Messages in this thread | | | Date | Thu, 3 Jul 2008 18:16:10 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH] Do not clobber pgdat->nr_zones during memory initialisation |
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On (03/07/08 09:44), Linus Torvalds didst pronounce: > > > On Thu, 3 Jul 2008, Mel Gorman wrote: > > > > Subject: [PATCH] Do not clobber pgdat->nr_zones during memory initialisation > > Heh. I already applied it as ObviouslyCorrect(tm), but did the > simplification I already pointed out (and which your second version > already had) and rewrote your commit message a bit. So it's now committed > as follows.. >
Perfect. The log even looks like it was written by a sane person. Thanks for that.
> Linus > > --- > commit 494de90098784b8e2797598cefdd34188884ec2e > Author: Mel Gorman <mel@csn.ul.ie> > Date: Thu Jul 3 05:27:51 2008 +0100 > > Do not overwrite nr_zones on !NUMA when initialising zlcache_ptr > > The non-NUMA case of build_zonelist_cache() would initialize the > zlcache_ptr for both node_zonelists[] to NULL. > > Which is problematic, since non-NUMA only has a single node_zonelists[] > entry, and trying to zero the non-existent second one just overwrote the > nr_zones field instead. > > As kswapd uses this value to determine what reclaim work is necessary, > the result is that kswapd never reclaims. This causes processes to > stall frequently in low-memory situations as they always direct reclaim. > This patch initialises zlcache_ptr correctly. > > Signed-off-by: Mel Gorman <mel@csn.ul.ie> > Tested-by: Dan Williams <dan.j.williams@intel.com> > [ Simplified patch a bit ] > Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> > --- > mm/page_alloc.c | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 2f55295..f32fae3 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2328,7 +2328,6 @@ static void build_zonelists(pg_data_t *pgdat) > static void build_zonelist_cache(pg_data_t *pgdat) > { > pgdat->node_zonelists[0].zlcache_ptr = NULL; > - pgdat->node_zonelists[1].zlcache_ptr = NULL; > } > > #endif /* CONFIG_NUMA */ >
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
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