From: Scott Moser <dzickus@lorax.boston.redhat.com>
Date: Wed, 5 Dec 2007 13:11:39 -0500
Subject: [ppc64] unequal allocation of hugepages
Message-id: Pine.LNX.4.64.0712051309320.19799@squad5-lp1.lab.boston.redhat.com
O-Subject: [PATCH RHEL5u2] bz239790 Unequal allocation of hugepages on pseries [1/3] - revised
Bugzilla: 239790

    Introduce alloc_pages_thisnode() to help deal with THISNODE allocations
    without introducing the GFP flags in RH5.1.

    If a node's first fallback node is a different node, then it must not
    have any memory on it. So fail to satisfy the THISNODE allocation.

    Setup the zonelist so that the first different node in the list will
    result in __alloc_pages bailing.

    Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>

--
 include/linux/gfp.h |   32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

Acked-by: David Howells <dhowells@redhat.com>

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 92383d0..5ef5296 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -109,6 +109,38 @@ static inline int arch_free_page(struct page *page, int order) { return 0; }
 extern struct page *
 FASTCALL(__alloc_pages(gfp_t, unsigned int, struct zonelist *));
 
+static inline struct page *alloc_pages_thisnode(int nid, gfp_t gfp_mask,
+						unsigned int order)
+{
+	struct zonelist *zl;
+	struct zonelist thisnode_zl;
+	int i;
+
+	if (unlikely(order >= MAX_ORDER))
+		return NULL;
+
+	/* Unknown node is current node */
+	if (nid < 0)
+		nid = numa_node_id();
+
+	zl = NODE_DATA(nid)->node_zonelists + gfp_zone(gfp_mask);
+	/*
+	 * If the first fallback node is a different node, then this
+	 * node has no memory
+	 */
+	if (zl->zones[0]->zone_pgdat->node_id != nid)
+		return NULL;
+
+	for (i = 1; zl->zones[i] != NULL; i++) {
+		if (zl->zones[i]->zone_pgdat->node_id != nid)
+			break;
+		thisnode_zl.zones[i] = zl->zones[i];
+	}
+	thisnode_zl.zones[i] = NULL;
+
+	return __alloc_pages(gfp_mask, order, &thisnode_zl);
+}
+
 static inline struct page *alloc_pages_node(int nid, gfp_t gfp_mask,
 						unsigned int order)
 {