Re: [PATCH] oom: skip frozen tasks

From: David Rientjes
Date: Tue Aug 23 2011 - 16:18:27 EST


On Tue, 23 Aug 2011, Konstantin Khlebnikov wrote:

> All frozen tasks are unkillable, and if one of them has TIF_MEMDIE
> we must kill something else to avoid deadlock. After this patch
> select_bad_process() will skip frozen task before checking TIF_MEMDIE.
>

The caveat is that if the task in the refrigerator is not OOM_DISABLE and
there are no other eligible tasks (system wide, in the cpuset, or in the
memcg) to kill, then the machine will panic as a result of this when, in
the past, we would simply issue the SIGKILL and keep looping in the page
allocator until it is thawed.

So you may actually be trading a stall waiting for this thread to thaw for
what would now be a panic, and that's not clearly better to me.
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