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Date: Thu, 7 May 2009 10:23:03 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
       Frederic Weisbecker <fweisbec@gmail.com>,
       Li Zefan <lizf@cn.fujitsu.com>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 1/7] ring-buffer: remove unneeded conditional in
	rb_reserve_next
Message-ID: <20090507082303.GE12285@elte.hu>
References: <20090507031335.815354104@goodmis.org> <20090507031433.562803300@goodmis.org>
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* Steven Rostedt <rostedt@goodmis.org> wrote:

> From: Steven Rostedt <srostedt@redhat.com>
> 
> The code in __rb_reserve_next checks on page overflow if it is the
> original commiter and then resets the page back to the original
> setting.  Although this is fine, and the code is correct, it is
> a bit fragil. Some experimental work I did breaks it easily.

s/fragil/fragile

> The better and more robust solution is to have all commiters that
> overflow the page, simply subtract what they added.
> 
> [ Impact: more robust ring buffer account management ]

it's a bit faster too (eliminates two branches) - so a 
micro-optimization as well.

	Ingo