Re: [PATCH] trace: Set oom_score_adj to maximum for ring bufferallocating process

[David Rientjes]

On Thu, 26 May 2011, Steven Rostedt wrote:

> Hmm, have you tried this in practice? Yes we may kill the "echo" command
> but it doesn't stop the ring buffer from being allocated, and thus
> killing the echo command may not be enough, and those critical processes
> that you are trying to protect will be killed next.
> 
> Perhaps we should change the allocation of the ring buffer or detect OOM
> triggering. Maybe make all the allocations ATOMIC, thus it will be
> either available or not, and fail instead of trying to swap out other
> memory for the allocation.
> 

My impression of this was that it was attempting to avoid killing a 
different process by means of the oom killer rather than avoiding swap.  I 
don't think there's anything wrong with using GFP_KERNEL, but I'd suggest 
also using __GFP_NORETRY so the allocation calls into direct reclaim but 
will avoid oom killing anything and simply failing instead.
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