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>
#include <align.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");
       
    size = ALIGN_UP(size, sizeof(__native));
 
    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 590	Rev 591
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	#include <align.h>	37	#include <align.h>
38		38
39	/*	39	/*
40	* First-fit algorithm.	40	* First-fit algorithm.
41	* Simple, but hopefully correct.	41	* Simple, but hopefully correct.
42	* Chunks being freed are tested for mergability with their neighbours.	42	* Chunks being freed are tested for mergability with their neighbours.
43	*/	43	*/
44		44
45	static chunk_t *chunk0;	45	static chunk_t *chunk0;
46	static spinlock_t heaplock;	46	static spinlock_t heaplock;
47		47
48	void early_heap_init(__address heap, size_t size)	48	void early_heap_init(__address heap, size_t size)
49	{	49	{
50	spinlock_initialize(&heaplock, "heap_lock");	50	spinlock_initialize(&heaplock, "heap_lock");
51	memsetb(heap, size, 0);	51	memsetb(heap, size, 0);
52	chunk0 = (chunk_t *) heap;	52	chunk0 = (chunk_t *) heap;
53	chunk0->used = 0;	53	chunk0->used = 0;
54	chunk0->size = size - sizeof(chunk_t);	54	chunk0->size = size - sizeof(chunk_t);
55	chunk0->next = NULL;	55	chunk0->next = NULL;
56	chunk0->prev = NULL;	56	chunk0->prev = NULL;
57	}	57	}
58		58
59	/*	59	/*
60	* Uses first-fit algorithm.	60	* Uses first-fit algorithm.
61	*/	61	*/
62	void *early_malloc(size_t size)	62	void *early_malloc(size_t size)
63	{	63	{
64	ipl_t ipl;	64	ipl_t ipl;
65	chunk_t x, y, *z;	65	chunk_t x, y, *z;
66		66
67	size = ALIGN_UP(size, sizeof(__native));	-
68		-
69	if (size == 0)	67	if (size == 0)
70	panic("zero-size allocation request");	68	panic("zero-size allocation request");
71		69
-		70	size = ALIGN_UP(size, sizeof(__native));
-		71
72	x = chunk0;	72	x = chunk0;
73	ipl = interrupts_disable();	73	ipl = interrupts_disable();
74	spinlock_lock(&heaplock);	74	spinlock_lock(&heaplock);
75	while (x) {	75	while (x) {
76	if (x->used \|\| x->size < size) {	76	if (x->used \|\| x->size < size) {
77	x = x->next;	77	x = x->next;
78	continue;	78	continue;
79	}	79	}
80		80
81	x->used = 1;	81	x->used = 1;
82		82
83	/*	83	/*
84	* If the chunk exactly matches required size or if truncating	84	* If the chunk exactly matches required size or if truncating
85	* it would not provide enough space for storing a new chunk	85	* it would not provide enough space for storing a new chunk
86	* header plus at least one byte of data, we are finished.	86	* header plus at least one byte of data, we are finished.
87	*/	87	*/
88	if (x->size < size + sizeof(chunk_t) + 1) {	88	if (x->size < size + sizeof(chunk_t) + 1) {
89	spinlock_unlock(&heaplock);	89	spinlock_unlock(&heaplock);
90	interrupts_restore(ipl);	90	interrupts_restore(ipl);
91	return &x->data[0];	91	return &x->data[0];
92	}	92	}
93		93
94	/*	94	/*
95	* Truncate x and create a new chunk.	95	* Truncate x and create a new chunk.
96	*/	96	*/
97	y = (chunk_t *) (((__address) x) + size + sizeof(chunk_t));	97	y = (chunk_t *) (((__address) x) + size + sizeof(chunk_t));
98	y->used = 0;	98	y->used = 0;
99	y->size = x->size - size - sizeof(chunk_t);	99	y->size = x->size - size - sizeof(chunk_t);
100	y->prev = x;	100	y->prev = x;
101	y->next = NULL;	101	y->next = NULL;
102		102
103	if (z = x->next) {	103	if (z = x->next) {
104	z->prev = y;	104	z->prev = y;
105	y->next = z;	105	y->next = z;
106	}	106	}
107		107
108	x->size = size;	108	x->size = size;
109	x->next = y;	109	x->next = y;
110	spinlock_unlock(&heaplock);	110	spinlock_unlock(&heaplock);
111	interrupts_restore(ipl);	111	interrupts_restore(ipl);
112		112
113	return &x->data[0];	113	return &x->data[0];
114	}	114	}
115	spinlock_unlock(&heaplock);	115	spinlock_unlock(&heaplock);
116	interrupts_restore(ipl);	116	interrupts_restore(ipl);
117	return NULL;	117	return NULL;
118	}	118	}
119		119
120	void early_free(void *ptr)	120	void early_free(void *ptr)
121	{	121	{
122	ipl_t ipl;	122	ipl_t ipl;
123	chunk_t x, y, *z;	123	chunk_t x, y, *z;
124		124
125	if (!ptr)	125	if (!ptr)
126	panic("free on NULL");	126	panic("free on NULL");
127		127
128		128
129	y = (chunk_t ) (((__u8 ) ptr) - sizeof(chunk_t));	129	y = (chunk_t ) (((__u8 ) ptr) - sizeof(chunk_t));
130	if (y->used != 1)	130	if (y->used != 1)
131	panic("freeing unused/damaged chunk");	131	panic("freeing unused/damaged chunk");
132		132
133	ipl = interrupts_disable();	133	ipl = interrupts_disable();
134	spinlock_lock(&heaplock);	134	spinlock_lock(&heaplock);
135	x = y->prev;	135	x = y->prev;
136	z = y->next;	136	z = y->next;
137	/* merge x and y */	137	/* merge x and y */
138	if (x && !x->used) {	138	if (x && !x->used) {
139	x->size += y->size + sizeof(chunk_t);	139	x->size += y->size + sizeof(chunk_t);
140	x->next = z;	140	x->next = z;
141	if (z)	141	if (z)
142	z->prev = x;	142	z->prev = x;
143	y = x;	143	y = x;
144	}	144	}
145	/* merge y and z or merge (x merged with y) and z */	145	/* merge y and z or merge (x merged with y) and z */
146	if (z && !z->used) {	146	if (z && !z->used) {
147	y->size += z->size + sizeof(chunk_t);	147	y->size += z->size + sizeof(chunk_t);
148	y->next = z->next;	148	y->next = z->next;
149	if (z->next) {	149	if (z->next) {
150	/* y is either y or x */	150	/* y is either y or x */
151	z->next->prev = y;	151	z->next->prev = y;
152	}	152	}
153	}	153	}
154	y->used = 0;	154	y->used = 0;
155	spinlock_unlock(&heaplock);	155	spinlock_unlock(&heaplock);
156	interrupts_restore(ipl);	156	interrupts_restore(ipl);
157	}	157	}
158		158

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/mm/heap.c – Rev 590 → 591