On Thu, Mar 7, 2024 at 5:08 PM Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> wrote: > > From: Alexei Starovoitov <ast@xxxxxxxxxx> > > v2->v3: > - contains bpf bits only, but cc-ing past audience for continuity > - since prerequisite patches landed, this series focus on the main > functionality of bpf_arena. > - adopted Andrii's approach to support arena in libbpf. > - simplified LLVM support. Instead of two instructions it's now only one. > - switched to cond_break (instead of open coded iters) in selftests > - implemented several follow-ups that will be sent after this set > . remember first IP and bpf insn that faulted in arena. > report to user space via bpftool > . copy paste and tweak glob_match() aka mini-regex as a selftests/bpf > - see patch 1 for detailed description of bpf_arena > > v1->v2: > - Improved commit log with reasons for using vmap_pages_range() in arena. > Thanks to Johannes > - Added support for __arena global variables in bpf programs > - Fixed race conditions spotted by Barret > - Fixed wrap32 issue spotted by Barret > - Fixed bpf_map_mmap_sz() the way Andrii suggested > > The work on bpf_arena was inspired by Barret's work: > https://github.com/google/ghost-userspace/blob/main/lib/queue.bpf.h > that implements queues, lists and AVL trees completely as bpf programs > using giant bpf array map and integer indices instead of pointers. > bpf_arena is a sparse array that allows to use normal C pointers to > build such data structures. Last few patches implement page_frag > allocator, link list and hash table as bpf programs. > > v1: > bpf programs have multiple options to communicate with user space: > - Various ring buffers (perf, ftrace, bpf): The data is streamed > unidirectionally from bpf to user space. > - Hash map: The bpf program populates elements, and user space consumes > them via bpf syscall. > - mmap()-ed array map: Libbpf creates an array map that is directly > accessed by the bpf program and mmap-ed to user space. It's the fastest > way. Its disadvantage is that memory for the whole array is reserved at > the start. > > Alexei Starovoitov (13): > bpf: Introduce bpf_arena. > bpf: Disasm support for addr_space_cast instruction. > bpf: Add x86-64 JIT support for PROBE_MEM32 pseudo instructions. > bpf: Add x86-64 JIT support for bpf_addr_space_cast instruction. > bpf: Recognize addr_space_cast instruction in the verifier. > bpf: Recognize btf_decl_tag("arg:arena") as PTR_TO_ARENA. > libbpf: Add __arg_arena to bpf_helpers.h > libbpf: Add support for bpf_arena. > bpftool: Recognize arena map type > bpf: Add helper macro bpf_addr_space_cast() > selftests/bpf: Add unit tests for bpf_arena_alloc/free_pages > selftests/bpf: Add bpf_arena_list test. > selftests/bpf: Add bpf_arena_htab test. > > Andrii Nakryiko (1): > libbpf: Recognize __arena global varaibles. > > arch/x86/net/bpf_jit_comp.c | 231 +++++++- > include/linux/bpf.h | 10 +- > include/linux/bpf_types.h | 1 + > include/linux/bpf_verifier.h | 1 + > include/linux/filter.h | 4 + > include/uapi/linux/bpf.h | 14 + > kernel/bpf/Makefile | 3 + > kernel/bpf/arena.c | 558 ++++++++++++++++++ > kernel/bpf/btf.c | 19 +- > kernel/bpf/core.c | 16 + > kernel/bpf/disasm.c | 10 + > kernel/bpf/log.c | 3 + > kernel/bpf/syscall.c | 42 ++ > kernel/bpf/verifier.c | 123 +++- > .../bpf/bpftool/Documentation/bpftool-map.rst | 2 +- > tools/bpf/bpftool/gen.c | 13 + > tools/bpf/bpftool/map.c | 2 +- > tools/include/uapi/linux/bpf.h | 14 + > tools/lib/bpf/bpf_helpers.h | 1 + > tools/lib/bpf/libbpf.c | 163 ++++- > tools/lib/bpf/libbpf.h | 2 +- > tools/lib/bpf/libbpf_probes.c | 7 + > tools/testing/selftests/bpf/DENYLIST.aarch64 | 2 + > tools/testing/selftests/bpf/DENYLIST.s390x | 2 + > tools/testing/selftests/bpf/bpf_arena_alloc.h | 67 +++ > .../testing/selftests/bpf/bpf_arena_common.h | 70 +++ > tools/testing/selftests/bpf/bpf_arena_htab.h | 100 ++++ > tools/testing/selftests/bpf/bpf_arena_list.h | 92 +++ > .../testing/selftests/bpf/bpf_experimental.h | 43 ++ > .../selftests/bpf/prog_tests/arena_htab.c | 88 +++ > .../selftests/bpf/prog_tests/arena_list.c | 68 +++ > .../selftests/bpf/prog_tests/verifier.c | 2 + > .../testing/selftests/bpf/progs/arena_htab.c | 48 ++ > .../selftests/bpf/progs/arena_htab_asm.c | 5 + > .../testing/selftests/bpf/progs/arena_list.c | 87 +++ > .../selftests/bpf/progs/verifier_arena.c | 146 +++++ > tools/testing/selftests/bpf/test_loader.c | 9 +- > 37 files changed, 2028 insertions(+), 40 deletions(-) > create mode 100644 kernel/bpf/arena.c > create mode 100644 tools/testing/selftests/bpf/bpf_arena_alloc.h > create mode 100644 tools/testing/selftests/bpf/bpf_arena_common.h > create mode 100644 tools/testing/selftests/bpf/bpf_arena_htab.h > create mode 100644 tools/testing/selftests/bpf/bpf_arena_list.h > create mode 100644 tools/testing/selftests/bpf/prog_tests/arena_htab.c > create mode 100644 tools/testing/selftests/bpf/prog_tests/arena_list.c > create mode 100644 tools/testing/selftests/bpf/progs/arena_htab.c > create mode 100644 tools/testing/selftests/bpf/progs/arena_htab_asm.c > create mode 100644 tools/testing/selftests/bpf/progs/arena_list.c > create mode 100644 tools/testing/selftests/bpf/progs/verifier_arena.c > > -- > 2.43.0 > Besides a few comments on patch #1 (and maybe one or two potential corner case issues I mentioned, which can be easily fixed), the series looked good. So I've applied patches as is. I fixed typo ("varaibles") in one of the commit subjects while applying. Also, in one of the selftests you hard-coded PAGE_SIZE to 4096, which isn't correct on some architectures, so please see how you can make it not hard-coded (but still work for both bpf and user code). It seemed minor enough to not delay patches (either way those architectures don't support ARENA just yet).
