Re: [PATCH v2 6/9] rcu: use __this_cpu_read helper instead ofper_cpu_ptr(p, raw_smp_processor_id())

[Christoph Lameter]

On Mon, 5 Nov 2012, 锟斤拷锟斤拷 wrote:

> I guarantee that x86-64 don't use gs register here. run test again锟斤拷
> Maybe there is some optimizations for __this_cpu_read call on x86-64锟斤拷 not
> sure.

There is no optimization that I know of unless the compiler eliminated the
__this_cpu_read completely. gs: is necessary to perform the implied
relocation in this_cpu_read().