On Fri, 20 Oct 2006, KAMEZAWA Hiroyuki wrote: > Maximun phyisical address size of Itanium2 looks 50bits. Then, we need > sizeof (struct page) * (50 - PAGE_SHIFT) size of virtual address space. Right. That is 4TB which can be a portion of the 128TB VMALLOC space. Have you seen my patchset that does the calculation on linux-ia674? > > #ifdef CONFIG_PGTABLE_4 > #define PGDIR_SHIFT (PUD_SHIFT + (PTRS_PER_PTD_SHIFT)) > #else > #define PGDIR_SHIFT (PMD_SHIFT + (PTRS_PER_PTD_SHIFT)) > #endif > > Then, considering PAGE_SHIFT=14 case, > 4-level-page-table mapsize:(1 << (4 * PAGE_SHIFT - 9) -> (1 << 47) > 3-level-page-table mapsize:(1 << (3 * PAGE_SHIFT - 6) -> (1 << 36) You are missing one PAGE_SHIFT (the page that is referred to !) 3 level is 47. 4 level is 58. - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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