1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
|
/*
* linux/arch/arm/mm/init.c
*
* Copyright (C) 1995, 1996 Russell King
*/
#include <linux/config.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/head.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#ifdef CONFIG_BLK_DEV_INITRD
#include <linux/blk.h>
#endif
#include <asm/system.h>
#include <asm/segment.h>
#include <asm/pgtable.h>
#include <asm/dma.h>
#include <asm/hardware.h>
#include <asm/proc/mm-init.h>
pgd_t swapper_pg_dir[PTRS_PER_PGD];
extern char _etext, _stext, _edata, __bss_start, _end;
extern char __init_begin, __init_end;
int do_check_pgt_cache(int low, int high)
{
int freed = 0;
if(pgtable_cache_size > high) {
do {
if(pgd_quicklist)
free_pgd_slow(get_pgd_fast()), freed++;
if(pmd_quicklist)
free_pmd_slow(get_pmd_fast()), freed++;
if(pte_quicklist)
free_pte_slow(get_pte_fast()), freed++;
} while(pgtable_cache_size > low);
}
return freed;
}
/*
* BAD_PAGE is the page that is used for page faults when linux
* is out-of-memory. Older versions of linux just did a
* do_exit(), but using this instead means there is less risk
* for a process dying in kernel mode, possibly leaving a inode
* unused etc..
*
* BAD_PAGETABLE is the accompanying page-table: it is initialized
* to point to BAD_PAGE entries.
*
* ZERO_PAGE is a special page that is used for zero-initialized
* data and COW.
*/
#if PTRS_PER_PTE != 1
unsigned long *empty_bad_page_table;
pte_t *__bad_pagetable(void)
{
int i;
pte_t bad_page;
bad_page = BAD_PAGE;
for (i = 0; i < PTRS_PER_PTE; i++)
empty_bad_page_table[i] = (unsigned long)pte_val(bad_page);
return (pte_t *) empty_bad_page_table;
}
#endif
unsigned long *empty_zero_page;
unsigned long *empty_bad_page;
pte_t __bad_page(void)
{
memzero (empty_bad_page, PAGE_SIZE);
return pte_nocache(pte_mkdirty(mk_pte((unsigned long) empty_bad_page, PAGE_SHARED)));
}
void show_mem(void)
{
extern void show_net_buffers(void);
int i,free = 0,total = 0,reserved = 0;
int shared = 0;
printk("Mem-info:\n");
show_free_areas();
printk("Free swap: %6dkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
i = MAP_NR(high_memory);
while (i-- > 0) {
total++;
if (PageReserved(mem_map+i))
reserved++;
else if (!atomic_read(&mem_map[i].count))
free++;
else
shared += atomic_read(&mem_map[i].count) - 1;
}
printk("%d pages of RAM\n",total);
printk("%d free pages\n",free);
printk("%d reserved pages\n",reserved);
printk("%d pages shared\n",shared);
show_buffers();
#ifdef CONFIG_NET
show_net_buffers();
#endif
}
/*
* paging_init() sets up the page tables...
*/
__initfunc(unsigned long paging_init(unsigned long start_mem, unsigned long end_mem))
{
extern unsigned long free_area_init(unsigned long, unsigned long);
start_mem = PAGE_ALIGN(start_mem);
empty_zero_page = (unsigned long *)start_mem;
start_mem += PAGE_SIZE;
empty_bad_page = (unsigned long *)start_mem;
start_mem += PAGE_SIZE;
#if PTRS_PER_PTE != 1
empty_bad_page_table = (unsigned long *)start_mem;
start_mem += PTRS_PER_PTE * sizeof (void *);
#endif
memzero (empty_zero_page, PAGE_SIZE);
start_mem = setup_pagetables (start_mem, end_mem);
flush_tlb_all();
update_memc_all();
return free_area_init(start_mem, end_mem);
}
/*
* mem_init() marks the free areas in the mem_map and tells us how much
* memory is free. This is done after various parts of the system have
* claimed their memory after the kernel image.
*/
__initfunc(void mem_init(unsigned long start_mem, unsigned long end_mem))
{
extern void sound_init(void);
int codepages = 0;
int reservedpages = 0;
int datapages = 0;
int initpages = 0;
unsigned long tmp;
end_mem &= PAGE_MASK;
high_memory = (void *)end_mem;
max_mapnr = num_physpages = MAP_NR(end_mem);
/* mark usable pages in the mem_map[] */
mark_usable_memory_areas(&start_mem, end_mem);
for (tmp = PAGE_OFFSET; tmp < end_mem ; tmp += PAGE_SIZE) {
if (PageReserved(mem_map+MAP_NR(tmp))) {
if (tmp >= KERNTOPHYS(_stext) &&
tmp < KERNTOPHYS(_edata)) {
if (tmp < KERNTOPHYS(_etext))
codepages++;
else
datapages++;
} else if (tmp >= KERNTOPHYS(__init_begin)
&& tmp < KERNTOPHYS(__init_end))
initpages++;
else if (tmp >= KERNTOPHYS(__bss_start)
&& tmp < (unsigned long) start_mem)
datapages++;
else
reservedpages++;
continue;
}
atomic_set(&mem_map[MAP_NR(tmp)].count, 1);
#ifdef CONFIG_BLK_DEV_INITRD
if (!initrd_start || (tmp < initrd_start || tmp >= initrd_end))
#endif
free_page(tmp);
}
printk ("Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init)\n",
(unsigned long) nr_free_pages << (PAGE_SHIFT-10),
max_mapnr << (PAGE_SHIFT-10),
codepages << (PAGE_SHIFT-10),
reservedpages << (PAGE_SHIFT-10),
datapages << (PAGE_SHIFT-10),
initpages << (PAGE_SHIFT-10));
}
void free_initmem (void)
{
unsigned long addr;
addr = (unsigned long)(&__init_begin);
for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
mem_map[MAP_NR(addr)].flags &= ~(1 << PG_reserved);
atomic_set(&mem_map[MAP_NR(addr)].count, 1);
free_page(addr);
}
printk ("Freeing unused kernel memory: %dk freed\n", (&__init_end - &__init_begin) >> 10);
}
void si_meminfo(struct sysinfo *val)
{
int i;
i = MAP_NR(high_memory);
val->totalram = 0;
val->sharedram = 0;
val->freeram = nr_free_pages << PAGE_SHIFT;
val->bufferram = buffermem;
while (i-- > 0) {
if (PageReserved(mem_map+i))
continue;
val->totalram++;
if (!atomic_read(&mem_map[i].count))
continue;
val->sharedram += atomic_read(&mem_map[i].count) - 1;
}
val->totalram <<= PAGE_SHIFT;
val->sharedram <<= PAGE_SHIFT;
}
|
