the blist code are used in the swap code * (vm/swap_pager.c). * * 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 __FBSDID("$FreeBSD$"); #ifdef _KERNEL #include #include #include #include #include #include #include #include #else #ifndef BLIST_NO_DEBUG #define BLIST_DEBUG #endif #include #include #include #include #include #include #include #define bitcount64(x) __bitcount64((uint64_t)(x)) #define malloc(a,b,c) calloc(a, 1) #define free(a,b) free(a) #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_leaf_alloc(blmeta_t *scan, daddr_t blk, int count, + daddr_t cursor); static daddr_t blst_meta_alloc(blmeta_t *scan, daddr_t blk, daddr_t count, daddr_t radix, daddr_t skip, daddr_t cursor); 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, daddr_t 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 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, daddr_t radix, daddr_t skip, daddr_t blk); static daddr_t blst_radix_init(blmeta_t *scan, daddr_t radix, daddr_t skip, daddr_t count); #ifndef _KERNEL static void blst_radix_print(blmeta_t *scan, daddr_t blk, daddr_t radix, daddr_t 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 than 0 * flags - malloc flags * * The smallest blist consists of a single leaf node capable of * managing BLIST_BMAP_RADIX blocks. */ blist_t blist_create(daddr_t blocks, int flags) { blist_t bl; daddr_t nodes, radix, skip; /* * Calculate radix and skip field used for scanning. */ radix = BLIST_BMAP_RADIX; skip = 0; while (radix < blocks) { radix *= BLIST_META_RADIX; skip = (skip + 1) * BLIST_META_RADIX; } nodes = 1 + blst_radix_init(NULL, radix, skip, blocks); bl = malloc(sizeof(struct blist), M_SWAP, flags); if (bl == NULL) return (NULL); bl->bl_blocks = blocks; bl->bl_radix = radix; bl->bl_skip = skip; bl->bl_cursor = 0; bl->bl_root = malloc(nodes * sizeof(blmeta_t), M_SWAP, flags); if (bl->bl_root == NULL) { free(bl, M_SWAP); return (NULL); } blst_radix_init(bl->bl_root, radix, skip, blocks); #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->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; /* * 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 * reduce the hint, stopping further iterations. */ while (count <= bl->bl_root->bm_bighint) { if (bl->bl_radix == BLIST_BMAP_RADIX) - blk = blst_leaf_alloc(bl->bl_root, 0, count); + blk = blst_leaf_alloc(bl->bl_root, 0, count, + bl->bl_cursor); else blk = blst_meta_alloc(bl->bl_root, 0, count, bl->bl_radix, bl->bl_skip, bl->bl_cursor); if (blk != SWAPBLK_NONE) { bl->bl_cursor = blk + count; return (blk); } else if (bl->bl_cursor != 0) bl->bl_cursor = 0; } return (SWAPBLK_NONE); } /* * blist_avail() - return the number of free blocks. */ daddr_t blist_avail(blist_t bl) { if (bl->bl_radix == BLIST_BMAP_RADIX) return (bitcount64(bl->bl_root->u.bmu_bitmap)); else return (bl->bl_root->u.bmu_avail); } /* * 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); } } /* * 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) { daddr_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); return (filled); } 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, 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, 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. + * This is the core of the allocator and is optimized for the + * BLIST_BMAP_RADIX block allocation case. Otherwise, execution + * time is proportional to log2(count) + log2(BLIST_BMAP_RADIX). */ static daddr_t -blst_leaf_alloc( - blmeta_t *scan, - daddr_t blk, - int count -) { - u_daddr_t orig = scan->u.bmu_bitmap; +blst_leaf_alloc(blmeta_t *scan, daddr_t blk, int count, daddr_t cursor) +{ + u_daddr_t mask; + int count1, hi, lo, mid, num_shifts, range1, range_ext; - if (orig == 0) { + if (count == BLIST_BMAP_RADIX) { /* - * 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. + * Optimize allocation of BLIST_BMAP_RADIX bits. If this wasn't + * a special case, then forming the final value of 'mask' below + * would require special handling to avoid an invalid left shift + * when count equals the number of bits in mask. */ + if (~scan->u.bmu_bitmap != 0) { + scan->bm_bighint = BLIST_BMAP_RADIX - 1; + return (SWAPBLK_NONE); + } + if (cursor != blk) + return (SWAPBLK_NONE); + scan->u.bmu_bitmap = 0; scan->bm_bighint = 0; - return(SWAPBLK_NONE); + return (blk); } - if (count == 1) { + range1 = 0; + count1 = count - 1; + num_shifts = fls(count1); + mask = scan->u.bmu_bitmap; + while (mask != 0 && num_shifts > 0) { /* - * Optimized code to allocate one bit out of the bitmap + * If bit i is set in mask, then bits in [i, i+range1] are set + * in scan->u.bmu_bitmap. The value of range1 is equal to + * count1 >> num_shifts. Grow range and reduce num_shifts to 0, + * while preserving these invariants. The updates to mask leave + * fewer bits set, but each bit that remains set represents a + * longer string of consecutive bits set in scan->u.bmu_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 &= ~((u_daddr_t)1 << r); - return(blk + r); + num_shifts--; + range_ext = range1 + ((count1 >> num_shifts) & 1); + mask &= mask >> range_ext; + range1 += range_ext; } - if (count <= BLIST_BMAP_RADIX) { + if (mask == 0) { /* - * 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. + * Update bighint. There is no allocation bigger than range1 + * available in this leaf. */ - int j; - int n = BLIST_BMAP_RADIX - count; - u_daddr_t mask; + scan->bm_bighint = range1; + return (SWAPBLK_NONE); + } - mask = (u_daddr_t)-1 >> n; + /* + * Discard any candidates that appear before the cursor. + */ + lo = cursor - blk; + mask &= ~(u_daddr_t)0 << lo; - for (j = 0; j <= n; ++j) { - if ((orig & mask) == mask) { - scan->u.bmu_bitmap &= ~mask; - return(blk + j); - } - mask = (mask << 1); - } + if (mask == 0) + return (SWAPBLK_NONE); + + /* + * The least significant set bit in mask marks the start of the first + * available range of sufficient size. Clear all the bits but that one, + * and then perform a binary search to find its position. + */ + mask &= -mask; + hi = BLIST_BMAP_RADIX - count1; + while (lo + 1 < hi) { + mid = (lo + hi) >> 1; + if ((mask >> mid) != 0) + lo = mid; + else + hi = mid; } + /* - * We couldn't allocate count in this subtree, update bighint. + * Set in mask exactly the bits being allocated, and clear them from + * the set of available bits. */ - scan->bm_bighint = count - 1; - return(SWAPBLK_NONE); + mask = (mask << count) - mask; + scan->u.bmu_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 blk, daddr_t count, daddr_t radix, daddr_t skip, daddr_t cursor) { daddr_t i, next_skip, r; int child; bool scan_from_start; if (scan->u.bmu_avail < count) { /* * The meta node's hint must be too large if the allocation * exceeds the number of free blocks. Reduce the hint, and * return failure. */ scan->bm_bighint = scan->u.bmu_avail; return (SWAPBLK_NONE); } next_skip = skip / BLIST_META_RADIX; /* * An ALL-FREE meta node requires special handling before allocating * any of its blocks. */ if (scan->u.bmu_avail == radix) { radix /= BLIST_META_RADIX; /* * Reinitialize each of the meta node's children. An ALL-FREE * meta node cannot have a terminator in any subtree. */ for (i = 1; i <= skip; i += next_skip) { if (next_skip == 1) scan[i].u.bmu_bitmap = (u_daddr_t)-1; else scan[i].u.bmu_avail = radix; scan[i].bm_bighint = radix; } } else { radix /= BLIST_META_RADIX; } if (count > radix) { /* * The allocation exceeds the number of blocks that are * managed by a subtree of this meta node. */ panic("allocation too large"); } scan_from_start = cursor == blk; child = (cursor - blk) / radix; blk += child * radix; for (i = 1 + child * next_skip; i <= skip; i += next_skip) { if (count <= scan[i].bm_bighint) { /* * The allocation might fit in the i'th subtree. */ if (next_skip == 1) { - r = blst_leaf_alloc(&scan[i], blk, count); + r = blst_leaf_alloc(&scan[i], blk, count, + cursor > blk ? cursor : blk); } else { r = blst_meta_alloc(&scan[i], blk, count, radix, next_skip - 1, cursor > blk ? cursor : blk); } if (r != SWAPBLK_NONE) { scan->u.bmu_avail -= count; return (r); } } else if (scan[i].bm_bighint == (daddr_t)-1) { /* * Terminator */ break; } blk += radix; } /* * We couldn't allocate count in this subtree, update bighint. */ if (scan_from_start && 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, daddr_t skip, daddr_t blk) { daddr_t i, next_skip, v; int child; #if 0 printf("free (%llx,%lld) FROM (%llx,%lld)\n", (long long)freeBlk, (long long)count, (long long)blk, (long long)radix ); #endif next_skip = skip / BLIST_META_RADIX; 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; child = (freeBlk - blk) / radix; blk += child * radix; i = 1 + child * next_skip; while (i <= skip && blk < freeBlk + count) { 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 ) { daddr_t i, next_skip; /* * 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 & ((u_daddr_t)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 = 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 daddr_t blst_leaf_fill(blmeta_t *scan, daddr_t blk, int count) { int n = blk & (BLIST_BMAP_RADIX - 1); daddr_t nblks; u_daddr_t mask; mask = ((u_daddr_t)-1 << n) & ((u_daddr_t)-1 >> (BLIST_BMAP_RADIX - count - n)); /* Count the number of blocks that we are allocating. */ nblks = bitcount64(scan->u.bmu_bitmap & mask); 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 daddr_t blst_meta_fill(blmeta_t *scan, daddr_t allocBlk, daddr_t count, daddr_t radix, daddr_t skip, daddr_t blk) { daddr_t i, nblks, next_skip, v; int child; if (count > radix) { /* * The allocation exceeds the number of blocks that are * managed by this meta node. */ panic("allocation too large"); } 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 = 0; return nblks; } next_skip = skip / BLIST_META_RADIX; /* * An ALL-FREE meta node requires special handling before allocating * any of its blocks. */ if (scan->u.bmu_avail == radix) { radix /= BLIST_META_RADIX; /* * Reinitialize each of the meta node's children. An ALL-FREE * meta node cannot have a terminator in any subtree. */ for (i = 1; i <= skip; i += next_skip) { 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; } nblks = 0; child = (allocBlk - blk) / radix; blk += child * radix; i = 1 + child * next_skip; while (i <= skip && blk < allocBlk + count) { 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 than the calculated radix due to the large * RADIX values we use. */ static daddr_t blst_radix_init(blmeta_t *scan, daddr_t radix, daddr_t skip, daddr_t count) { daddr_t i, memindex, next_skip; 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 = (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, daddr_t skip, int tab) { daddr_t i, next_skip; if (radix == BLIST_BMAP_RADIX) { printf( "%*.*s(%08llx,%lld): bitmap %016llx 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 = 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 ); 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, M_WAITOK); blist_free(bl, 0, size); for (;;) { char buf[1024]; long long da = 0; long long count = 0; printf("%lld/%lld/%lld> ", (long long)blist_avail(bl), (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, M_WAITOK); } 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", &da, &count) == 2) { blist_free(bl, da, count); } else { printf("?\n"); } break; case 'l': if (sscanf(buf + 1, "%llx %lld", &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" "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