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-rw-r--r--mm/hugetlb.c37
-rw-r--r--mm/internal.h28
2 files changed, 64 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 421aee9..e6afe52 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -354,11 +354,26 @@ static int vma_has_reserves(struct vm_area_struct *vma)
return 0;
}
+static void clear_gigantic_page(struct page *page,
+ unsigned long addr, unsigned long sz)
+{
+ int i;
+ struct page *p = page;
+
+ might_sleep();
+ for (i = 0; i < sz/PAGE_SIZE; i++, p = mem_map_next(p, page, i)) {
+ cond_resched();
+ clear_user_highpage(p, addr + i * PAGE_SIZE);
+ }
+}
static void clear_huge_page(struct page *page,
unsigned long addr, unsigned long sz)
{
int i;
+ if (unlikely(sz > MAX_ORDER_NR_PAGES))
+ return clear_gigantic_page(page, addr, sz);
+
might_sleep();
for (i = 0; i < sz/PAGE_SIZE; i++) {
cond_resched();
@@ -366,12 +381,32 @@ static void clear_huge_page(struct page *page,
}
}
+static void copy_gigantic_page(struct page *dst, struct page *src,
+ unsigned long addr, struct vm_area_struct *vma)
+{
+ int i;
+ struct hstate *h = hstate_vma(vma);
+ struct page *dst_base = dst;
+ struct page *src_base = src;
+ might_sleep();
+ for (i = 0; i < pages_per_huge_page(h); ) {
+ cond_resched();
+ copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
+
+ i++;
+ dst = mem_map_next(dst, dst_base, i);
+ src = mem_map_next(src, src_base, i);
+ }
+}
static void copy_huge_page(struct page *dst, struct page *src,
unsigned long addr, struct vm_area_struct *vma)
{
int i;
struct hstate *h = hstate_vma(vma);
+ if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES))
+ return copy_gigantic_page(dst, src, addr, vma);
+
might_sleep();
for (i = 0; i < pages_per_huge_page(h); i++) {
cond_resched();
@@ -2130,7 +2165,7 @@ same_page:
if (zeropage_ok)
pages[i] = ZERO_PAGE(0);
else
- pages[i] = page + pfn_offset;
+ pages[i] = mem_map_offset(page, pfn_offset);
get_page(pages[i]);
}
diff --git a/mm/internal.h b/mm/internal.h
index e4e728b..f482460 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -176,6 +176,34 @@ static inline void free_page_mlock(struct page *page) { }
#endif /* CONFIG_UNEVICTABLE_LRU */
/*
+ * Return the mem_map entry representing the 'offset' subpage within
+ * the maximally aligned gigantic page 'base'. Handle any discontiguity
+ * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
+ */
+static inline struct page *mem_map_offset(struct page *base, int offset)
+{
+ if (unlikely(offset >= MAX_ORDER_NR_PAGES))
+ return pfn_to_page(page_to_pfn(base) + offset);
+ return base + offset;
+}
+
+/*
+ * Iterator over all subpages withing the maximally aligned gigantic
+ * page 'base'. Handle any discontiguity in the mem_map.
+ */
+static inline struct page *mem_map_next(struct page *iter,
+ struct page *base, int offset)
+{
+ if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
+ unsigned long pfn = page_to_pfn(base) + offset;
+ if (!pfn_valid(pfn))
+ return NULL;
+ return pfn_to_page(pfn);
+ }
+ return iter + 1;
+}
+
+/*
* FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
* so all functions starting at paging_init should be marked __init
* in those cases. SPARSEMEM, however, allows for memory hotplug,
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