support for backlog

Change-Id: Id8f503234e7afaa284e6b97dc264eb3a2af145c7

arch/arm64/kernel/timer.c

@@ -111,6 +111,8 @@ static void timer_handler(void *priv)
 		/* set timer re-enable for periodic */
 		arch_timer_reg_write(ARCH_TIMER_REG_TVAL, clocks);
 		arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl);
+
+		do_backlog();
 	}
 }
 

arch/x86_64/kernel/cpu.c

@@ -952,6 +952,8 @@ void handle_interrupt(int vector, struct x86_user_context *regs)
 		v->flags |= CPU_FLAG_NEED_RESCHED;
 		ihk_mc_spinlock_unlock(&v->runq_lock, irqstate);
 		dkprintf("timer[%lu]: CPU_FLAG_NEED_RESCHED \n", rdtsc());
+
+		do_backlog();
 	}
 	else if (vector == LOCAL_PERF_VECTOR) {
 		struct siginfo info;

kernel/cls.c

@@ -17,6 +17,7 @@
 #include <ihk/lock.h>
 #include <ihk/mm.h>
 #include <ihk/page_alloc.h>
+#include <kmalloc.h>
 #include <cls.h>
 #include <page.h>
 #include <rusage_private.h>
@@ -42,6 +43,7 @@ void cpu_local_var_init(void)
 		clv[i].monitor = monitor->cpu + i;
 		clv[i].rusage = rusage.cpu + i;
 		INIT_LIST_HEAD(&clv[i].smp_func_req_list);
+		INIT_LIST_HEAD(&clv[i].backlog_list);
 #ifdef ENABLE_PER_CPU_ALLOC_CACHE
 		clv[i].free_chunks.rb_node = NULL;
 #endif
@@ -67,3 +69,54 @@ void preempt_disable(void)
 	if (cpu_local_var_initialized)
 		++cpu_local_var(no_preempt);
 }
+
+int add_backlog(int (*func)(void *arg), void *arg)
+{
+	struct backlog *bl;
+	struct cpu_local_var *v = get_this_cpu_local_var();
+	unsigned long irqstate;
+
+	if (!(bl = kmalloc(sizeof(struct backlog), IHK_MC_AP_NOWAIT))) {
+		return -ENOMEM;
+	}
+	INIT_LIST_HEAD(&bl->list);
+	bl->func = func;
+	bl->arg = arg;
+	irqstate = ihk_mc_spinlock_lock(&v->backlog_lock);
+	list_add_tail(&bl->list, &v->backlog_list);
+	ihk_mc_spinlock_unlock(&v->backlog_lock, irqstate);
+	irqstate = ihk_mc_spinlock_lock(&v->runq_lock);
+	v->flags |= CPU_FLAG_NEED_RESCHED;
+	ihk_mc_spinlock_unlock(&v->runq_lock, irqstate);
+	set_timer(0);
+	return 0;
+}
+
+void do_backlog(void)
+{
+	unsigned long irqstate;
+	struct list_head list;
+	struct cpu_local_var *v = get_this_cpu_local_var();
+	struct backlog *bl;
+	struct backlog *next;
+
+	INIT_LIST_HEAD(&list);
+	irqstate = ihk_mc_spinlock_lock(&v->backlog_lock);
+	list_for_each_entry_safe(bl, next, &v->backlog_list, list) {
+		list_del(&bl->list);
+		list_add_tail(&bl->list, &list);
+	}
+	ihk_mc_spinlock_unlock(&v->backlog_lock, irqstate);
+
+	list_for_each_entry_safe(bl, next, &list, list) {
+		list_del(&bl->list);
+		if (bl->func(bl->arg)) {
+			irqstate = ihk_mc_spinlock_lock(&v->backlog_lock);
+			list_add_tail(&bl->list, &v->backlog_list);
+			ihk_mc_spinlock_unlock(&v->backlog_lock, irqstate);
+		}
+		else {
+			kfree(bl);
+		}
+	}
+}

kernel/include/cls.h

@@ -59,6 +59,12 @@ struct smp_func_call_request {
 	struct list_head list;
 };
 
+struct backlog {
+	struct list_head list;
+	int (*func)(void *arg);
+	void *arg;
+};
+
 struct cpu_local_var {
 	/* malloc */
 	struct list_head free_list;
@@ -103,6 +109,9 @@ struct cpu_local_var {
 
 	struct process_vm *on_fork_vm;
 
+	ihk_spinlock_t backlog_lock;
+	struct list_head backlog_list;
+
 	/* UTI */
 	void *uti_futex_resp;
 #ifdef ENABLE_PER_CPU_ALLOC_CACHE
@@ -123,4 +132,7 @@ static struct cpu_local_var *get_this_cpu_local_var(void)
 
 #define cpu_local_var_with_override(name, clv_override) (clv_override ? clv_override->name : get_this_cpu_local_var()->name)
 
+int add_backlog(int (*func)(void *arg), void *arg);
+void do_backlog(void);
+
 #endif

kernel/process.c

@@ -3301,7 +3301,8 @@ void set_timer(int runq_locked)
 	}
 
 	/* Toggle timesharing if CPU core is oversubscribed */
-	if (num_running > 1 || v->current->itimer_enabled) {
+	if (num_running > 1 || v->current->itimer_enabled ||
+	    !list_empty(&v->backlog_list)) {
 		if (!cpu_local_var(timer_enabled)) {
 			lapic_timer_enable(/*10000000*/1000000);
 			cpu_local_var(timer_enabled) = 1;