mm: direct mapping count in /proc/meminfo is error

RFC Xishi Qiu 2 participants 3 messages Nov 20, 2015 Memory management

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Xishi Qiu

author

2015-11-20 08:17 UTC #0 lore raw

I find the direct mapping count in /proc/meminfo is error. The value should be equal to the size of init_memory_mapping which showed in boot log.

I add some print to show direct_pages_count[] immediately after init_memory_mapping(). The reason is that we double counting.

Here is the log(kernel v4.4):
...

[    0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff]  // called from "init_memory_mapping(0, ISA_END_ADDRESS);"
[    0.000000]  [mem 0x00000000-0x000fffff] page 4k
[    0.000000] BRK [0x01ebf000, 0x01ebffff] PGTABLE
[    0.000000] BRK [0x01ec0000, 0x01ec0fff] PGTABLE
[    0.000000] BRK [0x01ec1000, 0x01ec1fff] PGTABLE
[    0.000000] init_memory_mapping: [mem 0xc3fe00000-0xc3fffffff]  // called from "memory_map_top_down(ISA_END_ADDRESS, end);"
[    0.000000]  [mem 0xc3fe00000-0xc3fffffff] page 1G  // increase count of PG_LEVEL_1G in c00000000(48G)-c3fffffff(49G) one time
[    0.000000] init_memory_mapping: [mem 0xc20000000-0xc3fdfffff]
[    0.000000]  [mem 0xc20000000-0xc3fdfffff] page 1G  // increase count of PG_LEVEL_1G in c00000000(48G)-c3fffffff(49G) two time
[    0.000000] init_memory_mapping: [mem 0x00100000-0xbf78ffff]
[    0.000000]  [mem 0x00100000-0x001fffff] page 4k
[    0.000000]  [mem 0x00200000-0x3fffffff] page 2M
[    0.000000]  [mem 0x40000000-0x7fffffff] page 1G
[    0.000000]  [mem 0x80000000-0xbf5fffff] page 2M
[    0.000000]  [mem 0xbf600000-0xbf78ffff] page 4k
[    0.000000] init_memory_mapping: [mem 0x100000000-0xc1fffffff]
[    0.000000]  [mem 0x100000000-0xc1fffffff] page 1G  // increase count of PG_LEVEL_1G in c00000000(48G)-c3fffffff(49G) three time
...
[    0.000000] DirectMap4k:        3648 kB
[    0.000000] DirectMap2M:     2084864 kB
[    0.000000] DirectMap1G:    50331648 kB

euler-linux:~ # cat /proc/meminfo | grep DirectMap

DirectMap4k:       91712 kB
DirectMap2M:     4093952 kB
DirectMap1G:    48234496 kB

total DirectMap is 48234496 + 4093952 + 91712 = 52420160kb

		    50331648 + 2084864 + 3648 = 52420160kb

total init_memory_mapping is 50323008kb

52420160kb - 50323008kb = 2097152kb = 2G

However I haven't find a better way to fix it, any ideas?

Thanks,
Xishi Qiu

Tang Chen

2015-11-20 08:46 UTC #1 lore raw

Hi Shi,

Would you please share where did you add the printk debug info ?

Thanks. :)

Quoted 43 lines · Xishi Qiu

I find the direct mapping count in /proc/meminfo is error. The value should be equal to the size of init_memory_mapping which showed in boot log.

I add some print to show direct_pages_count[] immediately after init_memory_mapping(). The reason is that we double counting.

Here is the log(kernel v4.4):
...

[    0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff]  // called from "init_memory_mapping(0, ISA_END_ADDRESS);"
[    0.000000]  [mem 0x00000000-0x000fffff] page 4k
[    0.000000] BRK [0x01ebf000, 0x01ebffff] PGTABLE
[    0.000000] BRK [0x01ec0000, 0x01ec0fff] PGTABLE
[    0.000000] BRK [0x01ec1000, 0x01ec1fff] PGTABLE
[    0.000000] init_memory_mapping: [mem 0xc3fe00000-0xc3fffffff]  // called from "memory_map_top_down(ISA_END_ADDRESS, end);"
[    0.000000]  [mem 0xc3fe00000-0xc3fffffff] page 1G  // increase count of PG_LEVEL_1G in c00000000(48G)-c3fffffff(49G) one time
[    0.000000] init_memory_mapping: [mem 0xc20000000-0xc3fdfffff]
[    0.000000]  [mem 0xc20000000-0xc3fdfffff] page 1G  // increase count of PG_LEVEL_1G in c00000000(48G)-c3fffffff(49G) two time
[    0.000000] init_memory_mapping: [mem 0x00100000-0xbf78ffff]
[    0.000000]  [mem 0x00100000-0x001fffff] page 4k
[    0.000000]  [mem 0x00200000-0x3fffffff] page 2M
[    0.000000]  [mem 0x40000000-0x7fffffff] page 1G
[    0.000000]  [mem 0x80000000-0xbf5fffff] page 2M
[    0.000000]  [mem 0xbf600000-0xbf78ffff] page 4k
[    0.000000] init_memory_mapping: [mem 0x100000000-0xc1fffffff]
[    0.000000]  [mem 0x100000000-0xc1fffffff] page 1G  // increase count of PG_LEVEL_1G in c00000000(48G)-c3fffffff(49G) three time
...
[    0.000000] DirectMap4k:        3648 kB
[    0.000000] DirectMap2M:     2084864 kB
[    0.000000] DirectMap1G:    50331648 kB

euler-linux:~ # cat /proc/meminfo | grep DirectMap

DirectMap4k:       91712 kB
DirectMap2M:     4093952 kB
DirectMap1G:    48234496 kB

total DirectMap is 48234496 + 4093952 + 91712 = 52420160kb

		    50331648 + 2084864 + 3648 = 52420160kb

total init_memory_mapping is 50323008kb

52420160kb - 50323008kb = 2097152kb = 2G

Quoted 8 lines

However I haven't find a better way to fix it, any ideas?
Thanks,
Xishi Qiu
.

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Xishi Qiu

author

2015-11-20 09:47 UTC #2 lore raw

Quoted 4 lines · Tang Chen

Hi Shi,
Would you please share where did you add the printk debug info ?

Sure, at the end of init_mem_mapping(), I add a new function, like arch_report_meminfo(), just change "seq_printf" to "printk".

Thanks,
Xishi Qiu

Quoted 58 lines

Thanks. :)

Quoted 43 lines · Xishi Qiu

I find the direct mapping count in /proc/meminfo is error. The value should be equal to the size of init_memory_mapping which showed in boot log.

I add some print to show direct_pages_count[] immediately after init_memory_mapping(). The reason is that we double counting.

Here is the log(kernel v4.4):
...

[    0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff]  // called from "init_memory_mapping(0, ISA_END_ADDRESS);"
[    0.000000]  [mem 0x00000000-0x000fffff] page 4k
[    0.000000] BRK [0x01ebf000, 0x01ebffff] PGTABLE
[    0.000000] BRK [0x01ec0000, 0x01ec0fff] PGTABLE
[    0.000000] BRK [0x01ec1000, 0x01ec1fff] PGTABLE
[    0.000000] init_memory_mapping: [mem 0xc3fe00000-0xc3fffffff]  // called from "memory_map_top_down(ISA_END_ADDRESS, end);"
[    0.000000]  [mem 0xc3fe00000-0xc3fffffff] page 1G  // increase count of PG_LEVEL_1G in c00000000(48G)-c3fffffff(49G) one time
[    0.000000] init_memory_mapping: [mem 0xc20000000-0xc3fdfffff]
[    0.000000]  [mem 0xc20000000-0xc3fdfffff] page 1G  // increase count of PG_LEVEL_1G in c00000000(48G)-c3fffffff(49G) two time
[    0.000000] init_memory_mapping: [mem 0x00100000-0xbf78ffff]
[    0.000000]  [mem 0x00100000-0x001fffff] page 4k
[    0.000000]  [mem 0x00200000-0x3fffffff] page 2M
[    0.000000]  [mem 0x40000000-0x7fffffff] page 1G
[    0.000000]  [mem 0x80000000-0xbf5fffff] page 2M
[    0.000000]  [mem 0xbf600000-0xbf78ffff] page 4k
[    0.000000] init_memory_mapping: [mem 0x100000000-0xc1fffffff]
[    0.000000]  [mem 0x100000000-0xc1fffffff] page 1G  // increase count of PG_LEVEL_1G in c00000000(48G)-c3fffffff(49G) three time
...
[    0.000000] DirectMap4k:        3648 kB
[    0.000000] DirectMap2M:     2084864 kB
[    0.000000] DirectMap1G:    50331648 kB

euler-linux:~ # cat /proc/meminfo | grep DirectMap

DirectMap4k:       91712 kB
DirectMap2M:     4093952 kB
DirectMap1G:    48234496 kB

total DirectMap is 48234496 + 4093952 + 91712 = 52420160kb

            50331648 + 2084864 + 3648 = 52420160kb

total init_memory_mapping is 50323008kb

52420160kb - 50323008kb = 2097152kb = 2G

Quoted 8 lines

However I haven't find a better way to fix it, any ideas?
Thanks,
Xishi Qiu
.