linux-kernel - Re: [PATCH 2/5] mm: remove unlikly NULL from kfree

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Date:	Wed, 25 Mar 2009 15:51:49 +0200
From:	Pekka Enberg <penberg@...helsinki.fi>
To:	Hua Zhong <hzhong@...il.com>
Cc:	Steven Rostedt <rostedt@...dmis.org>, linux-kernel@...r.kernel.org,
	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Peter Zijlstra <peterz@...radead.org>,
	Roland McGrath <roland@...hat.com>,
	Nick Piggin <nickpiggin@...oo.com.au>,
	Steven Rostedt <srostedt@...hat.com>,
	Christoph Lameter <cl@...ux-foundation.org>,
	Matt Mackall <mpm@...enic.com>,
	Al Viro <viro@...iv.linux.org.uk>
Subject: Re: [PATCH 2/5] mm: remove unlikly NULL from kfree

On Wed, 2009-03-25 at 01:02 -0700, Hua Zhong wrote:
>> > But those are _error handling paths_ (at least supposed to be). I
>> > wonder which call-sites are responsible for this. Can frtrace help us
>> > here?
>>
>> I am not sure why you call these error paths.
>>
>> I submitted the same patch two years ago, and you are still holding the same
>> argument.
>>
>> http://www.archivum.info/linux.kernel/2006-04/msg06042.html
>>
>> Have you used likely profiler? These are real numbers. If you insist on
>> calling them error paths then error paths are obviously the norm.

On Wed, Mar 25, 2009 at 10:06 AM, Pekka Enberg <penberg@...helsinki.fi> wrote:
> I am not denying the results, I am just saying that they don't make much
> sense to me. Like I said, I would love to see the actual call-sites to
> prove my argument wrong.

OK, so according to Steven, audit_syscall_exit() is one such call-site
that shows up in the traces. I don't really understand what's going on
there but if it is sane, maybe that warrants the removal of unlikely()
from kfree(). Hmm?
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