mcctrl/mcexec: fix per-process data reference counting

executer/include/uprotocol.h

@@ -43,6 +43,7 @@
 #define MCEXEC_UP_GET_CREDV	 0x30a0290b
 #define MCEXEC_UP_GET_NODES  0x30a0290c
 #define MCEXEC_UP_GET_CPUSET  0x30a0290d
+#define MCEXEC_UP_CREATE_PPD  0x30a0290e
 
 #define MCEXEC_UP_PREPARE_DMA    0x30a02910
 #define MCEXEC_UP_FREE_DMA       0x30a02911

executer/kernel/mcctrl/control.c

@@ -324,20 +324,17 @@ static long mcexec_debug_log(ihk_os_t os, unsigned long arg)
 }
 
 int mcexec_close_exec(ihk_os_t os);
+int mcexec_destroy_per_process_data(ihk_os_t os);
 
 static void release_handler(ihk_os_t os, void *param)
 {
 	struct release_handler_info *info = param;
 	struct ikc_scd_packet isp;
 	int os_ind = ihk_host_os_get_index(os);
-	struct mcctrl_usrdata *usrdata = ihk_host_os_get_usrdata(os);
-	struct mcctrl_per_proc_data *ppd = NULL;
 
-	ppd = mcctrl_get_per_proc_data(usrdata, info->pid);
-	if (ppd) {
-		mcctrl_put_per_proc_data(ppd);
 	mcexec_close_exec(os);
-	}
+
+	mcexec_destroy_per_process_data(os);
 
 	memset(&isp, '\0', sizeof isp);
 	isp.msg = SCD_MSG_CLEANUP_PROCESS;
@@ -923,16 +920,20 @@ void mcctrl_put_per_proc_data(struct mcctrl_per_proc_data *ppd)
 	if (!ppd)
 		return;
 
-	if (!atomic_dec_and_test(&ppd->refcount))
-		return;
-
-	dprintk("%s: deallocating PPD for pid %d\n", __FUNCTION__, ppd->pid);
 	hash = (ppd->pid & MCCTRL_PER_PROC_DATA_HASH_MASK);
 
+	/* Removal from hash table and the refcount reaching zero
+	 * have to happen atomically */
 	write_lock_irqsave(&ppd->ud->per_proc_data_hash_lock[hash], flags);
+	if (!atomic_dec_and_test(&ppd->refcount)) {
+		write_unlock_irqrestore(&ppd->ud->per_proc_data_hash_lock[hash], flags);
+		return;
+	}
+
 	list_del(&ppd->hash);
 	write_unlock_irqrestore(&ppd->ud->per_proc_data_hash_lock[hash], flags);
 
+	dprintk("%s: deallocating PPD for pid %d\n", __FUNCTION__, ppd->pid);
 	for (i = 0; i < MCCTRL_PER_THREAD_DATA_HASH_SIZE; i++) {
 		struct mcctrl_per_thread_data *ptd;
 		struct mcctrl_per_thread_data *next;
@@ -943,7 +944,9 @@ void mcctrl_put_per_proc_data(struct mcctrl_per_proc_data *ppd)
 			packet = ptd->data;
 			list_del(&ptd->hash);
 			kfree(ptd);
-			__return_syscall(ppd->ud->os, packet, -EINTR,
+			/* We use ERESTARTSYS to tell the LWK that the proxy
+			 * process is gone and the application should be terminated */
+			__return_syscall(ppd->ud->os, packet, -ERESTARTSYS,
 					packet->req.rtid);
 			ihk_ikc_release_packet(
 			            (struct ihk_ikc_free_packet *)packet,
@@ -956,7 +959,10 @@ void mcctrl_put_per_proc_data(struct mcctrl_per_proc_data *ppd)
 		list_del(&wqhln->list);
 		packet = wqhln->packet;
 		kfree(wqhln);
-		__return_syscall(ppd->ud->os, packet, -EINTR,
+
+		/* We use ERESTARTSYS to tell the LWK that the proxy
+		 * process is gone and the application should be terminated */
+		__return_syscall(ppd->ud->os, packet, -ERESTARTSYS,
 				packet->req.rtid);
 		ihk_ikc_release_packet((struct ihk_ikc_free_packet *)packet,
 				       (ppd->ud->channels + packet->ref)->c);
@@ -987,7 +993,9 @@ int mcexec_syscall(struct mcctrl_usrdata *ud, struct ikc_scd_packet *packet)
 				"syscall nr: %lu\n",
 				__FUNCTION__, pid, packet->req.number);
 
-		__return_syscall(ud->os, packet, -EINTR,
+		/* We use ERESTARTSYS to tell the LWK that the proxy
+		 * process is gone and the application should be terminated */
+		__return_syscall(ud->os, packet, -ERESTARTSYS,
 				packet->req.rtid);
 		ihk_ikc_release_packet((struct ihk_ikc_free_packet *)packet,
 				      (ud->channels + packet->ref)->c);
@@ -1126,12 +1134,22 @@ retry_alloc:
 	}
 	ihk_ikc_spinlock_unlock(&ppd->wq_list_lock, irqflags);
 
-	if (ret && !wqhln->req) {
+	if (ret == -ERESTARTSYS) {
+		/* Is the request valid? */
+		if (wqhln->req) {
+			packet = wqhln->packet;
 			kfree(wqhln);
 			wqhln = NULL;
 			ret = -EINTR;
 			goto put_ppd_out;
 		}
+		else {
+			kfree(wqhln);
+			wqhln = NULL;
+			ret = -EINTR;
+			goto put_ppd_out;
+		}
+	}
 
 	packet = wqhln->packet;
 	kfree(wqhln);
@@ -1401,30 +1419,23 @@ mcexec_getcredv(int __user *virt)
 	return 0;
 }
 
-int mcexec_open_exec(ihk_os_t os, char * __user filename)
+int mcexec_create_per_process_data(ihk_os_t os)
 {
-	struct file *file;
-	struct mckernel_exec_file *mcef;
-	struct mckernel_exec_file *mcef_iter;
-	int retval;
-	int os_ind = ihk_host_os_get_index(os);
-	char *pathbuf = NULL;
-	char *fullpath = NULL;
-	char *kfilename = NULL;
 	struct mcctrl_usrdata *usrdata = ihk_host_os_get_usrdata(os);
 	struct mcctrl_per_proc_data *ppd = NULL;
-	int i, len;
+	int i;
 
-	if (os_ind < 0) {
+	ppd = mcctrl_get_per_proc_data(usrdata, task_tgid_vnr(current));
+	if (ppd) {
+		printk("%s: WARNING: per-process data for pid %d already exists\n",
+				__FUNCTION__, task_tgid_vnr(current));
+		mcctrl_put_per_proc_data(ppd);
 		return -EINVAL;
 	}
 
-	ppd = mcctrl_get_per_proc_data(usrdata, task_tgid_vnr(current));
-
-	if (!ppd) {
 	ppd = kmalloc(sizeof(*ppd), GFP_KERNEL);
 	if (!ppd) {
-			printk("ERROR: allocating per process data\n");
+		printk("%s: ERROR: allocating per-process data\n", __FUNCTION__);
 		return -ENOMEM;
 	}
 
@@ -1442,7 +1453,8 @@ int mcexec_open_exec(ihk_os_t os, char * __user filename)
 	spin_lock_init(&ppd->wq_list_lock);
 	memset(&ppd->cpu_set, 0, sizeof(cpumask_t));
 	ppd->ikc_target_cpu = 0;
-		/* Final ref will be dropped in close_exec() */
+	/* Final ref will be dropped in release_handler() through
+	 * mcexec_destroy_per_process_data() */
 	atomic_set(&ppd->refcount, 1);
 
 	for (i = 0; i < MCCTRL_PER_THREAD_DATA_HASH_SIZE; ++i) {
@@ -1452,23 +1464,65 @@ int mcexec_open_exec(ihk_os_t os, char * __user filename)
 
 	if (mcctrl_add_per_proc_data(usrdata, ppd->pid, ppd) < 0) {
 		printk("%s: error adding per process data\n", __FUNCTION__);
-			retval = -EINVAL;
 		kfree(ppd);
-			goto out;
+		return -EINVAL;
 	}
+
+	dprintk("%s: PID: %d, counter: %d\n",
+		__FUNCTION__, ppd->pid, atomic_read(&ppd->refcount));
+
+	return 0;
+}
+
+int mcexec_destroy_per_process_data(ihk_os_t os)
+{
+	struct mcctrl_usrdata *usrdata = ihk_host_os_get_usrdata(os);
+	struct mcctrl_per_proc_data *ppd = NULL;
+
+	ppd = mcctrl_get_per_proc_data(usrdata, task_tgid_vnr(current));
+
+	if (ppd) {
+		/* One for the reference and one for deallocation.
+		 * XXX: actual deallocation may not happen here */
+		mcctrl_put_per_proc_data(ppd);
+		mcctrl_put_per_proc_data(ppd);
+	}
+	else {
+		printk("WARNING: no per process data for PID %d ?\n",
+				task_tgid_vnr(current));
+	}
+
+	return 0;
+}
+
+
+int mcexec_open_exec(ihk_os_t os, char * __user filename)
+{
+	struct file *file;
+	struct mckernel_exec_file *mcef;
+	struct mckernel_exec_file *mcef_iter;
+	int retval;
+	int os_ind = ihk_host_os_get_index(os);
+	char *pathbuf = NULL;
+	char *fullpath = NULL;
+	char *kfilename = NULL;
+	int len;
+
+	if (os_ind < 0) {
+		return -EINVAL;
 	}
 
 	pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY);
 	if (!pathbuf) {
 		retval = -ENOMEM;
-		goto out_put_ppd;
+		goto out;
 	}
 
 	kfilename = kmalloc(PATH_MAX, GFP_TEMPORARY);
 	if (!kfilename) {
 		retval = -ENOMEM;
 		kfree(pathbuf);
-		goto out_put_ppd;
+		goto out;
 	}
 
 	len = strncpy_from_user(kfilename, filename, PATH_MAX);
@@ -1530,35 +1584,15 @@ out_put_file:
 out_free:
 	kfree(pathbuf);
 	kfree(kfilename);
-out_put_ppd:
-	mcctrl_put_per_proc_data(ppd);
 out:
 	return retval;
 }
 
-
 int mcexec_close_exec(ihk_os_t os)
 {
 	struct mckernel_exec_file *mcef = NULL;
 	int found = 0;
 	int os_ind = ihk_host_os_get_index(os);	
-	struct mcctrl_usrdata *usrdata = ihk_host_os_get_usrdata(os);
-	struct mcctrl_per_proc_data *ppd = NULL;
-
-	ppd = mcctrl_get_per_proc_data(usrdata, task_tgid_vnr(current));
-
-	if (ppd) {
-		/* One for the reference and one for deallocation */
-		mcctrl_put_per_proc_data(ppd);
-		mcctrl_put_per_proc_data(ppd);
-
-		dprintk("pid: %d, tid: %d: rpgtable for %d (0x%lx) removed\n",
-				task_tgid_vnr(current), current->pid, ppd->pid, ppd->rpgtable);
-	}
-	else {
-		printk("WARNING: no per process data for pid %d ?\n", 
-				task_tgid_vnr(current));
-	}
 
 	if (os_ind < 0) {
 		return EINVAL;
@@ -1987,6 +2021,9 @@ long __mcctrl_control(ihk_os_t os, unsigned int req, unsigned long arg,
 	case MCEXEC_UP_GET_CPU:
 		return mcexec_get_cpu(os);
 
+	case MCEXEC_UP_CREATE_PPD:
+		return mcexec_create_per_process_data(os);
+
 	case MCEXEC_UP_GET_NODES:
 		return mcexec_get_nodes(os);
 

executer/kernel/mcctrl/driver.c

@@ -69,6 +69,7 @@ static struct ihk_os_user_call_handler mcctrl_uchs[] = {
 	{ .request = MCEXEC_UP_GET_CPU, .func = mcctrl_ioctl },
 	{ .request = MCEXEC_UP_GET_NODES, .func = mcctrl_ioctl },
 	{ .request = MCEXEC_UP_GET_CPUSET, .func = mcctrl_ioctl },
+	{ .request = MCEXEC_UP_CREATE_PPD, .func = mcctrl_ioctl },
 	{ .request = MCEXEC_UP_STRNCPY_FROM_USER, .func = mcctrl_ioctl },
 	{ .request = MCEXEC_UP_NEW_PROCESS, .func = mcctrl_ioctl },
 	{ .request = MCEXEC_UP_PREPARE_DMA, .func = mcctrl_ioctl },

executer/user/mcexec.c

@@ -1741,6 +1741,13 @@ int main(int argc, char **argv)
 		exit(1);
 	}
 
+	/* Register per-process structure in mcctrl */
+	if (ioctl(fd, MCEXEC_UP_CREATE_PPD) != 0) {
+		perror("creating mcctrl per-process structure");
+		close(fd);
+		exit(1);
+	}
+
 	/* Partitioned execution, obtain CPU set */
 	if (nr_processes > 0) {
 		struct get_cpu_set_arg cpu_set_arg;
@@ -2440,6 +2447,13 @@ gettid_out:
 					goto fork_child_sync_pipe;
 				}
 
+				if (ioctl(fd, MCEXEC_UP_CREATE_PPD) != 0) {
+					fs->status = -errno;
+					fprintf(stderr, "ERROR: creating PPD %s\n", dev);
+
+					goto fork_child_sync_pipe;
+				}
+
 				/* Reinit signals and syscall threads */
 				init_sigaction();
 

kernel/syscall.c

@@ -301,6 +301,15 @@ long do_syscall(struct syscall_request *req, int cpu, int pid)
 		--thread->in_syscall_offload;
 	}
 
+	/* -ERESTARTSYS indicates that the proxy process is gone
+	 * and the application should be terminated */
+	if (rc == -ERESTARTSYS && req->number != __NR_exit_group) {
+		kprintf("%s: proxy PID %d is dead, terminate()\n",
+			__FUNCTION__, thread->proc->pid);
+		thread->proc->nohost = 1;
+		terminate(-1, 0);
+	}
+
 #ifdef PROFILE_ENABLE
 	if (req->number < PROFILE_SYSCALL_MAX) {
 		profile_event_add(profile_syscall2offload(req->number),