Now user_events auto-cleanup upon the last reference by default. This
makes it not possible to use the dynamics event file via tracefs.
Document that auto-cleanup is enabled by default and remove the refernce
to /sys/kernel/tracing/dynamic_events file to make this clear.
Link: https://lkml.kernel.org/r/20230614163336.5797-7-beaub@linux.microsoft.com
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The ABI for user_events has changed from mmap() based to remote writes.
Update the documentation to reflect these changes, add new section for
unregistering events since lifetime is now tied to tasks instead of
files.
Link: https://lkml.kernel.org/r/20230328235219.203-10-beaub@linux.microsoft.com
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The canonical location for the tracefs filesystem is at /sys/kernel/tracing.
But, from Documentation/trace/ftrace.rst:
Before 4.1, all ftrace tracing control files were within the debugfs
file system, which is typically located at /sys/kernel/debug/tracing.
For backward compatibility, when mounting the debugfs file system,
the tracefs file system will be automatically mounted at:
/sys/kernel/debug/tracing
Many parts of Documentation still reference this older debugfs path, so
let's update them to avoid confusion.
Signed-off-by: Ross Zwisler <zwisler@google.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20230125213251.2013791-1-zwisler@google.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Update the documentation to reflect the new ABI requirements and how to
use the byte index with the mask properly to check event status.
Link: https://lkml.kernel.org/r/20220728233309.1896-7-beaub@linux.microsoft.com
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Add a documentation file about user_events with example code, etc.
explaining how it may be used.
Link: https://lkml.kernel.org/r/20220118204326.2169-13-beaub@linux.microsoft.com
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
