Messages in this thread | | | Date | Mon, 23 Sep 2013 18:01:30 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] hotplug: Optimize {get,put}_online_cpus() |
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On Mon, Sep 23, 2013 at 08:50:59AM -0700, Paul E. McKenney wrote: > Not a problem, just stuff the idx into some per-task thing. Either > task_struct or taskinfo will work fine.
Still not seeing the point of using srcu though..
srcu_read_lock() vs synchronize_srcu() is the same but far more expensive than preempt_disable() vs synchronize_sched().
> Or to put it another way, if the underlying slow-path mutex is > reader-preference, then the whole thing will be reader-preference.
Right, so 1) we have no such mutex so we're going to have to open-code that anyway, and 2) like I just explained in the other email, I want the pending writer case to be _fast_ as well.
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