• Minchan Kim's avatar
    memory-hotplug: fix zone stat mismatch · 5a883813
    Minchan Kim authored
    During memory-hotplug, I found NR_ISOLATED_[ANON|FILE] are increasing,
    causing the kernel to hang.  When the system doesn't have enough free
    pages, it enters reclaim but never reclaim any pages due to
    too_many_isolated()==true and loops forever.
    
    The cause is that when we do memory-hotadd after memory-remove,
    __zone_pcp_update() clears a zone's ZONE_STAT_ITEMS in setup_pageset()
    although the vm_stat_diff of all CPUs still have values.
    
    In addtion, when we offline all pages of the zone, we reset them in
    zone_pcp_reset without draining so we loss some zone stat item.
    Reviewed-by: default avatarWen Congyang <wency@cn.fujitsu.com>
    Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
    Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
    Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
    Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    5a883813
vmstat.c 33.6 KB