From: Raz Ben Yehuda

SOS is a platform aimed to assign a service to an offloaded processor.
This patch is the facility for SOS (http://sos-linux.cvs.sourceforge.net/sos-linux/)

Signed-off-by: Raz Ben Yehuda
---
arch/x86/kernel/process.c | 42 +++++++++++++++++++++++++++++++++
arch/x86/kernel/process_32.c | 2 +
arch/x86/kernel/process_64.c | 2 +
arch/x86/kernel/smpboot.c | 9 +++----
include/linux/cpu.h | 20 +++++++++++++++
kernel/cpu.c | 1
6 files changed, 72 insertions(+), 4 deletions(-)


diff -uprN -X dontdiff linux-2.6.27/arch/x86/kernel/process_32.c linux-2.6.27-dbg/arch/x86/kernel/process_32.c
--- linux-2.6.27/arch/x86/kernel/process_32.c 2008-10-10 00:13:53.000000000 +0200
+++ linux-2.6.27-dbg/arch/x86/kernel/process_32.c 2008-10-13 23:29:04.000000000 +0200
@@ -106,6 +106,8 @@ static inline void play_dead(void)
*/
local_irq_disable();
/* mask all interrupts, flush any and all caches, and halt */
+ if (is_sossed(raw_smp_processor_id()))
+ run_sos();
wbinvd_halt();
}
#else
diff -uprN -X dontdiff linux-2.6.27/arch/x86/kernel/process_64.c linux-2.6.27-dbg/arch/x86/kernel/process_64.c
--- linux-2.6.27/arch/x86/kernel/process_64.c 2008-10-10 00:13:53.000000000 +0200
+++ linux-2.6.27-dbg/arch/x86/kernel/process_64.c 2008-10-13 23:14:21.000000000 +0200
@@ -101,6 +101,8 @@ static inline void play_dead(void)

local_irq_disable();
/* mask all interrupts, flush any and all caches, and halt */
+ if (is_sossed(raw_smp_processor_id()))
+ run_sos();
wbinvd_halt();
}
#else
diff -uprN -X dontdiff linux-2.6.27/arch/x86/kernel/process.c linux-2.6.27-dbg/arch/x86/kernel/process.c
--- linux-2.6.27/arch/x86/kernel/process.c 2008-10-10 00:13:53.000000000 +0200
+++ linux-2.6.27-dbg/arch/x86/kernel/process.c 2008-10-13 23:29:44.000000000 +0200
@@ -371,3 +371,45 @@ static int __init idle_setup(char *str)
}
early_param("idle", idle_setup);

+#ifdef CONFIG_HOTPLUG_CPU
+struct hotplug_cpu{
+ long flags;
+ void (*hotplug_cpu_dead)(void);
+};
+
+#define CPU_SOS 31
+
+DEFINE_PER_CPU(struct hotplug_cpu, soscpu);
+
+void unregister_sos(int cpuid)
+{
+ struct hotplug_cpu *cpu = &per_cpu(soscpu, cpuid);
+ cpu->hotplug_cpu_dead = NULL;
+ clear_bit(CPU_SOS, &cpu->flags);
+}
+EXPORT_SYMBOL_GPL(unregister_sos);
+
+int is_sossed(int cpuid)
+{
+ struct hotplug_cpu *cpu = &per_cpu(soscpu, cpuid);
+ return test_bit(CPU_SOS, &cpu->flags);
+}
+
+int register_sos(void (*sos_callback)(void), int cpuid)
+{
+ struct hotplug_cpu *cpu = &per_cpu(soscpu, cpuid);
+ if (is_sossed(cpuid))
+ return -1;
+ cpu->hotplug_cpu_dead = sos_callback;
+ set_bit(CPU_SOS, &cpu->flags);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(register_sos);
+
+void run_sos(void)
+{
+ int cpuid = raw_smp_processor_id();
+ struct hotplug_cpu *cpu = &per_cpu(soscpu, cpuid);
+ cpu->hotplug_cpu_dead();
+}
+#endif
diff -uprN -X dontdiff linux-2.6.27/arch/x86/kernel/smpboot.c linux-2.6.27-dbg/arch/x86/kernel/smpboot.c
--- linux-2.6.27/arch/x86/kernel/smpboot.c 2008-10-10 00:13:53.000000000 +0200
+++ linux-2.6.27-dbg/arch/x86/kernel/smpboot.c 2008-10-13 23:22:48.000000000 +0200
@@ -827,8 +827,8 @@ static int __cpuinit do_boot_cpu(int api
/* if can't get pda memory, can't start cpu */
}
#endif
-
- alternatives_smp_switch(1);
+ if (!is_sossed(cpu))
+ alternatives_smp_switch(1);

c_idle.idle = get_idle_for_cpu(cpu);

@@ -1393,8 +1393,9 @@ void __cpu_die(unsigned int cpu)
for (i = 0; i < 10; i++) {
/* They ack this in play_dead by setting CPU_DEAD */
if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
- printk(KERN_INFO "CPU %d is now offline\n", cpu);
- if (1 == num_online_cpus())
+ printk(KERN_INFO "CPU %d is now offline %s\n", cpu,
+ is_sossed(cpu) ? "and SOSSED" : "");
+ if (1 == num_online_cpus() && !is_sossed(cpu))
alternatives_smp_switch(0);
return;
}
diff -uprN -X dontdiff linux-2.6.27/include/linux/cpu.h linux-2.6.27-dbg/include/linux/cpu.h
--- linux-2.6.27/include/linux/cpu.h 2008-10-10 00:13:53.000000000 +0200
+++ linux-2.6.27-dbg/include/linux/cpu.h 2008-10-13 23:23:42.000000000 +0200
@@ -44,6 +44,7 @@ extern int sched_create_sysfs_power_savi

#ifdef CONFIG_HOTPLUG_CPU
extern void unregister_cpu(struct cpu *cpu);
+extern void unregister_sos(int cpuid);
#endif
struct notifier_block;

@@ -52,6 +53,9 @@ struct notifier_block;
#ifdef CONFIG_HOTPLUG_CPU
extern int register_cpu_notifier(struct notifier_block *nb);
extern void unregister_cpu_notifier(struct notifier_block *nb);
+extern int register_sos(void (*hotplug_cpu_dead)(void), int cpuid);
+extern int is_sossed(int cpuid);
+extern void run_sos(void);
#else

#ifndef MODULE
@@ -61,11 +65,27 @@ static inline int register_cpu_notifier(
{
return 0;
}
+
+static inline int register_sos(void (*hotplug_cpu_dead)(void), int cpuid);
+{
+ return 0;
+}
#endif

static inline void unregister_cpu_notifier(struct notifier_block *nb)
{
}
+
+static inline void unregister_sos(int cpuid)
+{
+}
+static inline int is_sossed(int cpuid)
+{
+ return 0;
+}
+static inline void run_sos(void)
+{
+}
#endif

int cpu_up(unsigned int cpu);
diff -uprN -X dontdiff linux-2.6.27/kernel/cpu.c linux-2.6.27-dbg/kernel/cpu.c
--- linux-2.6.27/kernel/cpu.c 2008-10-10 00:13:53.000000000 +0200
+++ linux-2.6.27-dbg/kernel/cpu.c 2008-10-13 23:14:21.000000000 +0200
@@ -389,6 +389,7 @@ out:
cpu_maps_update_done();
return err;
}
+EXPORT_SYMBOL(cpu_up);

#ifdef CONFIG_PM_SLEEP_SMP
static cpumask_t frozen_cpus;

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