dcadb2ba8d
* Imported radix bitmap tree implementation from FreeBSD and adjusted it for Haiku. * Make use of the radix tree in the swap support implementation instead of using simple bitmaps. This will allow for faster swap slot allocations. ATM Haiku doesn't benefit that much, since we always allocate single pages, but that will change eventually. git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27355 a95241bf-73f2-0310-859d-f6bbb57e9c96
77 lines
2.8 KiB
C
77 lines
2.8 KiB
C
/*-
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* Copyright (c) 1998 Matthew Dillon. All Rights Reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* The radix bitmap structure is ported from FreeBSD and is only used
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* in swap system at the time.
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*/
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#ifndef _KERNEL_UTIL_RADIX_BITMAP_H
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#define _KERNEL_UTIL_RADIX_BITMAP_H
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#include <SupportDefs.h>
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typedef uint32 swap_addr_t;
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typedef uint32 bitmap_t;
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typedef struct radix_node {
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union {
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bitmap_t bitmap; // bitmap for the slots if we are a leaf
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int32 available; // available slots under us if we are not a leaf
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} u;
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int32 big_hint; // the biggest continuous slots under us
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} radix_node;
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// Bitmap which uses radix tree for hinting.
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// The radix tree is stored in an array.
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typedef struct radix_bitmap {
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swap_addr_t free_slots; // # of free slots
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swap_addr_t radix; // coverage radix
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swap_addr_t skip; // starting skip
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radix_node *root; // root of radix tree, actually it is an array
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swap_addr_t root_size; // size of the array(# of nodes in the tree)
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} radix_bitmap;
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#define BITMAP_RADIX (sizeof(swap_addr_t) * 8)
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#define NODE_RADIX 16
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#define SWAP_SLOT_NONE ((swap_addr_t)-1)
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extern radix_bitmap *radix_bitmap_create(uint32 slots);
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extern swap_addr_t radix_bitmap_alloc(radix_bitmap *bmp, uint32 count);
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extern void radix_bitmap_dealloc(radix_bitmap *bmp, swap_addr_t slotIndex,
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uint32 count);
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extern void radix_bitmap_destroy(radix_bitmap *bmp);
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#endif // _KERNEL_UTIL_RADIX_BITMAP_H
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