[PATCH v2 0/3] tracing: Add dynamic strings for synthetic events

[Tom Zanussi <zanussi@kernel.org>]

Hi,

This is v2 of the dynamic string support for synthetic events.

v1 was missing some very important code in the in-kernel API functions
that should have reserved room for dynamic strings.  This adds it
along also some additional test code in the synth_event_gen_test
module that tests the dynamic strings for those APIs.

I also added Axel's changelog text to the 'tracing: Fix
parse_synth_field() error handling' patch and used ssize_t as he also
suggested.  Thanks, Axel!  I also noticed that the original patch
didn't use <= as it should have, so changed that as well.

Neither my command-line tests or the synth_event_gen_test module are
showing any problems at this point for me...

Tom

Original v1 text:

This patchset adds support for dynamic strings for synthetic events,
as requested by Axel Rasmussen.

Actually, the first two patches should be applied in any case - the
first just changes the current max string length and the second fixes
a bug I found while testing.

It works fine for my simple test cases, but I still need to do a lot
more testing, especially of the in-kernel API parts, which don't
affect Axel's use case.

Anyway, Axel, please try it out and send me your Tested-by: if it
works for you, and your broken testcase(s) if it doesn't. ;-)

Thanks,

Tom

The following changes since commit 106c076d23cca67c959a6fd1ccadb5b3ef01ddc9:

  mmap_lock: add tracepoints around lock acquisition (2020-09-23 08:48:08 -0500)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/zanussi/linux-trace.git ftrace/synth-dynstring-v2

Tom Zanussi (3):
  tracing: Change STR_VAR_MAX_LEN
  tracing: Fix parse_synth_field() error handling
  tracing: Add support for dynamic strings to synthetic events

 Documentation/trace/events.rst      |  15 +-
 Documentation/trace/histogram.rst   |  18 +++
 kernel/trace/synth_event_gen_test.c |  18 ++-
 kernel/trace/trace_events_hist.c    |   9 ++
 kernel/trace/trace_events_synth.c   | 243 ++++++++++++++++++++++++----
 kernel/trace/trace_synth.h          |   6 +-
 6 files changed, 269 insertions(+), 40 deletions(-)

-- 
2.17.1