WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/mm/buddy.c


/*
 * Copyright (C) 2005 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not 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.
 */
 
#include <mm/buddy.h>
#include <mm/frame.h>
#include <mm/heap.h>
#include <arch/types.h>
#include <typedefs.h>
#include <list.h>
#include <debug.h>
 
/** Create buddy system
 *
 * Allocate memory for and initialize new buddy system.
 *
 * @param max_order The biggest allocable size will be 2^max_order.
 * @param op Operations for new buddy system.
 * @param data Pointer to be used by implementation.
 *
 * @return New buddy system.
 */
buddy_system_t *buddy_system_create(__u8 max_order, buddy_system_operations_t *op, void *data)
{
    buddy_system_t *b;
    int i;
 
    ASSERT(max_order < BUDDY_SYSTEM_INNER_BLOCK);
 
    ASSERT(op->find_buddy);
    ASSERT(op->set_order);
    ASSERT(op->get_order);
    ASSERT(op->bisect);
    ASSERT(op->coalesce);
 
    /*
     * Allocate memory for structure describing the whole buddy system.
     */
    b = (buddy_system_t *) early_malloc(sizeof(buddy_system_t));
   
    if (b) {
        /*
         * Allocate memory for all orders this buddy system will work with.
         */
        b->order = (link_t *) early_malloc(max_order * sizeof(link_t));
        if (!b->order) {
            early_free(b);
            return NULL;
        }
   
        for (i = 0; i < max_order; i++)
            list_initialize(&b->order[i]);
   
        b->max_order = max_order;
        b->op = op;
        b->data = data;
    }
   
    return b;
}
 
/** Allocate block from buddy system.
 *
 * @param b Buddy system pointer.
 * @param i Returned block will be 2^i big.
 *
 * @return Block of data represented by link_t.
 */
link_t *buddy_system_alloc(buddy_system_t *b, __u8 i)
{
    link_t *res, *hlp;
 
    ASSERT(i < b->max_order);
 
    /*
     * If the list of order i is not empty,
     * the request can be immediatelly satisfied.
     */
    if (!list_empty(&b->order[i])) {
        res = b->order[i].next;
        list_remove(res);
        return res;
    }
   
    /*
     * If order i is already the maximal order,
     * the request cannot be satisfied.
     */
    if (i == b->max_order - 1)
        return NULL;
 
    /*
     * Try to recursively satisfy the request from higher order lists.
     */
    hlp = buddy_system_alloc(b, i + 1);
   
    /*
     * The request could not be satisfied
     * from higher order lists.
     */
    if (!hlp)
        return NULL;
       
    res = hlp;
   
    /*
     * Bisect the block and set order of both of its parts to i.
     */
    hlp = b->op->bisect(b, res);
    b->op->set_order(b, res, i);
    b->op->set_order(b, hlp, i);
   
    /*
     * Return the other half to buddy system.
     */
    buddy_system_free(b, hlp);
   
    return res;
   
}
 
/** Return block to buddy system.
 *
 * @param b Buddy system pointer.
 * @param block Block to return.
 */
void buddy_system_free(buddy_system_t *b, link_t *block)
{
    link_t *buddy, *hlp;
    __u8 i;
   
    /*
     * Determine block's order.
     */
    i = b->op->get_order(b, block);
 
    ASSERT(i < b->max_order);
 
    if (i != b->max_order - 1) {
        /*
         * See if there is any buddy in the list of order i.
         */
        buddy = b->op->find_buddy(b, block);
        if (buddy) {
 
            ASSERT(b->op->get_order(b, buddy) == i);
       
            /*
             * Remove buddy from the list of order i.
             */
            list_remove(buddy);
       
            /*
             * Invalidate order of both block and buddy.
             */
            b->op->set_order(b, block, BUDDY_SYSTEM_INNER_BLOCK);
            b->op->set_order(b, buddy, BUDDY_SYSTEM_INNER_BLOCK);
       
            /*
             * Coalesce block and buddy into one block.
             */
            hlp = b->op->coalesce(b, block, buddy);
 
            /*
             * Set order of the coalesced block to i + 1.
             */
            b->op->set_order(b, hlp, i + 1);
 
            /*
             * Recursively add the coalesced block to the list of order i + 1.
             */
            buddy_system_free(b, hlp);
            return;
        }
    }
 
    /*
     * Insert block into the list of order i.
     */
    list_append(block, &b->order[i]);
 
}
 

Rev 490	Rev 501
1	/*	1	/*
2	* Copyright (C) 2005 Jakub Jermar	2	* Copyright (C) 2005 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	#include <mm/buddy.h>	29	#include <mm/buddy.h>
30	#include <mm/frame.h>	30	#include <mm/frame.h>
31	#include <mm/heap.h>	31	#include <mm/heap.h>
32	#include <arch/types.h>	32	#include <arch/types.h>
33	#include <typedefs.h>	33	#include <typedefs.h>
34	#include <list.h>	34	#include <list.h>
35	#include <debug.h>	35	#include <debug.h>
36		36
37	/** Create buddy system	37	/** Create buddy system
38	*	38	*
39	* Allocate memory for and initialize new buddy system.	39	* Allocate memory for and initialize new buddy system.
40	*	40	*
41	* @param max_order The biggest allocable size will be 2^max_order.	41	* @param max_order The biggest allocable size will be 2^max_order.
42	* @param op Operations for new buddy system.	42	* @param op Operations for new buddy system.
43	* @param data Pointer to be used by implementation.	43	* @param data Pointer to be used by implementation.
44	*	44	*
45	* @return New buddy system.	45	* @return New buddy system.
46	*/	46	*/
47	buddy_system_t buddy_system_create(__u8 max_order, buddy_system_operations_t op, void *data)	47	buddy_system_t buddy_system_create(__u8 max_order, buddy_system_operations_t op, void *data)
48	{	48	{
49	buddy_system_t *b;	49	buddy_system_t *b;
50	int i;	50	int i;
51		51
52	ASSERT(max_order < BUDDY_SYSTEM_INNER_BLOCK);	52	ASSERT(max_order < BUDDY_SYSTEM_INNER_BLOCK);
53		53
54	ASSERT(op->find_buddy);	54	ASSERT(op->find_buddy);
55	ASSERT(op->set_order);	55	ASSERT(op->set_order);
56	ASSERT(op->get_order);	56	ASSERT(op->get_order);
57	ASSERT(op->bisect);	57	ASSERT(op->bisect);
58	ASSERT(op->coalesce);	58	ASSERT(op->coalesce);
59		59
60	/*	60	/*
61	* Allocate memory for structure describing the whole buddy system.	61	* Allocate memory for structure describing the whole buddy system.
62	*/	62	*/
63	b = (buddy_system_t *) early_malloc(sizeof(buddy_system_t));	63	b = (buddy_system_t *) early_malloc(sizeof(buddy_system_t));
64		64
65	if (b) {	65	if (b) {
66	/*	66	/*
67	* Allocate memory for all orders this buddy system will work with.	67	* Allocate memory for all orders this buddy system will work with.
68	*/	68	*/
69	b->order = (link_t ) early_malloc(max_order sizeof(link_t));	69	b->order = (link_t ) early_malloc(max_order sizeof(link_t));
70	if (!b->order) {	70	if (!b->order) {
71	early_free(b);	71	early_free(b);
72	return NULL;	72	return NULL;
73	}	73	}
74		74
75	for (i = 0; i < max_order; i++)	75	for (i = 0; i < max_order; i++)
76	list_initialize(&b->order[i]);	76	list_initialize(&b->order[i]);
77		77
78	b->max_order = max_order;	78	b->max_order = max_order;
79	b->op = op;	79	b->op = op;
80	b->data = data;	80	b->data = data;
81	}	81	}
82		82
83	return b;	83	return b;
84	}	84	}
85		85
86	/** Allocate block from buddy system.	86	/** Allocate block from buddy system.
87	*	87	*
88	* @param b Buddy system pointer.	88	* @param b Buddy system pointer.
89	* @param i Returned block will be 2^i big.	89	* @param i Returned block will be 2^i big.
90	*	90	*
91	* @return Block of data represented by link_t.	91	* @return Block of data represented by link_t.
92	*/	92	*/
93	link_t buddy_system_alloc(buddy_system_t b, __u8 i)	93	link_t buddy_system_alloc(buddy_system_t b, __u8 i)
94	{	94	{
95	link_t res, hlp;	95	link_t res, hlp;
96		96
97	ASSERT(i < b->max_order);	97	ASSERT(i < b->max_order);
98		98
99	/*	99	/*
100	* If the list of order i is not empty,	100	* If the list of order i is not empty,
101	* the request can be immediatelly satisfied.	101	* the request can be immediatelly satisfied.
102	*/	102	*/
103	if (!list_empty(&b->order[i])) {	103	if (!list_empty(&b->order[i])) {
104	res = b->order[i].next;	104	res = b->order[i].next;
105	list_remove(res);	105	list_remove(res);
106	return res;	106	return res;
107	}	107	}
108		108
109	/*	109	/*
110	* If order i is already the maximal order,	110	* If order i is already the maximal order,
111	* the request cannot be satisfied.	111	* the request cannot be satisfied.
112	*/	112	*/
113	if (i == b->max_order - 1)	113	if (i == b->max_order - 1)
114	return NULL;	114	return NULL;
115		115
116	/*	116	/*
117	* Try to recursively satisfy the request from higher order lists.	117	* Try to recursively satisfy the request from higher order lists.
118	*/	118	*/
119	hlp = buddy_system_alloc(b, i + 1);	119	hlp = buddy_system_alloc(b, i + 1);
120		120
121	/*	121	/*
122	* The request could not be satisfied	122	* The request could not be satisfied
123	* from higher order lists.	123	* from higher order lists.
124	*/	124	*/
125	if (!hlp)	125	if (!hlp)
126	return NULL;	126	return NULL;
127		127
128	res = hlp;	128	res = hlp;
129		129
130	/*	130	/*
131	* Bisect the block and set order of both of its parts to i.	131	* Bisect the block and set order of both of its parts to i.
132	*/	132	*/
133	hlp = b->op->bisect(b, res);	133	hlp = b->op->bisect(b, res);
134	b->op->set_order(b, res, i);	134	b->op->set_order(b, res, i);
135	b->op->set_order(b, hlp, i);	135	b->op->set_order(b, hlp, i);
136		136
137	/*	137	/*
138	* Return the other half to buddy system.	138	* Return the other half to buddy system.
139	*/	139	*/
140	buddy_system_free(b, hlp);	140	buddy_system_free(b, hlp);
141		141
142	return res;	142	return res;
143		143
144	}	144	}
145		145
146	/** Return block to buddy system.	146	/** Return block to buddy system.
147	*	147	*
148	* @param b Buddy system pointer.	148	* @param b Buddy system pointer.
149	* @param block Block to return.	149	* @param block Block to return.
150	*/	150	*/
151	void buddy_system_free(buddy_system_t b, link_t block)	151	void buddy_system_free(buddy_system_t b, link_t block)
152	{	152	{
153	link_t buddy, hlp;	153	link_t buddy, hlp;
154	__u8 i;	154	__u8 i;
155		155
156	/*	156	/*
157	* Determine block's order.	157	* Determine block's order.
158	*/	158	*/
159	i = b->op->get_order(b, block);	159	i = b->op->get_order(b, block);
160		160
161	ASSERT(i < b->max_order);	161	ASSERT(i < b->max_order);
162		162
163	if (i != b->max_order - 1) {	163	if (i != b->max_order - 1) {
164	/*	164	/*
165	* See if there is any buddy in the list of order i.	165	* See if there is any buddy in the list of order i.
166	*/	166	*/
167	buddy = b->op->find_buddy(b, block);	167	buddy = b->op->find_buddy(b, block);
168	if (buddy) {	168	if (buddy) {
169		169
170	ASSERT(b->op->get_order(b, buddy) == i);	170	ASSERT(b->op->get_order(b, buddy) == i);
171		171
172	/*	172	/*
173	* Remove buddy from the list of order i.	173	* Remove buddy from the list of order i.
174	*/	174	*/
175	list_remove(buddy);	175	list_remove(buddy);
176		176
177	/*	177	/*
178	* Invalidate order of both block and buddy.	178	* Invalidate order of both block and buddy.
179	*/	179	*/
180	b->op->set_order(b, block, BUDDY_SYSTEM_INNER_BLOCK);	180	b->op->set_order(b, block, BUDDY_SYSTEM_INNER_BLOCK);
181	b->op->set_order(b, buddy, BUDDY_SYSTEM_INNER_BLOCK);	181	b->op->set_order(b, buddy, BUDDY_SYSTEM_INNER_BLOCK);
182		182
183	/*	183	/*
184	* Coalesce block and buddy into one block.	184	* Coalesce block and buddy into one block.
185	*/	185	*/
186	hlp = b->op->coalesce(b, block, buddy);	186	hlp = b->op->coalesce(b, block, buddy);
187		187
188	/*	188	/*
189	* Set order of the coalesced block to i + 1.	189	* Set order of the coalesced block to i + 1.
190	*/	190	*/
191	b->op->set_order(b, hlp, i + 1);	191	b->op->set_order(b, hlp, i + 1);
192		192
193	/*	193	/*
194	* Recursively add the coalesced block to the list of order i + 1.	194	* Recursively add the coalesced block to the list of order i + 1.
195	*/	195	*/
196	buddy_system_free(b, hlp);	196	buddy_system_free(b, hlp);
197	return;	197	return;
198	}	198	}
199	}	199	}
200		200
201	/*	201	/*
202	* Insert block into the list of order i.	202	* Insert block into the list of order i.
203	*/	203	*/
204	list_append(block, &b->order[i]);	204	list_append(block, &b->order[i]);
205		205
206	}	206	}
207		207

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/mm/buddy.c @ 1239 – Rev 490 → 501