Messages in this thread |  | | Date | Tue, 16 Sep 2008 00:20:57 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH] Mark the correct zone as full when scanning zonelists |
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On (11/09/08 14:41), Andrew Morton didst pronounce: > On Thu, 11 Sep 2008 22:25:51 +0100 > Mel Gorman <mel@csn.ul.ie> wrote: > > > The for_each_zone_zonelist() uses a struct zoneref *z cursor when scanning > > zonelists to keep track of where in the zonelist it is. The zoneref that > > is returned corresponds to the the next zone that is to be scanned, not > > the current one as it originally thought of as an opaque list. > > > > When the page allocator is scanning a zonelist, it marks zones that it > > temporarily full zones to eliminate near-future scanning attempts. > > That sentence needs help. > > > It uses > > the zoneref for the marking and consequently the incorrect zone gets marked > > full. This leads to a suitable zone being skipped in the mistaken belief > > it is full. This patch corrects the problem by changing zoneref to be the > > current zone being scanned instead of the next one. > > Applicable to 2.6.26 as well, yes? > > > Someone reported a bug a few weeks ago which I think this patch will fix, > yes? I don't remember who that was, nor do I recall the precise details > of what the userspace-visible (mis)behaviour was. > > Are you able to fill in the gaps here?
I searched through the archives and couldn't find a bug report that this patch may be the fix to. However, I understand that the initial leader could have been a lot better.
> Put yourself in the position of > a poor little -stable maintainer scratching his head wondering ytf he > was sent this patch. > > Thanks. >
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
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