Re: [patch] HWBKPT: Make bp_len type to u64 generic across the arch

From: Frederic Weisbecker
Date: Mon Feb 01 2010 - 12:45:15 EST


On Mon, Feb 01, 2010 at 09:23:04AM +0100, Peter Zijlstra wrote:
> On Sat, 2010-01-30 at 19:38 +0100, Frederic Weisbecker wrote:
> > > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> > > index 1438463..30c78bd 100644
> > > --- a/include/linux/perf_event.h
> > > +++ b/include/linux/perf_event.h
> > > @@ -211,11 +211,9 @@ struct perf_event_attr {
> > > __u32 wakeup_watermark; /* bytes before wakeup */
> > > };
> > >
> > > - __u32 __reserved_2;
> > > -
> > > - __u64 bp_addr;
> > > __u32 bp_type;
> > > - __u32 bp_len;
> > > + __u64 bp_addr;
> > > + __u64 bp_len;
> > > };
> >
> >
> >
> > Peter, what do you think about this new layout?
> > Putting the bp_type right after the wakeup_* fields
> > is going to remove the padding difference between
> > 64 and 32 archs. That looks better than the __reserved_2
> > we had.
>
> Right, I think this works nicely in that all elements will be naturally
> aligned and not result in different layouts between 32/64 bit builds.
>
> > If this patch can make it for .33, it would be nice.
>
> It has to make .33, if it doesn't you're hosed because then the old
> layout is fixed in stone.
>


Truly.
I'll send a pull request to Ingo quickly then.

Thanks.

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