diff options
| -rw-r--r-- | mm/hugetlb.c | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 41b1038..d5987a8 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -13,6 +13,7 @@ #include <linux/pagemap.h> #include <linux/mempolicy.h> #include <linux/cpuset.h> +#include <linux/mutex.h> #include <asm/page.h> #include <asm/pgtable.h> @@ -26,6 +27,10 @@ unsigned long max_huge_pages; static struct list_head hugepage_freelists[MAX_NUMNODES]; static unsigned int nr_huge_pages_node[MAX_NUMNODES]; static unsigned int free_huge_pages_node[MAX_NUMNODES]; +/* + * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages + */ +static DEFINE_SPINLOCK(hugetlb_lock); static void clear_huge_page(struct page *page, unsigned long addr) { @@ -50,11 +55,6 @@ static void copy_huge_page(struct page *dst, struct page *src, } } -/* - * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages - */ -static DEFINE_SPINLOCK(hugetlb_lock); - static void enqueue_huge_page(struct page *page) { int nid = page_to_nid(page); @@ -508,14 +508,24 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, pte_t *ptep; pte_t entry; int ret; + static DEFINE_MUTEX(hugetlb_instantiation_mutex); ptep = huge_pte_alloc(mm, address); if (!ptep) return VM_FAULT_OOM; + /* + * Serialize hugepage allocation and instantiation, so that we don't + * get spurious allocation failures if two CPUs race to instantiate + * the same page in the page cache. + */ + mutex_lock(&hugetlb_instantiation_mutex); entry = *ptep; - if (pte_none(entry)) - return hugetlb_no_page(mm, vma, address, ptep, write_access); + if (pte_none(entry)) { + ret = hugetlb_no_page(mm, vma, address, ptep, write_access); + mutex_unlock(&hugetlb_instantiation_mutex); + return ret; + } ret = VM_FAULT_MINOR; @@ -525,6 +535,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, if (write_access && !pte_write(entry)) ret = hugetlb_cow(mm, vma, address, ptep, entry); spin_unlock(&mm->page_table_lock); + mutex_unlock(&hugetlb_instantiation_mutex); return ret; } |
