Re: [patch v2] oom: replace PF_OOM_ORIGIN with toggling oom_score_adj

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

> 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: David Rientjes <rientjes@google.com>
> ---
>  v2: s/OOM_SCORE_ADJ_MIN/OOM_SCORE_ADJ_MAX/ as pointed out by
>      KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>

Good patch.
	Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>




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