Date: Sun, 15 May 2005 16:52:42 +0200
From: Tomasz Torcz <zdzichu@irc.pl>
To: linux-kernel@vger.kernel.org
Subject: Re: Hyper-Threading Vulnerability
Message-ID: <20050515145241.GA5627@irc.pl>
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References: <1115963481.1723.3.camel@alderaan.trey.hu> <m164xnatpt.fsf@muc.de> <20050513211609.75216bf8.diegocg@gmail.com> <20050515095446.GE68736@muc.de> <Pine.LNX.4.58.0505151550160.8633@artax.karlin.mff.cuni.cz> <20050515141207.GB94354@muc.de>
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On Sun, May 15, 2005 at 04:12:07PM +0200, Andi Kleen wrote:
> > > > However they've patched the FreeBSD kernel to "workaround?" it:
> > > > ftp://ftp.freebsd.org/pub/FreeBSD/CERT/patches/SA-05:09/htt5.patch
> > >
> > > That's a similar stupid idea as they did with the disk write
> > > cache (lowering the MTBFs of their disks by considerable factors,
> > > which is much worse than the power off data loss problem)
> > > Let's not go down this path please.
> > 
> > What wrong did they do with disk write cache?
> 
> They turned it off by default, which according to disk vendors
> lowers the MTBF of your disk to a fraction of the original value.
> 
> I bet the total amount of valuable data lost for FreeBSD users because
> of broken disks is much much bigger than what they gained from not losing
> in the rather hard to hit power off cases.

 Aren't I/O barriers a way to safely use write cache?

-- 
Tomasz Torcz                 "God, root, what's the difference?"
zdzichu@irc.-nie.spam-.pl         "God is more forgiving."

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