On Thu, 01 Mar 2007 03:47:39 -0800 Zachary Amsden <[EMAIL PROTECTED]> wrote:
> Rusty Russell wrote: > > On Thu, 2007-03-01 at 03:34 -0800, Zachary Amsden wrote: > > > >> What would be really, really nice would be to statically check all > >> callsites that issue irq disables actually keep irqs disabled. > >> Presumably, there was a reason they disabled irqs, and re-enabling them > >> underneath their noses, even if it is to avoid a race, breaks the logic > >> behind that reason. > >> > > > > For the moment, how about a BUG_ON() in on_each_cpu()? > > > > Sounds quite decent. But why does on_each_cpu need to disable > interrupts at all? It just calls func(), then re-enables interrupts. > So whatever was going to happen during func() that might not be > interrupt safe could just be done in the callee, avoiding the rather > expensive mess of disabling and re-enabling interrupts for those cases > where it doesn't matter. The handler for smp_call_function() is called with local interrupts disabled (from the IPI handler). So to provide a consistent call environment for that handler, on_each_cpu() will also disable local interrupts when making the direct call on this CPU. Similarly the !CONFIG_SMP version of on_each_cpu() disables local interrupts when running the caller's function. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
