mm: filter based on a nodemask as well as a gfp_mask

The MPOL_BIND policy creates a zonelist that is used for allocations
controlled by that mempolicy.  As the per-node zonelist is already being
filtered based on a zone id, this patch adds a version of __alloc_pages() that
takes a nodemask for further filtering.  This eliminates the need for
MPOL_BIND to create a custom zonelist.

A positive benefit of this is that allocations using MPOL_BIND now use the
local node's distance-ordered zonelist instead of a custom node-id-ordered
zonelist.  I.e., pages will be allocated from the closest allowed node with
available memory.

[Lee.Schermerhorn@hp.com: Mempolicy: update stale documentation and comments]
[Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask]
[Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask rework]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 13 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index a220b13cbfaf..c9923e3c9a3b 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1958,22 +1958,14 @@ nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
 }
 
 /**
- * cpuset_zonelist_valid_mems_allowed - check zonelist vs. curremt mems_allowed
- * @zl: the zonelist to be checked
+ * cpuset_nodemask_valid_mems_allowed - check nodemask vs. curremt mems_allowed
+ * @nodemask: the nodemask to be checked
  *
- * Are any of the nodes on zonelist zl allowed in current->mems_allowed?
+ * Are any of the nodes in the nodemask allowed in current->mems_allowed?
  */
-int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl)
+int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
 {
-        int i;
-
-        for (i = 0; zl->_zonerefs[i].zone; i++) {
-                int nid = zonelist_node_idx(&zl->_zonerefs[i]);
-
-                if (node_isset(nid, current->mems_allowed))
-                        return 1;
-        }
-        return 0;
+        return nodes_intersects(*nodemask, current->mems_allowed);
 }
 
 /*