Re: [PATCH bpf-next v6 0/5] libbpf: Support automatic pinning of maps using 'pinning' BTF attribute

From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: "Toke Høiland-Jørgensen" <toke@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>,
	Alexei Starovoitov <ast@kernel.org>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	David Miller <davem@davemloft.net>,
	Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf-next v6 0/5] libbpf: Support automatic pinning of maps using 'pinning' BTF attribute
Date: Sat, 2 Nov 2019 12:09:09 -0700	[thread overview]
Message-ID: <CAEf4BzYXhoaiH5x9YZ99ABUMngsjBVRAYJBm+oMbnAHnpn-18g@mail.gmail.com> (raw)
In-Reply-To: <157269297658.394725.10672376245672095901.stgit@toke.dk>

On Sat, Nov 2, 2019 at 4:09 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>
> This series adds support to libbpf for reading 'pinning' settings from BTF-based
> map definitions. It introduces a new open option which can set the pinning path;
> if no path is set, /sys/fs/bpf is used as the default. Callers can customise the
> pinning between open and load by setting the pin path per map, and still get the
> automatic reuse feature.
>
> The semantics of the pinning is similar to the iproute2 "PIN_GLOBAL" setting,
> and the eventual goal is to move the iproute2 implementation to be based on
> libbpf and the functions introduced in this series.
>
> Changelog:
>
> v6:
>   - Fix leak of struct bpf_object in selftest
>   - Make struct bpf_map arg const in bpf_map__is_pinned() and bpf_map__get_pin_path()
>
> v5:
>   - Don't pin maps with pinning set, but with a value of LIBBPF_PIN_NONE
>   - Add a few more selftests:
>     - Should not pin map with pinning set, but value LIBBPF_PIN_NONE
>     - Should fail to load a map with an invalid pinning value
>     - Should fail to re-use maps with parameter mismatch
>   - Alphabetise libbpf.map
>   - Whitespace and typo fixes
>
> v4:
>   - Don't check key_type_id and value_type_id when checking for map reuse
>     compatibility.
>   - Move building of map->pin_path into init_user_btf_map()
>   - Get rid of 'pinning' attribute in struct bpf_map
>   - Make sure we also create parent directory on auto-pin (new patch 3).
>   - Abort the selftest on error instead of attempting to continue.
>   - Support unpinning all pinned maps with bpf_object__unpin_maps(obj, NULL)
>   - Support pinning at map->pin_path with bpf_object__pin_maps(obj, NULL)
>   - Make re-pinning a map at the same path a noop
>   - Rename the open option to pin_root_path
>   - Add a bunch more self-tests for pin_maps(NULL) and unpin_maps(NULL)
>   - Fix a couple of smaller nits
>
> v3:
>   - Drop bpf_object__pin_maps_opts() and just use an open option to customise
>     the pin path; also don't touch bpf_object__{un,}pin_maps()
>   - Integrate pinning and reuse into bpf_object__create_maps() instead of having
>     multiple loops though the map structure
>   - Make errors in map reuse and pinning fatal to the load procedure
>   - Add selftest to exercise pinning feature
>   - Rebase series to latest bpf-next
>
> v2:
>   - Drop patch that adds mounting of bpffs
>   - Only support a single value of the pinning attribute
>   - Add patch to fixup error handling in reuse_fd()
>   - Implement the full automatic pinning and map reuse logic on load
>
> ---
>
> Toke Høiland-Jørgensen (5):
>       libbpf: Fix error handling in bpf_map__reuse_fd()
>       libbpf: Store map pin path and status in struct bpf_map
>       libbpf: Move directory creation into _pin() functions
>       libbpf: Add auto-pinning of maps when loading BPF objects
>       selftests: Add tests for automatic map pinning
>
>

For the series:

Acked-by: Andrii Nakryiko <andriin@fb.com>

>  tools/lib/bpf/bpf_helpers.h                        |    6
>  tools/lib/bpf/libbpf.c                             |  385 ++++++++++++++++----
>  tools/lib/bpf/libbpf.h                             |   21 +
>  tools/lib/bpf/libbpf.map                           |    3
>  tools/testing/selftests/bpf/prog_tests/pinning.c   |  210 +++++++++++
>  tools/testing/selftests/bpf/progs/test_pinning.c   |   31 ++
>  .../selftests/bpf/progs/test_pinning_invalid.c     |   16 +
>  7 files changed, 591 insertions(+), 81 deletions(-)
>  create mode 100644 tools/testing/selftests/bpf/prog_tests/pinning.c
>  create mode 100644 tools/testing/selftests/bpf/progs/test_pinning.c
>  create mode 100644 tools/testing/selftests/bpf/progs/test_pinning_invalid.c
>