Apply memory policies to top two highest zones when highest zone is ZONE_MOVABLE

The NUMA layer only supports NUMA policies for the highest zone.  When
ZONE_MOVABLE is configured with kernelcore=, the the highest zone becomes
ZONE_MOVABLE.  The result is that policies are 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, it's always functionally equivalent.

The patch has been tested on a variety of machines both NUMA and non-NUMA
covering x86, x86_64 and ppc64.  No abnormal results were seen in
kernbench, tbench, dbench or hackbench.  It passes regression tests from
the numactl package with and without kernelcore= once numactl tests are
patched to wait for vmstat counters to update.

akpm: this is the nasty hack to fix NUMA mempolicies in the presence of
ZONE_MOVABLE and kernelcore= in 2.6.23.  Christoph says "For .24 either merge
the mobility or get the other solution that Mel is working on.  That solution
would only use a single zonelist per node and filter on the fly.  That may
help performance and also help to make memory policies work better."

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by:  Lee Schermerhorn <lee.schermerhorn@hp.com>
Tested-by:  Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index e147cf5..5bdd656 100644 (file)
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -166,7 +166,7 @@ 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 --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 3ea68cd..4e56273 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -410,6 +410,24 @@ struct zonelist {
 #endif
 };
 
+#ifdef CONFIG_NUMA
+/*
+ * Only custom zonelists like MPOL_BIND need to be filtered as part of
+ * policies. As described in the comment for struct zonelist_cache, these
+ * zonelists will not have a zlcache so zlcache_ptr will not be set. Use
+ * that to determine if the zonelists needs to be filtered or not.
+ */
+static inline int alloc_should_filter_zonelist(struct zonelist *zonelist)
+{
+       return !zonelist->zlcache_ptr;
+}
+#else
+static inline int alloc_should_filter_zonelist(struct zonelist *zonelist)
+{
+       return 0;
+}
+#endif /* CONFIG_NUMA */
+
 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
 struct node_active_region {
        unsigned long start_pfn;

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 71b84b4..172abff 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -149,7 +149,7 @@ static struct zonelist *bind_zonelist(nodemask_t *nodes)
           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];

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3da85b8..6427653 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1157,6 +1157,7 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order,
        nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
        int zlc_active = 0;             /* set if using zonelist_cache */
        int did_zlc_setup = 0;          /* just call zlc_setup() one time */
+       enum zone_type highest_zoneidx = -1; /* Gets set for policy zonelists */
 
 zonelist_scan:
        /*
@@ -1166,6 +1167,18 @@ zonelist_scan:
        z = zonelist->zones;
 
        do {
+               /*
+                * In NUMA, this could be a policy zonelist which contains
+                * zones that may not be allowed by the current gfp_mask.
+                * Check the zone is allowed by the current flags
+                */
+               if (unlikely(alloc_should_filter_zonelist(zonelist))) {
+                       if (highest_zoneidx == -1)
+                               highest_zoneidx = gfp_zone(gfp_mask);
+                       if (zone_idx(*z) > highest_zoneidx)
+                               continue;
+               }
+
                if (NUMA_BUILD && zlc_active &&
                        !zlc_zone_worth_trying(zonelist, z, allowednodes))
                                continue;