Re: [PATCH] Make RCU task_struct safe for oprofile
From: Ingo Molnar
Date: Sun Nov 27 2005 - 07:30:10 EST
* Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:
> Applying RCU to the task structure broke oprofile, because
> free_task_notify() can now be called from softirq. This means that
> the task_mortuary lock must be acquired with irq disabled in order to
> avoid intermittent self-deadlock. Since irq is now disabled, the
> critical section within process_task_mortuary() has been restructured
> to be O(1) in order to maximize scalability and minimize realtime
> latency degradation.
> Kudos to Wu Fengguang for finding this problem!
thanks, i applied this to the -rt tree.
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