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  • Lai Jiangshan's avatar
    memory_hotplug: fix possible incorrect node_states[N_NORMAL_MEMORY] · d9713679
    Lai Jiangshan authored
    
    
    Currently memory_hotplug only manages the node_states[N_HIGH_MEMORY], it
    forgets to manage node_states[N_NORMAL_MEMORY].  This may cause
    node_states[N_NORMAL_MEMORY] to become incorrect.
    
    Example, if a node is empty before online, and we online a memory which is
    in ZONE_NORMAL.  And after online, node_states[N_HIGH_MEMORY] is correct,
    but node_states[N_NORMAL_MEMORY] is incorrect, the online code doesn't set
    the new online node to node_states[N_NORMAL_MEMORY].
    
    The same thing will happen when offlining (the offline code doesn't clear
    the node from node_states[N_NORMAL_MEMORY] when needed).  Some memory
    managment code depends node_states[N_NORMAL_MEMORY], so we have to fix up
    the node_states[N_NORMAL_MEMORY].
    
    We add node_states_check_changes_online() and
    node_states_check_changes_offline() to detect whether
    node_states[N_HIGH_MEMORY] and node_states[N_NORMAL_MEMORY] are changed
    while hotpluging.
    
    Also add @status_change_nid_normal to struct memory_notify, thus the
    memory hotplug callbacks know whether the node_states[N_NORMAL_MEMORY] are
    changed.  (We can add a @flags and reuse @status_change_nid instead of
    introducing @status_change_nid_normal, but it will add much more
    complexity in memory hotplug callback in every subsystem.  So introducing
    @status_change_nid_normal is better and it doesn't change the sematics of
    @status_change_nid)
    
    Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
    Cc: David Rientjes <rientjes@google.com>
    Cc: Minchan Kim <minchan.kim@gmail.com>
    Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
    Cc: Rob Landley <rob@landley.net>
    Cc: Jiang Liu <jiang.liu@huawei.com>
    Cc: Kay Sievers <kay.sievers@vrfy.org>
    Cc: Greg Kroah-Hartman <gregkh@suse.de>
    Cc: Mel Gorman <mgorman@suse.de>
    Cc: Wen Congyang <wency@cn.fujitsu.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    d9713679