linux-kernel - RE: [PATCH v5 07/12] perf/x86: no counter allocation support

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Message-ID: <286AC319A985734F985F78AFA26841F73DF71EAF@shsmsx102.ccr.corp.intel.com>
Date:   Fri, 15 Feb 2019 08:49:49 +0000
From:   "Wang, Wei W" <wei.w.wang@...el.com>
To:     'Andi Kleen' <ak@...ux.intel.com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "pbonzini@...hat.com" <pbonzini@...hat.com>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "Liang, Kan" <kan.liang@...el.com>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "rkrcmar@...hat.com" <rkrcmar@...hat.com>,
        "Xu, Like" <like.xu@...el.com>,
        "jannh@...gle.com" <jannh@...gle.com>,
        "arei.gonglei@...wei.com" <arei.gonglei@...wei.com>,
        "jmattson@...gle.com" <jmattson@...gle.com>
Subject: RE: [PATCH v5 07/12] perf/x86: no counter allocation support

On Friday, February 15, 2019 12:26 AM, Andi Kleen wrote:
> > diff --git a/include/uapi/linux/perf_event.h
> > b/include/uapi/linux/perf_event.h index 9de8780..ec97a70 100644
> > --- a/include/uapi/linux/perf_event.h
> > +++ b/include/uapi/linux/perf_event.h
> > @@ -372,7 +372,8 @@ struct perf_event_attr {
> >  				context_switch :  1, /* context switch data */
> >  				write_backward :  1, /* Write ring buffer from
> end to beginning */
> >  				namespaces     :  1, /* include namespaces
> data */
> > -				__reserved_1   : 35;
> > +				no_counter     :  1, /* no counter allocation */
> 
> Not sure we really want to expose this in the user ABI. Perhaps make it a
> feature of the in kernel API only?

OK. I plan to move it to the perf_event struct.

Best,
Wei