Re: [PATCH 1/5] oom: select_bad_process: check PF_KTHREAD insteadof !mm to skip kthreads

From: David Rientjes
Date: Tue Jun 01 2010 - 16:36:58 EST


On Mon, 31 May 2010, KOSAKI Motohiro wrote:

> From: Oleg Nesterov <oleg@xxxxxxxxxx>
> Subject: oom: select_bad_process: check PF_KTHREAD instead of !mm to skip kthreads
>
> select_bad_process() thinks a kernel thread can't have ->mm != NULL, this
> is not true due to use_mm().
>
> Change the code to check PF_KTHREAD.
>
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>

This is already pushed in my oom killer rewrite as patch 14/18 "check
PF_KTHREAD instead of !mm to skip kthreads".

This does not need to be merged immediately since it's not vital: use_mm()
is only temporary state and these kthreads will once again be excluded
when they call unuse_mm(). The worst case scenario here is that the oom
killer will erroneously select one of these kthreads which cannot die and
will need to reselect another task on its next call.
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