Listing 2. Kernel Patch Implementing Processor Affinity

--- 2.3.38-pset/include/linux/sched.h.~1~	Tue Jan 11 14:46:45
2000
+++ 2.3.38-pset/include/linux/sched.h	Tue Jan 11 17:58:52 2000
@@ -363,6 +363,7 @@
	u32 self_exec_id;
/* Protection of fields allocatio/deallocation */
	struct semaphore exit_sem;

+	int bind_cpu;

 };

 /*

@@ -430,6 +431,7 @@

 /* signals */	SPIN_LOCK_UNLOCKED, &init_signals, {{0}}, {{0}}, NULL,
&init_task.sigqueue, 0, 0, \

 /* exec cts */	0,0, \

 /* exit_sem */	__MUTEX_INITIALIZER(name.exit_sem),	

+NO_PROC_ID,

 }

 #ifndef INIT_TASK_SIZE

--- 2.3.38-pset/kernel/sched.c.~1~	Sun Jan  9 20:45:31 2000

+++ 2.3.38-pset/kernel/sched.c	Tue Jan 11 18:16:45 2000

@@ -72,11 +72,13 @@

 	struct schedule_data {

 		struct task_struct * curr;

 		cycles_t last_schedule;

+		int bind;

 	} schedule_data;

 	char __pad [SMP_CACHE_BYTES];

 } aligned_data [NR_CPUS] __cacheline_aligned = { {{&init_task,0}}};

 #define cpu_curr(cpu) aligned_data[(cpu)].schedule_data.curr

+#define cpu_bind(cpu) (aligned_data[(cpu)].bind)

 struct kernel_stat kstat = { 0 };

@@ -94,6 +96,25 @@

 void scheduling_functions_start_here(void) { }

+static int not_deadlocking(void)

+

+	int i;

+

+	for (i = 0; i < smp_num_cpus; i++) {

+		int cpu;

+

+		cpu = cpu_logical_map(i);

+		if (!cpu_bind(cpu))

+			return 1;

+	}

+	return 0;

+}

+

+void set_bind_cpu(int cpu, int set)

+{

+	cpu_bind(cpu_logical_map(cpu)) = set;

+}

+

 /*

  * This is the function that decides how desirable a process is..

  * You can weigh different processes against each other depending

@@ -111,6 +132,9 @@

 static inline int goodness(struct task_struct * p, int this_cpu,
struct
mm_struct *this_mm)

 {

 	int weight;

+

+	if (not_deadlocking() && cpu_bind(this_cpu) && p->bind_cpu != this_cpu)

+		return 0;



 	/*

 	 * Realtime process, select the first one on the

--- 2.3.38-pset/kernel/sys.c.~1~	Tue Nov  2 12:06:25 1999

+++ 2.3.38-pset/kernel/sys.c	Tue Jan 11 18:18:34 2000

@@ -1027,6 +1027,19 @@

 			}

 			current->dumpable = arg2;

 			break;

+		case PR_SET_CPU:

+			{

+				extern void set_bind_cpu(int, int);

+

+				error = -EINVAL;

+				if (arg2 >= smp_num_cpus || arg2 < 0)

+					break;

+

+				error = 0;

+				current->bind_cpu = cpu_logical_map(arg2);

+				set_bind_cpu(arg3, 1);

+				break;

+			}

 		default:

 			error = -EINVAL;

 			break;