Subject: Re: [patch 8/9] Guest page hinting: discarded page list.
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Reply-To: schwidefsky@de.ibm.com
To: Dave Hansen <haveblue@us.ibm.com>
Cc: linux-kernel@vger.kernel.org, virtualization@lists.osdl.org, akpm@osdl.org,
       nickpiggin@yahoo.com.au, frankeh@watson.ibm.com, rhim@cc.gateh.edu
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References: <20060901111117.GI15684@skybase>
	 <1157123836.28577.77.camel@localhost.localdomain>
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Organization: IBM Corporation
Date: Fri, 01 Sep 2006 17:40:19 +0200
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On Fri, 2006-09-01 at 08:17 -0700, Dave Hansen wrote:
> > +#if defined(CONFIG_PAGE_DISCARD_LIST)
> > +       if (page_host_discards() && unlikely(PageDiscarded(page))) {
> > +               local_irq_disable();
> > +               list_add_tail(&page->lru,
> > +                             &__get_cpu_var(page_discard_list));
> > +               local_irq_enable();
> > +               return;
> > +       }
> > +#endif 
> 
> If PageDiscarded() was #ifdef'd in the header, you wouldn't need this in
> the .c file.

No, unfortunately not. There is a new variable page_discard_list that is
only defined if CONFG_PAGE_DISCARD_LIST is set. The compiler will
complain about the absence of the variable, even if the code is never
reached because PageDiscarded always returns 0.

-- 
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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