resources/foma.cpp

   1 /* Quarn OS
   2  *
   3  * Fixed-size Objects Memory Allocator
   4  *
   5  * Copyright (C) 2008-2009 Pawel Dziepak
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  */
  22
  23 /* Propably this implementation is LE only */
  24
  25 #include "foma.h"
  26 #include "memm.h"
  27
  28 #include "arch/low/fast_util.h"
  29 #include "services/kernel_state.h"
  30 #include "manes/manec.h"
  31 #include "physmem.h"
  32
  33 using namespace arch;
  34 using namespace manes;
  35 using namespace resources;
  36
  37 bool foma::initialize() {
  38 }
  39
  40 foma::foma() {
  41         physical = manec::get()->get<physmem>("/physmem");
  42         memory_size = manec::get()->state()->get_memory_size();
  43
  44         start_heap = (void*)0x300000;
  45         for (int i = 0; i < 20; i++)
  46                 first_block[i] = 0;
  47 }
  48
  49 void *foma::get_page(int size) {
  50         void *addr = physical->allocate_space(0x1000);
  51
  52         *(unsigned int*)addr = 1 << size;
  53
  54         return addr;
  55 }
  56
  57 int alloc_memory = 0;
  58
  59 void *foma::allocate(unsigned int fixed_size, unsigned int size) {
  60         unsigned int index = log2up(fixed_size);
  61
  62         assert("foma: attempt to allocate too big object", index > PAGE_SHIFT);
  63
  64         if (first_block[index] == 0) {
  65                 first_block[index] = (unsigned int*)((unsigned int)get_page(index) + (1 << index));
  66
  67                 unsigned int i = 0;
  68                 /* O(1) !!! */
  69                 for (; i < PAGE_SIZE - fixed_size; i+= fixed_size) {
  70                         *(unsigned int*)((unsigned int)first_block[index] + i) = (unsigned int)first_block[index] + i + fixed_size;
  71                 }
  72                 *(unsigned int*)((unsigned int)first_block[index] + i - fixed_size ) = 0;
  73
  74                 alloc_memory += fixed_size;
  75         }
  76
  77         /* Allocate object */
  78         unsigned int *next_block = (unsigned int*)*first_block[index];
  79         unsigned int *found_block = first_block[index];
  80
  81         first_block[index] = next_block;
  82
  83         return (void*)found_block;
  84 }
  85
  86 void foma::deallocate(void *ptr, unsigned int size) {
  87         unsigned int index = log2up(size);
  88         unsigned int fixed_size = 1 << index;
  89
  90         if (fixed_size < 4)
  91                 return;
  92
  93         assert("foma: attempt to deallocate too big object", index > PAGE_SHIFT);
  94         if (index > PAGE_SHIFT)
  95                 return;
  96
  97         unsigned int next_block = (unsigned int)first_block[index];
  98         unsigned int *new_first_block = (unsigned int*)ptr;
  99
 100         first_block[index] = new_first_block;
 101         *new_first_block = next_block;
 102 }
 103
 104 //#if DEBUG_MODE == CONF_YES
 105 int resources::foma::used_memory = 0;
 106 //#endif
 107
 108 void *foma::allocate_space(unsigned int size) {
 109         if (size == 0)
 110                 return (void*)0;
 111
 112         if (size < PAGE_SIZE) {
 113                 unsigned int fixed_size = 1 << log2up(size < sizeof(void*) ? sizeof(void*) : size);
 114 #if DEBUG_MODE == CONF_YES
 115         used_memory += size;
 116         alloc_memory += fixed_size;
 117 #endif
 118                 return allocate(fixed_size < sizeof(void*) ? sizeof(void*) : fixed_size, size);
 119         } else {
 120                 void *first_page = get_page(PAGE_SHIFT + 1);
 121                 for (int i = size - PAGE_SIZE; i > 0; i -= PAGE_SIZE)
 122                         get_page(PAGE_SHIFT + 1);
 123
 124                 return first_page;
 125         }
 126 }
 127
 128 void foma::deallocate_space(void *ptr) {
 129         assert("foma: attempt to free null pointer", ptr == 0);
 130         if ((unsigned int)ptr < 0x300000 || (unsigned int)ptr >= 0x400000) {
 131                 assert((string)"foma: attempt to free object not created by foma: 0x"  + string((int)ptr,true),1);
 132                 return;
 133         }
 134
 135         unsigned int size = get_size(ptr);
 136
 137         if (size < PAGE_SIZE) {
 138                 deallocate(ptr, size);
 139         } else {
 140                 debug("foma: deallocating object larger than page");
 141         }
 142 }
 143
 144 unsigned int foma::get_size(void *ptr) const {
 145         return *(unsigned int*)((unsigned int)ptr & ~(PAGE_SIZE - 1));
 146 }
 147
 148 void foma::register_type() {
 149         manec::get()->register_type<foma>("foma", "allocator");
 150 }
 151