mm: numa: initialise numa balancing after jump label initialisation

The command line parsing takes place before jump labels are initialised
which generates a warning if numa_balancing= is specified and
CONFIG_JUMP_LABEL is set.

On older kernels before commit c4b2c0c5f647 ("static_key: WARN on usage
before jump_label_init was called") the kernel would have crashed.  This
patch enables automatic numa balancing later in the initialisation
process if numa_balancing= is specified.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 6 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 36cb46cddf61..79cea01f9f78 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2654,7 +2654,7 @@ void mpol_free_shared_policy(struct shared_policy *p)
 }
 
 #ifdef CONFIG_NUMA_BALANCING
-static bool __initdata numabalancing_override;
+static int __initdata numabalancing_override;
 
 static void __init check_numabalancing_enable(void)
 {
@@ -2663,9 +2663,15 @@ static void __init check_numabalancing_enable(void)
         if (IS_ENABLED(CONFIG_NUMA_BALANCING_DEFAULT_ENABLED))
                 numabalancing_default = true;
 
+        /* Parsed by setup_numabalancing. override == 1 enables, -1 disables */
+        if (numabalancing_override)
+                set_numabalancing_state(numabalancing_override == 1);
+
         if (nr_node_ids > 1 && !numabalancing_override) {
-                printk(KERN_INFO "Enabling automatic NUMA balancing. "
-                        "Configure with numa_balancing= or the kernel.numa_balancing sysctl");
+                printk(KERN_INFO "%s automatic NUMA balancing. "
+                        "Configure with numa_balancing= or the "
+                        "kernel.numa_balancing sysctl",
+                        numabalancing_default ? "Enabling" : "Disabling");
                 set_numabalancing_state(numabalancing_default);
         }
 }
@@ -2675,13 +2681,12 @@ static int __init setup_numabalancing(char *str)
         int ret = 0;
         if (!str)
                 goto out;
-        numabalancing_override = true;
 
         if (!strcmp(str, "enable")) {
-                set_numabalancing_state(true);
+                numabalancing_override = 1;
                 ret = 1;
         } else if (!strcmp(str, "disable")) {
-                set_numabalancing_state(false);
+                numabalancing_override = -1;
                 ret = 1;
         }
 out: