linux-kernel - Re: [PATCH] perf: x86: fix callgraphs of 32-bit processes on 64-bit kernels V2.

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Message-ID: <20100317095957.GG17146@elte.hu>
Date:	Wed, 17 Mar 2010 10:59:57 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	T?r?k Edwin <edwintorok@...il.com>
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] perf: x86: fix callgraphs of 32-bit processes on 64-bit
 kernels V2.


* T?r?k Edwin <edwintorok@...il.com> wrote:

> >> +	    }
> >> +	    return;
> > 
> > This whole new block should probably be in a helper inline?
> 
> To reduce indenting, or why?

Mainly to increase cleanliness. We want code that isolates separate blocks of 
logic into separate sections. So a simple construct of:

        if (perf_callchain_user32(regs, entry))
                return;

will tell the reader of the code that 'ok, this is 32-bit compat stuff'. It 
doesnt, at this level, intrude into the main logic of that function. Then if 
we look at perf_callchain_user32() we see all the 32-bit compat stack frame 
walking details.

Thanks,

	Ingo
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