On Fri, Dec 13, 2013 at 02:10:07PM +0000, Mel Gorman wrote: > Indications from Johannes that he wanted this. Needs some data and/or > justification why > thrash protection needs it plus docs describing how MPOL_LOCAL is now > different before > it should be considered finished. I do not necessarily agree this patch is > necessary > but it's worth punting it out there for discussion and testing.
I demonstrated enormous gains in the original submission of the fair allocation patch and your tests haven't really shown downsides to the cache-over-nodes portion of it. So I don't see why we should revert the cache-over-nodes fairness without any supporting data. Reverting cross-node fairness for anon and slab is a good idea. It was always about cache and the original patch was too broad stroked, but it doesn't invalidate everything it was about. I can see, however, that we might want to make this configurable, but I'm not eager on exporting user interfaces unless we have to. As the node-local fairness was never questioned by anybody, is it necessary to make it configurable? Shouldn't we be okay with just a single vm.pagecache_interleave (name by Rik) sysctl that defaults to 1 but allows users to go back to pagecache obeying mempolicy? > Not signed off > --- > mm/page_alloc.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index bf49918..bce40c0 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1885,7 +1885,8 @@ unsigned __bitwise__ zone_distribute_mode __read_mostly; > #define DISTRIBUTE_STUPID_ANON > (DISTRIBUTE_LOCAL_ANON|DISTRIBUTE_REMOTE_ANON) > #define DISTRIBUTE_STUPID_FILE > (DISTRIBUTE_LOCAL_FILE|DISTRIBUTE_REMOTE_FILE) > #define DISTRIBUTE_STUPID_SLAB > (DISTRIBUTE_LOCAL_SLAB|DISTRIBUTE_REMOTE_SLAB) > -#define DISTRIBUTE_DEFAULT > (DISTRIBUTE_LOCAL_ANON|DISTRIBUTE_LOCAL_FILE|DISTRIBUTE_LOCAL_SLAB) > +#define DISTRIBUTE_DEFAULT > (DISTRIBUTE_LOCAL_ANON|DISTRIBUTE_LOCAL_FILE|DISTRIBUTE_LOCAL_SLAB| \ > + DISTRIBUTE_REMOTE_FILE) > > /* Only these GFP flags are affected by the fair zone allocation policy */ > #define DISTRIBUTE_GFP_MASK ((GFP_MOVABLE_MASK|__GFP_PAGECACHE)) > -- > 1.8.4 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majord...@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"d...@kvack.org";> em...@kvack.org </a> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
