1 files changed, 14 insertions, 1 deletions

diff --git a/mm/allocpercpu.c b/mm/allocpercpu.c
index 7e58322b7134..b0012e27fea8 100644
--- a/mm/allocpercpu.c
+++ b/mm/allocpercpu.c
@@ -6,6 +6,10 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 
+#ifndef cache_line_size
+#define cache_line_size()       L1_CACHE_BYTES
+#endif
+
 /**
  * percpu_depopulate - depopulate per-cpu data for given cpu
  * @__pdata: per-cpu data to depopulate
@@ -52,6 +56,11 @@ void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu)
         struct percpu_data *pdata = __percpu_disguise(__pdata);
         int node = cpu_to_node(cpu);
 
+        /*
+         * We should make sure each CPU gets private memory.
+         */
+        size = roundup(size, cache_line_size());
+
         BUG_ON(pdata->ptrs[cpu]);
         if (node_online(node))
                 pdata->ptrs[cpu] = kmalloc_node(size, gfp|__GFP_ZERO, node);
@@ -98,7 +107,11 @@ EXPORT_SYMBOL_GPL(__percpu_populate_mask);
  */
 void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
 {
-        void *pdata = kzalloc(nr_cpu_ids * sizeof(void *), gfp);
+        /*
+         * We allocate whole cache lines to avoid false sharing
+         */
+        size_t sz = roundup(nr_cpu_ids * sizeof(void *), cache_line_size());
+        void *pdata = kzalloc(sz, gfp);
         void *__pdata = __percpu_disguise(pdata);
 
         if (unlikely(!pdata))