Messages in this thread | | | Subject | Re: [PATCH 2/3] FRV: Permit __do_IRQ() to be dispensed with | From | Benjamin Herrenschmidt <> | Date | Sat, 09 Sep 2006 17:26:41 +1000 |
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On Sat, 2006-09-09 at 07:12 +0200, Ingo Molnar wrote: > * David Howells <dhowells@redhat.com> wrote: > > > +#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ > > > +#ifdef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ > > > +#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ > > I think the myriad of arch switches and the resulting #ifdef noise, just > to get rid of a _single_ unused global function, is pretty lame. (and > that's of course not your fault) > > The real solution would be to use gcc -ffunction-sections plus ld > --gc-sections to automatically get rid of unused global functions, at > link time. I'm wondering how hard it would be to enhance kbuild to do > that - x86_64 already uses -ffunction-sections (if CONFIG_REORDER), so > the big question is how usable is ld --gc-sections. Such a feature would > be quite important for embedded systems (and for RAM footprint in > general) as it would save a significant amount of .text and .data.
It can't optimize __do_IRQ() out in any case if one uses generic_handle_irq() because of the test in there which can't be predicted at compile time. My fault ... Maybe we should go back to having generic_handle_irq() not do the NULL test and not call __do_IRQ() and have another generic_handle_irq_compat() or some stupid name like that do what the current generic_handle_irq() does. I added that to handle the case of partial conversion (which we still have to deal with on powerpc as arch/ppc hasn't been converted).
Ben.
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