NUMA: hide non-existing nodes from /sys/devices/system/node listing

executer/include/uprotocol.h

@@ -41,6 +41,7 @@
 #define MCEXEC_UP_NEW_PROCESS	 0x30a02909
 #define MCEXEC_UP_GET_CRED	 0x30a0290a
 #define MCEXEC_UP_GET_CREDV	 0x30a0290b
+#define MCEXEC_UP_GET_NODES  0x30a0290c
 
 #define MCEXEC_UP_PREPARE_DMA    0x30a02910
 #define MCEXEC_UP_FREE_DMA       0x30a02911

executer/kernel/mcctrl/control.c

@@ -450,6 +450,16 @@ static long mcexec_get_cpu(ihk_os_t os)
 	return info->n_cpus;
 }
 
+static long mcexec_get_nodes(ihk_os_t os)
+{
+	struct mcctrl_usrdata *usrdata = ihk_host_os_get_usrdata(os);
+
+	if (!usrdata || !usrdata->mem_info)
+		return -EINVAL;
+
+	return usrdata->mem_info->n_numa_nodes;
+}
+
 int mcctrl_add_per_proc_data(struct mcctrl_usrdata *ud, int pid, 
 	struct mcctrl_per_proc_data *ppd)
 {
@@ -1268,6 +1278,9 @@ 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_GET_NODES:
+		return mcexec_get_nodes(os);
+
 	case MCEXEC_UP_STRNCPY_FROM_USER:
 		return mcexec_strncpy_from_user(os, 
 				(struct strncpy_from_user_desc *)arg);

executer/kernel/mcctrl/driver.c

@@ -60,6 +60,7 @@ static struct ihk_os_user_call_handler mcctrl_uchs[] = {
 	{ .request = MCEXEC_UP_LOAD_SYSCALL, .func = mcctrl_ioctl },
 	{ .request = MCEXEC_UP_SEND_SIGNAL, .func = mcctrl_ioctl },
 	{ .request = MCEXEC_UP_GET_CPU, .func = mcctrl_ioctl },
+	{ .request = MCEXEC_UP_GET_NODES, .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/kernel/mcctrl/sysfs_files.c

@@ -679,6 +679,8 @@ static int setup_node_files(struct mcctrl_usrdata *udp)
 	param.ptr = &udp->numa_online;
 	sysfsm_createf(udp->os, SYSFS_SNOOPING_OPS_pbl, &param, 0444,
 			"/sys/devices/system/node/online");
+	sysfsm_createf(udp->os, SYSFS_SNOOPING_OPS_pbl, &param, 0444,
+			"/sys/devices/system/node/possible");
 
 	list_for_each_entry(p, &udp->node_topology_list, chain) {
 		struct sysfs_handle handle;

executer/user/mcexec.c

@@ -41,6 +41,7 @@
 #include <sys/mman.h>
 #include <asm/unistd.h>
 #include <sched.h>
+#include <dirent.h>
 
 #include <termios.h>
 #include <sys/ioctl.h>
@@ -1732,6 +1733,63 @@ do_generic_syscall(
 
 		ret = 0;
 	}
+	/* Fake that nodeX in /sys/devices/system/node do not exist,
+	 * where X >= number of LWK NUMA nodes */
+	else if (w->sr.number == __NR_getdents && ret > 0) {
+		struct linux_dirent {
+			long           d_ino;
+			off_t          d_off;
+			unsigned short d_reclen;
+			char           d_name[];
+		};
+		struct linux_dirent *d;
+		char *buf = (char *)w->sr.args[1];
+		int bpos = 0;
+		int nodes,len;
+		char proc_path[PATH_MAX];
+		char path[PATH_MAX];
+
+		sprintf(proc_path, "/proc/self/fd/%d", (int)w->sr.args[0]);
+
+		/* Get filename */
+		if ((len = readlink(proc_path, path, sizeof(path))) < 0) {
+			fprintf(stderr, "%s: error: readlink() failed for %s\n",
+				__FUNCTION__, proc_path);
+			goto out;
+		}
+		path[len] = 0;
+
+		/* Not /sys/devices/system/node ? */
+		if (strcmp(path, "/sys/devices/system/node"))
+			goto out;
+
+		nodes = ioctl(fd, MCEXEC_UP_GET_NODES, 0);
+		if (nodes == -1) {
+			goto out;
+		}
+
+		d = (struct linux_dirent *) (buf + bpos);
+		for (bpos = 0; bpos < ret; ) {
+			int nodeid, tmp_reclen;
+			d = (struct linux_dirent *) (buf + bpos);
+
+			if (sscanf(d->d_name, "node%d", &nodeid) != 1) {
+				bpos += d->d_reclen;
+				continue;
+			}
+
+			if (nodeid >= nodes) {
+				tmp_reclen = d->d_reclen;
+				memmove(buf + bpos,
+						buf + bpos + tmp_reclen,
+						ret - bpos - tmp_reclen);
+				ret -= tmp_reclen;
+				continue;
+			}
+
+			bpos += d->d_reclen;
+		}
+	}
 
 out:
 	__dprintf("do_generic_syscall(%ld):%ld (%#lx)\n", w->sr.number, ret, ret);