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 implentation.
 *
 * @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.
 *
 * 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.
 *
 * 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 430	Rev 489
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 implentation.
43	*	44	*
44	* @return New buddy system.	45	* @return New buddy system.
45	*/	46	*/
46	buddy_system_t buddy_system_create(__u8 max_order, buddy_system_operations_t op)	47	buddy_system_t buddy_system_create(__u8 max_order, buddy_system_operations_t op, void *data)
47	{	48	{
48	buddy_system_t *b;	49	buddy_system_t *b;
49	int i;	50	int i;
50		51
51	ASSERT(max_order < BUDDY_SYSTEM_INNER_BLOCK);	52	ASSERT(max_order < BUDDY_SYSTEM_INNER_BLOCK);
52		53
53	ASSERT(op->find_buddy);	54	ASSERT(op->find_buddy);
54	ASSERT(op->set_order);	55	ASSERT(op->set_order);
55	ASSERT(op->get_order);	56	ASSERT(op->get_order);
56	ASSERT(op->bisect);	57	ASSERT(op->bisect);
57	ASSERT(op->coalesce);	58	ASSERT(op->coalesce);
58		59
59	/*	60	/*
60	* Allocate memory for structure describing the whole buddy system.	61	* Allocate memory for structure describing the whole buddy system.
61	*/	62	*/
62	b = (buddy_system_t *) early_malloc(sizeof(buddy_system_t));	63	b = (buddy_system_t *) early_malloc(sizeof(buddy_system_t));
63		64
64	if (b) {	65	if (b) {
65	/*	66	/*
66	* Allocate memory for all orders this buddy system will work with.	67	* Allocate memory for all orders this buddy system will work with.
67	*/	68	*/
68	b->order = (link_t ) early_malloc(max_order sizeof(link_t));	69	b->order = (link_t ) early_malloc(max_order sizeof(link_t));
69	if (!b->order) {	70	if (!b->order) {
70	early_free(b);	71	early_free(b);
71	return NULL;	72	return NULL;
72	}	73	}
73		74
74	for (i = 0; i < max_order; i++)	75	for (i = 0; i < max_order; i++)
75	list_initialize(&b->order[i]);	76	list_initialize(&b->order[i]);
76		77
77	b->max_order = max_order;	78	b->max_order = max_order;
78	b->op = op;	79	b->op = op;
-		80	b->data = data;
79	}	81	}
80		82
81	return b;	83	return b;
82	}	84	}
83		85
84	/** Allocate block from buddy system.	86	/** Allocate block from buddy system.
85	*	87	*
86	* Allocate block from buddy system.	88	* Allocate block from buddy system.
87	*	89	*
88	* @param b Buddy system pointer.	90	* @param b Buddy system pointer.
89	* @param i Returned block will be 2^i big.	91	* @param i Returned block will be 2^i big.
90	*	92	*
91	* @return Block of data represented by link_t.	93	* @return Block of data represented by link_t.
92	*/	94	*/
93	link_t buddy_system_alloc(buddy_system_t b, __u8 i)	95	link_t buddy_system_alloc(buddy_system_t b, __u8 i)
94	{	96	{
95	link_t res, hlp;	97	link_t res, hlp;
96		98
97	ASSERT(i < b->max_order);	99	ASSERT(i < b->max_order);
98		100
99	/*	101	/*
100	* If the list of order i is not empty,	102	* If the list of order i is not empty,
101	* the request can be immediatelly satisfied.	103	* the request can be immediatelly satisfied.
102	*/	104	*/
103	if (!list_empty(&b->order[i])) {	105	if (!list_empty(&b->order[i])) {
104	res = b->order[i].next;	106	res = b->order[i].next;
105	list_remove(res);	107	list_remove(res);
106	return res;	108	return res;
107	}	109	}
108		110
109	/*	111	/*
110	* If order i is already the maximal order,	112	* If order i is already the maximal order,
111	* the request cannot be satisfied.	113	* the request cannot be satisfied.
112	*/	114	*/
113	if (i == b->max_order - 1)	115	if (i == b->max_order - 1)
114	return NULL;	116	return NULL;
115		117
116	/*	118	/*
117	* Try to recursively satisfy the request from higher order lists.	119	* Try to recursively satisfy the request from higher order lists.
118	*/	120	*/
119	hlp = buddy_system_alloc(b, i + 1);	121	hlp = buddy_system_alloc(b, i + 1);
120		122
121	/*	123	/*
122	* The request could not be satisfied	124	* The request could not be satisfied
123	* from higher order lists.	125	* from higher order lists.
124	*/	126	*/
125	if (!hlp)	127	if (!hlp)
126	return NULL;	128	return NULL;
127		129
128	res = hlp;	130	res = hlp;
129		131
130	/*	132	/*
131	* Bisect the block and set order of both of its parts to i.	133	* Bisect the block and set order of both of its parts to i.
132	*/	134	*/
133	hlp = b->op->bisect(res);	135	hlp = b->op->bisect(b, res);
134	b->op->set_order(res, i);	136	b->op->set_order(b, res, i);
135	b->op->set_order(hlp, i);	137	b->op->set_order(b, hlp, i);
136		138
137	/*	139	/*
138	* Return the other half to buddy system.	140	* Return the other half to buddy system.
139	*/	141	*/
140	buddy_system_free(b, hlp);	142	buddy_system_free(b, hlp);
141		143
142	return res;	144	return res;
143		145
144	}	146	}
145		147
146	/** Return block to buddy system.	148	/** Return block to buddy system.
147	*	149	*
148	* Return block to buddy system.	150	* Return block to buddy system.
149	*	151	*
150	* @param b Buddy system pointer.	152	* @param b Buddy system pointer.
151	* @param block Block to return.	153	* @param block Block to return.
152	*/	154	*/
153	void buddy_system_free(buddy_system_t b, link_t block)	155	void buddy_system_free(buddy_system_t b, link_t block)
154	{	156	{
155	link_t buddy, hlp;	157	link_t buddy, hlp;
156	__u8 i;	158	__u8 i;
157		159
158	/*	160	/*
159	* Determine block's order.	161	* Determine block's order.
160	*/	162	*/
161	i = b->op->get_order(block);	163	i = b->op->get_order(b, block);
162		164
163	ASSERT(i < b->max_order);	165	ASSERT(i < b->max_order);
164		166
165	if (i != b->max_order - 1) {	167	if (i != b->max_order - 1) {
166	/*	168	/*
167	* See if there is any buddy in the list of order i.	169	* See if there is any buddy in the list of order i.
168	*/	170	*/
169	buddy = b->op->find_buddy(block);	171	buddy = b->op->find_buddy(b, block);
170	if (buddy) {	172	if (buddy) {
171		173
172	ASSERT(b->op->get_order(buddy) == i);	174	ASSERT(b->op->get_order(b, buddy) == i);
173		175
174	/*	176	/*
175	* Remove buddy from the list of order i.	177	* Remove buddy from the list of order i.
176	*/	178	*/
177	list_remove(buddy);	179	list_remove(buddy);
178		180
179	/*	181	/*
180	* Invalidate order of both block and buddy.	182	* Invalidate order of both block and buddy.
181	*/	183	*/
182	b->op->set_order(block, BUDDY_SYSTEM_INNER_BLOCK);	184	b->op->set_order(b, block, BUDDY_SYSTEM_INNER_BLOCK);
183	b->op->set_order(buddy, BUDDY_SYSTEM_INNER_BLOCK);	185	b->op->set_order(b, buddy, BUDDY_SYSTEM_INNER_BLOCK);
184		186
185	/*	187	/*
186	* Coalesce block and buddy into one block.	188	* Coalesce block and buddy into one block.
187	*/	189	*/
188	hlp = b->op->coalesce(block, buddy);	190	hlp = b->op->coalesce(b, block, buddy);
189		191
190	/*	192	/*
191	* Set order of the coalesced block to i + 1.	193	* Set order of the coalesced block to i + 1.
192	*/	194	*/
193	b->op->set_order(hlp, i + 1);	195	b->op->set_order(b, hlp, i + 1);
194		196
195	/*	197	/*
196	* Recursively add the coalesced block to the list of order i + 1.	198	* Recursively add the coalesced block to the list of order i + 1.
197	*/	199	*/
198	buddy_system_free(b, hlp);	200	buddy_system_free(b, hlp);
199	return;	201	return;
200	}	202	}
201	}	203	}
202		204
203	/*	205	/*
204	* Insert block into the list of order i.	206	* Insert block into the list of order i.
205	*/	207	*/
206	list_append(block, &b->order[i]);	208	list_append(block, &b->order[i]);
207		209
208	}	210	}
209		211

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/mm/buddy.c @ 1248 – Rev 430 → 489