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SubjectRe: [PATCH] [9/9] GBPAGES: Do kernel direct mapping at boot using GB pages
On Tue, 29 Jan 2008, Andi Kleen wrote:
>
> +static unsigned long direct_entry(unsigned long paddr)

Please use a more sensible function name. This one has no association
with the functionality at all.

> +{
> + unsigned long entry;

New line please

> + entry = __PAGE_KERNEL_LARGE|paddr;
> + entry &= __supported_pte_mask;
> + return entry;
> +}

> +static void init_gbpages(void)
> +{
> +#ifdef CONFIG_DEBUG_PAGEALLOC
> + /* debug pagealloc causes too much recursion with gbpages */
> + if (direct_gbpages == 0)
> + return;
> +#endif
> + if (direct_gbpages >= 0 && cpu_has_gbpages) {
> + printk(KERN_INFO "Using GB pages for direct mapping\n");
> + direct_gbpages = 1;
> + } else
> + direct_gbpages = 0;
> +}

Please use simple boolean logic. gbpages are either enabled or disabled.

> +static void split_gb_page(pud_t *pud, unsigned long paddr)
> +{
> + int i;
> + pmd_t *pmd;
> + struct page *p = alloc_page(GFP_KERNEL);
> + if (!p)
> + return;
> +
> + paddr &= PUD_PAGE_MASK;
> + pmd = page_address(p);
> + for (i = 0; i < PTRS_PER_PTE; i++, paddr += PMD_PAGE_SIZE)
> + pmd[i] = __pmd(direct_entry(paddr));
> + pud_populate(NULL, pud, pmd);
> +}
> +
> /*
> * Unmap a kernel mapping if it exists. This is useful to avoid
> * prefetches from the CPU leading to inconsistent cache lines.
> @@ -467,6 +511,8 @@ __clear_kernel_mapping(unsigned long add
> continue;
>
> pud = pud_offset(pgd, address);
> + if (pud_large(*pud))
> + split_gb_page(pud, __pa(address));
> if (pud_none(*pud))
> continue;

As I said before, this needs to use CPA and not implement another variant.

Thanks,
tglx




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