[v4,0/6] tracing: export event trace and trace_marker

Message

Tingwei Zhang Sept. 26, 2020, 12:59 a.m. UTC

Ftrace has ability to export trace packets to other destination.
Currently, only function trace can be exported. This series extends the
support to event trace and trace_maker. STM is one possible destination to
export ftrace. Use separate channel for each CPU to avoid mixing up packets
from different CPUs together.

Change from v3:
Round up number of channels to power of 2. (Alex)

Change from v2:
Change flag definition to BIT(). (Steven)
Add comment in stm_ftrace_write() to clarify it's safe to use 
smp_processor_id() here since preempt is disabled. (Steven) 

Change from v1:
All changes are suggested by Steven Rostedt.
User separate flag to control function trace, event trace and trace mark.
Allocate channels according to num_possible_cpu() dynamically.
Move ftrace_exports routines up so all ftrace can use them.

Tingwei Zhang (6):
  stm class: ftrace: change dependency to TRACING
  tracing: add flag to control different traces
  tracing: add trace_export support for event trace
  tracing: add trace_export support for trace_marker
  stm class: ftrace: enable supported trace export flag
  stm class: ftrace: use different channel accroding to CPU

 drivers/hwtracing/stm/Kconfig  |   2 +-
 drivers/hwtracing/stm/ftrace.c |   7 +-
 include/linux/trace.h          |   7 +
 kernel/trace/trace.c           | 270 ++++++++++++++++++---------------
 4 files changed, 159 insertions(+), 127 deletions(-)