Hi Tom, On Fri, 24 Jan 2020 16:56:11 -0600 Tom Zanussi <zanussi@xxxxxxxxxx> wrote: > Hi, > > This is v3 of 'tracing: Add support for in-kernel dynamic event API', > incorporating changes based on suggestions from Masami and Steven. > > - Rebased to trace/for-next > > - Regularized the entire API to use synth_event_*, kprobe_event_*, > dynevent_*, and added some new macros and functions to make things > more consistent > > - Introduced trace_array_find_get() and used it in > trace_array_get_file() as suggested > > - Removed exports from dynevent_cmd functions that didn't need to be > exported > > - Switched the param order of __kprobe_event_gen_cmd_start() to fix > a problem found building with clang. Apparently varargs and > implicit promotion of types like bool don't mix. Thanks to Nick > Desaulniers for pointing that out. > > - Updated the documentation for all of the above > > Text from the v2 posting: > > This is v2 of the previous 'tracing: Add support for in-kernel > synthetic event API', and is largely a rewrite based on suggestions > from Masami to expand the scope to include other types of dynamic > events such as kprobe events, in addition to the original sythetic > event focus. Yeah, v3 basically looks good to me now :) Please see my comment on [4/12]. Others are good. You can put my Acked-by to those patches. Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> except for [04/12]. Thank you! > > The functionality of the original API remains available, though it's > in a slightly different form due to the use of the new dynevent_cmd > API it's now based on. The dynevent_cmd API provides a common dynamic > event command generation capability that both the synthetic event API > and the kprobe event API are now based on, and there are now test > modules demonstrating both the synthetic event and kprobes APIs. > > A couple of the patches are snippets from Masami's 'tracing: > bootconfig: Boot-time tracing and Extra boot config' series, and the > patch implementing the dynevent_cmd API includes some of the > spnprintf() generating code from that patchset. > > Because I used Masami's gen_*_cmd() naming suggestion for generating > the commands, the previous patchset's generate_*() functions were > renamed to trace_*() to avoid confusion, and probably is better naming > anyway. > > An overview of the user-visible changes in comparison to v1: > > - create_synth_event() using an array of synth_desc_fields remains > unchanged and works the same way as previously > > - gen_synth_cmd() takes a variable-length number of args which > represent 'type field;' pairs. Using this with no field args > basically replaces the previous 'create_empty_synth_event()' > > - The 'add_synth_field()' and 'add_synth_fields()' function from v1 > are essentially the same except that they now take a dynevent_cmd > instead of a synth_event pointer > > - The finalize_synth_event() from v1 is replaced by > create_dynevent() in the new version. > > - The new v2 API includes some additional functions to initialize > the dynevent_cmd - synth_dynevent_cmd() is used to do that. While > it's an extra step, it makes it easier to do error handling. > > - There's a new trace_synth_event() function that traces a synthetic > event using a variable-arg list of values. > > - The original generate_synth_event() using an array of values is > now called trace_synth_event_array(). > > - For piecewise event tracing, the original > generate_synth_event_start() and generate_synth_event_end() have > now been renamed to trace_synth_event_end(). > > - add_next_synth_val() and add_synth_val() remain the same. > > - A similar API and test module demonstrating the API has been added > for kprobe events > > - Both the synthetic events and kprobe events API is based on the > dynevent_cmd API, newly added > > - The Documentation for all of the above has been updated > > Text from the orginal v1 posting: > > I've recently had several requests and suggestions from users to add > support for the creation and generation of synthetic events from > kernel code such as modules, and not just from the available command > line commands. > > This patchset adds support for that. The first three patches add some > minor preliminary setup, followed by the two main patches that add the > ability to create and generate synthetic events from the kernel. The > next patch adds a test module that demonstrates actual use of the API > and verifies that it works as intended, followed by Documentation. > > Special thanks to Artem Bityutskiy, who worked with me over several > iterations of the API, and who had many great suggestions on the > details of the interface, and pointed out several problems with the > code itself. > > The following changes since commit 659ded30272d67a04b3692f0bfa12263be20d790: > > trace/kprobe: Remove unused MAX_KPROBE_CMDLINE_SIZE (2020-01-22 07:07:38 -0500) > > are available in the git repository at: > > git://git.kernel.org/pub/scm/linux/kernel/git/zanussi/linux-trace.git ftrace/synth-event-gen-v3 > > Tom Zanussi (12): > tracing: Add trace_array_find/_get() to find instance trace arrays > tracing: Add trace_get/put_event_file() > tracing: Add synth_event_delete() > tracing: Add dynamic event command creation interface > tracing: Add synthetic event command generation functions > tracing: Change trace_boot to use synth_event interface > tracing: Add synth_event_trace() and related functions > tracing: Add synth event generation test module > tracing: Add kprobe event command generation functions > tracing: Change trace_boot to use kprobe_event interface > tracing: Add kprobe event command generation test module > tracing: Documentation for in-kernel synthetic event API > > Documentation/trace/events.rst | 515 ++++++++++++++++++++ > include/linux/trace_events.h | 124 +++++ > kernel/trace/Kconfig | 25 + > kernel/trace/Makefile | 2 + > kernel/trace/kprobe_event_gen_test.c | 225 +++++++++ > kernel/trace/synth_event_gen_test.c | 523 ++++++++++++++++++++ > kernel/trace/trace.c | 43 +- > kernel/trace/trace.h | 36 ++ > kernel/trace/trace_boot.c | 66 ++- > kernel/trace/trace_events.c | 325 +++++++++++++ > kernel/trace/trace_events_hist.c | 896 ++++++++++++++++++++++++++++++++++- > kernel/trace/trace_kprobe.c | 160 ++++++- > 12 files changed, 2868 insertions(+), 72 deletions(-) > create mode 100644 kernel/trace/kprobe_event_gen_test.c > create mode 100644 kernel/trace/synth_event_gen_test.c > > -- > 2.14.1 > -- Masami Hiramatsu <mhiramat@xxxxxxxxxx>
