mm: add alloc_pages_exact_nid()

Add a alloc_pages_exact_nid() that allocates on a specific node.

The naming is quite broken, but fixing that would need a larger renaming
action.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: tweak comment]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 37 insertions, 12 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 454191a2517..570d944daeb 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2317,6 +2317,21 @@ void free_pages(unsigned long addr, unsigned int order)
 
 EXPORT_SYMBOL(free_pages);
 
+static void *make_alloc_exact(unsigned long addr, unsigned order, size_t size)
+{
+        if (addr) {
+                unsigned long alloc_end = addr + (PAGE_SIZE << order);
+                unsigned long used = addr + PAGE_ALIGN(size);
+
+                split_page(virt_to_page((void *)addr), order);
+                while (used < alloc_end) {
+                        free_page(used);
+                        used += PAGE_SIZE;
+                }
+        }
+        return (void *)addr;
+}
+
 /**
  * alloc_pages_exact - allocate an exact number physically-contiguous pages.
  * @size: the number of bytes to allocate
@@ -2336,22 +2351,32 @@ void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
         unsigned long addr;
 
         addr = __get_free_pages(gfp_mask, order);
-        if (addr) {
-                unsigned long alloc_end = addr + (PAGE_SIZE << order);
-                unsigned long used = addr + PAGE_ALIGN(size);
-
-                split_page(virt_to_page((void *)addr), order);
-                while (used < alloc_end) {
-                        free_page(used);
-                        used += PAGE_SIZE;
-                }
-        }
-
-        return (void *)addr;
+        return make_alloc_exact(addr, order, size);
 }
 EXPORT_SYMBOL(alloc_pages_exact);
 
 /**
+ * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
+ *                         pages on a node.
+ * @size: the number of bytes to allocate
+ * @gfp_mask: GFP flags for the allocation
+ *
+ * Like alloc_pages_exact(), but try to allocate on node nid first before falling
+ * back.
+ * Note this is not alloc_pages_exact_node() which allocates on a specific node,
+ * but is not exact.
+ */
+void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
+{
+        unsigned order = get_order(size);
+        struct page *p = alloc_pages_node(nid, gfp_mask, order);
+        if (!p)
+                return NULL;
+        return make_alloc_exact((unsigned long)page_address(p), order, size);
+}
+EXPORT_SYMBOL(alloc_pages_exact_nid);
+
+/**
  * free_pages_exact - release memory allocated via alloc_pages_exact()
  * @virt: the value returned by alloc_pages_exact.
  * @size: size of allocation, same value as passed to alloc_pages_exact().