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authorAndy Whitcroft <apw@shadowen.org>2008-11-06 12:53:26 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2008-11-06 15:41:18 -0800
commit69d177c2fc702d402b17fdca2190d5a7e3ca55c5 (patch)
tree2040e0a84b7c07c29ac6fb6e51e125de52256f5d /mm/hugetlb.c
parent22bece00dc1f28dd3374c55e464c9f02eb642876 (diff)
hugetlbfs: handle pages higher order than MAX_ORDER
When working with hugepages, hugetlbfs assumes that those hugepages are smaller than MAX_ORDER. Specifically it assumes that the mem_map is contigious and uses that to optimise access to the elements of the mem_map that represent the hugepage. Gigantic pages (such as 16GB pages on powerpc) by definition are of greater order than MAX_ORDER (larger than MAX_ORDER_NR_PAGES in size). This means that we can no longer make use of the buddy alloctor guarentees for the contiguity of the mem_map, which ensures that the mem_map is at least contigious for maximmally aligned areas of MAX_ORDER_NR_PAGES pages. This patch adds new mem_map accessors and iterator helpers which handle any discontiguity at MAX_ORDER_NR_PAGES boundaries. It then uses these to implement gigantic page versions of copy_huge_page and clear_huge_page, and to allow follow_hugetlb_page handle gigantic pages. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Cc: Jon Tollefson <kniht@linux.vnet.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: <stable@kernel.org> [2.6.27.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c37
1 files changed, 36 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 421aee99b84a..e6afe527bd09 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]);
}