linux-kernel - Re: [PATCH] x86: Make variable_test

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Message-ID: <m2d3e936fn.fsf@firstfloor.org>
Date:	Thu, 06 Oct 2011 19:02:20 -0700
From:	Andi Kleen <andi@...stfloor.org>
To:	"hpanvin\@gmail.com" <hpa@...or.com>
Cc:	Josh Stone <jistone@...hat.com>, linux-kernel@...r.kernel.org,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, x86@...nel.org,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
	Jakub Jelinek <jakub@...hat.com>
Subject: Re: [PATCH] x86: Make variable_test_bit reference all of *addr

"hpanvin@...il.com" <hpa@...or.com> writes:


> This is concerning... the kernel relies heavily on asm volatile being a universal memory consumer.  If that is suddenly broken, we are f*** in many, many, MANY places in the kernel all of a sudden!

I don't think that's true. We generally add "memory" clobbers for this
purpose. asm volatile just means "don't move" 

Just this one doesn't have it for unknown reasons (someone overoptimizing?)

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only
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