bd6b3b355a
Andrii Nakryiko says: ==================== Add new open options and per-program setters to control BTF and program loading log verboseness and allow providing custom log buffers to capture logs of interest. Note how custom log_buf and log_level are orthogonal, which matches previous (alas less customizable) behavior of libbpf, even though it sort of worked by accident: if someone specified log_level = 1 in bpf_object__load_xattr(), first attempt to load any BPF program resulted in wasted bpf() syscall with -EINVAL due to !!log_buf != !!log_level. Then on retry libbpf would allocated log_buffer and try again, after which prog loading would succeed and libbpf would print verbose program loading log through its print callback. This behavior is now documented and made more efficient, not wasting unnecessary syscall. But additionally, log_level can be controlled globally on a per-bpf_object level through bpf_object_open_opts, as well as on a per-program basis with bpf_program__set_log_buf() and bpf_program__set_log_level() APIs. Now that we have a more future-proof way to set log_level, deprecate bpf_object__load_xattr(). v2->v3: - added log_buf selftests for bpf_prog_load() and bpf_btf_load(); - fix !log_buf in bpf_prog_load (John); - fix log_level==0 in bpf_btf_load (thanks selftest!); v1->v2: - fix log_level == 0 handling of bpf_prog_load, add as patch #1 (Alexei); - add comments explaining log_buf_size overflow prevention (Alexei). ==================== Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.