Messages in this thread | | | Date | Mon, 2 Sep 2013 15:20:13 +0900 | From | Yasuaki Ishimatsu <> | Subject | Re: [RFC PATCH v3 04/35] mm: Initialize node memory regions during boot |
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(2013/08/30 22:15), Srivatsa S. Bhat wrote: > Initialize the node's memory-regions structures with the information about > the region-boundaries, at boot time. > > Based-on-patch-by: Ankita Garg <gargankita@gmail.com> > Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> > --- > > include/linux/mm.h | 4 ++++ > mm/page_alloc.c | 28 ++++++++++++++++++++++++++++ > 2 files changed, 32 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index f022460..18fdec4 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -627,6 +627,10 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) > #define LAST_NID_MASK ((1UL << LAST_NID_WIDTH) - 1) > #define ZONEID_MASK ((1UL << ZONEID_SHIFT) - 1) > > +/* Hard-code memory region size to be 512 MB for now. */ > +#define MEM_REGION_SHIFT (29 - PAGE_SHIFT) > +#define MEM_REGION_SIZE (1UL << MEM_REGION_SHIFT) > + > static inline enum zone_type page_zonenum(const struct page *page) > { > return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK; > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index b86d7e3..bb2d5d4 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -4809,6 +4809,33 @@ static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat) > #endif /* CONFIG_FLAT_NODE_MEM_MAP */ > } > > +static void __meminit init_node_memory_regions(struct pglist_data *pgdat) > +{ > + int nid = pgdat->node_id; > + unsigned long start_pfn = pgdat->node_start_pfn; > + unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages; > + struct node_mem_region *region; > + unsigned long i, absent; > + int idx; > + > + for (i = start_pfn, idx = 0; i < end_pfn; > + i += region->spanned_pages, idx++) { > +
> + region = &pgdat->node_regions[idx];
It seems that overflow easily occurs. node_regions[] has 256 entries and MEM_REGION_SIZE is 512MiB. So if the pgdat has more than 128 GiB, overflow will occur. Am I wrong?
Thanks, Yasuaki Ishimatsu
> + region->pgdat = pgdat; > + region->start_pfn = i; > + region->spanned_pages = min(MEM_REGION_SIZE, end_pfn - i); > + region->end_pfn = region->start_pfn + region->spanned_pages; > + > + absent = __absent_pages_in_range(nid, region->start_pfn, > + region->end_pfn); > + > + region->present_pages = region->spanned_pages - absent; > + } > + > + pgdat->nr_node_regions = idx; > +} > + > void __paginginit free_area_init_node(int nid, unsigned long *zones_size, > unsigned long node_start_pfn, unsigned long *zholes_size) > { > @@ -4837,6 +4864,7 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size, > > free_area_init_core(pgdat, start_pfn, end_pfn, > zones_size, zholes_size); > + init_node_memory_regions(pgdat); > } > > #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP >
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