Re: NMI handling rework

From: Zwane Mwaikambo (zwane@holomorphy.com)
Date: Fri Nov 15 2002 - 00:12:29 EST

On Thu, 14 Nov 2002, Corey Minyard wrote:

> RCU does. Basically, the code pulls it from the list atomically wrt to
> the NMI handler, and uses RCU to schedule the actual free of the data to
> be done after all CPUs have gone to idle or returned from interrupts.
> It's subtle, you have to think about it a little. But it does work.

Still not convinced, i still want to know which interrupt rate and how
many processors. Are the following functions really protected from say
NMIs at 300,000/s? request_nmi actually looks dodgiest.

static void free_nmi_handler(void *arg)
{
        struct nmi_handler *handler = arg;

        INIT_LIST_HEAD(&(handler->link));
        complete(&(handler->complete));
}

void release_nmi(struct nmi_handler *handler)
{
        spin_lock(&nmi_handler_lock);
        list_del_rcu(&(handler->link));
        init_completion(&(handler->complete));
        call_rcu(&(handler->rcu), free_nmi_handler, handler);
        spin_unlock(&nmi_handler_lock);
} 

-- 
function.linuxpower.ca

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