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Subject[QUESTION 1/2] Simple question about pagemap
Sorry for simple question.

1. Why physical address is greater than the installed memory?

-- Installed memory is 8GB

RHEL7# grep MemTotal /proc/meminfo
MemTotal: 7840900 kB

RHEL7# dmidecode | grep -A 5 'Memory Device' | grep Size
Size: 4096 MB
Size: No Module Installed
Size: 4096 MB
Size: No Module Installed


-- Physical address is greater than 8GB

RHEL7# wc -c /proc/kpageflags
19136504 /proc/kpageflags

19136504 / 8Bytes x 4KB = 9.125GB


-- My program which is using pagemap shows following.
( From left, Phy_addr, Phy_addr(hex), Virtual_addr(hex), process(PID), kpageflags, [kpagecount] )

9 G 127 M 112 K 247f1c000 v_addr: 7f8bf44b7000 NetworkManager (630)
__RU_lA____M_____________ [56]
9 G 127 M 116 K 247f1d000 v_addr: 7fa9b3adf000 gdm-session-wor(1964)
__RU_lA____M_____________ [5]
9 G 127 M 120 K 247f1e000 v_addr: 7f177ce2e000 systemd-journal(514)
__RU_lA____M_____________ [87]


-- crash shows same physical address.

crash> vtop -c 514 7f177ce2e000
VIRTUAL PHYSICAL
7f177ce2e000 247f1e000



Why greater than installed memory?


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