Messages in this thread | | | Date | Thu, 5 Feb 2009 10:41:38 +0000 | From | Mel Gorman <> | Subject | Re: HOLES_IN_ZONE... |
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On Thu, Feb 05, 2009 at 02:14:29AM -0800, David Miller wrote: > From: Mel Gorman <mel@csn.ul.ie> > Date: Thu, 5 Feb 2009 10:10:23 +0000 > > > On Wed, Feb 04, 2009 at 10:26:51PM -0800, David Miller wrote: > > > As a suggestion, it would have been a lot more pleasant if the code > > > validated this requirement (in the !HOLES_IN_ZONE case) at boot time > > > instead of after 2 hours of stress testing :-( > > > > > > > Nice maybe, but we'd take a hit on pfn_valid_within() which goes from > > being compiled-away on architectures that don't need it to being > > a read of a shared cacheline and a branch. > > I said at boot time Mel, not in the fast paths.
pfn_valid_within() is not used in any critical paths, but it's used in the page free path so it would be a hit there.
> Meaning, we'd > check it after all the available ranges get registered and > tossed into the free page lists. >
It's not a free-list problem, it's walkers of PFN ranges. Anyway, it's not important to the current problem.
> Anyways, it appears we have a fix already, read the rest of > the thread. >
Yes. Thanks Kamezawa Hiroyu for the fix.
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
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