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由 Toke Høiland-Jørgensen 提交于
This adds support to libbpf for setting map pinning information as part of the BTF map declaration, to get automatic map pinning (and reuse) on load. The pinning type currently only supports a single PIN_BY_NAME mode, where each map will be pinned by its name in a path that can be overridden, but defaults to /sys/fs/bpf. Since auto-pinning only does something if any maps actually have a 'pinning' BTF attribute set, we default the new option to enabled, on the assumption that seamless pinning is what most callers want. When a map has a pin_path set at load time, libbpf will compare the map pinned at that location (if any), and if the attributes match, will re-use that map instead of creating a new one. If no existing map is found, the newly created map will instead be pinned at the location. Programs wanting to customise the pinning can override the pinning paths using bpf_map__set_pin_path() before calling bpf_object__load() (including setting it to NULL to disable pinning of a particular map). Signed-off-by: NToke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: NAlexei Starovoitov <ast@kernel.org> Acked-by: NAndrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/157269298092.394725.3966306029218559681.stgit@toke.dk
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