| .. _memleak: |
| |
| ***************** |
| Memory leaks |
| ***************** |
| |
| Memory traces |
| ============= |
| |
| VPP supports memory traces to help debug (suspected) memory leaks. Each |
| allocation/deallocation is instrumented so that the number of allocations and |
| current global allocated size is maintained for each unique allocation stack |
| trace. |
| |
| Looking at a memory trace can help diagnose where memory is (over-)used, and |
| comparing memory traces at different point in time can help diagnose if and |
| where memory leaks happen. |
| |
| To enable memory traces on main-heap: |
| |
| .. code-block:: console |
| |
| $ vppctl memory-trace on main-heap |
| |
| To dump memory traces for analysis: |
| |
| .. code-block:: console |
| |
| $ vppctl show memory-trace on main-heap |
| Thread 0 vpp_main |
| base 0x7fffb6422000, size 1g, locked, unmap-on-destroy, name 'main heap' |
| page stats: page-size 4K, total 262144, mapped 30343, not-mapped 231801 |
| numa 0: 30343 pages, 118.53m bytes |
| total: 1023.99M, used: 115.49M, free: 908.50M, trimmable: 908.48M |
| free chunks 451 free fastbin blks 0 |
| max total allocated 1023.99M |
| |
| Bytes Count Sample Traceback |
| 31457440 1 0x7fffbb31ad00 clib_mem_alloc_aligned_at_offset + 0x80 |
| clib_mem_alloc_aligned + 0x26 |
| alloc_aligned_8_8 + 0xe1 |
| clib_bihash_instantiate_8_8 + 0x76 |
| clib_bihash_init2_8_8 + 0x2ec |
| clib_bihash_init_8_8 + 0x6a |
| l2fib_table_init + 0x54 |
| set_int_l2_mode + 0x89 |
| int_l3 + 0xb4 |
| vlib_cli_dispatch_sub_commands + 0xeee |
| vlib_cli_dispatch_sub_commands + 0xc62 |
| vlib_cli_dispatch_sub_commands + 0xc62 |
| 266768 5222 0x7fffbd79f978 clib_mem_alloc_aligned_at_offset + 0x80 |
| vec_resize_allocate_memory + 0xa8 |
| _vec_resize_inline + 0x240 |
| unix_cli_file_add + 0x83d |
| unix_cli_listen_read_ready + 0x10b |
| linux_epoll_input_inline + 0x943 |
| linux_epoll_input + 0x39 |
| dispatch_node + 0x336 |
| vlib_main_or_worker_loop + 0xbf1 |
| vlib_main_loop + 0x1a |
| vlib_main + 0xae7 |
| thread0 + 0x3e |
| .... |
| |
| libc memory traces |
| ================== |
| |
| Internal VPP memory allocations rely on VPP main-heap, however when using |
| external libraries, esp. in plugins (e.g. OpenSSL library used by the IKEv2 |
| plugin), those external libraries usually manages memory using the standard |
| libc malloc()/free()/... calls. This, in turn, makes use of the default |
| libc heap. |
| |
| VPP has no knowledge of this heap and tools such as memory traces cannot be |
| used. |
| |
| In order to enable the use of standard VPP debugging tools, this library |
| replaces standard libc memory management calls with version using VPP |
| main-heap. |
| |
| To use it, you need to use the `LD_PRELOAD` mechanism, e.g. |
| |
| .. code-block:: console |
| |
| ~# LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libvppmem_preload.so /usr/bin/vpp -c /etc/vpp/startup.conf |
| |
| You can then use tools such as memory traces as usual. |