[packet/generator] Fatal crash when creating more than 847 generators

[ronanj]

Open Perf is crashing when too many generators are created. It is expected that OP can handle such a situation nicely without crash.

acketio::dpdk::worker_controller::add_source", "message": "Adding source gen-847 to port port0 (idx = 0, queue = 1) on worker 6"}
{"time": "2020-10-28T11:08:01Z", "level": "info", "thread": "op_pio", "tag": "lib.eal", "message": "EAL: memzone_reserve_aligned_thread_unsafe(): No more room in config"}
terminate called after throwing an instance of 'std::runtime_error'
  what():  Could not create DPDK packet pool: No space left on device
Thread 15 "op_pio" received signal SIGABRT, Aborted.
[Switching to Thread 0x7ffff6426700 (LWP 11995)]
__GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
50	../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
(gdb) bt
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#1  0x00007ffff7c4f535 in __GI_abort () at abort.c:79
#2  0x0000000000d34f0a in __gnu_cxx::__verbose_terminate_handler() [clone .cold.1] ()
#3  0x0000000000d34e26 in __cxxabiv1::__terminate(void (*)()) ()
#4  0x0000000000d34e61 in std::terminate() ()
#5  0x0000000000d34d94 in __cxa_throw ()
#6  0x0000000001053838 in packet_pool ()
    at /root/project/src/modules/packetio/memory/dpdk/packet_pool.cpp:96
#7  0x00000000010863af in make_packet_pool ()
    at /root/project/src/modules/packetio/workers/dpdk/tx_source.cpp:22
#8  tx_source () at /root/project/src/modules/packetio/workers/dpdk/tx_source.cpp:30
#9  0x000000000108d2c5 in add_source ()
    at /root/project/src/modules/packetio/workers/dpdk/worker_controller.cpp:863
#10 0x0000000001097ad2 in add_source ()
    at /root/project/src/modules/packetio/generic_workers.hpp:257
#11 0x000000000102a0fc in add_source ()
    at /root/project/src/modules/packetio/generic_workers.hpp:110
#12 handle_request () at /root/project/src/modules/packetio/internal_server.cpp:33
#13 0x000000000102c770 in operator()<openperf::packetio::internal::api::request_source_add> () at /root/project/src/modules/packetio/internal_server.cpp:171