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authorAshok Raj <ashok.raj@intel.com>2005-06-25 14:55:00 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-25 16:24:30 -0700
commit76e4f660d9f4c6d1bb473f72be2988c35eaca948 (patch)
tree3a0b3ae0cc12d6f0d96bf1f3b564f8470e0f72ae /arch/x86_64/kernel/process.c
parente6982c671c560da4a0bc5c908cbcbec12bd5991d (diff)
[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>
Diffstat (limited to 'arch/x86_64/kernel/process.c')
-rw-r--r--arch/x86_64/kernel/process.c29
1 files changed, 28 insertions, 1 deletions
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index 15fa35a81a7..1d91271796e 100644
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -8,7 +8,8 @@
*
* X86-64 port
* Andi Kleen.
- *
+ *
+ * CPU hotplug support - ashok.raj@intel.com
* $Id: process.c,v 1.38 2002/01/15 10:08:03 ak Exp $
*/
@@ -18,6 +19,7 @@
#include <stdarg.h>
+#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
@@ -154,6 +156,29 @@ void cpu_idle_wait(void)
}
EXPORT_SYMBOL_GPL(cpu_idle_wait);
+#ifdef CONFIG_HOTPLUG_CPU
+DECLARE_PER_CPU(int, cpu_state);
+
+#include <asm/nmi.h>
+/* We don't actually take CPU down, just spin without interrupts. */
+static inline void play_dead(void)
+{
+ idle_task_exit();
+ wbinvd();
+ mb();
+ /* Ack it */
+ __get_cpu_var(cpu_state) = CPU_DEAD;
+
+ while (1)
+ safe_halt();
+}
+#else
+static inline void play_dead(void)
+{
+ BUG();
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
/*
* The idle thread. There's no useful work to be
* done, so just try to conserve power and have a
@@ -174,6 +199,8 @@ void cpu_idle (void)
idle = pm_idle;
if (!idle)
idle = default_idle;
+ if (cpu_is_offline(smp_processor_id()))
+ play_dead();
idle();
}