Messages in this thread | | | Subject | Re: [patch] x86: allow ZONE_DMA to be configurable | From | "H. Peter Anvin" <> | Date | Wed, 13 Oct 2010 19:38:03 -0700 |
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How do you know it is not a fatal condition?
"David Rientjes" <rientjes@google.com> wrote:
>On Wed, 13 Oct 2010, H. Peter Anvin wrote: > >> And the value of those additional options is what? I'd consider adding >> this to the sewer pit called CONFIG_EMBEDDED (with a BUG_ON, not a >> warning... sheesh) > >BUG_ON() could panic the machine which would be rather unfortunate if we >simply tried to load a driver that the kernel no longer supports because >it doesn't have DMA. A WARN_ON() seems much more appropriate to identify >what the problem was. It's not a fatal condition. > >> but only if there is any demonstrable value other >> than a trivial amount of code (kilobytes?) in exchange for a bunch of >> crap #ifdef. >> > >The data savings is about 1% and the text savings is about 0.1% with all >three options disabled: > >7922297 1245500 989600 10157397 9afd55 vmlinux.before >7914674 1232700 989472 10136846 9aad0e vmlinux.after > >This is the only #ifdef necessary to make CONFIG_ZONE_DMA=n compile and >CONFIG_GENERIC_ISA_DMA=n would require two additional #ifdefs >(CONFIG_ISA_DMA_API=n would require none). We carry this patch >internally, so it would be trivial to send follow-up patches that do that >if this patch is merged.
-- Sent from my mobile phone. Please pardon any lack of formatting.
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