Messages in this thread | | | From | Bjorn Helgaas <> | Date | Wed, 29 Feb 2012 17:42:36 -0700 | Subject | Re: [PATCH 02/39] x86, PCI: have own version for pcibios_bus_to_resource |
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On Wed, Feb 29, 2012 at 4:33 PM, Yinghai Lu <yinghai@kernel.org> wrote: > On Wed, Feb 29, 2012 at 3:20 PM, Bjorn Helgaas <bhelgaas@google.com> wrote: >> On Wed, Feb 29, 2012 at 4:07 PM, Yinghai Lu <yinghai@kernel.org> wrote: >>> x86 does not need to offset the address. So we can skip that costing offset >>> searching. >> >> I tried to start a discussion about this patch (and others), but I >> don't think you responded: >> http://marc.info/?l=linux-pci&m=133036414506921&w=2 > > this patch does reduce some not needed ops. > > and it does not affects your effects,
It does affect my efforts in that this patch adds back x86 complexity that I don't think is necessary.
And this patch makes it so the pci_add_resource_offset() interface exists and appears to work on x86, but if somebody tries to use it, it *doesn't* work. I don't like to write code like that. I think it's poor style.
> and it just make x86 not get punished.
What punishment are you worried about? I really don't think you'll be able to measure any performance impact.
I agree that the x86 code you add *is* simpler than the generic version. But I think the *overall* complexity is higher because now you have to look at two versions (generic and x86) and convince yourself that it's safe to use the x86 version.
Bjorn
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