PERCPU : __percpu_alloc_mask() can dynamically size percpu_data storage

upstream commit: b3242151906372f30f57feaa43b4cac96a23edb1

Instead of allocating a fix sized array of NR_CPUS pointers for percpu_data,
we can use nr_cpu_ids, which is generally < NR_CPUS.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 926adaae0f9610885d5d64e341410a9b96900312..1702ab56ed3cc2db2d60ff4f7922f7e3eb2f01f4 100644 (file)
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -34,7 +34,7 @@
 #ifdef CONFIG_SMP
 
 struct percpu_data {
-       void *ptrs[NR_CPUS];
+       void *ptrs[1];
 };
 
 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)

diff --git a/mm/allocpercpu.c b/mm/allocpercpu.c
index 00b02623f008e924856329770c68ad0d3c3d7917..7e58322b7134ff1d04e40269e030bdd53e1c87f6 100644 (file)
--- a/mm/allocpercpu.c
+++ b/mm/allocpercpu.c
@@ -98,7 +98,7 @@ EXPORT_SYMBOL_GPL(__percpu_populate_mask);
  */
 void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
 {
-       void *pdata = kzalloc(sizeof(struct percpu_data), gfp);
+       void *pdata = kzalloc(nr_cpu_ids * sizeof(void *), gfp);
        void *__pdata = __percpu_disguise(pdata);
 
        if (unlikely(!pdata))