diff options
Diffstat (limited to 'arch/x86/mm/gup.c')
| -rw-r--r-- | arch/x86/mm/gup.c | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c index 738e6593799..dbe34b93137 100644 --- a/arch/x86/mm/gup.c +++ b/arch/x86/mm/gup.c @@ -8,6 +8,7 @@ #include <linux/mm.h> #include <linux/vmstat.h> #include <linux/highmem.h> +#include <linux/swap.h> #include <asm/pgtable.h> @@ -89,6 +90,7 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr, VM_BUG_ON(!pfn_valid(pte_pfn(pte))); page = pte_page(pte); get_page(page); + SetPageReferenced(page); pages[*nr] = page; (*nr)++; @@ -103,6 +105,17 @@ static inline void get_head_page_multiple(struct page *page, int nr) VM_BUG_ON(page != compound_head(page)); VM_BUG_ON(page_count(page) == 0); atomic_add(nr, &page->_count); + SetPageReferenced(page); +} + +static inline void get_huge_page_tail(struct page *page) +{ + /* + * __split_huge_page_refcount() cannot run + * from under us. + */ + VM_BUG_ON(atomic_read(&page->_count) < 0); + atomic_inc(&page->_count); } static noinline int gup_huge_pmd(pmd_t pmd, unsigned long addr, @@ -128,6 +141,8 @@ static noinline int gup_huge_pmd(pmd_t pmd, unsigned long addr, do { VM_BUG_ON(compound_head(page) != head); pages[*nr] = page; + if (PageTail(page)) + get_huge_page_tail(page); (*nr)++; page++; refs++; @@ -148,7 +163,18 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, pmd_t pmd = *pmdp; next = pmd_addr_end(addr, end); - if (pmd_none(pmd)) + /* + * The pmd_trans_splitting() check below explains why + * pmdp_splitting_flush has to flush the tlb, to stop + * this gup-fast code from running while we set the + * splitting bit in the pmd. Returning zero will take + * the slow path that will call wait_split_huge_page() + * if the pmd is still in splitting state. gup-fast + * can't because it has irq disabled and + * wait_split_huge_page() would never return as the + * tlb flush IPI wouldn't run. + */ + if (pmd_none(pmd) || pmd_trans_splitting(pmd)) return 0; if (unlikely(pmd_large(pmd))) { if (!gup_huge_pmd(pmd, addr, next, write, pages, nr)) |