On Sun, Nov 08, 2020 at 10:10:57PM +0800, Muchun Song wrote:
> +static inline unsigned int pgtable_pages_to_prealloc_per_hpage(struct hstate *h)
> +{
> + unsigned long vmemmap_size = vmemmap_pages_size_per_hpage(h);
> +
> + /*
> + * No need pre-allocate page tabels when there is no vmemmap pages
> + * to free.
s /tabels/tables/
> +static int vmemmap_pgtable_prealloc(struct hstate *h, struct page *page)
> +{
> + int i;
> + pgtable_t pgtable;
> + unsigned int nr = pgtable_pages_to_prealloc_per_hpage(h);
> +
> + if (!nr)
> + return 0;
> +
> + vmemmap_pgtable_init(page);
> +
> + for (i = 0; i < nr; i++) {
> + pte_t *pte_p;
> +
> + pte_p = pte_alloc_one_kernel(&init_mm);
> + if (!pte_p)
> + goto out;
> + vmemmap_pgtable_deposit(page, virt_to_page(pte_p));
> + }
> +
> + return 0;
> +out:
> + while (i-- && (pgtable = vmemmap_pgtable_withdraw(page)))
> + pte_free_kernel(&init_mm, page_to_virt(pgtable));
would not be enough to:
while (pgtable = vmemmap_pgtable_withdrag(page))
pte_free_kernel(&init_mm, page_to_virt(pgtable));
> + return -ENOMEM;
> +}
> +
> +static void vmemmap_pgtable_free(struct hstate *h, struct page *page)
> +{
> + pgtable_t pgtable;
> + unsigned int nr = pgtable_pages_to_prealloc_per_hpage(h);
> +
> + if (!nr)
> + return;
We can get rid of "nr" and its check and keep only the check below, right?
AFAICS, they go together, e.g: if page_huge_pte does not return null,
it means that we preallocated a pagetable, and viceversa.
> +
> + pgtable = page_huge_pte(page);
> + if (!pgtable)
> + return;
> +
> + while (nr-- && (pgtable = vmemmap_pgtable_withdraw(page)))
> + pte_free_kernel(&init_mm, page_to_virt(pgtable));
Same as above, that "nr" can go?
--
Oscar Salvador
SUSE L3
