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

[Minchan Kim <minchan.kim@gmail.com>]

On Thu, Apr 14, 2011 at 9:41 AM, David Rientjes <rientjes@google.com> wrote:
> 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>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>

Seem to be reasonable and code don't have a problem.
But couldn't we make the function in general(ex, passed task_struct)
and use it when we change oom_score_adj(ex, oom_score_adj_write)?

-- 
Kind regards,
Minchan Kim

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