Messages in this thread | | | From | Andy Lutomirski <> | Date | Sun, 9 Jun 2019 21:26:29 -0700 | Subject | Re: [PATCH v4 3/5] x86/umwait: Add sysfs interface to control umwait C0.2 state |
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On Sun, Jun 9, 2019 at 9:14 PM Fenghua Yu <fenghua.yu@intel.com> wrote: > > On Sat, Jun 08, 2019 at 03:52:03PM -0700, Andy Lutomirski wrote: > > On Fri, Jun 7, 2019 at 3:10 PM Fenghua Yu <fenghua.yu@intel.com> wrote: > > > > > > C0.2 state in umwait and tpause instructions can be enabled or disabled > > > on a processor through IA32_UMWAIT_CONTROL MSR register. > > > > > > > > +static u32 get_umwait_control_c02(void) > > > +{ > > > + return umwait_control_cached & MSR_IA32_UMWAIT_CONTROL_C02; > > > +} > > > + > > > +static u32 get_umwait_control_max_time(void) > > > +{ > > > + return umwait_control_cached & MSR_IA32_UMWAIT_CONTROL_MAX_TIME; > > > +} > > > + > > > > I'm not convinced that these helpers make the code any more readable. > > The helpers reduce length of statements that call them. Otherwise, all of > the statements would be easily over 80 characters. > > Plus, each of the helpers is called multiple places in #0003 and #0004. > So the helpers make the patches smaller and cleaner. >
I was imagining things like:
umwait_control_cached &= ~MSR_IA32_UMWAIT_CONTROL_C02; if (whatever condition) umwait_control_cached |= MSR_IA32_UMWAIT_CONTROL_C02; umwait_control_cached &= ~MSR_IA32_UMWAIT_CONTROL_MAX_TIME; umwait_control_cached |= new_max_time;
You could save 8 characters by just calling the variable umwait_control.
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