add new cpu state CPU_STATUS_RESERVED

arch/x86/kernel/syscall.c

@@ -95,6 +95,7 @@ int obtain_clone_cpuid() {
         }
         goto retry; 
     }
+	get_cpu_local_var(cpuid)->status = CPU_STATUS_RESERVED;
     ihk_mc_spinlock_unlock_noirq(&cpuid_head_lock);
  out:
     return cpuid;

kernel/include/cls.h

@@ -30,6 +30,7 @@ struct malloc_header {
 #define CPU_STATUS_DISABLE	(0)
 #define CPU_STATUS_IDLE		(1)
 #define CPU_STATUS_RUNNING	(2)
+#define CPU_STATUS_RESERVED	(3)
 extern ihk_spinlock_t	cpu_status_lock;
 
 #define CPU_FLAG_NEED_RESCHED	0x1U

kernel/include/process.h

@@ -444,5 +444,6 @@ void cpu_clear(int cpu, cpu_set_t *cpu_set, ihk_spinlock_t *lock);
 
 struct process *findthread_and_lock(int pid, int tid, ihk_spinlock_t **savelock, unsigned long *irqstate);
 void process_unlock(void *savelock, unsigned long irqstate);
+void release_cpuid(int cpuid);
 
 #endif

kernel/process.c

@@ -1996,7 +1996,8 @@ static void idle(void)
 {
 	struct cpu_local_var *v = get_this_cpu_local_var();
 
-	v->status = CPU_STATUS_IDLE;
+	if(v->status == CPU_STATUS_RUNNING)
+		v->status = CPU_STATUS_IDLE;
 	cpu_enable_interrupt();
 
 	while (1) {
@@ -2021,7 +2022,8 @@ static void idle(void)
 		 * 4) The idle process was resumed, and halted for waiting for
 		 *    the interrupt that had already been handled.
 		 */
-		if (v->status == CPU_STATUS_IDLE) {
+		if (v->status == CPU_STATUS_IDLE ||
+		    v->status == CPU_STATUS_RESERVED) {
 			long s;
 			struct process *p;
 
@@ -2034,7 +2036,8 @@ static void idle(void)
 			}
 			ihk_mc_spinlock_unlock(&v->runq_lock, s);
 		}
-		if (v->status == CPU_STATUS_IDLE) {
+		if (v->status == CPU_STATUS_IDLE ||
+		    v->status == CPU_STATUS_RESERVED) {
 			cpu_safe_halt();
 		}
 		else {
@@ -2189,19 +2192,8 @@ redo:
 
 		/* No process? Run idle.. */
 		if (!next) {
-			list_for_each_entry_safe(proc, tmp, &(v->runq), sched_list) {
-				if (proc->ftn->status & (PS_INTERRUPTIBLE |
-				                         PS_UNINTERRUPTIBLE |
-				                         PS_STOPPED |
-				                         PS_TRACED)) {
-					next = proc;
-					break;
-				}
-			}
-			if (!next) {
-				next = &cpu_local_var(idle);
-				v->status = CPU_STATUS_IDLE;
-			}
+			next = &cpu_local_var(idle);
+			v->status = v->runq_len? CPU_STATUS_RESERVED: CPU_STATUS_IDLE;
 		}
 	}
 
@@ -2258,6 +2250,13 @@ redo:
 	}
 }
 
+void
+release_cpuid(int cpuid)
+{
+	if (!get_cpu_local_var(cpuid)->runq_len)
+		get_cpu_local_var(cpuid)->status = CPU_STATUS_IDLE;
+}
+
 void check_need_resched(void)
 {
 	struct cpu_local_var *v = get_this_cpu_local_var();

kernel/syscall.c

@@ -1745,6 +1745,7 @@ unsigned long do_fork(int clone_flags, unsigned long newsp,
 						clone_flags);
 	
 	if (!new) {
+		release_cpuid(cpuid);
 		return -ENOMEM;
 	}
 
@@ -1764,6 +1765,7 @@ unsigned long do_fork(int clone_flags, unsigned long newsp,
 			kprintf("ERROR: forking host process\n");
 			
 			/* TODO: clean-up new */
+			release_cpuid(cpuid);
 			return -EFAULT;
 		}
 
@@ -1811,6 +1813,7 @@ unsigned long do_fork(int clone_flags, unsigned long newsp,
 		if (ihk_mc_pt_virt_to_phys(new->vm->page_table, 
 					(void *)child_tidptr, &phys)) { 
 			kprintf("ERROR: looking up physical addr for child process\n");
+			release_cpuid(cpuid);
 			return -EFAULT; 
 		}