From: "Wang, Wei W" <wei.w.wang@intel.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: "andrew.cooper3@citrix.com" <andrew.cooper3@citrix.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [PATCH v3 04/11] x86/intel_pstate: relocate the driver register function
Date: Tue, 23 Jun 2015 08:01:42 +0000 [thread overview]
Message-ID: <286AC319A985734F985F78AFA26841F7996F3E@shsmsx102.ccr.corp.intel.com> (raw)
In-Reply-To: <558927600200007800087EFA@mail.emea.novell.com>
On 23/06/2015 15:31, Jan Beulich wrote:
> >>> On 23.06.15 at 05:40, <wei.w.wang@intel.com> wrote:
> > On 18/06/2015 22:30, Jan Beulich wrote:
> >> >>> On 11.06.15 at 10:27, <wei.w.wang@intel.com> wrote:
> >> > -static int __init cpufreq_presmp_init(void)
> >> > +int cpufreq_register_driver(struct cpufreq_driver *driver_data)
> >> > {
> >> > void *cpu = (void *)(long)smp_processor_id();
> >> > cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
> >> > + if (!driver_data || !driver_data->init
> >> > + || !driver_data->verify || !driver_data->exit
> >> > + || (!driver_data->target == !driver_data->setpolicy))
> >>
> >> Do you really want/need to enforce this policy (target set if and
> >> only if setpolicy is not set) here? And if that's to uniformly hold,
> >> the two could be put into a union...
> >
> > driver_data->target() is used by a driver which relies on the old
> > Governor framework.
> > driver_data->setpolicy() is used by a driver which implements its
> > internal governor.
> > So, the driver either uses the old Governor framework or has its own
> > private internal governor.
> > We shouldn't change to use union, because in many places, we
> > distinguish the two by checking if it's using "->target" or "->setpolicy".
>
> The distinction between the two driver modes shouldn't be based on
> arbitrary accessors they may or may not implement. There should be a
> dedicated flag or alike.
This is not arbitrary - "->target()" is dedicated to the Governor framework, and "->setpolicy" is dedicated to the internal governor implementation. The Linux kernel also takes advantage of this method. I think we don't need to add another new functionally equivalent flag to do so.
Shall we keep using it?
Best,
Wei
next prev parent reply other threads:[~2015-06-23 8:01 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-11 8:27 [PATCH v3 04/11] x86/intel_pstate: relocate the driver register function Wei Wang
2015-06-18 14:30 ` Jan Beulich
2015-06-23 3:40 ` Wang, Wei W
2015-06-23 7:31 ` Jan Beulich
2015-06-23 8:01 ` Wang, Wei W [this message]
2015-06-23 8:11 ` Jan Beulich
2015-06-23 8:24 ` Wang, Wei W
2015-06-23 8:37 ` Jan Beulich
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