7 files changed, 92 insertions, 28 deletions

diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 8821e1f75b44..826b15e914e2 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -30,10 +30,19 @@ void cpuset_update_task_memory_state(void);
                 nodes_subset((nodes), current->mems_allowed)
 int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl);
 
-extern int __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask);
-static int inline cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
+extern int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask);
+extern int __cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask);
+
+static int inline cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
+{
+        return number_of_cpusets <= 1 ||
+                __cpuset_zone_allowed_softwall(z, gfp_mask);
+}
+
+static int inline cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
 {
-        return number_of_cpusets <= 1 || __cpuset_zone_allowed(z, gfp_mask);
+        return number_of_cpusets <= 1 ||
+                __cpuset_zone_allowed_hardwall(z, gfp_mask);
 }
 
 extern int cpuset_excl_nodes_overlap(const struct task_struct *p);
@@ -94,7 +103,12 @@ static inline int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl)
         return 1;
 }
 
-static inline int cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
+static inline int cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
+{
+        return 1;
+}
+
+static inline int cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
 {
         return 1;
 }
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 2c3b4431472b..232aed2b10f9 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2342,32 +2342,48 @@ static const struct cpuset *nearest_exclusive_ancestor(const struct cpuset *cs)
 }
 
 /**
- * cpuset_zone_allowed - Can we allocate memory on zone z's memory node?
+ * cpuset_zone_allowed_softwall - Can we allocate on zone z's memory node?
  * @z: is this zone on an allowed node?
- * @gfp_mask: memory allocation flags (we use __GFP_HARDWALL)
+ * @gfp_mask: memory allocation flags
  *
- * If we're in interrupt, yes, we can always allocate.  If zone
+ * If we're in interrupt, yes, we can always allocate.  If
+ * __GFP_THISNODE is set, yes, we can always allocate.  If zone
  * z's node is in our tasks mems_allowed, yes.  If it's not a
  * __GFP_HARDWALL request and this zone's nodes is in the nearest
  * mem_exclusive cpuset ancestor to this tasks cpuset, yes.
  * Otherwise, no.
  *
+ * If __GFP_HARDWALL is set, cpuset_zone_allowed_softwall()
+ * reduces to cpuset_zone_allowed_hardwall().  Otherwise,
+ * cpuset_zone_allowed_softwall() might sleep, and might allow a zone
+ * from an enclosing cpuset.
+ *
+ * cpuset_zone_allowed_hardwall() only handles the simpler case of
+ * hardwall cpusets, and never sleeps.
+ *
+ * The __GFP_THISNODE placement logic is really handled elsewhere,
+ * by forcibly using a zonelist starting at a specified node, and by
+ * (in get_page_from_freelist()) refusing to consider the zones for
+ * any node on the zonelist except the first.  By the time any such
+ * calls get to this routine, we should just shut up and say 'yes'.
+ *
  * GFP_USER allocations are marked with the __GFP_HARDWALL bit,
  * and do not allow allocations outside the current tasks cpuset.
  * GFP_KERNEL allocations are not so marked, so can escape to the
- * nearest mem_exclusive ancestor cpuset.
+ * nearest enclosing mem_exclusive ancestor cpuset.
  *
- * Scanning up parent cpusets requires callback_mutex.  The __alloc_pages()
- * routine only calls here with __GFP_HARDWALL bit _not_ set if
- * it's a GFP_KERNEL allocation, and all nodes in the current tasks
- * mems_allowed came up empty on the first pass over the zonelist.
- * So only GFP_KERNEL allocations, if all nodes in the cpuset are
- * short of memory, might require taking the callback_mutex mutex.
+ * Scanning up parent cpusets requires callback_mutex.  The
+ * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
+ * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
+ * current tasks mems_allowed came up empty on the first pass over
+ * the zonelist.  So only GFP_KERNEL allocations, if all nodes in the
+ * cpuset are short of memory, might require taking the callback_mutex
+ * mutex.
  *
  * The first call here from mm/page_alloc:get_page_from_freelist()
- * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets, so
- * no allocation on a node outside the cpuset is allowed (unless in
- * interrupt, of course).
+ * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
+ * so no allocation on a node outside the cpuset is allowed (unless
+ * in interrupt, of course).
  *
  * The second pass through get_page_from_freelist() doesn't even call
  * here for GFP_ATOMIC calls.  For those calls, the __alloc_pages()
@@ -2380,12 +2396,12 @@ static const struct cpuset *nearest_exclusive_ancestor(const struct cpuset *cs)
  *      GFP_USER     - only nodes in current tasks mems allowed ok.
  *
  * Rule:
- *    Don't call cpuset_zone_allowed() if you can't sleep, unless you
+ *    Don't call cpuset_zone_allowed_softwall if you can't sleep, unless you
  *    pass in the __GFP_HARDWALL flag set in gfp_flag, which disables
  *    the code that might scan up ancestor cpusets and sleep.
- **/
+ */
 
-int __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
+int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
 {
         int node;                       /* node that zone z is on */
         const struct cpuset *cs;        /* current cpuset ancestors */
@@ -2415,6 +2431,40 @@ int __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
         return allowed;
 }
 
+/*
+ * cpuset_zone_allowed_hardwall - Can we allocate on zone z's memory node?
+ * @z: is this zone on an allowed node?
+ * @gfp_mask: memory allocation flags
+ *
+ * If we're in interrupt, yes, we can always allocate.
+ * If __GFP_THISNODE is set, yes, we can always allocate.  If zone
+ * z's node is in our tasks mems_allowed, yes.   Otherwise, no.
+ *
+ * The __GFP_THISNODE placement logic is really handled elsewhere,
+ * by forcibly using a zonelist starting at a specified node, and by
+ * (in get_page_from_freelist()) refusing to consider the zones for
+ * any node on the zonelist except the first.  By the time any such
+ * calls get to this routine, we should just shut up and say 'yes'.
+ *
+ * Unlike the cpuset_zone_allowed_softwall() variant, above,
+ * this variant requires that the zone be in the current tasks
+ * mems_allowed or that we're in interrupt.  It does not scan up the
+ * cpuset hierarchy for the nearest enclosing mem_exclusive cpuset.
+ * It never sleeps.
+ */
+
+int __cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
+{
+        int node;                       /* node that zone z is on */
+
+        if (in_interrupt() || (gfp_mask & __GFP_THISNODE))
+                return 1;
+        node = zone_to_nid(z);
+        if (node_isset(node, current->mems_allowed))
+                return 1;
+        return 0;
+}
+
 /**
  * cpuset_lock - lock out any changes to cpuset structures
  *
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0ccc7f230252..089092d152ab 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -73,7 +73,7 @@ static struct page *dequeue_huge_page(struct vm_area_struct *vma,
 
         for (z = zonelist->zones; *z; z++) {
                 nid = zone_to_nid(*z);
-                if (cpuset_zone_allowed(*z, GFP_HIGHUSER) &&
+                if (cpuset_zone_allowed_softwall(*z, GFP_HIGHUSER) &&
                     !list_empty(&hugepage_freelists[nid]))
                         break;
         }
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 223d9ccb7d64..64cf3c214634 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -177,7 +177,7 @@ static inline int constrained_alloc(struct zonelist *zonelist, gfp_t gfp_mask)
         nodemask_t nodes = node_online_map;
 
         for (z = zonelist->zones; *z; z++)
-                if (cpuset_zone_allowed(*z, gfp_mask))
+                if (cpuset_zone_allowed_softwall(*z, gfp_mask))
                         node_clear(zone_to_nid(*z), nodes);
                 else
                         return CONSTRAINT_CPUSET;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e6b17b2989e0..8c1a116875bc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1162,7 +1162,7 @@ zonelist_scan:
                         zone->zone_pgdat != zonelist->zones[0]->zone_pgdat))
                                 break;
                 if ((alloc_flags & ALLOC_CPUSET) &&
-                        !cpuset_zone_allowed(zone, gfp_mask))
+                        !cpuset_zone_allowed_softwall(zone, gfp_mask))
                                 goto try_next_zone;
 
                 if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
diff --git a/mm/slab.c b/mm/slab.c
index 9d3550086c93..b856786a3a30 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3262,7 +3262,7 @@ retry:
         for (z = zonelist->zones; *z && !obj; z++) {
                 nid = zone_to_nid(*z);
 
-                if (cpuset_zone_allowed(*z, flags | __GFP_HARDWALL) &&
+                if (cpuset_zone_allowed_hardwall(*z, flags) &&
                         cache->nodelists[nid] &&
                         cache->nodelists[nid]->free_objects)
                                 obj = ____cache_alloc_node(cache,
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 093f5fe6dd77..e9813b06c7a3 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -984,7 +984,7 @@ static unsigned long shrink_zones(int priority, struct zone **zones,
                 if (!populated_zone(zone))
                         continue;
 
-                if (!cpuset_zone_allowed(zone, __GFP_HARDWALL))
+                if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
                         continue;
 
                 note_zone_scanning_priority(zone, priority);
@@ -1034,7 +1034,7 @@ unsigned long try_to_free_pages(struct zone **zones, gfp_t gfp_mask)
         for (i = 0; zones[i] != NULL; i++) {
                 struct zone *zone = zones[i];
 
-                if (!cpuset_zone_allowed(zone, __GFP_HARDWALL))
+                if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
                         continue;
 
                 lru_pages += zone->nr_active + zone->nr_inactive;
@@ -1089,7 +1089,7 @@ out:
         for (i = 0; zones[i] != 0; i++) {
                 struct zone *zone = zones[i];
 
-                if (!cpuset_zone_allowed(zone, __GFP_HARDWALL))
+                if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
                         continue;
 
                 zone->prev_priority = priority;
@@ -1354,7 +1354,7 @@ void wakeup_kswapd(struct zone *zone, int order)
                 return;
         if (pgdat->kswapd_max_order < order)
                 pgdat->kswapd_max_order = order;
-        if (!cpuset_zone_allowed(zone, __GFP_HARDWALL))
+        if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
                 return;
         if (!waitqueue_active(&pgdat->kswapd_wait))
                 return;