WebSVN – HelenOS – Diff – /SPARTAN/trunk/src/mm/heap.c


/*
 * Copyright (C) 2001-2004 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/heap.h>
#include <synch/spinlock.h>
#include <func.h>
#include <memstr.h>
#include <panic.h>
#include <arch/types.h>
 
/*
 * First-fit algorithm.
 * Simple, but hopefully correct.
 * Chunks being freed are tested for mergability with their neighbours.
 */
 
static chunk_t *chunk0;
static spinlock_t heaplock;
 
void heap_init(__address heap, __u32 size)
{
    spinlock_initialize(&heaplock);
    memsetb(heap, size, 0);
    chunk0 = (chunk_t *) heap;
    chunk0->used = 0;
    chunk0->size = size - sizeof(chunk_t);
    chunk0->next = NULL;
    chunk0->prev = NULL;
}
 
/*
 * Uses first-fit algorithm.
 */
void *malloc(size_t size)
{
    pri_t pri;
    chunk_t *x, *y, *z;
 
    if (size == 0)
        panic("malloc: zero-size allocation request");
       
    x = chunk0;
    pri = cpu_priority_high();
    spinlock_lock(&heaplock);      
    while (x) {
        if (x->used || x->size < size) {
            x = x->next;
            continue;
        }
       
        x->used = 1;
   
        /*
         * If the chunk exactly matches required size or if truncating
         * it would not provide enough space for storing a new chunk
         * header plus at least one byte of data, we are finished.
         */
        if (x->size < size + sizeof(chunk_t) + 1) {
            spinlock_unlock(&heaplock);
            cpu_priority_restore(pri);
            return &x->data[0];
        }
 
        /*
         * Truncate x and create a new chunk.
         */
        y = (chunk_t *) (((__address) x) + size + sizeof(chunk_t));
        y->used = 0;
        y->size = x->size - size - sizeof(chunk_t);
        y->prev = x;
        y->next = NULL;
       
        if (z = x->next) {
            z->prev = y;
            y->next = z;
        }
       
        x->size = size;
        x->next = y;
        spinlock_unlock(&heaplock);
        cpu_priority_restore(pri);
 
        return &x->data[0];
    }
    spinlock_unlock(&heaplock);
    cpu_priority_restore(pri);
    return NULL;
}
 
void free(void *ptr)
{
    pri_t pri;
    chunk_t *x, *y, *z;
 
    if (!ptr)
        panic("free on NULL");
 
 
    y = (chunk_t *) (((__u8 *) ptr) - sizeof(chunk_t));
    if (y->used != 1)
        panic("freeing unused/damaged chunk");
 
    pri = cpu_priority_high();
    spinlock_lock(&heaplock);
    x = y->prev;
    z = y->next;
    /* merge x and y */
    if (x && !x->used) {
        x->size += y->size + sizeof(chunk_t);
        x->next = z;
        if (z)
            z->prev = x;
        y = x;
    }
    /* merge y and z or merge (x merged with y) and z */
    if (z && !z->used) {
        y->size += z->size + sizeof(chunk_t);
        y->next = z->next;
        if (z->next)  {
            /* y is either y or x */
            z->next->prev = y;
        }
    }
    y->used = 0;
    spinlock_unlock(&heaplock);
    cpu_priority_restore(pri);
}
 

Rev 68	Rev 72
1	/*	1	/*
2	* Copyright (C) 2001-2004 Jakub Jermar	2	* Copyright (C) 2001-2004 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/heap.h>	29	#include <mm/heap.h>
30	#include <synch/spinlock.h>	30	#include <synch/spinlock.h>
31	#include <func.h>	31	#include <func.h>
32	#include <memstr.h>	32	#include <memstr.h>
33	#include <panic.h>	33	#include <panic.h>
34	#include <arch/types.h>	34	#include <arch/types.h>
35		35
36	/*	36	/*
37	* First-fit algorithm.	37	* First-fit algorithm.
38	* Simple, but hopefully correct.	38	* Simple, but hopefully correct.
39	* Chunks being freed are tested for mergability with their neighbours.	39	* Chunks being freed are tested for mergability with their neighbours.
40	*/	40	*/
41		41
42	static chunk_t *chunk0;	42	static chunk_t *chunk0;
43	static spinlock_t heaplock;	43	static spinlock_t heaplock;
44		44
45	void heap_init(__address heap, int size)	45	void heap_init(__address heap, __u32 size)
46	{	46	{
47	spinlock_initialize(&heaplock);	47	spinlock_initialize(&heaplock);
48	memsetb(heap,size,0);	48	memsetb(heap, size, 0);
49	chunk0 = (chunk_t *) heap;	49	chunk0 = (chunk_t *) heap;
50	chunk0->used = 0;	50	chunk0->used = 0;
51	chunk0->size = size - sizeof(chunk_t);	51	chunk0->size = size - sizeof(chunk_t);
52	chunk0->next = NULL;	52	chunk0->next = NULL;
53	chunk0->prev = NULL;	53	chunk0->prev = NULL;
54	}	54	}
55		55
56	/*	56	/*
57	* Uses first-fit algorithm.	57	* Uses first-fit algorithm.
58	*/	58	*/
59	void *malloc(int size)	59	void *malloc(size_t size)
60	{	60	{
61	pri_t pri;	61	pri_t pri;
62	chunk_t x, y, *z;	62	chunk_t x, y, *z;
63		63
64	if (size == 0)	64	if (size == 0)
65	panic("malloc: zero-size allocation request");	65	panic("malloc: zero-size allocation request");
66		66
67	x = chunk0;	67	x = chunk0;
68	pri = cpu_priority_high();	68	pri = cpu_priority_high();
69	spinlock_lock(&heaplock);	69	spinlock_lock(&heaplock);
70	while (x) {	70	while (x) {
71	if (x->used \|\| x->size < size) {	71	if (x->used \|\| x->size < size) {
72	x = x->next;	72	x = x->next;
73	continue;	73	continue;
74	}	74	}
75		75
76	x->used = 1;	76	x->used = 1;
77		77
78	/*	78	/*
79	* If the chunk exactly matches required size or if truncating	79	* If the chunk exactly matches required size or if truncating
80	* it would not provide enough space for storing a new chunk	80	* it would not provide enough space for storing a new chunk
81	* header plus at least one byte of data, we are finished.	81	* header plus at least one byte of data, we are finished.
82	*/	82	*/
83	if (x->size < size + sizeof(chunk_t) + 1) {	83	if (x->size < size + sizeof(chunk_t) + 1) {
84	spinlock_unlock(&heaplock);	84	spinlock_unlock(&heaplock);
85	cpu_priority_restore(pri);	85	cpu_priority_restore(pri);
86	return &x->data[0];	86	return &x->data[0];
87	}	87	}
88		88
89	/*	89	/*
90	* Truncate x and create a new chunk.	90	* Truncate x and create a new chunk.
91	*/	91	*/
92	y = (chunk_t *) (((__address) x) + size + sizeof(chunk_t));	92	y = (chunk_t *) (((__address) x) + size + sizeof(chunk_t));
93	y->used = 0;	93	y->used = 0;
94	y->size = x->size - size - sizeof(chunk_t);	94	y->size = x->size - size - sizeof(chunk_t);
95	y->prev = x;	95	y->prev = x;
96	y->next = NULL;	96	y->next = NULL;
97		97
98	if (z = x->next) {	98	if (z = x->next) {
99	z->prev = y;	99	z->prev = y;
100	y->next = z;	100	y->next = z;
101	}	101	}
102		102
103	x->size = size;	103	x->size = size;
104	x->next = y;	104	x->next = y;
105	spinlock_unlock(&heaplock);	105	spinlock_unlock(&heaplock);
106	cpu_priority_restore(pri);	106	cpu_priority_restore(pri);
107		107
108	return &x->data[0];	108	return &x->data[0];
109	}	109	}
110	spinlock_unlock(&heaplock);	110	spinlock_unlock(&heaplock);
111	cpu_priority_restore(pri);	111	cpu_priority_restore(pri);
112	return NULL;	112	return NULL;
113	}	113	}
114		114
115	void free(void *ptr)	115	void free(void *ptr)
116	{	116	{
117	pri_t pri;	117	pri_t pri;
118	chunk_t x, y, *z;	118	chunk_t x, y, *z;
119		119
120	if (!ptr)	120	if (!ptr)
121	panic("free on NULL");	121	panic("free on NULL");
122		122
123		123
124	y = (chunk_t ) (((__u8 ) ptr) - sizeof(chunk_t));	124	y = (chunk_t ) (((__u8 ) ptr) - sizeof(chunk_t));
125	if (y->used != 1)	125	if (y->used != 1)
126	panic("freeing unused/damaged chunk");	126	panic("freeing unused/damaged chunk");
127		127
128	pri = cpu_priority_high();	128	pri = cpu_priority_high();
129	spinlock_lock(&heaplock);	129	spinlock_lock(&heaplock);
130	x = y->prev;	130	x = y->prev;
131	z = y->next;	131	z = y->next;
132	/* merge x and y */	132	/* merge x and y */
133	if (x && !x->used) {	133	if (x && !x->used) {
134	x->size += y->size + sizeof(chunk_t);	134	x->size += y->size + sizeof(chunk_t);
135	x->next = z;	135	x->next = z;
136	if (z)	136	if (z)
137	z->prev = x;	137	z->prev = x;
138	y = x;	138	y = x;
139	}	139	}
140	/* merge y and z or merge (x merged with y) and z */	140	/* merge y and z or merge (x merged with y) and z */
141	if (z && !z->used) {	141	if (z && !z->used) {
142	y->size += z->size + sizeof(chunk_t);	142	y->size += z->size + sizeof(chunk_t);
143	y->next = z->next;	143	y->next = z->next;
144	if (z->next) {	144	if (z->next) {
145	/* y is either y or x */	145	/* y is either y or x */
146	z->next->prev = y;	146	z->next->prev = y;
147	}	147	}
148	}	148	}
149	y->used = 0;	149	y->used = 0;
150	spinlock_unlock(&heaplock);	150	spinlock_unlock(&heaplock);
151	cpu_priority_restore(pri);	151	cpu_priority_restore(pri);
152	}	152	}
153		153

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(root)/SPARTAN/trunk/src/mm/heap.c @ 102 – Rev 68 → 72