Subject:[ PATCH 001:003] OFFSCHED CORE

[raz ben yehuda <raziebe@gmail.com>]

		OFFSCHED support.

. A callback invoked just before halting the processor.
. SMP alternative work-around. we do not run smp alternatives if we are
   left with a single processor.
. A set of utilities used by the offsched driver.

process.c |  109 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
smpboot.c |   13 +++++--
2 files changed, 118 insertions(+), 4 deletions(-)

Signed-off-by: raziebe@gmail.com
---
diff -X 2.6.30-offsched/Documentation/dontdiff -urN tmp/linux-2.6.30/arch/x86/kernel/process.c 2.6.30-offsched/arch/x86/kernel/process.c
--- tmp/linux-2.6.30/arch/x86/kernel/process.c	2009-06-10 06:05:27.000000000 +0300
+++ 2.6.30-offsched/arch/x86/kernel/process.c	2009-08-21 22:02:44.000000000 +0300
@@ -613,3 +613,112 @@
 }
 early_param("idle", idle_setup);
 
+#ifdef CONFIG_HOTPLUG_CPU
+struct hotplug_cpu{
+	long flags;
+	void (*hotplug_cpu_dead)(void);
+};
+
+static long 	offsched_services;
+
+#define CPU_OFFSCHED		31
+#define CPU_OFFSCHED_KMEM	30
+#define SERVICE_TIMER		01
+#define SERVICE_NAPI		02
+
+DEFINE_PER_CPU(struct hotplug_cpu, offschedcpu);
+
+void unregister_offsched(int cpuid)
+{
+	struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
+	cpu->hotplug_cpu_dead = NULL;
+	clear_bit(CPU_OFFSCHED, &cpu->flags);
+}
+EXPORT_SYMBOL_GPL(unregister_offsched);
+
+int is_offsched(int cpuid)
+{
+	struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
+	return test_bit(CPU_OFFSCHED, &cpu->flags);
+}
+EXPORT_SYMBOL_GPL(is_offsched);
+
+int is_offsched_kmem(int cpuid)
+{
+	struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
+	return test_bit(CPU_OFFSCHED_KMEM, &cpu->flags);
+}
+EXPORT_SYMBOL_GPL(is_offsched_kmem);
+
+void set_offsched_kmem(int cpuid)
+{
+	struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
+	set_bit(CPU_OFFSCHED_KMEM, &cpu->flags);
+}
+EXPORT_SYMBOL_GPL(set_offsched_kmem);
+
+void unset_offsched_kmem(int cpuid)
+{
+	struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
+	clear_bit(CPU_OFFSCHED_KMEM, &cpu->flags);
+}
+EXPORT_SYMBOL_GPL(unset_offsched_kmem);
+
+int register_offsched(void (*offsched_callback)(void), int cpuid)
+{
+	struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
+	if (is_offsched(cpuid))
+		return -1;
+	cpu->hotplug_cpu_dead = offsched_callback;
+	set_bit(CPU_OFFSCHED, &cpu->flags);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(register_offsched);
+
+void run_offsched(void)
+{
+	int cpuid = raw_smp_processor_id();
+	struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid);
+	cpu->hotplug_cpu_dead();
+}
+
+int  offsched_is_napi_avail(void)
+{
+	return SERVICE_NAPI & offsched_services;
+}
+
+int (*offsched_rule)(void *);
+EXPORT_SYMBOL(offsched_rule);
+/*
+* if we a have filter than apply filter.
+* return 0 if packet should go to kernel
+* return 1 if packet should go to offsched.
+*/
+int offsched_pkt(void *s)
+{
+	if (offsched_rule)
+		return offsched_rule(s);
+	return 0;
+}
+
+void offsched_register_napi(void)
+{
+	offsched_services |= SERVICE_NAPI;
+}
+EXPORT_SYMBOL_GPL(offsched_register_napi);
+
+void offsched_unregister_napi(void)
+{
+	offsched_services &= ~SERVICE_NAPI;
+}
+EXPORT_SYMBOL_GPL(offsched_unregister_napi);
+
+/*
+ * napi scheudule is called in offsched context.
+*/
+void offsched_napi_schedule(void *n)
+{
+
+}
+
+#endif
diff -X 2.6.30-offsched/Documentation/dontdiff -urN tmp/linux-2.6.30/arch/x86/kernel/smpboot.c 2.6.30-offsched/arch/x86/kernel/smpboot.c
--- tmp/linux-2.6.30/arch/x86/kernel/smpboot.c	2009-06-10 06:05:27.000000000 +0300
+++ 2.6.30-offsched/arch/x86/kernel/smpboot.c	2009-07-25 13:59:19.000000000 +0300
@@ -39,6 +39,8 @@
  *	Glauber Costa		:	i386 and x86_64 integration
  */
 
+#define DEBUG
+
 #include <linux/init.h>
 #include <linux/smp.h>
 #include <linux/module.h>
@@ -686,8 +688,8 @@
 	};
 
 	INIT_WORK(&c_idle.work, do_fork_idle);
-
-	alternatives_smp_switch(1);
+	if (!is_offsched(cpu))
+		alternatives_smp_switch(1);
 
 	c_idle.idle = get_idle_for_cpu(cpu);
 
@@ -1283,8 +1285,9 @@
 	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_offsched(cpu) ? "and OFFSCHED" : "");
+			if (1 == num_online_cpus() && !is_offsched(cpu))
 				alternatives_smp_switch(0);
 			return;
 		}
@@ -1313,6 +1316,8 @@
 void native_play_dead(void)
 {
 	play_dead_common();
+	if (is_offsched(raw_smp_processor_id()))
+		run_offsched();
 	wbinvd_halt();
 }