Messages in this thread | | | Date | Wed, 30 Apr 2008 15:56:47 -0700 | From | Jeremy Fitzhardinge <> | Subject | Re: [PATCH 1/10] Add generic helpers for arch IPI function calls |
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Jens Axboe wrote: > +/* > + * smp_call_function_single - Run a function on a specific CPU > + * @func: The function to run. This must be fast and non-blocking. > + * @info: An arbitrary pointer to pass to the function. > + * @retry: Unused >
I wonder if it isn't finally time to drop this parameter? Now that there aren't a zillion arch implementations of this to fix, we only need to fix a dozen or so callers.
> + * @wait: If true, wait until function has completed on other CPUs. > + * > + * Returns 0 on success, else a negative status code. > + */ > [...] > +/** > + * smp_call_function_mask(): Run a function on a set of other CPUs. > + * @mask: The set of cpus to run on. > + * @func: The function to run. This must be fast and non-blocking. > + * @info: An arbitrary pointer to pass to the function. > + * @wait: If true, wait (atomically) until function has completed on other CPUs. > + * > + * Returns 0 on success, else a negative status code. > + * > + * If @wait is true, then returns once @func has returned. > + * > + * You must not call this function with disabled interrupts or from a > + * hardware interrupt handler or from a bottom half handler. >
Mention preemption needs to be disabled? Or allow preemption and take appropriate precautions internally? It's not obvious to me that all the callers are calling with preemption disabled.
> + */ > +int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info, > + int wait) > +{ > + struct call_function_data *data; > + cpumask_t allbutself; > + unsigned long flags; > + int cpu, num_cpus; > + > + /* Can deadlock when called with interrupts disabled */ > + WARN_ON(wait && irqs_disabled()); > WARN_ON(preemptible())? preempt_disable()?
> + > + cpu = smp_processor_id(); > + allbutself = cpu_online_map; > + cpu_clear(cpu, allbutself); > + cpus_and(mask, mask, allbutself); > + num_cpus = cpus_weight(mask); > J
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