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    mm/memory-hotplug: fix lowmem count overflow when offline pages · 76422578
    Wanpeng Li authored
    
    
    commit cea27eb2a202959783f81254c48c250ddd80e129 upstream.
    
    The logic for the memory-remove code fails to correctly account the
    Total High Memory when a memory block which contains High Memory is
    offlined as shown in the example below.  The following patch fixes it.
    
    Before logic memory remove:
    
    MemTotal:        7603740 kB
    MemFree:         6329612 kB
    Buffers:           94352 kB
    Cached:           872008 kB
    SwapCached:            0 kB
    Active:           626932 kB
    Inactive:         519216 kB
    Active(anon):     180776 kB
    Inactive(anon):   222944 kB
    Active(file):     446156 kB
    Inactive(file):   296272 kB
    Unevictable:           0 kB
    Mlocked:               0 kB
    HighTotal:       7294672 kB
    HighFree:        5704696 kB
    LowTotal:         309068 kB
    LowFree:          624916 kB
    
    After logic memory remove:
    
    MemTotal:        7079452 kB
    MemFree:         5805976 kB
    Buffers:           94372 kB
    Cached:           872000 kB
    SwapCached:            0 kB
    Active:           626936 kB
    Inactive:         519236 kB
    Active(anon):     180780 kB
    Inactive(anon):   222944 kB
    Active(file):     446156 kB
    Inactive(file):   296292 kB
    Unevictable:           0 kB
    Mlocked:               0 kB
    HighTotal:       7294672 kB
    HighFree:        5181024 kB
    LowTotal:       4294752076 kB
    LowFree:          624952 kB
    
    [mhocko@suse.cz: fix CONFIG_HIGHMEM=n build]
    Signed-off-by: default avatarWanpeng Li <liwanp@linux.vnet.ibm.com>
    Reviewed-by: default avatarMichal Hocko <mhocko@suse.cz>
    Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
    Cc: David Rientjes <rientjes@google.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    76422578