f52679b788
The recent kernel added lost count can be read from either read(2) or ring buffer data with PERF_SAMPLE_READ. As it's a variable length data we need to access it according to the format info. But for perf tools use cases, PERF_FORMAT_ID is always set. So we can only check PERF_FORMAT_LOST bit to determine the data format. Add sample_read_value_size() and next_sample_read_value() helpers to make it a bit easier to access. Use them in all places where it reads the struct sample_read_value. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20220819003644.508916-5-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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.