use per-process wait queues for system call request processing in mcexec so that multiple processes can share the per-core system call channels

executer/include/uprotocol.h

@@ -93,6 +93,7 @@ struct syscall_request {
 struct syscall_wait_desc {
 	unsigned long cpu;
 	struct syscall_request sr;
+	int pid;
 };
 
 struct syscall_load_desc {

executer/kernel/control.c

@@ -267,10 +267,37 @@ static long mcexec_get_cpu(ihk_os_t os)
 	return info->n_cpus;
 }
 
-int mcexec_syscall(struct mcctrl_channel *c, unsigned long arg)
+int mcexec_syscall(struct mcctrl_channel *c, int pid, unsigned long arg)
 {
+	struct wait_queue_head_list_node *wqhln = NULL;
+	struct wait_queue_head_list_node *wqhln_iter;
+	unsigned long flags;
+
+	/* Look up per-process wait queue head with pid */
+	flags = ihk_ikc_spinlock_lock(&c->wq_list_lock);
+	list_for_each_entry(wqhln_iter, &c->wq_list, list) {
+		if (wqhln_iter->pid == pid) {
+			wqhln = wqhln_iter;
+			break;
+		}
+	}
+
+	if (!wqhln) {
+retry_alloc:
+		wqhln = kmalloc(sizeof(*wqhln), GFP_KERNEL);
+		if (!wqhln) {
+			printk("WARNING: coudln't alloc wait queue head, retrying..\n");
+			goto retry_alloc;
+		}
+
+		wqhln->pid = pid;
+		init_waitqueue_head(&wqhln->wq_syscall);
+		list_add_tail(&wqhln->list, &c->wq_list);
+	}
+	ihk_ikc_spinlock_unlock(&c->wq_list_lock, flags);
+
 	c->req = 1;
-	wake_up(&c->wq_syscall);
+	wake_up(&wqhln->wq_syscall);
 
 	return 0;
 }
@@ -287,16 +314,21 @@ int mcexec_wait_syscall(ihk_os_t os, struct syscall_wait_desc *__user req)
 	struct syscall_wait_desc swd;
 	struct mcctrl_channel *c;
 	struct mcctrl_usrdata *usrdata = ihk_host_os_get_usrdata(os);
+	struct wait_queue_head_list_node *wqhln;
+	struct wait_queue_head_list_node *wqhln_iter;
+	int ret = 0;
+	unsigned long irqflags;
 #ifndef DO_USER_MODE
 	unsigned long s, w, d;
 #endif
 	
 //printk("mcexec_wait_syscall swd=%p req=%p size=%d\n", &swd, req, sizeof(swd.cpu));
-	if (copy_from_user(&swd, req, sizeof(swd.cpu))) {
+	if (copy_from_user(&swd, req, sizeof(swd))) {
 		return -EFAULT;
 	}
 
-if(swd.cpu >= usrdata->num_channels)return -EINVAL;
+	if (swd.cpu >= usrdata->num_channels)
+		return -EINVAL;
 
 	c = get_peer_channel(usrdata, current);
 	if (c) {
@@ -308,9 +340,43 @@ if(swd.cpu >= usrdata->num_channels)return -EINVAL;
 
 #ifdef DO_USER_MODE
 retry:
-	if (wait_event_interruptible(c->wq_syscall, c->req)) {
+	/* Prepare per-process wait queue head */
+retry_alloc:
+	wqhln = kmalloc(sizeof(*wqhln), GFP_KERNEL);
+	if (!wqhln) {
+		printk("WARNING: coudln't alloc wait queue head, retrying..\n");
+		goto retry_alloc;
+	}
+
+	wqhln->pid = swd.pid;	
+	init_waitqueue_head(&wqhln->wq_syscall);
+	
+	irqflags = ihk_ikc_spinlock_lock(&c->wq_list_lock);
+	/* First see if there is one wait queue already */
+	list_for_each_entry(wqhln_iter, &c->wq_list, list) {
+		if (wqhln_iter->pid == current->tgid) {
+			kfree(wqhln);
+			wqhln = wqhln_iter;
+			list_del(&wqhln->list);
+			printk("DEBUG: wait queue head was already available in syscall wait\n");
+			break;
+		}
+	}
+	list_add_tail(&wqhln->list, &c->wq_list);
+	ihk_ikc_spinlock_unlock(&c->wq_list_lock, irqflags);
+
+	ret = wait_event_interruptible(wqhln->wq_syscall, c->req);
+	
+	/* Remove per-process wait queue head */
+	irqflags = ihk_ikc_spinlock_lock(&c->wq_list_lock);
+	list_del(&wqhln->list);
+	ihk_ikc_spinlock_unlock(&c->wq_list_lock, irqflags);
+	kfree(wqhln);
+
+	if (ret) {
 		return -EINTR;
 	}
+
 	c->req = 0;
 #if 1
 	mb();

executer/kernel/ikc.c

@@ -40,7 +40,7 @@
 
 void mcexec_prepare_ack(ihk_os_t os, unsigned long arg, int err);
 static void mcctrl_ikc_init(ihk_os_t os, int cpu, unsigned long rphys, struct ihk_ikc_channel_desc *c);
-int mcexec_syscall(struct mcctrl_channel *c, unsigned long arg);
+int mcexec_syscall(struct mcctrl_channel *c, int pid, unsigned long arg);
 
 static int syscall_packet_handler(struct ihk_ikc_channel_desc *c,
                                   void *__packet, void *__os)
@@ -62,7 +62,7 @@ static int syscall_packet_handler(struct ihk_ikc_channel_desc *c,
 		break;
 
 	case SCD_MSG_SYSCALL_ONESIDE:
-		mcexec_syscall(usrdata->channels + pisp->ref, pisp->arg);
+		mcexec_syscall(usrdata->channels + pisp->ref, pisp->pid, pisp->arg);
 		break;
 	}
 
@@ -219,7 +219,9 @@ static int connect_handler(struct ihk_ikc_channel_info *param)
 		return 1;
 	}
 	param->packet_handler = syscall_packet_handler;
-	init_waitqueue_head(&usrdata->channels[cpu].wq_syscall);
+	
+	INIT_LIST_HEAD(&usrdata->channels[cpu].wq_list);
+	spin_lock_init(&usrdata->channels[cpu].wq_list_lock);
 
 	usrdata->channels[cpu].c = c;
 	kprintf("syscall: MC CPU %d connected. c=%p\n", cpu, c);
@@ -238,7 +240,9 @@ static int connect_handler2(struct ihk_ikc_channel_info *param)
 	cpu = usrdata->num_channels - 1;
 
 	param->packet_handler = syscall_packet_handler;
-	init_waitqueue_head(&usrdata->channels[cpu].wq_syscall);
+	
+	INIT_LIST_HEAD(&usrdata->channels[cpu].wq_list);
+	spin_lock_init(&usrdata->channels[cpu].wq_list_lock);
 
 	usrdata->channels[cpu].c = c;
 	kprintf("syscall: MC CPU %d connected. c=%p\n", cpu, c);

executer/kernel/mcctrl.h

@@ -56,6 +56,7 @@
 struct ikc_scd_packet {
 	int msg;
 	int ref;
+	int pid;
 	int err;
 	unsigned long arg;
 };
@@ -88,6 +89,12 @@ struct syscall_params {
 	unsigned long *doorbell_va;
 };
 
+struct wait_queue_head_list_node {
+	struct list_head list;
+	wait_queue_head_t wq_syscall;
+	int pid;
+};
+
 struct mcctrl_channel {
 	struct ihk_ikc_channel_desc *c;
 	struct syscall_params param;
@@ -95,7 +102,8 @@ struct mcctrl_channel {
 	void *dma_buf;
 
 	int req;
-	wait_queue_head_t wq_syscall;
+	struct list_head wq_list;
+	ihk_spinlock_t wq_list_lock;
 };
 
 struct mcctrl_usrdata {

executer/kernel/syscall.c

@@ -57,7 +57,7 @@
 static long pager_call(ihk_os_t os, struct syscall_request *req);
 
 #ifdef SC_DEBUG
-//static struct ihk_dma_request last_request;
+static struct ihk_dma_request last_request;
 
 static void print_dma_lastreq(void)
 {
@@ -241,8 +241,43 @@ static int remote_page_fault(struct mcctrl_usrdata *usrdata, void *fault_addr, u
 	resp->status = STATUS_PAGE_FAULT;
 
 	for (;;) {
+		struct wait_queue_head_list_node *wqhln;
+		struct wait_queue_head_list_node *wqhln_iter;
+		unsigned long irqflags;
+		
+retry_alloc:
+		wqhln = kmalloc(sizeof(*wqhln), GFP_KERNEL);
+		if (!wqhln) {
+			printk("WARNING: coudln't alloc wait queue head, retrying..\n");
+			goto retry_alloc;
+		}
+
+		/* Prepare per-process wait queue head */
+		wqhln->pid = current->tgid;	
+		init_waitqueue_head(&wqhln->wq_syscall);
+
+		irqflags = ihk_ikc_spinlock_lock(&channel->wq_list_lock);
+		/* First see if there is a wait queue already */
+		list_for_each_entry(wqhln_iter, &channel->wq_list, list) {
+			if (wqhln_iter->pid == current->tgid) {
+				kfree(wqhln);
+				wqhln = wqhln_iter;
+				list_del(&wqhln->list);
+				break;
+			}
+		}
+		list_add_tail(&wqhln->list, &channel->wq_list);
+		ihk_ikc_spinlock_unlock(&channel->wq_list_lock, irqflags);
+
 		/* wait for response */
-		error = wait_event_interruptible(channel->wq_syscall, channel->req);
+		error = wait_event_interruptible(wqhln->wq_syscall, channel->req);
+
+		/* Remove per-process wait queue head */
+		irqflags = ihk_ikc_spinlock_lock(&channel->wq_list_lock);
+		list_del(&wqhln->list);
+		ihk_ikc_spinlock_unlock(&channel->wq_list_lock, irqflags);
+		kfree(wqhln);
+
 		if (error) {
 			printk("remote_page_fault:interrupted. %d\n", error);
 			goto out;

executer/user/mcexec.c

@@ -664,7 +664,7 @@ int main(int argc, char **argv)
 	argv[optind + 2] = NULL;
 	argc -= (optind - 1);
 
-	printf("target_core: %d, device: %s, command: ", target_core, dev);
+	__dprintf("target_core: %d, device: %s, command: ", target_core, dev);
 	for (i = 1; i < argc; ++i) {
 		printf("%s ", argv[i]);
 	}
@@ -966,6 +966,7 @@ int main_loop(int fd, int cpu, pthread_mutex_t *lock)
 	struct timeval tv;
 
 	w.cpu = cpu;
+	w.pid = getpid();
 
 	while (((ret = ioctl(fd, MCEXEC_UP_WAIT_SYSCALL, (unsigned long)&w)) == 0) || (ret == -1 && errno == EINTR)) {
 

kernel/include/syscall.h

@@ -87,6 +87,7 @@ struct user_desc {
 struct ikc_scd_packet {
 	int msg;
 	int ref;
+	int pid;
 	int err;
 	unsigned long arg;
 };

kernel/syscall.c

@@ -116,6 +116,9 @@ static void send_syscall(struct syscall_request *req, int cpu)
 
 		scp = &get_cpu_local_var(0)->scp2;
 		syscall_channel = get_cpu_local_var(0)->syscall_channel2;
+		
+		/* XXX: is this really going to work if multiple processes 
+		 * exit/receive signals at the same time?? */
 		cpu = num_processors;
 	}
 	else{
@@ -144,8 +147,9 @@ static void send_syscall(struct syscall_request *req, int cpu)
 #ifdef SYSCALL_BY_IKC
 	packet.msg = SCD_MSG_SYSCALL_ONESIDE;
 	packet.ref = cpu;
+	packet.pid = cpu_local_var(current)->pid;
 	packet.arg = scp->request_rpa;	
-	
+	dkprintf("send syscall, nr: %d, pid: %d\n", req->number, packet.pid);
 	ihk_ikc_send(syscall_channel, &packet, 0); 
 #endif
 }
@@ -186,6 +190,8 @@ long do_syscall(struct syscall_request *req, ihk_mc_user_context_t *ctx, int cpu
 		}
 	
 		if (res->status == STATUS_PAGE_FAULT) {
+			dkprintf("STATUS_PAGE_FAULT in syscall, pid: %d\n", 
+					cpu_local_var(current)->pid);		
 			error = page_fault_process(get_cpu_local_var(cpu)->current,
 					(void *)res->fault_address,
 					res->fault_reason);