Messages in this thread | | | Date | Thu, 12 Oct 2017 17:13:34 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH v9 2/5] x86/cpuid: Add generic table for cpuid dependencies |
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On Thu, 12 Oct 2017, Ingo Molnar wrote: > > * Andi Kleen <andi@firstfloor.org> wrote: > > > --- /dev/null > > +++ b/arch/x86/kernel/cpu/cpuid-deps.c > > @@ -0,0 +1,109 @@ > > +/* Declare dependencies between CPUIDs */ > > +#include <linux/kernel.h> > > +#include <linux/init.h> > > +#include <linux/module.h> > > +#include <asm/cpufeature.h> > > + > > +struct cpuid_dep { > > + unsigned short feature; > > + unsigned short depends; > > +}; > > Why are these 16-bit fields? 16-bit data types should be avoided as much as > possible, as they generate suboptimal code.
I was looking at that as well and decided that we preferrably have a compressed data structure. The code which walks the table is hardly performance critical and the difference in text size is marginal.
Thanks,
tglx
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