Kernel support for processor affinity.

Change-Id: Ie84a805bad58032085208a98b1b31393def681cb
Reviewed-on: http://gfwr801.rchland.ibm.com:8080/gerrit/100
Tested-by: Jenkins Server
Reviewed-by: Douglas R. Gilbert <dgilbert@us.ibm.com>
Reviewed-by: Andrew J. Geissler <andrewg@us.ibm.com>
Reviewed-by: Nicholas E. Bofferding <bofferdn@us.ibm.com>

3 files changed, 37 insertions, 4 deletions

diff --git a/src/kernel/cpumgr.C b/src/kernel/cpumgr.C
index 46d1baa93..9f8e1feec 100644
--- a/src/kernel/cpumgr.C
+++ b/src/kernel/cpumgr.C
@@ -55,6 +55,7 @@ void CpuManager::startCPU(ssize_t i)
 	// Initialize CPU.
 	cpu->cpu = i;
 	cpu->scheduler = &Singleton<Scheduler>::instance();
+        cpu->scheduler_extra = NULL;
 	cpu->kernel_stack = 
 	    (void*) (((uint64_t)PageManager::allocatePage(4)) + 16320);
 	
diff --git a/src/kernel/scheduler.C b/src/kernel/scheduler.C
index cb3cb5e95..ef0c3c005 100644
--- a/src/kernel/scheduler.C
+++ b/src/kernel/scheduler.C
@@ -10,7 +10,22 @@ void Scheduler::addTask(task_t* t)
 {
     if (t->cpu->idle_task != t)
     {
-	iv_taskList.insert(t);
+        // If task is pinned to this CPU, add to the per-CPU queue.
+        if (0 != t->affinity_pinned)
+        {
+            // Allocate a per-CPU queue if this is the first pinning CPU.
+            if (NULL == t->cpu->scheduler_extra)
+            {
+                t->cpu->scheduler_extra = new Runqueue_t();
+            }
+            // Insert into queue.
+            static_cast<Runqueue_t*>(t->cpu->scheduler_extra)->insert(t);
+        }
+        // Not pinned, add to global run-queue.
+        else
+        {
+	    iv_taskList.insert(t);
+        }
     }
 }
 
@@ -21,11 +36,25 @@ void Scheduler::returnRunnable()
 
 void Scheduler::setNextRunnable()
 {
-    task_t* t = iv_taskList.remove();
+    task_t* t = NULL;
+    cpu_t* cpu = CpuManager::getCurrentCPU();
+    
+    // Check for ready task in local run-queue, if it exists.
+    if (NULL != cpu->scheduler_extra)
+    {
+        t = static_cast<Runqueue_t*>(cpu->scheduler_extra)->remove();
+    }
+    
+    // Check for ready task in global run-queue.
+    if (NULL == t)
+    {
+        t = iv_taskList.remove();
+    }
 
+    // Choose idle task if no other ready task is available.
     if (NULL == t)
     {
-	t = CpuManager::getCurrentCPU()->idle_task;
+	t = cpu->idle_task;
 	// TODO: Set short decrementer.
         setDEC(TimeManager::getTimeSliceCount());
     }
@@ -33,6 +62,6 @@ void Scheduler::setNextRunnable()
     {
         setDEC(TimeManager::getTimeSliceCount());
     }
-    
+   
     TaskManager::setCurrentTask(t);
 }
diff --git a/src/kernel/taskmgr.C b/src/kernel/taskmgr.C
index 0ddc3918a..8225b7da3 100644
--- a/src/kernel/taskmgr.C
+++ b/src/kernel/taskmgr.C
@@ -4,6 +4,7 @@
 #include <kernel/pagemgr.H>
 #include <kernel/cpumgr.H>
 #include <arch/ppc.H>
+#include <string.h>
 
 void TaskManager::idleTaskLoop(void* unused)
 {
@@ -49,6 +50,8 @@ task_t* TaskManager::_createTask(TaskManager::task_fn_t t,
 				 void* p, bool withStack)
 {
     task_t* task = new task_t;
+    memset(task, '\0', sizeof(task_t));
+
     task->tid = this->getNextTid();
 
     // Function pointer 't' is actually a TOC entry.