Currently bpf is using the memlock rlimit for the memory accounting. This approach has its downsides and over time has created a significant amount of problems:
1) The limit is per-user, but because most bpf operations are performed as root, the limit has a little value. 2) It's hard to come up with a specific maximum value. Especially because the counter is shared with non-bpf users (e.g. memlock() users). Any specific value is either too low and creates false failures or too high and useless. 3) Charging is not connected to the actual memory allocation. Bpf code should manually calculate the estimated cost and precharge the counter, and then take care of uncharging, including all fail paths. It adds to the code complexity and makes it easy to leak a charge. 4) There is no simple way of getting the current value of the counter. We've used drgn for it, but it's far from being convenient. 5) Cryptic -EPERM is returned on exceeding the limit. Libbpf even had a function to "explain" this case for users. In order to overcome these problems let's switch to the memcg-based memory accounting of bpf objects. With the recent addition of the percpu memory accounting, now it's possible to provide a comprehensive accounting of memory used by bpf programs and maps. This approach has the following advantages: 1) The limit is per-cgroup and hierarchical. It's way more flexible and allows a better control over memory usage by different workloads. 2) The actual memory consumption is taken into account. It happens automatically on the allocation time if __GFP_ACCOUNT flags is passed. Uncharging is also performed automatically on releasing the memory. So the code on the bpf side becomes simpler and safer. 3) There is a simple way to get the current value and statistics. The patchset consists of the following parts: 1) memcg-based accounting for various bpf objects: progs and maps 2) removal of the rlimit-based accounting 3) removal of rlimit adjustments in userspace tools and tests v2: - fixed build issue, caused by the remaining rlimit-based accounting for sockhash maps Roman Gushchin (35): bpf: memcg-based memory accounting for bpf progs bpf: memcg-based memory accounting for bpf maps bpf: refine memcg-based memory accounting for arraymap maps bpf: refine memcg-based memory accounting for cpumap maps bpf: memcg-based memory accounting for cgroup storage maps bpf: refine memcg-based memory accounting for devmap maps bpf: refine memcg-based memory accounting for hashtab maps bpf: memcg-based memory accounting for lpm_trie maps bpf: memcg-based memory accounting for bpf ringbuffer bpf: memcg-based memory accounting for socket storage maps bpf: refine memcg-based memory accounting for sockmap and sockhash maps bpf: refine memcg-based memory accounting for xskmap maps bpf: eliminate rlimit-based memory accounting for arraymap maps bpf: eliminate rlimit-based memory accounting for bpf_struct_ops maps bpf: eliminate rlimit-based memory accounting for cpumap maps bpf: eliminate rlimit-based memory accounting for cgroup storage maps bpf: eliminate rlimit-based memory accounting for devmap maps bpf: eliminate rlimit-based memory accounting for hashtab maps bpf: eliminate rlimit-based memory accounting for lpm_trie maps bpf: eliminate rlimit-based memory accounting for queue_stack_maps maps bpf: eliminate rlimit-based memory accounting for reuseport_array maps bpf: eliminate rlimit-based memory accounting for bpf ringbuffer bpf: eliminate rlimit-based memory accounting for sockmap and sockhash maps bpf: eliminate rlimit-based memory accounting for stackmap maps bpf: eliminate rlimit-based memory accounting for socket storage maps bpf: eliminate rlimit-based memory accounting for xskmap maps bpf: eliminate rlimit-based memory accounting infra for bpf maps bpf: eliminate rlimit-based memory accounting for bpf progs bpf: libbpf: cleanup RLIMIT_MEMLOCK usage bpf: bpftool: do not touch RLIMIT_MEMLOCK bpf: runqslower: don't touch RLIMIT_MEMLOCK bpf: selftests: delete bpf_rlimit.h bpf: selftests: don't touch RLIMIT_MEMLOCK bpf: samples: do not touch RLIMIT_MEMLOCK perf: don't touch RLIMIT_MEMLOCK include/linux/bpf.h | 23 --- kernel/bpf/arraymap.c | 30 +--- kernel/bpf/bpf_struct_ops.c | 19 +-- kernel/bpf/core.c | 20 +-- kernel/bpf/cpumap.c | 20 +-- kernel/bpf/devmap.c | 23 +-- kernel/bpf/hashtab.c | 33 +--- kernel/bpf/local_storage.c | 38 ++--- kernel/bpf/lpm_trie.c | 17 +- kernel/bpf/queue_stack_maps.c | 16 +- kernel/bpf/reuseport_array.c | 12 +- kernel/bpf/ringbuf.c | 33 ++-- kernel/bpf/stackmap.c | 16 +- kernel/bpf/syscall.c | 152 ++---------------- net/core/bpf_sk_storage.c | 23 +-- net/core/sock_map.c | 40 ++--- net/xdp/xskmap.c | 13 +- samples/bpf/hbm.c | 1 - samples/bpf/map_perf_test_user.c | 11 -- samples/bpf/offwaketime_user.c | 2 - samples/bpf/sockex2_user.c | 2 - samples/bpf/sockex3_user.c | 2 - samples/bpf/spintest_user.c | 2 - samples/bpf/syscall_tp_user.c | 2 - samples/bpf/task_fd_query_user.c | 5 - samples/bpf/test_lru_dist.c | 3 - samples/bpf/test_map_in_map_user.c | 9 -- samples/bpf/test_overhead_user.c | 2 - samples/bpf/trace_event_user.c | 2 - samples/bpf/tracex2_user.c | 6 - samples/bpf/tracex3_user.c | 6 - samples/bpf/tracex4_user.c | 6 - samples/bpf/tracex5_user.c | 3 - samples/bpf/tracex6_user.c | 3 - samples/bpf/xdp1_user.c | 6 - samples/bpf/xdp_adjust_tail_user.c | 6 - samples/bpf/xdp_monitor_user.c | 6 - samples/bpf/xdp_redirect_cpu_user.c | 6 - samples/bpf/xdp_redirect_map_user.c | 6 - samples/bpf/xdp_redirect_user.c | 6 - samples/bpf/xdp_router_ipv4_user.c | 6 - samples/bpf/xdp_rxq_info_user.c | 6 - samples/bpf/xdp_sample_pkts_user.c | 6 - samples/bpf/xdp_tx_iptunnel_user.c | 6 - samples/bpf/xdpsock_user.c | 7 - tools/bpf/bpftool/common.c | 7 - tools/bpf/bpftool/feature.c | 2 - tools/bpf/bpftool/main.h | 2 - tools/bpf/bpftool/map.c | 2 - tools/bpf/bpftool/pids.c | 1 - tools/bpf/bpftool/prog.c | 3 - tools/bpf/bpftool/struct_ops.c | 2 - tools/bpf/runqslower/runqslower.c | 16 -- tools/lib/bpf/libbpf.c | 31 +--- tools/lib/bpf/libbpf.h | 5 - tools/perf/builtin-trace.c | 10 -- tools/perf/tests/builtin-test.c | 6 - tools/perf/util/Build | 1 - tools/perf/util/rlimit.c | 29 ---- tools/perf/util/rlimit.h | 6 - tools/testing/selftests/bpf/bench.c | 16 -- tools/testing/selftests/bpf/bpf_rlimit.h | 28 ---- .../selftests/bpf/flow_dissector_load.c | 1 - .../selftests/bpf/get_cgroup_id_user.c | 1 - .../bpf/prog_tests/select_reuseport.c | 1 - .../selftests/bpf/prog_tests/sk_lookup.c | 1 - .../selftests/bpf/progs/bpf_iter_bpf_map.c | 5 +- .../selftests/bpf/progs/map_ptr_kern.c | 5 - tools/testing/selftests/bpf/test_btf.c | 1 - .../selftests/bpf/test_cgroup_storage.c | 1 - tools/testing/selftests/bpf/test_dev_cgroup.c | 1 - tools/testing/selftests/bpf/test_lpm_map.c | 1 - tools/testing/selftests/bpf/test_lru_map.c | 1 - tools/testing/selftests/bpf/test_maps.c | 1 - tools/testing/selftests/bpf/test_netcnt.c | 1 - tools/testing/selftests/bpf/test_progs.c | 1 - .../selftests/bpf/test_skb_cgroup_id_user.c | 1 - tools/testing/selftests/bpf/test_sock.c | 1 - tools/testing/selftests/bpf/test_sock_addr.c | 1 - .../testing/selftests/bpf/test_sock_fields.c | 1 - .../selftests/bpf/test_socket_cookie.c | 1 - tools/testing/selftests/bpf/test_sockmap.c | 1 - tools/testing/selftests/bpf/test_sysctl.c | 1 - tools/testing/selftests/bpf/test_tag.c | 1 - .../bpf/test_tcp_check_syncookie_user.c | 1 - .../testing/selftests/bpf/test_tcpbpf_user.c | 1 - .../selftests/bpf/test_tcpnotify_user.c | 1 - tools/testing/selftests/bpf/test_verifier.c | 1 - .../testing/selftests/bpf/test_verifier_log.c | 2 - tools/testing/selftests/bpf/xdping.c | 6 - tools/testing/selftests/net/reuseport_bpf.c | 20 --- 91 files changed, 97 insertions(+), 794 deletions(-) delete mode 100644 tools/perf/util/rlimit.c delete mode 100644 tools/perf/util/rlimit.h delete mode 100644 tools/testing/selftests/bpf/bpf_rlimit.h -- 2.26.2