Steven Rostedt (Google) fe835e3ca4 function_graph: Use static_call and branch to optimize return function
In most cases function graph is used by a single user. Instead of calling
a loop to call function graph callbacks in this case, call the function
return callback directly.

Use the static_key that is set when the function graph tracer has less
than 2 callbacks registered. It will do the direct call in that case, and
will do the loop over all callers when there are 2 or more callbacks
registered.

Link: https://lore.kernel.org/linux-trace-kernel/20240603190824.921460797@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Guo Ren <guoren@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-04 10:38:23 -04:00
2024-06-02 13:30:53 -07:00
2024-06-01 14:35:57 -07:00
2024-05-22 12:13:40 -07:00
2024-05-22 09:43:07 -07:00
2024-05-31 16:41:52 +02:00
2024-06-01 08:28:24 -07:00
2024-05-31 08:58:36 -07:00
2022-09-28 09:02:20 +02:00
2022-10-10 12:00:45 -07:00
2024-05-31 12:11:44 -07:00
2024-06-02 15:44:56 -07:00
2024-03-18 03:36:32 -06:00

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 reStructuredText 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.
Description
Linux kernel stable tree
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