Re: [PATCH] Use integer fields lookup for gfp_zone and check for errors in flags passed to the page allocator

[Mel Gorman <mel@csn.ul.ie>]

On Tue, May 26, 2009 at 02:04:35PM -0400, Christoph Lameter wrote:
> On Mon, 25 May 2009, Mel Gorman wrote:
> 
> > I expect that the machine would start running into reclaim issues with
> > enough uptime because it'll not be using Highmem as it should. Similarly,
> > the GFP_DMA32 may also be a problem as the new implementation is going
> > ZONE_DMA when ZONE_NORMAL would have been ok in this case.
> 
> Right. The fallback for DMA32 is wrong. Should fall back to ZONE_NORMAL.
> Not to DMA. And the config variable to check for highmem was wrong.
> 

That fixed things right up on x86 at least and it looks good. I've queued
up a few tests with the patch applied on x86, x86-64 and ppc64. Hopefully
it'll go smoothly.

For your patch + fix merged

Acked-by: Mel Gorman <mel@csn.ul.ie>

> 
> Subject: Fix gfp zone patch
> 
> 1. If there is no DMA32 fall back to NORMAL instead of DMA
> 
> 2. Use the correct config variable for HIGHMEM
> 
> Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
> 
> 
> ---
>  include/linux/gfp.h |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> Index: linux-2.6/include/linux/gfp.h
> ===================================================================
> --- linux-2.6.orig/include/linux/gfp.h	2009-05-26 12:59:19.000000000 -0500
> +++ linux-2.6/include/linux/gfp.h	2009-05-26 12:59:31.000000000 -0500
> @@ -112,7 +112,7 @@ static inline int allocflags_to_migratet
>  		((gfp_flags & __GFP_RECLAIMABLE) != 0);
>  }
> 
> -#ifdef CONFIG_ZONE_HIGHMEM
> +#ifdef CONFIG_HIGHMEM
>  #define OPT_ZONE_HIGHMEM ZONE_HIGHMEM
>  #else
>  #define OPT_ZONE_HIGHMEM ZONE_NORMAL
> @@ -127,7 +127,7 @@ static inline int allocflags_to_migratet
>  #ifdef CONFIG_ZONE_DMA32
>  #define OPT_ZONE_DMA32 ZONE_DMA32
>  #else
> -#define OPT_ZONE_DMA32 OPT_ZONE_DMA
> +#define OPT_ZONE_DMA32 ZONE_NORMAL
>  #endif
> 
>  /*
> 

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab

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