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-rw-r--r--mm/hugetlb.c58
1 files changed, 53 insertions, 5 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 05bc9af4fca9..72acbb29d2cc 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -247,6 +247,9 @@ static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
/* Decrement the reserved pages in the hugepage pool by one */
static void decrement_hugepage_resv_vma(struct vm_area_struct *vma)
{
+ if (vma->vm_flags & VM_NORESERVE)
+ return;
+
if (vma->vm_flags & VM_SHARED) {
/* Shared mappings always use reserves */
resv_huge_pages--;
@@ -720,25 +723,65 @@ static void return_unused_surplus_pages(unsigned long unused_resv_pages)
}
}
+/*
+ * Determine if the huge page at addr within the vma has an associated
+ * reservation. Where it does not we will need to logically increase
+ * reservation and actually increase quota before an allocation can occur.
+ * Where any new reservation would be required the reservation change is
+ * prepared, but not committed. Once the page has been quota'd allocated
+ * an instantiated the change should be committed via vma_commit_reservation.
+ * No action is required on failure.
+ */
+static int vma_needs_reservation(struct vm_area_struct *vma, unsigned long addr)
+{
+ struct address_space *mapping = vma->vm_file->f_mapping;
+ struct inode *inode = mapping->host;
+
+ if (vma->vm_flags & VM_SHARED) {
+ pgoff_t idx = vma_pagecache_offset(vma, addr);
+ return region_chg(&inode->i_mapping->private_list,
+ idx, idx + 1);
+
+ } else {
+ if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER))
+ return 1;
+ }
+
+ return 0;
+}
+static void vma_commit_reservation(struct vm_area_struct *vma,
+ unsigned long addr)
+{
+ struct address_space *mapping = vma->vm_file->f_mapping;
+ struct inode *inode = mapping->host;
+
+ if (vma->vm_flags & VM_SHARED) {
+ pgoff_t idx = vma_pagecache_offset(vma, addr);
+ region_add(&inode->i_mapping->private_list, idx, idx + 1);
+ }
+}
+
static struct page *alloc_huge_page(struct vm_area_struct *vma,
unsigned long addr, int avoid_reserve)
{
struct page *page;
struct address_space *mapping = vma->vm_file->f_mapping;
struct inode *inode = mapping->host;
- unsigned int chg = 0;
+ unsigned int chg;
/*
* Processes that did not create the mapping will have no reserves and
* will not have accounted against quota. Check that the quota can be
* made before satisfying the allocation
+ * MAP_NORESERVE mappings may also need pages and quota allocated
+ * if no reserve mapping overlaps.
*/
- if (!(vma->vm_flags & VM_SHARED) &&
- !is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
- chg = 1;
+ chg = vma_needs_reservation(vma, addr);
+ if (chg < 0)
+ return ERR_PTR(chg);
+ if (chg)
if (hugetlb_get_quota(inode->i_mapping, chg))
return ERR_PTR(-ENOSPC);
- }
spin_lock(&hugetlb_lock);
page = dequeue_huge_page_vma(vma, addr, avoid_reserve);
@@ -755,6 +798,8 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
set_page_refcounted(page);
set_page_private(page, (unsigned long) mapping);
+ vma_commit_reservation(vma, addr);
+
return page;
}
@@ -1560,6 +1605,9 @@ int hugetlb_reserve_pages(struct inode *inode,
{
long ret, chg;
+ if (vma && vma->vm_flags & VM_NORESERVE)
+ return 0;
+
/*
* Shared mappings base their reservation on the number of pages that
* are already allocated on behalf of the file. Private mappings need