linux-kernel - Re: [PATCH] [1/4] x86: MCE: Make polling timer interval per CPU

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Message-ID: <20090408114038.GB14687@one.firstfloor.org>
Date:	Wed, 8 Apr 2009 13:40:38 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
Cc:	Andi Kleen <andi@...stfloor.org>, hpa@...or.com,
	linux-kernel@...r.kernel.org, mingo@...e.hu, tglx@...utronix.de
Subject: Re: [PATCH] [1/4] x86: MCE: Make polling timer interval per CPU

On Wed, Apr 08, 2009 at 08:30:45PM +0900, Hidetoshi Seto wrote:
> Andi Kleen wrote:
> >>> +	if (!*n)
> >>> +		*n = check_interval * HZ;
> >>> +	if (!*n)
> >>>  		return;
> > 
> > The !*n will return for check_interval == 0 because 0*HZ is still 0 so it should be 
> > equivalent. Did I miss something?
> 
> At First, *n is 0 on boot.
> And then soon it will be initialized to non-zero (check_interval * HZ)
> by the first if-statement.
> 
> After that if check_interval is changed via sysfs while *n is non-zero,
> which if-statement runs?

Ok got your point now. The first if (!*n) needs to be dropped indeed.
Will respin that patch.

Thanks.

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