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Re: [Xen-devel] [PATCH v3 5/4] x86: reduce code size of struct cpu_info member accesses



>>> On 25.03.16 at 19:47, <konrad.wilk@xxxxxxxxxx> wrote:
> On Thu, Mar 17, 2016 at 10:14:22AM -0600, Jan Beulich wrote:
> 
> Something is off with your patch. This is 5/4 :-)

Well, yes - this got added later on top of the previously sent series,
to make the dependency obvious.

>> Instead of addressing these fields via the base of the stack (which
>> uniformly requires 4-byte displacements), address them from the end
>> (which for everything other than guest_cpu_user_regs requires just
>> 1-byte ones). This yields a code size reduction somewhere between 8k
>> and 12k in my builds.
> 
> Also you made the macro a bit different - the %r is removed.
> 
> Particular reason? 

This is an integral part of the change, so the macro can derive
e.g. both %eax and %rax from the passed argument

Jan


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