linux-kernel - Re: [PATCH] mm: fix page_mkclean_one (was: 2.6.19 file content corruption on ext3)

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Message-Id: <1166693175.27750.7.camel@localhost>
Date:	Thu, 21 Dec 2006 10:26:15 +0100
From:	Martin Schwidefsky <schwidefsky@...ibm.com>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:	Linus Torvalds <torvalds@...l.org>,
	Martin Michlmayr <tbm@...ius.com>,
	Hugh Dickins <hugh@...itas.com>,
	Nick Piggin <nickpiggin@...oo.com.au>,
	Arjan van de Ven <arjan@...radead.org>,
	Andrei Popa <andrei.popa@...eo.ro>,
	Andrew Morton <akpm@...l.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Florian Weimer <fw@...eb.enyo.de>,
	Marc Haber <mh+linux-kernel@...schlus.de>,
	Heiko Carstens <heiko.carstens@...ibm.com>,
	Arnd Bergmann <arnd.bergmann@...ibm.com>,
	gordonfarquharson@...il.com
Subject: Re: [PATCH] mm: fix page_mkclean_one (was: 2.6.19 file content
	corruption on ext3)

On Thu, 2006-12-21 at 10:20 +0100, Peter Zijlstra wrote:
> > Now you are flushing the tlb twice. ptep_clear_flush clears the pte and
> > flushes the tlb, ptep_establish sets the new pte and flushes the tlb.
> > Not good. Use set_pte_at instead of the ptep_establish.
> 
> Yeah, sorry, I already noticed and corrected that :-|
> 
> Also, I'm dubious about the while thing and stuck a WARN_ON(ret) thing
> at the beginning of the loop. flush_tlb_page() does IPI the other cpus
> to flush their tlb too, so there should not be a SMP race, Arjan?

The while loop is protected by the pte lock and flush_tlb_page has to
remove the tlbs on all cpus. So yes, I think the while loop is not
necessary.

-- 
blue skies,
  Martin.

Martin Schwidefsky
Linux for zSeries Development & Services
IBM Deutschland Entwicklung GmbH

"Reality continues to ruin my life." - Calvin.


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