Messages in this thread | | | Date | Mon, 26 Jun 2006 17:05:56 +0200 | Subject | Re: 2.6.17-mm1 | From | Franck Bui-Huu <> |
| |
Mel Gorman wrote: > > Lets close this out first and then figure out where to go next. The following > patch should fix the problem where mem_map is offset twice when ARCH_PFN_OFFSET > != 0 and documents what ARCH_PFN_OFFSET is for. >
why not dropping the initial patch, and resubmit the whole thing that can be called an optimization rather than a fix ?
> Signed-off-by: Mel Gorman <mel@csn.ul.ie> > diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.17-mm2-clean/include/asm-generic/memory_model.h linux-2.6.17-mm2-archpfnfix/include/asm-generic/memory_model.h > --- linux-2.6.17-mm2-clean/include/asm-generic/memory_model.h 2006-06-26 11:38:21.000000000 +0100 > +++ linux-2.6.17-mm2-archpfnfix/include/asm-generic/memory_model.h 2006-06-26 15:22:19.000000000 +0100 > @@ -6,6 +6,20 @@ > > #if defined(CONFIG_FLATMEM) > > +/* > + * With FLATMEM, the mem_map on node 0 is used as the global mem_map. > + * This implicitly assumes that NODE_DATA(0)->node_start_pfn == 0 and > + * represents the first physical page frame in the system. This is not > + * always the case as an architecture may start physical memory at 3GB > + * for example. Rather than allocating an empty mem_map to represent > + * the non-existent memory, ARCH_PFN_OFFSET is subtracted from > + * NODE_DATA(0)->node_mem_map such that; > + * > + * PFN 0 = mem_map = NODE_DATA(0)->node_mem_map - ARCH_PFN_OFFSET > + * > + * One would expect NODE_DATA(0)->node_start_pfn == ARCH_PFN_OFFSET but > + * depending on how memory is initialised, this is not always the case. > + */ > #ifndef ARCH_PFN_OFFSET > #define ARCH_PFN_OFFSET (0UL) > #endif > @@ -28,9 +42,8 @@ > */ > #if defined(CONFIG_FLATMEM) > > -#define __pfn_to_page(pfn) (mem_map + ((pfn) - ARCH_PFN_OFFSET)) > -#define __page_to_pfn(page) ((unsigned long)((page) - mem_map) + \ > - ARCH_PFN_OFFSET) > +#define __pfn_to_page(pfn) (mem_map + (pfn)) > +#define __page_to_pfn(page) ((unsigned long)((page) - mem_map)) > #elif defined(CONFIG_DISCONTIGMEM) > > #define __pfn_to_page(pfn) \ > diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.17-mm2-clean/mm/page_alloc.c linux-2.6.17-mm2-archpfnfix/mm/page_alloc.c > --- linux-2.6.17-mm2-clean/mm/page_alloc.c 2006-06-26 11:38:21.000000000 +0100 > +++ linux-2.6.17-mm2-archpfnfix/mm/page_alloc.c 2006-06-26 15:11:29.000000000 +0100 > @@ -2103,7 +2103,7 @@ static void __init alloc_node_mem_map(st > * is true. Adjust map relative to node_mem_map to > * maintain this relationship. > */ > - map -= pgdat->node_start_pfn; > + map -= ARCH_PFN_OFFSET;
why not moving this inside the if statement below ?
> } > #ifdef CONFIG_FLATMEM > /* >
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |