diff options
Diffstat (limited to 'arch/powerpc/mm/gup.c')
-rw-r--r-- | arch/powerpc/mm/gup.c | 235 |
1 files changed, 0 insertions, 235 deletions
diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c deleted file mode 100644 index d8746684f60..00000000000 --- a/arch/powerpc/mm/gup.c +++ /dev/null @@ -1,235 +0,0 @@ -/* - * Lockless get_user_pages_fast for powerpc - * - * Copyright (C) 2008 Nick Piggin - * Copyright (C) 2008 Novell Inc. - */ -#undef DEBUG - -#include <linux/sched.h> -#include <linux/mm.h> -#include <linux/hugetlb.h> -#include <linux/vmstat.h> -#include <linux/pagemap.h> -#include <linux/rwsem.h> -#include <asm/pgtable.h> - -#ifdef __HAVE_ARCH_PTE_SPECIAL - -/* - * The performance critical leaf functions are made noinline otherwise gcc - * inlines everything into a single function which results in too much - * register pressure. - */ -static noinline int gup_pte_range(pmd_t pmd, unsigned long addr, - unsigned long end, int write, struct page **pages, int *nr) -{ - unsigned long mask, result; - pte_t *ptep; - - result = _PAGE_PRESENT|_PAGE_USER; - if (write) - result |= _PAGE_RW; - mask = result | _PAGE_SPECIAL; - - ptep = pte_offset_kernel(&pmd, addr); - do { - pte_t pte = ACCESS_ONCE(*ptep); - struct page *page; - /* - * Similar to the PMD case, NUMA hinting must take slow path - */ - if (pte_numa(pte)) - return 0; - - if ((pte_val(pte) & mask) != result) - return 0; - VM_BUG_ON(!pfn_valid(pte_pfn(pte))); - page = pte_page(pte); - if (!page_cache_get_speculative(page)) - return 0; - if (unlikely(pte_val(pte) != pte_val(*ptep))) { - put_page(page); - return 0; - } - pages[*nr] = page; - (*nr)++; - - } while (ptep++, addr += PAGE_SIZE, addr != end); - - return 1; -} - -static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, - int write, struct page **pages, int *nr) -{ - unsigned long next; - pmd_t *pmdp; - - pmdp = pmd_offset(&pud, addr); - do { - pmd_t pmd = ACCESS_ONCE(*pmdp); - - next = pmd_addr_end(addr, end); - /* - * If we find a splitting transparent hugepage we - * return zero. That will result in taking the slow - * path which will call wait_split_huge_page() - * if the pmd is still in splitting state - */ - if (pmd_none(pmd) || pmd_trans_splitting(pmd)) - return 0; - if (pmd_huge(pmd) || pmd_large(pmd)) { - /* - * NUMA hinting faults need to be handled in the GUP - * slowpath for accounting purposes and so that they - * can be serialised against THP migration. - */ - if (pmd_numa(pmd)) - return 0; - - if (!gup_hugepte((pte_t *)pmdp, PMD_SIZE, addr, next, - write, pages, nr)) - return 0; - } else if (is_hugepd(pmdp)) { - if (!gup_hugepd((hugepd_t *)pmdp, PMD_SHIFT, - addr, next, write, pages, nr)) - return 0; - } else if (!gup_pte_range(pmd, addr, next, write, pages, nr)) - return 0; - } while (pmdp++, addr = next, addr != end); - - return 1; -} - -static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, - int write, struct page **pages, int *nr) -{ - unsigned long next; - pud_t *pudp; - - pudp = pud_offset(&pgd, addr); - do { - pud_t pud = ACCESS_ONCE(*pudp); - - next = pud_addr_end(addr, end); - if (pud_none(pud)) - return 0; - if (pud_huge(pud)) { - if (!gup_hugepte((pte_t *)pudp, PUD_SIZE, addr, next, - write, pages, nr)) - return 0; - } else if (is_hugepd(pudp)) { - if (!gup_hugepd((hugepd_t *)pudp, PUD_SHIFT, - addr, next, write, pages, nr)) - return 0; - } else if (!gup_pmd_range(pud, addr, next, write, pages, nr)) - return 0; - } while (pudp++, addr = next, addr != end); - - return 1; -} - -int __get_user_pages_fast(unsigned long start, int nr_pages, int write, - struct page **pages) -{ - struct mm_struct *mm = current->mm; - unsigned long addr, len, end; - unsigned long next; - unsigned long flags; - pgd_t *pgdp; - int nr = 0; - - pr_devel("%s(%lx,%x,%s)\n", __func__, start, nr_pages, write ? "write" : "read"); - - start &= PAGE_MASK; - addr = start; - len = (unsigned long) nr_pages << PAGE_SHIFT; - end = start + len; - - if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ, - start, len))) - return 0; - - pr_devel(" aligned: %lx .. %lx\n", start, end); - - /* - * XXX: batch / limit 'nr', to avoid large irq off latency - * needs some instrumenting to determine the common sizes used by - * important workloads (eg. DB2), and whether limiting the batch size - * will decrease performance. - * - * It seems like we're in the clear for the moment. Direct-IO is - * the main guy that batches up lots of get_user_pages, and even - * they are limited to 64-at-a-time which is not so many. - */ - /* - * This doesn't prevent pagetable teardown, but does prevent - * the pagetables from being freed on powerpc. - * - * So long as we atomically load page table pointers versus teardown, - * we can follow the address down to the the page and take a ref on it. - */ - local_irq_save(flags); - - pgdp = pgd_offset(mm, addr); - do { - pgd_t pgd = ACCESS_ONCE(*pgdp); - - pr_devel(" %016lx: normal pgd %p\n", addr, - (void *)pgd_val(pgd)); - next = pgd_addr_end(addr, end); - if (pgd_none(pgd)) - break; - if (pgd_huge(pgd)) { - if (!gup_hugepte((pte_t *)pgdp, PGDIR_SIZE, addr, next, - write, pages, &nr)) - break; - } else if (is_hugepd(pgdp)) { - if (!gup_hugepd((hugepd_t *)pgdp, PGDIR_SHIFT, - addr, next, write, pages, &nr)) - break; - } else if (!gup_pud_range(pgd, addr, next, write, pages, &nr)) - break; - } while (pgdp++, addr = next, addr != end); - - local_irq_restore(flags); - - return nr; -} - -int get_user_pages_fast(unsigned long start, int nr_pages, int write, - struct page **pages) -{ - struct mm_struct *mm = current->mm; - int nr, ret; - - start &= PAGE_MASK; - nr = __get_user_pages_fast(start, nr_pages, write, pages); - ret = nr; - - if (nr < nr_pages) { - pr_devel(" slow path ! nr = %d\n", nr); - - /* Try to get the remaining pages with get_user_pages */ - start += nr << PAGE_SHIFT; - pages += nr; - - down_read(&mm->mmap_sem); - ret = get_user_pages(current, mm, start, - nr_pages - nr, write, 0, pages, NULL); - up_read(&mm->mmap_sem); - - /* Have to be a bit careful with return values */ - if (nr > 0) { - if (ret < 0) - ret = nr; - else - ret += nr; - } - } - - return ret; -} - -#endif /* __HAVE_ARCH_PTE_SPECIAL */ |