android_kernel_xiaomi_sm8350/kernel/trace
Steven Rostedt 32464779a1 ftrace: fix dyn ftrace filter selection
Impact: clean up and fix for dyn ftrace filter selection

The previous logic of the dynamic ftrace selection of enabling
or disabling functions was complex and incorrect. This patch simplifies
the code and corrects the usage. This simplification also makes the
code more robust.

Here is the correct logic:

  Given a function that can be traced by dynamic ftrace:

  If the function is not to be traced, disable it if it was enabled.
  (this is if the function is in the set_ftrace_notrace file)

  (filter is on if there exists any functions in set_ftrace_filter file)

  If the filter is on, and we are enabling functions:
    If the function is in set_ftrace_filter, enable it if it is not
      already enabled.
    If the function is not in set_ftrace_filter, disable it if it is not
      already disabled.

  Otherwise, if the filter is off and we are enabling function tracing:
    Enable the function if it is not already enabled.

  Otherwise, if we are disabling function tracing:
    Disable the function if it is not already disabled.

This code now sets or clears the ENABLED flag in the record, and at the
end it will enable the function if the flag is set, or disable the function
if the flag is cleared.

The parameters for the function that does the above logic is also
simplified. Instead of passing in confusing "new" and "old" where
they might be swapped if the "enabled" flag is not set. The old logic
even had one of the above always NULL and had to be filled in. The new
logic simply passes in one parameter called "nop". A "call" is calculated
in the code, and at the end of the logic, when we know we need to either
disable or enable the function, we can then use the "nop" and "call"
properly.

This code is more robust than the previous version.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-19 00:19:47 -05:00
..
ftrace.c ftrace: fix dyn ftrace filter selection 2008-11-19 00:19:47 -05:00
Kconfig tracing, alpha: undefined reference to `save_stack_trace' 2008-11-03 10:12:13 +01:00
Makefile ftrace: rename FTRACE to FUNCTION_TRACER 2008-10-20 18:27:03 +02:00
ring_buffer.c ring-buffer: prevent infinite looping on time stamping 2008-11-10 21:47:37 -05:00
trace_boot.c tracing/fastboot: fix printk format typo in boot tracer 2008-10-14 10:39:23 +02:00
trace_functions.c ftrace: rename the ftrace tracer to function 2008-10-20 18:27:04 +02:00
trace_irqsoff.c ftrace: rename FTRACE to FUNCTION_TRACER 2008-10-20 18:27:03 +02:00
trace_mmiotrace.c ftrace: preempt disable over interrupt disable 2008-10-14 10:39:09 +02:00
trace_nop.c ftrace: make work with new ring buffer 2008-10-14 10:38:57 +02:00
trace_sched_switch.c ftrace: make some tracers reentrant 2008-10-14 10:39:20 +02:00
trace_sched_wakeup.c ftrace: rename FTRACE to FUNCTION_TRACER 2008-10-20 18:27:03 +02:00
trace_selftest_dynamic.c ftrace: fix dynamic ftrace selftest 2008-05-23 21:13:23 +02:00
trace_selftest.c ftrace: remove daemon 2008-10-23 16:00:22 +02:00
trace_stack.c ftrace: stack tracer only record when on stack 2008-10-20 18:31:37 +02:00
trace_sysprof.c ftrace: make work with new ring buffer 2008-10-14 10:38:57 +02:00
trace.c Merge branch 'devel' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/urgent 2008-11-11 09:16:20 +01:00
trace.h ftrace: handle archs that do not support irqs_disabled_flags 2008-10-31 00:03:26 +01:00