Subject: Re: [PATCH 1/3] perf events: fix WARN_ON_ONCE for 64-bit raw data,
 SW events
From: Peter Zijlstra <peterz@infradead.org>
To: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: David Ahern <daahern@cisco.com>, linux-perf-users@vger.kernel.org,
        linux-kernel@vger.kernel.org, mingo@elte.hu, paulus@samba.org
In-Reply-To: <20110218170450.GB302@ghostprotocols.net>
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Date: Fri, 18 Feb 2011 18:13:09 +0100
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On Fri, 2011-02-18 at 15:04 -0200, Arnaldo Carvalho de Melo wrote:
> Em Fri, Feb 18, 2011 at 04:01:31PM +0100, Peter Zijlstra escreveu:
> > On Fri, 2011-02-18 at 12:53 -0200, Arnaldo Carvalho de Melo wrote:
> > > > So size should be changed to u64 rather than modifying the
> > > WARN_ON_ONCE?
> > > 
> > > Yeah, I guess so, 32-bit has to die it seems, gets in the way of
> > > testing
> > > :-) 
> > 
> > No!
> > 
> > 1) don't use RAW unless you have to
> > 2) you don't have to, goto 1
> > 3) if you do anyway, ensure its properly padded
> 
> Ok, but using that struct definition on 32-bit land, will lead to non 8 byte
> alignment, right?

Nope, its just fine.. it defaults to an empty 4byte payload ;-)

Its just that any custom payload must be of size 4+8*n bytes.
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