Messages in this thread | | | Date | Mon, 9 Nov 2020 18:21:44 +0100 | From | Oscar Salvador <> | Subject | Re: [PATCH v3 05/21] mm/hugetlb: Introduce pgtable allocation/freeing helpers |
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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
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