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-rw-r--r--arch/x86/mm/numa.c17
-rw-r--r--include/linux/bitmap.h1
-rw-r--r--include/linux/nodemask.h8
-rw-r--r--kernel/fork.c4
-rw-r--r--lib/bitmap.c2
5 files changed, 31 insertions, 1 deletions
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 550df481acc..10c27bb1e95 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -2,6 +2,7 @@
#include <linux/topology.h>
#include <linux/module.h>
#include <linux/bootmem.h>
+#include <linux/random.h>
#ifdef CONFIG_DEBUG_PER_CPU_MAPS
# define DBG(x...) printk(KERN_DEBUG x)
@@ -65,3 +66,19 @@ const struct cpumask *cpumask_of_node(int node)
}
EXPORT_SYMBOL(cpumask_of_node);
#endif
+
+/*
+ * Return the bit number of a random bit set in the nodemask.
+ * (returns -1 if nodemask is empty)
+ */
+int __node_random(const nodemask_t *maskp)
+{
+ int w, bit = -1;
+
+ w = nodes_weight(*maskp);
+ if (w)
+ bit = bitmap_ord_to_pos(maskp->bits,
+ get_random_int() % w, MAX_NUMNODES);
+ return bit;
+}
+EXPORT_SYMBOL(__node_random);
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index daf8c480c78..6fb2720882f 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -141,6 +141,7 @@ extern int bitmap_find_free_region(unsigned long *bitmap, int bits, int order);
extern void bitmap_release_region(unsigned long *bitmap, int pos, int order);
extern int bitmap_allocate_region(unsigned long *bitmap, int pos, int order);
extern void bitmap_copy_le(void *dst, const unsigned long *src, int nbits);
+extern int bitmap_ord_to_pos(const unsigned long *bitmap, int n, int bits);
#define BITMAP_LAST_WORD_MASK(nbits) \
( \
diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
index dba35e41337..8a8f1d09c13 100644
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -66,6 +66,8 @@
* int num_online_nodes() Number of online Nodes
* int num_possible_nodes() Number of all possible Nodes
*
+ * int node_random(mask) Random node with set bit in mask
+ *
* int node_online(node) Is some node online?
* int node_possible(node) Is some node possible?
*
@@ -430,6 +432,10 @@ static inline void node_set_offline(int nid)
node_clear_state(nid, N_ONLINE);
nr_online_nodes = num_node_state(N_ONLINE);
}
+
+#define node_random(mask) __node_random(&(mask))
+extern int __node_random(const nodemask_t *maskp);
+
#else
static inline int node_state(int node, enum node_states state)
@@ -460,6 +466,8 @@ static inline int num_node_state(enum node_states state)
#define node_set_online(node) node_set_state((node), N_ONLINE)
#define node_set_offline(node) node_clear_state((node), N_ONLINE)
+
+static inline int node_random(const nodemask_t mask) { return 0; }
#endif
#define node_online_map node_states[N_ONLINE]
diff --git a/kernel/fork.c b/kernel/fork.c
index 4d57d9e3a6e..2e9cc3139ec 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1079,6 +1079,10 @@ static struct task_struct *copy_process(unsigned long clone_flags,
}
mpol_fix_fork_child_flag(p);
#endif
+#ifdef CONFIG_CPUSETS
+ p->cpuset_mem_spread_rotor = node_random(p->mems_allowed);
+ p->cpuset_slab_spread_rotor = node_random(p->mems_allowed);
+#endif
#ifdef CONFIG_TRACE_IRQFLAGS
p->irq_events = 0;
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
diff --git a/lib/bitmap.c b/lib/bitmap.c
index ffb78c916cc..d7137e7e06e 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -672,7 +672,7 @@ static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
*
* The bit positions 0 through @bits are valid positions in @buf.
*/
-static int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
+int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
{
int pos = 0;