mm, mempolicy: rename slab_node for clarity

slab_node() is actually a mempolicy function, so rename it to
mempolicy_slab_node() to make it clearer that it used for processes with
mempolicies.

At the same time, cleanup its code by saving numa_mem_id() in a local
variable (since we require a node with memory, not just any node) and
remove an obsolete comment that assumes the mempolicy is actually passed
into the function.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Tim Hockin <thockin@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 10 insertions, 13 deletions

diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 5f1ea756aace..cfe55dfca015 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -151,7 +151,7 @@ extern struct zonelist *huge_zonelist(struct vm_area_struct *vma,
 extern bool init_nodemask_of_mempolicy(nodemask_t *mask);
 extern bool mempolicy_nodemask_intersects(struct task_struct *tsk,
                                 const nodemask_t *mask);
-extern unsigned slab_node(void);
+extern unsigned int mempolicy_slab_node(void);
 
 extern enum zone_type policy_zone;
 
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index e3ab02822799..0ad0ba31979f 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1782,21 +1782,18 @@ static unsigned interleave_nodes(struct mempolicy *policy)
 /*
  * Depending on the memory policy provide a node from which to allocate the
  * next slab entry.
- * @policy must be protected by freeing by the caller.  If @policy is
- * the current task's mempolicy, this protection is implicit, as only the
- * task can change it's policy.  The system default policy requires no
- * such protection.
  */
-unsigned slab_node(void)
+unsigned int mempolicy_slab_node(void)
 {
         struct mempolicy *policy;
+        int node = numa_mem_id();
 
         if (in_interrupt())
-                return numa_node_id();
+                return node;
 
         policy = current->mempolicy;
         if (!policy || policy->flags & MPOL_F_LOCAL)
-                return numa_node_id();
+                return node;
 
         switch (policy->mode) {
         case MPOL_PREFERRED:
@@ -1816,11 +1813,11 @@ unsigned slab_node(void)
                 struct zonelist *zonelist;
                 struct zone *zone;
                 enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
-                zonelist = &NODE_DATA(numa_node_id())->node_zonelists[0];
+                zonelist = &NODE_DATA(node)->node_zonelists[0];
                 (void)first_zones_zonelist(zonelist, highest_zoneidx,
                                                         &policy->v.nodes,
                                                         &zone);
-                return zone ? zone->node : numa_node_id();
+                return zone ? zone->node : node;
         }
 
         default:
diff --git a/mm/slab.c b/mm/slab.c
index 9153c802e2fe..4b17f4c2e92d 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3042,7 +3042,7 @@ static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
         if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
                 nid_alloc = cpuset_slab_spread_node();
         else if (current->mempolicy)
-                nid_alloc = slab_node();
+                nid_alloc = mempolicy_slab_node();
         if (nid_alloc != nid_here)
                 return ____cache_alloc_node(cachep, flags, nid_alloc);
         return NULL;
@@ -3074,7 +3074,7 @@ static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
 
 retry_cpuset:
         cpuset_mems_cookie = read_mems_allowed_begin();
-        zonelist = node_zonelist(slab_node(), flags);
+        zonelist = node_zonelist(mempolicy_slab_node(), flags);
 
 retry:
         /*
diff --git a/mm/slub.c b/mm/slub.c
index fe6d7be22ef0..5b05e4fe9a1a 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1685,7 +1685,7 @@ static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
 
         do {
                 cpuset_mems_cookie = read_mems_allowed_begin();
-                zonelist = node_zonelist(slab_node(), flags);
+                zonelist = node_zonelist(mempolicy_slab_node(), flags);
                 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
                         struct kmem_cache_node *n;