Re: [ANNOUNCE] Linux 2.6 Real Time Kernel

[Ingo Molnar]

* Dipankar Sarma <dipankar@xxxxxxxxxx> wrote:

> It seems that way to me too. Long ago I implemented preemptible RCU,
> but did not follow it through because I believed it was not a good
> idea. The original patch is here :
> 
> http://www.uwsg.iu.edu/hypermail/linux/kernel/0205.1/0026.html
> 
> This allows read-side critical sections of RCU to be preempted. It
> will take a bit of work to re-use it in RCU as of now, but I don't
> think it makes sense to do so. My primary concern is DoS/OOM situation
> due to preempted tasks holding up RCU.

the DoS/OOM problems are serious i believe. Preemptible RCU in that
sense is 'RCU with no guarantee of progress', which sounds bad from a
design POV.

	Ingo
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