[PATCH] x86_64: CPU hotplug support
Experimental CPU hotplug patch for x86_64
-----------------------------------------
This supports logical CPU online and offline.
- Test with maxcpus=1, and then kick other cpu's off to test if init code
is all cleaned up. CONFIG_SCHED_SMT works as well.
- idle threads are forked on demand from keventd threads for clean startup
TBD:
1. Not tested on a real NUMA machine (tested with numa=fake=2)
2. Handle ACPI pieces for physical hotplug support.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Acked-by: Andi Kleen <ak@muc.de>
Acked-by: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Signed-off-by: Shaohua.li<shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/kernel/irq.c b/arch/x86_64/kernel/irq.c
index 62b112e..cc3fb85 100644
--- a/arch/x86_64/kernel/irq.c
+++ b/arch/x86_64/kernel/irq.c
@@ -14,6 +14,7 @@
#include <linux/interrupt.h>
#include <linux/seq_file.h>
#include <linux/module.h>
+#include <linux/delay.h>
#include <asm/uaccess.h>
#include <asm/io_apic.h>
@@ -106,3 +107,31 @@
return 1;
}
+#ifdef CONFIG_HOTPLUG_CPU
+void fixup_irqs(cpumask_t map)
+{
+ unsigned int irq;
+ static int warned;
+
+ for (irq = 0; irq < NR_IRQS; irq++) {
+ cpumask_t mask;
+ if (irq == 2)
+ continue;
+
+ cpus_and(mask, irq_affinity[irq], map);
+ if (any_online_cpu(mask) == NR_CPUS) {
+ printk("Breaking affinity for irq %i\n", irq);
+ mask = map;
+ }
+ if (irq_desc[irq].handler->set_affinity)
+ irq_desc[irq].handler->set_affinity(irq, mask);
+ else if (irq_desc[irq].action && !(warned++))
+ printk("Cannot set affinity for irq %i\n", irq);
+ }
+
+ /* That doesn't seem sufficient. Give it 1ms. */
+ local_irq_enable();
+ mdelay(1);
+ local_irq_disable();
+}
+#endif