tree 6ae2bcc5e17dbf11fcbdb0f066224e146d273097
parent 09d23a1d8a82e814bd56a4f121b80ea8214ac49d
author Steven Rostedt (Red Hat) <rostedt@goodmis.org> 1421771815 -0500
committer Steven Rostedt <rostedt@goodmis.org> 1422985720 -0500

tracefs: Add new tracefs file system

Add a separate file system to handle the tracing directory. Currently it
is part of debugfs, but that is starting to show its limits.

One thing is that in order to access the tracing infrastructure, you need
to mount debugfs. As that includes debugging from all sorts of sub systems
in the kernel, it is not considered advisable to mount such an all
encompassing debugging system.

Having the tracing system in its own file systems gives access to the
tracing sub system without needing to include all other systems.

Another problem with tracing using the debugfs system is that the
instances use mkdir to create sub buffers. debugfs does not support mkdir
from userspace so to implement it, special hacks were used. By controlling
the file system that the tracing infrastructure uses, this can be properly
done without hacks.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>