[PATCH 4/4] Apply MPOL_BIND policy to two highest zones when highest is ZONE_MOVABLE

Mel Gorman
2007-08-09T21:07:36Z

The NUMA layer only supports the MPOL_BIND NUMA policy for the highest
zone. When ZONE_MOVABLE is configured with kernelcore=, the the highest
zone becomes ZONE_MOVABLE. The result is that the bind policy policies is
only applied to allocations like anonymous pages and page cache allocated
from ZONE_MOVABLE when the zone is used.

This patch applies policies to the two highest zones when the highest zone
is ZONE_MOVABLE. As ZONE_MOVABLE consists of pages from the highest "real"
zone, these two zones are equivalent in policy terms.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
---

include/linux/mempolicy.h | 2 +-
mm/mempolicy.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.23-rc1-mm2-015_zoneid_zonelist/include/linux/mempolicy.h linux-2.6.23-rc1-mm2-020_treat_movable_highest/include/linux/mempolicy.h
--- linux-2.6.23-rc1-mm2-015_zoneid_zonelist/include/linux/mempolicy.h 2007-08-09 15:01:36.000000000 +0100
+++ linux-2.6.23-rc1-mm2-020_treat_movable_highest/include/linux/mempolicy.h 2007-08-09 15:52:23.000000000 +0100
@@ -157,7 +157,7 @@ extern enum zone_type policy_zone;

static inline void check_highest_zone(enum zone_type k)
{
- if (k > policy_zone)
+ if (k > policy_zone && k != ZONE_MOVABLE)
policy_zone = k;
}

diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.23-rc1-mm2-015_zoneid_zonelist/mm/mempolicy.c linux-2.6.23-rc1-mm2-020_treat_movable_highest/mm/mempolicy.c
--- linux-2.6.23-rc1-mm2-015_zoneid_zonelist/mm/mempolicy.c 2007-08-09 18:33:51.000000000 +0100
+++ linux-2.6.23-rc1-mm2-020_treat_movable_highest/mm/mempolicy.c 2007-08-09 18:33:42.000000000 +0100
@@ -151,7 +151,7 @@ static struct zonelist *bind_zonelist(no
lower zones etc. Avoid empty zones because the memory allocator
doesn't like them. If you implement node hot removal you
have to fix that. */
- k = policy_zone;
+ k = MAX_NR_ZONES - 1;
while (1) {
for_each_node_mask(nd, *nodes) {
struct zone *z = &NODE_DATA(nd)->node_zones[k];