需要从kernel 中得到内存的大小，从那里得到比较方便？

dreamice

void __init mem_init(void)
{
        long codesize, reservedpages, datasize, initsize;

        pci_iommu_alloc();

        /* clear_bss() already clear the empty_zero_page */

        reservedpages = 0;

        /* this will put all low memory onto the freelists */
#ifdef CONFIG_NUMA
        totalram_pages = numa_free_all_bootmem();
#else
        totalram_pages = free_all_bootmem();
#endif
        reservedpages = end_pfn - totalram_pages -
                                        absent_pages_in_range(0, end_pfn);
        after_bootmem = 1;

dreamice

内存初始化的时候，得出的这个值

T-Bagwell

1. 
   
2. void __init mem_init(void)
   
3. {
   
4.         int codesize, reservedpages, datasize, initsize;
   
5.         int tmp;
   
6. 
   
7.         pci_iommu_alloc();
   
8. 
   
9. #ifdef CONFIG_FLATMEM
   
10.         BUG_ON(!mem_map);
    
11. #endif
    
12.         /* this will put all low memory onto the freelists */
    
13.         totalram_pages += free_all_bootmem();
    
14. 
    
15.         reservedpages = 0;
    
16.         for (tmp = 0; tmp < max_low_pfn; tmp++)
    
17.                 /*
    
18.                  * Only count reserved RAM pages:
    
19.                  */
    
20.                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
    
21.                         reservedpages++;
    
22. 
    
23.         set_highmem_pages_init();
    
24. 
    
25.         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
    
26.         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
    
27.         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
    
28. 
    
29.         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
    
30.                         "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
    
31.                 nr_free_pages() << (PAGE_SHIFT-10),
    
32.                 num_physpages << (PAGE_SHIFT-10),
    
33.                 codesize >> 10,
    
34.                 reservedpages << (PAGE_SHIFT-10),
    
35.                 datasize >> 10,
    
36.                 initsize >> 10,
    
37.                 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
    
38.                );
    
39. 
    
40.         printk(KERN_INFO "virtual kernel memory layout:\n"
    
41.                 "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
    
42. #ifdef CONFIG_HIGHMEM
    
43.                 "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
    
44. #endif
    
45.                 "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
    
46.                 "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
    
47.                 "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
    
48.                 "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
    
49.                 "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
    
50.                 FIXADDR_START, FIXADDR_TOP,
    
51.                 (FIXADDR_TOP - FIXADDR_START) >> 10,
    
52. 
    
53. #ifdef CONFIG_HIGHMEM
    
54.                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
    
55.                 (LAST_PKMAP*PAGE_SIZE) >> 10,
    
56. #endif
    
57. 
    
58.                 VMALLOC_START, VMALLOC_END,
    
59.                 (VMALLOC_END - VMALLOC_START) >> 20,
    
60. 
    
61.                 (unsigned long)__va(0), (unsigned long)high_memory,
    
62.                 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
    
63. 
    
64.                 (unsigned long)&__init_begin, (unsigned long)&__init_end,
    
65.                 ((unsigned long)&__init_end -
    
66.                  (unsigned long)&__init_begin) >> 10,
    
67. 
    
68.                 (unsigned long)&_etext, (unsigned long)&_edata,
    
69.                 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
    
70. 
    
71.                 (unsigned long)&_text, (unsigned long)&_etext,
    
72.                 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
    
73. 
    
74.         /*
    
75.          * Check boundaries twice: Some fundamental inconsistencies can
    
76.          * be detected at build time already.
    
77.          */
    
78. #define __FIXADDR_TOP (-PAGE_SIZE)
    
79. #ifdef CONFIG_HIGHMEM
    
80.         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
    
81.         BUILD_BUG_ON(VMALLOC_END                        > PKMAP_BASE);
    
82. #endif
    
83. #define high_memory (-128UL << 20)
    
84.         BUILD_BUG_ON(VMALLOC_START                        >= VMALLOC_END);
    
85. #undef high_memory
    
86. #undef __FIXADDR_TOP
    
87. 
    
88. #ifdef CONFIG_HIGHMEM
    
89.         BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
    
90.         BUG_ON(VMALLOC_END                                > PKMAP_BASE);
    
91. #endif
    
92.         BUG_ON(VMALLOC_START                                >= VMALLOC_END);
    
93.         BUG_ON((unsigned long)high_memory                > VMALLOC_START);
    
94. 
    
95.         if (boot_cpu_data.wp_works_ok < 0)
    
96.                 test_wp_bit();
    
97. 
    
98.         save_pg_dir();
    
99.         zap_low_mappings(true);
    
100. }
     

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我也找到了

[ 本帖最后由 T-Bagwell 于 2009-12-8 16:39 编辑 ]

Godbach

但是proc中不是直接读取这个全局变量的，我看的内核时2.6.18.3

T-Bagwell

1. 
   
2. struct sysinfo {
   
3.         long uptime;                        /* Seconds since boot */
   
4.         unsigned long loads[3];                /* 1, 5, and 15 minute load averages */
   
5.         unsigned long totalram;                /* Total usable main memory size */
   
6.         unsigned long freeram;                /* Available memory size */
   
7.         unsigned long sharedram;        /* Amount of shared memory */
   
8.         unsigned long bufferram;        /* Memory used by buffers */
   
9.         unsigned long totalswap;        /* Total swap space size */
   
10.         unsigned long freeswap;                /* swap space still available */
    
11.         unsigned short procs;                /* Number of current processes */
    
12.         unsigned short pad;                /* explicit padding for m68k */
    
13.         unsigned long totalhigh;        /* Total high memory size */
    
14.         unsigned long freehigh;                /* Available high memory size */
    
15.         unsigned int mem_unit;                /* Memory unit size in bytes */
    
16.         char _f[20-2*sizeof(long)-sizeof(int)];        /* Padding: libc5 uses this.. */
    
17. };
    
18. 
    

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上面的在include/kernel.h


获得流程

1. 
   
2. void free_init_pages(char *what, unsigned long begin, unsigned long end)
   
3. {
   
4.         unsigned long addr = begin;
   
5. 
   
6.         if (addr >= end)
   
7.                 return;
   
8. 
   
9.         /*
   
10.          * If debugging page accesses then do not free this memory but
    
11.          * mark them not present - any buggy init-section access will
    
12.          * create a kernel page fault:
    
13.          */
    
14. #ifdef CONFIG_DEBUG_PAGEALLOC
    
15.         printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
    
16.                 begin, PAGE_ALIGN(end));
    
17.         set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
    
18. #else
    
19.         /*
    
20.          * We just marked the kernel text read only above, now that
    
21.          * we are going to free part of that, we need to make that
    
22.          * writeable first.
    
23.          */
    
24.         set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
    
25. 
    
26.         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
    
27. 
    
28.         for (; addr < end; addr += PAGE_SIZE) {
    
29.                 ClearPageReserved(virt_to_page(addr));
    
30.                 init_page_count(virt_to_page(addr));
    
31.                 memset((void *)(addr & ~(PAGE_SIZE-1)),
    
32.                         POISON_FREE_INITMEM, PAGE_SIZE);
    
33.                 free_page(addr);
    
34.                 totalram_pages++;
    
35.         }
    
36. #endif
    
37. }
    
38. 
    

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上面mm/init.c里

1. 
   
2. void si_meminfo(struct sysinfo *val)
   
3. {
   
4.         val->totalram = totalram_pages;
   
5.         val->sharedram = 0;
   
6.         val->freeram = global_page_state(NR_FREE_PAGES);
   
7.         val->bufferram = nr_blockdev_pages();
   
8.         val->totalhigh = totalhigh_pages;
   
9.         val->freehigh = nr_free_highpages();
   
10.         val->mem_unit = PAGE_SIZE;
    
11. }
    

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上面在mm/page_alloc.c里

1. 
   
2. static int meminfo_proc_show(struct seq_file *m, void *v)
   
3. {
   
4.         struct sysinfo i;
   
5.         unsigned long committed;
   
6.         unsigned long allowed;
   
7.         struct vmalloc_info vmi;
   
8.         long cached;
   
9.         unsigned long pages[NR_LRU_LISTS];
   
10.         int lru;
    
11. 
    
12. /*
    
13. * display in kilobytes.
    
14. */
    
15. #define K(x) ((x) << (PAGE_SHIFT - 10))
    
16.         si_meminfo(&i);
    
17.         si_swapinfo(&i);
    
18.         committed = percpu_counter_read_positive(&vm_committed_as);
    
19.         allowed = ((totalram_pages - hugetlb_total_pages())
    
20.                 * sysctl_overcommit_ratio / 100) + total_swap_pages;
    
21. 
    
22.         cached = global_page_state(NR_FILE_PAGES) -
    
23.                         total_swapcache_pages - i.bufferram;
    
24.         if (cached < 0)
    
25.                 cached = 0;
    
26. 
    
27.         get_vmalloc_info(&vmi);
    
28. 
    
29.         for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
    
30.                 pages[lru] = global_page_state(NR_LRU_BASE + lru);
    
31. 
    
32.         /*
    
33.          * Tagged format, for easy grepping and expansion.
    
34.          */
    
35.         seq_printf(m,
    
36.                 "MemTotal:       %8lu kB\n"
    
37.                 "MemFree:        %8lu kB\n"
    
38.                 "Buffers:        %8lu kB\n"
    
39.                 "Cached:         %8lu kB\n"
    
40.                 "SwapCached:     %8lu kB\n"
    
41.                 "Active:         %8lu kB\n"
    
42.                 "Inactive:       %8lu kB\n"
    
43.                 "Active(anon):   %8lu kB\n"
    
44.                 "Inactive(anon): %8lu kB\n"
    
45.                 "Active(file):   %8lu kB\n"
    
46.                 "Inactive(file): %8lu kB\n"
    
47.                 "Unevictable:    %8lu kB\n"
    
48.                 "Mlocked:        %8lu kB\n"
    
49. #ifdef CONFIG_HIGHMEM
    
50.                 "HighTotal:      %8lu kB\n"
    
51.                 "HighFree:       %8lu kB\n"
    
52.                 "LowTotal:       %8lu kB\n"
    
53.                 "LowFree:        %8lu kB\n"
    
54. #endif
    
55. #ifndef CONFIG_MMU
    
56.                 "MmapCopy:       %8lu kB\n"
    
57. #endif
    
58.                 "SwapTotal:      %8lu kB\n"
    
59.                 "SwapFree:       %8lu kB\n"
    
60.                 "Dirty:          %8lu kB\n"
    
61.                 "Writeback:      %8lu kB\n"
    
62.                 "AnonPages:      %8lu kB\n"
    
63.                 "Mapped:         %8lu kB\n"
    
64.                 "Shmem:          %8lu kB\n"
    
65.                 "Slab:           %8lu kB\n"
    
66.                 "SReclaimable:   %8lu kB\n"
    
67.                 "SUnreclaim:     %8lu kB\n"
    
68.                 "KernelStack:    %8lu kB\n"
    
69.                 "PageTables:     %8lu kB\n"
    
70. #ifdef CONFIG_QUICKLIST
    
71.                 "Quicklists:     %8lu kB\n"
    
72. #endif
    
73.                 "NFS_Unstable:   %8lu kB\n"
    
74.                 "Bounce:         %8lu kB\n"
    
75.                 "WritebackTmp:   %8lu kB\n"
    
76.                 "CommitLimit:    %8lu kB\n"
    
77.                 "Committed_AS:   %8lu kB\n"
    
78.                 "VmallocTotal:   %8lu kB\n"
    
79.                 "VmallocUsed:    %8lu kB\n"
    
80.                 "VmallocChunk:   %8lu kB\n"
    
81. #ifdef CONFIG_MEMORY_FAILURE
    
82.                 "HardwareCorrupted: %5lu kB\n"
    
83. #endif
    
84.                 ,
    
85.                 K(i.totalram),
    
86.                 K(i.freeram),
    
87.                 K(i.bufferram),
    
88.                 K(cached),
    
89.                 K(total_swapcache_pages),
    
90.                 K(pages[LRU_ACTIVE_ANON]   + pages[LRU_ACTIVE_FILE]),
    
91.                 K(pages[LRU_INACTIVE_ANON] + pages[LRU_INACTIVE_FILE]),
    
92.                 K(pages[LRU_ACTIVE_ANON]),
    
93.                 K(pages[LRU_INACTIVE_ANON]),
    
94.                 K(pages[LRU_ACTIVE_FILE]),
    
95.                 K(pages[LRU_INACTIVE_FILE]),
    
96.                 K(pages[LRU_UNEVICTABLE]),
    
97.                 K(global_page_state(NR_MLOCK)),
    
98. #ifdef CONFIG_HIGHMEM
    
99.                 K(i.totalhigh),
    
100.                 K(i.freehigh),
     
101.                 K(i.totalram-i.totalhigh),
     
102.                 K(i.freeram-i.freehigh),
     
103. #endif
     
104. #ifndef CONFIG_MMU
     
105.                 K((unsigned long) atomic_long_read(&mmap_pages_allocated)),
     
106. #endif
     
107.                 K(i.totalswap),
     
108.                 K(i.freeswap),
     
109.                 K(global_page_state(NR_FILE_DIRTY)),
     
110.                 K(global_page_state(NR_WRITEBACK)),
     
111.                 K(global_page_state(NR_ANON_PAGES)),
     
112.                 K(global_page_state(NR_FILE_MAPPED)),
     
113.                 K(global_page_state(NR_SHMEM)),
     
114.                 K(global_page_state(NR_SLAB_RECLAIMABLE) +
     
115.                                 global_page_state(NR_SLAB_UNRECLAIMABLE)),
     
116.                 K(global_page_state(NR_SLAB_RECLAIMABLE)),
     
117.                 K(global_page_state(NR_SLAB_UNRECLAIMABLE)),
     
118.                 global_page_state(NR_KERNEL_STACK) * THREAD_SIZE / 1024,
     
119.                 K(global_page_state(NR_PAGETABLE)),
     
120. #ifdef CONFIG_QUICKLIST
     
121.                 K(quicklist_total_size()),
     
122. #endif
     
123.                 K(global_page_state(NR_UNSTABLE_NFS)),
     
124.                 K(global_page_state(NR_BOUNCE)),
     
125.                 K(global_page_state(NR_WRITEBACK_TEMP)),
     
126.                 K(allowed),
     
127.                 K(committed),
     
128.                 (unsigned long)VMALLOC_TOTAL >> 10,
     
129.                 vmi.used >> 10,
     
130.                 vmi.largest_chunk >> 10
     
131. #ifdef CONFIG_MEMORY_FAILURE
     
132.                 ,atomic_long_read(&mce_bad_pages) << (PAGE_SHIFT - 10)
     
133. #endif
     
134.                 );
     
135. 
     
136.         hugetlb_report_meminfo(m);
     
137. 
     
138.         arch_report_meminfo(m);
     
139. 
     
140.         return 0;
     
141. #undef K
     
142. }
     

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输出出来了


希望没误人子弟

Godbach

晕，打分打错地方了。是给15楼的

platinum

看到这个贴子，想起一个游戏 —— 《挖金子》

s.t_seeyou

这么多人感兴趣啊,贴出实现的code了

#include <linux/kernel.h>
#include <linux/mm.h>

{

                                ...
                struct sysinfo i;
#define K(x) ((x) << (PAGE_SHIFT - 10))
                si_meminfo(&i);
                b.sdram_size=K(i.totalram);
#undef  K

                               ...
}

Godbach

呵呵，就是这块了，上面T-bagwell兄贴出来的一样

zestsh

请问仁兄的代码的内核版本是多少？我找到的相应代码不一样，static int meminfo_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data) -> static int meminfo_proc_show(struct seq_file *m, void *v)