Re: [PATCH 4/6] perf_counter: Add PERF_COUNTER_IOC_SET_FILTER ioctl

Tom Zanussi
2009-09-10T04:45:59Z

On Wed, 2009-09-09 at 10:18 +0800, Li Zefan wrote:
> >>>> Hrm,.. not at all sure about this.. what are the ABI implications?
> >>> I think the ABI should be fine if it's always a sub-set of C syntax.
> >>> That would be C expressions initially. Hm?
> >> Right, so I've no clue what filter expressions look like, and the
> >> changelog doesn't help us at all. It doesn't mention its a well
> >> considered decision to henceforth freeze the expression syntax.
> >>
> >> Of course, since filters so far only work with tracepoint things, and
> >> since you can only come by tracepoint things through debugfs, and since
> >> anything debugfs is basically a free-for-all ABI-less world, we might be
> >> good, but then this is a very ill-defined ioctl() indeed.
> >>
> >> So please, consider this well -- there might not be a second chance.
> >>
> >
> > I've been meaning to write up something about the event filters - here's
> > a first stab that hopefully helps explain them...
> >
>
> Great!
>
> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
>
> Could you add your SOB and send it to Ingo?
>
> Some nitpicks below:

Sure, I'll send a new version shortly - thanks for the suggestions.

Tom