1 files changed, 72 insertions, 0 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 0e0961b8c39c..8a32873fdbf7 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2030,6 +2030,78 @@ retry_cpuset:
 	return page;
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/**
+ * alloc_hugepage_vma: Allocate a hugepage for a VMA
+ * @gfp:
+ *   %GFP_USER	  user allocation.
+ *   %GFP_KERNEL  kernel allocations,
+ *   %GFP_HIGHMEM highmem/user allocations,
+ *   %GFP_FS	  allocation should not call back into a file system.
+ *   %GFP_ATOMIC  don't sleep.
+ *
+ * @vma:   Pointer to VMA or NULL if not available.
+ * @addr:  Virtual Address of the allocation. Must be inside the VMA.
+ * @order: Order of the hugepage for gfp allocation.
+ *
+ * This functions allocate a huge page from the kernel page pool and applies
+ * a NUMA policy associated with the VMA or the current process.
+ * For policy other than %MPOL_INTERLEAVE, we make sure we allocate hugepage
+ * only from the current node if the current node is part of the node mask.
+ * If we can't allocate a hugepage we fail the allocation and don' try to fallback
+ * to other nodes in the node mask. If the current node is not part of node mask
+ * or if the NUMA policy is MPOL_INTERLEAVE we use the allocator that can
+ * fallback to nodes in the policy node mask.
+ *
+ * When VMA is not NULL caller must hold down_read on the mmap_sem of the
+ * mm_struct of the VMA to prevent it from going away. Should be used for
+ * all allocations for pages that will be mapped into
+ * user space. Returns NULL when no page can be allocated.
+ *
+ * Should be called with vma->vm_mm->mmap_sem held.
+ *
+ */
+struct page *alloc_hugepage_vma(gfp_t gfp, struct vm_area_struct *vma,
+				unsigned long addr, int order)
+{
+	struct page *page;
+	nodemask_t *nmask;
+	struct mempolicy *pol;
+	int node = numa_node_id();
+	unsigned int cpuset_mems_cookie;
+
+retry_cpuset:
+	pol = get_vma_policy(vma, addr);
+	cpuset_mems_cookie = read_mems_allowed_begin();
+	/*
+	 * For interleave policy, we don't worry about
+	 * current node. Otherwise if current node is
+	 * in nodemask, try to allocate hugepage from
+	 * the current node. Don't fall back to other nodes
+	 * for THP.
+	 */
+	if (unlikely(pol->mode == MPOL_INTERLEAVE))
+		goto alloc_with_fallback;
+	nmask = policy_nodemask(gfp, pol);
+	if (!nmask || node_isset(node, *nmask)) {
+		mpol_cond_put(pol);
+		page = alloc_pages_exact_node(node, gfp, order);
+		if (unlikely(!page &&
+			     read_mems_allowed_retry(cpuset_mems_cookie)))
+			goto retry_cpuset;
+		return page;
+	}
+alloc_with_fallback:
+	mpol_cond_put(pol);
+	/*
+	 * if current node is not part of node mask, try
+	 * the allocation from any node, and we can do retry
+	 * in that case.
+	 */
+	return alloc_pages_vma(gfp, order, vma, addr, node);
+}
+#endif
+
 /**
  * 	alloc_pages_current - Allocate pages.
  *