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    oom: replace PF_OOM_ORIGIN with toggling oom_score_adj · 72788c38
    David Rientjes 提交于
    There's a kernel-wide shortage of per-process flags, so it's always
    helpful to trim one when possible without incurring a significant penalty.
     It's even more important when you're planning on adding a per- process
    flag yourself, which I plan to do shortly for transparent hugepages.
    
    PF_OOM_ORIGIN is used by ksm and swapoff to prefer current since it has a
    tendency to allocate large amounts of memory and should be preferred for
    killing over other tasks.  We'd rather immediately kill the task making
    the errant syscall rather than penalizing an innocent task.
    
    This patch removes PF_OOM_ORIGIN since its behavior is equivalent to
    setting the process's oom_score_adj to OOM_SCORE_ADJ_MAX.
    
    The process's old oom_score_adj is stored and then set to
    OOM_SCORE_ADJ_MAX during the time it used to have PF_OOM_ORIGIN.  The old
    value is then reinstated when the process should no longer be considered a
    high priority for oom killing.
    Signed-off-by: NDavid Rientjes <rientjes@google.com>
    Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
    Cc: Hugh Dickins <hughd@google.com>
    Cc: Izik Eidus <ieidus@redhat.com>
    Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    72788c38
swapfile.c 65.3 KB