[PATCH] x86_64: Reduce NMI watchdog stack usage

NR_CPUs can be quite big these days.  kmalloc the per CPU array instead of
putting it onto the stack

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index 61de0b34a01e..ec13eb97e8e6 100644
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -114,7 +114,7 @@ static __init int cpu_has_lapic(void)
 
 static int __init check_nmi_watchdog (void)
 {
-        int counts[NR_CPUS];
+        int *counts;
         int cpu;
 
         if (nmi_watchdog == NMI_NONE)
@@ -125,6 +125,12 @@ static int __init check_nmi_watchdog (void)
                 return -1; 
         }       
 
+        counts = kmalloc(NR_CPUS * sizeof(int),GFP_KERNEL);
+        if (!counts) {
+                nmi_watchdog = NMI_NONE;
+                return 0;
+        }
+
         printk(KERN_INFO "Testing NMI watchdog ... ");
 
         for (cpu = 0; cpu < NR_CPUS; cpu++)
@@ -139,6 +145,7 @@ static int __init check_nmi_watchdog (void)
                                cpu_pda[cpu].__nmi_count);
                         nmi_active = 0;
                         lapic_nmi_owner &= ~LAPIC_NMI_WATCHDOG;
+                        kfree(counts);
                         return -1;
                 }
         }
@@ -149,6 +156,7 @@ static int __init check_nmi_watchdog (void)
         if (nmi_watchdog == NMI_LOCAL_APIC)
                 nmi_hz = 1;
 
+        kfree(counts);
         return 0;
 }
 /* Have this called later during boot so counters are updating */