Impact: build fix on non-lockdep architectures
Some architectures do not support a way to read the irq flags that
is set from "local_irq_save(flags)" to determine if interrupts were
disabled or enabled. Ftrace uses this information to display to the user
if the trace occurred with interrupts enabled or disabled.
Besides the fact that those archs that do not support this will fail to
compile, unless they fix it, we do not want to have the trace simply
say interrupts were not disabled or they were enabled, without knowing
the real answer.
This patch adds a 'X' in the output to let the user know that the
architecture they are running on does not support a way for the tracer
to determine if interrupts were enabled or disabled. It also lets those
same archs compile with tracing enabled.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
I asked legal about the licensing of ftrace.txt, and they told me that,
unless the Documentation directory is specifically set up to handle non
GPL licenses (which it does not appear to be), then it would be best to
put ftrace.txt under the GPL.
This patch adds a dual license to ftrace.txt such that it is under both
the FDL and the GPL.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch includes ftrace.txt updates that address (mostly) comments from
Andrew Morton. It also includes updates that were suggested by Randy
Dunlap, John Kacur and David Teigland.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The following updates were recommended by Elias Oltmanns and Randy Dunlap.
[ updates based on Andrew Morton's comments are still to come. ]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the long awaited ftrace.txt. It explains in quite detail how to
use ftrace and the various tracers.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Steven Rostedt