WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/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>
#include <arch/asm.h>
#include <arch.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 early_heap_init(__address heap, size_t size)
{
    spinlock_initialize(&heaplock, "heap_lock");
    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 *early_malloc(size_t size)
{
    ipl_t ipl;
    chunk_t *x, *y, *z;
 
    if (size == 0)
        panic("zero-size allocation request");
       
    x = chunk0;
    ipl = interrupts_disable();
    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);
            interrupts_restore(ipl);
            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);
        interrupts_restore(ipl);
 
        return &x->data[0];
    }
    spinlock_unlock(&heaplock);
    interrupts_restore(ipl);
    return NULL;
}
 
void early_free(void *ptr)
{
    ipl_t ipl;
    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");
 
    ipl = interrupts_disable();
    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);
    interrupts_restore(ipl);
}
 

Rev 534	Rev 552
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	#include <arch/asm.h>	35	#include <arch/asm.h>
36	#include <arch.h>	36	#include <arch.h>
37		37
38	/*	38	/*
39	* First-fit algorithm.	39	* First-fit algorithm.
40	* Simple, but hopefully correct.	40	* Simple, but hopefully correct.
41	* Chunks being freed are tested for mergability with their neighbours.	41	* Chunks being freed are tested for mergability with their neighbours.
42	*/	42	*/
43		43
44	static chunk_t *chunk0;	44	static chunk_t *chunk0;
45	static spinlock_t heaplock;	45	static spinlock_t heaplock;
46		46
47	void early_heap_init(__address heap, size_t size)	47	void early_heap_init(__address heap, size_t size)
48	{	48	{
49	spinlock_initialize(&heaplock);	49	spinlock_initialize(&heaplock, "heap_lock");
50	memsetb(heap, size, 0);	50	memsetb(heap, size, 0);
51	chunk0 = (chunk_t *) heap;	51	chunk0 = (chunk_t *) heap;
52	chunk0->used = 0;	52	chunk0->used = 0;
53	chunk0->size = size - sizeof(chunk_t);	53	chunk0->size = size - sizeof(chunk_t);
54	chunk0->next = NULL;	54	chunk0->next = NULL;
55	chunk0->prev = NULL;	55	chunk0->prev = NULL;
56	}	56	}
57		57
58	/*	58	/*
59	* Uses first-fit algorithm.	59	* Uses first-fit algorithm.
60	*/	60	*/
61	void *early_malloc(size_t size)	61	void *early_malloc(size_t size)
62	{	62	{
63	ipl_t ipl;	63	ipl_t ipl;
64	chunk_t x, y, *z;	64	chunk_t x, y, *z;
65		65
66	if (size == 0)	66	if (size == 0)
67	panic("zero-size allocation request");	67	panic("zero-size allocation request");
68		68
69	x = chunk0;	69	x = chunk0;
70	ipl = interrupts_disable();	70	ipl = interrupts_disable();
71	spinlock_lock(&heaplock);	71	spinlock_lock(&heaplock);
72	while (x) {	72	while (x) {
73	if (x->used \|\| x->size < size) {	73	if (x->used \|\| x->size < size) {
74	x = x->next;	74	x = x->next;
75	continue;	75	continue;
76	}	76	}
77		77
78	x->used = 1;	78	x->used = 1;
79		79
80	/*	80	/*
81	* If the chunk exactly matches required size or if truncating	81	* If the chunk exactly matches required size or if truncating
82	* it would not provide enough space for storing a new chunk	82	* it would not provide enough space for storing a new chunk
83	* header plus at least one byte of data, we are finished.	83	* header plus at least one byte of data, we are finished.
84	*/	84	*/
85	if (x->size < size + sizeof(chunk_t) + 1) {	85	if (x->size < size + sizeof(chunk_t) + 1) {
86	spinlock_unlock(&heaplock);	86	spinlock_unlock(&heaplock);
87	interrupts_restore(ipl);	87	interrupts_restore(ipl);
88	return &x->data[0];	88	return &x->data[0];
89	}	89	}
90		90
91	/*	91	/*
92	* Truncate x and create a new chunk.	92	* Truncate x and create a new chunk.
93	*/	93	*/
94	y = (chunk_t *) (((__address) x) + size + sizeof(chunk_t));	94	y = (chunk_t *) (((__address) x) + size + sizeof(chunk_t));
95	y->used = 0;	95	y->used = 0;
96	y->size = x->size - size - sizeof(chunk_t);	96	y->size = x->size - size - sizeof(chunk_t);
97	y->prev = x;	97	y->prev = x;
98	y->next = NULL;	98	y->next = NULL;
99		99
100	if (z = x->next) {	100	if (z = x->next) {
101	z->prev = y;	101	z->prev = y;
102	y->next = z;	102	y->next = z;
103	}	103	}
104		104
105	x->size = size;	105	x->size = size;
106	x->next = y;	106	x->next = y;
107	spinlock_unlock(&heaplock);	107	spinlock_unlock(&heaplock);
108	interrupts_restore(ipl);	108	interrupts_restore(ipl);
109		109
110	return &x->data[0];	110	return &x->data[0];
111	}	111	}
112	spinlock_unlock(&heaplock);	112	spinlock_unlock(&heaplock);
113	interrupts_restore(ipl);	113	interrupts_restore(ipl);
114	return NULL;	114	return NULL;
115	}	115	}
116		116
117	void early_free(void *ptr)	117	void early_free(void *ptr)
118	{	118	{
119	ipl_t ipl;	119	ipl_t ipl;
120	chunk_t x, y, *z;	120	chunk_t x, y, *z;
121		121
122	if (!ptr)	122	if (!ptr)
123	panic("free on NULL");	123	panic("free on NULL");
124		124
125		125
126	y = (chunk_t ) (((__u8 ) ptr) - sizeof(chunk_t));	126	y = (chunk_t ) (((__u8 ) ptr) - sizeof(chunk_t));
127	if (y->used != 1)	127	if (y->used != 1)
128	panic("freeing unused/damaged chunk");	128	panic("freeing unused/damaged chunk");
129		129
130	ipl = interrupts_disable();	130	ipl = interrupts_disable();
131	spinlock_lock(&heaplock);	131	spinlock_lock(&heaplock);
132	x = y->prev;	132	x = y->prev;
133	z = y->next;	133	z = y->next;
134	/* merge x and y */	134	/* merge x and y */
135	if (x && !x->used) {	135	if (x && !x->used) {
136	x->size += y->size + sizeof(chunk_t);	136	x->size += y->size + sizeof(chunk_t);
137	x->next = z;	137	x->next = z;
138	if (z)	138	if (z)
139	z->prev = x;	139	z->prev = x;
140	y = x;	140	y = x;
141	}	141	}
142	/* merge y and z or merge (x merged with y) and z */	142	/* merge y and z or merge (x merged with y) and z */
143	if (z && !z->used) {	143	if (z && !z->used) {
144	y->size += z->size + sizeof(chunk_t);	144	y->size += z->size + sizeof(chunk_t);
145	y->next = z->next;	145	y->next = z->next;
146	if (z->next) {	146	if (z->next) {
147	/* y is either y or x */	147	/* y is either y or x */
148	z->next->prev = y;	148	z->next->prev = y;
149	}	149	}
150	}	150	}
151	y->used = 0;	151	y->used = 0;
152	spinlock_unlock(&heaplock);	152	spinlock_unlock(&heaplock);
153	interrupts_restore(ipl);	153	interrupts_restore(ipl);
154	}	154	}
155		155

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(root)/kernel/trunk/generic/src/mm/heap.c – Rev 534 → 552