summaryrefslogtreecommitdiff
path: root/mm
diff options
context:
space:
mode:
Diffstat (limited to 'mm')
-rw-r--r--mm/hugetlb.c44
1 files changed, 35 insertions, 9 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 92155db888b9..4c97c174e2e1 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1942,6 +1942,15 @@ retry:
lock_page(page);
}
+ /*
+ * If we are going to COW a private mapping later, we examine the
+ * pending reservations for this page now. This will ensure that
+ * any allocations necessary to record that reservation occur outside
+ * the spinlock.
+ */
+ if (write_access && !(vma->vm_flags & VM_SHARED))
+ vma_needs_reservation(h, vma, address);
+
spin_lock(&mm->page_table_lock);
size = i_size_read(mapping->host) >> huge_page_shift(h);
if (idx >= size)
@@ -1978,6 +1987,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
pte_t *ptep;
pte_t entry;
int ret;
+ struct page *pagecache_page = NULL;
static DEFINE_MUTEX(hugetlb_instantiation_mutex);
struct hstate *h = hstate_vma(vma);
@@ -2000,19 +2010,35 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
ret = 0;
+ /*
+ * If we are going to COW the mapping later, we examine the pending
+ * reservations for this page now. This will ensure that any
+ * allocations necessary to record that reservation occur outside the
+ * spinlock. For private mappings, we also lookup the pagecache
+ * page now as it is used to determine if a reservation has been
+ * consumed.
+ */
+ if (write_access && !pte_write(entry)) {
+ vma_needs_reservation(h, vma, address);
+
+ if (!(vma->vm_flags & VM_SHARED))
+ pagecache_page = hugetlbfs_pagecache_page(h,
+ vma, address);
+ }
+
spin_lock(&mm->page_table_lock);
/* Check for a racing update before calling hugetlb_cow */
if (likely(pte_same(entry, huge_ptep_get(ptep))))
- if (write_access && !pte_write(entry)) {
- struct page *page;
- page = hugetlbfs_pagecache_page(h, vma, address);
- ret = hugetlb_cow(mm, vma, address, ptep, entry, page);
- if (page) {
- unlock_page(page);
- put_page(page);
- }
- }
+ if (write_access && !pte_write(entry))
+ ret = hugetlb_cow(mm, vma, address, ptep, entry,
+ pagecache_page);
spin_unlock(&mm->page_table_lock);
+
+ if (pagecache_page) {
+ unlock_page(pagecache_page);
+ put_page(pagecache_page);
+ }
+
mutex_unlock(&hugetlb_instantiation_mutex);
return ret;