[0/2] tracing/hist: add a modulus operator

Message

Mark Rutland March 2, 2023, 5:17 p.m. UTC

I've been analysing some usercopy code, and wanted to cpature the spread
of sizes and alignment of copies for a workload. I found that histrogram
triggers were great for cpaturing the size, but there's not currently a
way to capture the alignment short of recording the entire base pointer
and post-processing the histogram, which is less than ideal.

These patches add a modulus operator to histogram expressions, so which
allows the alignment of pointers to be captured directly.

The first patch is a preparatory refactoring to the expression parsing
code, and the second actually adds the new operator.

Thanks,
Mark.

Mark Rutland (2):
  tracing/hist: simplify contains_operator()
  tracing/hist: add modulus operator

 Documentation/trace/histogram.rst |   4 +-
 kernel/trace/trace_events_hist.c  | 109 ++++++++++++++++--------------
 2 files changed, 62 insertions(+), 51 deletions(-)