dpdk version: 18.11
Ovs-dpdk runs as openvswitch account on the openstack environment. Use the
root account to run another --proc-type=secondary program,
such as dpdk-pdump or helloword with parameter --proc-type=secondary , and
it will report an Err: Cannot open '/var/run/dpdk/rte/config' for
rte_mem_config.
Check the source code eal.c:
int
eal_create_runtime_dir(void)
{
const char *directory = default_runtime_dir;
const char *xdg_runtime_dir = getenv("XDG_RUNTIME_DIR");
const char *fallback = "/tmp";
char tmp[PATH_MAX];
int ret;
if (getuid() != 0) {
/* try XDG path first, fall back to /tmp */
if (xdg_runtime_dir != NULL)
directory = xdg_runtime_dir;
else
directory = fallback;
}
/* create DPDK subdirectory under runtime dir */
ret = snprintf(tmp, sizeof(tmp), "%s/dpdk", directory);
if (ret < 0 || ret == sizeof(tmp)) {
RTE_LOG(ERR, EAL, "Error creating DPDK runtime path
name\n");
return -1;
}
/* create prefix-specific subdirectory under DPDK runtime dir */
ret = snprintf(runtime_dir, sizeof(runtime_dir), "%s/%s",
tmp, eal_get_hugefile_prefix());
if (ret < 0 || ret == sizeof(runtime_dir)) {
RTE_LOG(ERR, EAL, "Error creating prefix-specific runtime
path name\n");
return -1;
}
The root account is corresponds to the directory /var/run/DPDK/rte, but
openvswitch account is directory /var/run/openvswitch DPDK/rte.
Then, I changed to the openvswitch account and run the process again,
errors below were reported:
EAL: Detected 40 lcore(s)
EAL: Detected 2 NUMA nodes
EAL: Multi-process socket
/var/run/openvswitch/dpdk/rte/mp_socket_306857_7e76690dafe702
EAL: Probing VFIO support...
EAL: VFIO support initialized
EAL: Could not map memory from primary process
EAL: FATAL: Cannot init memory
EAL: Cannot init memory
There seems to be insufficient permissions. So, I change the code blow and
all the things get to be OK:
int
eal_create_runtime_dir(void)
{
const char *directory = default_runtime_dir;
const char *xdg_runtime_dir = getenv("XDG_RUNTIME_DIR");
const char *fallback = "/tmp";
char tmp[PATH_MAX];
int ret;
if (getuid() != 0) {
/* try XDG path first, fall back to /tmp */
if (xdg_runtime_dir != NULL)
directory = xdg_runtime_dir;
else
directory = fallback;
}
directory = "/var/run/openvswitch"; // added by my for test.........
/* create DPDK subdirectory under runtime dir */
ret = snprintf(tmp, sizeof(tmp), "%s/dpdk", directory);
if (ret < 0 || ret == sizeof(tmp)) {
RTE_LOG(ERR, EAL, "Error creating DPDK runtime path
name\n");
return -1;
}
This is supposed to be a DPDK BUG. Considering that the primary and
secondary processes may not be the same account,
process with parameter --proc-type=secondary should get the runtime
directory from the primary process instead of
generating a directory as it does now.
