linux-kernel - Re: [PATCH 14/21] x86/intel_rdt/cqm: Add mon

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Date:   Fri, 7 Jul 2017 08:22:22 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Shivappa Vikas <vikas.shivappa@...el.com>
cc:     Vikas Shivappa <vikas.shivappa@...ux.intel.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, hpa@...or.com, peterz@...radead.org,
        ravi.v.shankar@...el.com, tony.luck@...el.com,
        fenghua.yu@...el.com, andi.kleen@...el.com
Subject: Re: [PATCH 14/21] x86/intel_rdt/cqm: Add mon_data

On Thu, 6 Jul 2017, Shivappa Vikas wrote:
> On Sun, 2 Jul 2017, Thomas Gleixner wrote:
> > > +static bool __mon_event_count(u32 rmid, struct rmid_read *rr)
> > > +{
> > > +	u64 tval;
> > > +
> > > +	tval = __rmid_read(rmid, rr->evtid);
> > > +	if (tval & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL)) {
> > > +		rr->val = tval;
> > > +		return false;
> > > +	}
> > > +	switch (rr->evtid) {
> > > +	case QOS_L3_OCCUP_EVENT_ID:
> > > +		rr->val += tval;
> > > +		return true;
> > > +	default:
> > > +		return false;
> > 
> > I have no idea what that return code means.
> 
> false for the invalid event id and all errors for __rmid_read. (IOW all errors
> for __mon_event-read)

Sure, but why bool? What's wrong with proper error return codes, so issues
can be distinguished and potentially propagated in the callchain?

Thanks,

	tglx