numa: add a sysctl for numa_balancing
Add a working sysctl to enable/disable automatic numa memory balancing
at runtime.
This allows us to track down performance problems with this feature and
is generally a good idea.
This was possible earlier through debugfs, but only with special
debugging options set. Also fix the boot message.
[akpm@linux-foundation.org: s/sched_numa_balancing/sysctl_numa_balancing/]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h
index 31e0193..b13cf43 100644
--- a/include/linux/sched/sysctl.h
+++ b/include/linux/sched/sysctl.h
@@ -99,4 +99,8 @@
void __user *buffer, size_t *lenp,
loff_t *ppos);
+extern int sysctl_numa_balancing(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos);
+
#endif /* _SCHED_SYSCTL_H */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 4d6964e..7fea865 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1770,7 +1770,29 @@
numabalancing_enabled = enabled;
}
#endif /* CONFIG_SCHED_DEBUG */
-#endif /* CONFIG_NUMA_BALANCING */
+
+#ifdef CONFIG_PROC_SYSCTL
+int sysctl_numa_balancing(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ struct ctl_table t;
+ int err;
+ int state = numabalancing_enabled;
+
+ if (write && !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ t = *table;
+ t.data = &state;
+ err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
+ if (err < 0)
+ return err;
+ if (write)
+ set_numabalancing_state(state);
+ return err;
+}
+#endif
+#endif
/*
* fork()/clone()-time setup:
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 332cefc..693eac3 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -389,6 +389,15 @@
.mode = 0644,
.proc_handler = proc_dointvec,
},
+ {
+ .procname = "numa_balancing",
+ .data = NULL, /* filled in by handler */
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = sysctl_numa_balancing,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
#endif /* CONFIG_NUMA_BALANCING */
#endif /* CONFIG_SCHED_DEBUG */
{
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 0cd2c4d..947293e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2668,7 +2668,7 @@
if (nr_node_ids > 1 && !numabalancing_override) {
printk(KERN_INFO "Enabling automatic NUMA balancing. "
- "Configure with numa_balancing= or sysctl");
+ "Configure with numa_balancing= or the kernel.numa_balancing sysctl");
set_numabalancing_state(numabalancing_default);
}
}