On 25/04/2023 15:32, Masami Hiramatsu (Google) wrote: > On Tue, 25 Apr 2023 10:16:34 +0100 > Alan Maguire <alan.maguire@xxxxxxxxxx> wrote: > >> For cases like IPv6 addresses, having a means to supply tracing >> predicates for fields with more than 8 bytes would be convenient. >> This series provides a simple way to support this by allowing >> simple ==, != memory comparison with the predicate supplied when >> the size of the field exceeds 8 bytes. For example, to trace >> ::1, the predicate >> >> "dst == 0x00000000000000000000000000000001" >> >> ..could be used. > > Nice! > And I also would like to use something like "dst == ipv6(::1)" because > it seems easy to make a mistake on the number of zeros. > > Can we add such type casting feature to the filter? > that's a great idea; what would be the most consistent ftrace syntax for this do you think? I noticed that hist triggers append a modifier to the field name so would something like "dst.ipv6 == ::1" make sense maybe? Thanks! Alan > Thank you, > >> >> Patch 1 provides the support for > 8 byte fields via a memcmp()-style >> predicate. Patch 2 adds tests for filter predicates, and patch 3 >> documents the fact that for > 8 bytes. only == and != are supported. >> >> Changes since RFC [1]: >> >> - originally a fix was intermixed with the new functionality as >> patch 1 in series [1]; the fix landed separately >> - small tweaks to how filter predicates are defined via fn_num as >> opposed to via fn directly >> >> [1] https://lore.kernel.org/lkml/1659910883-18223-1-git-send-email-alan.maguire@xxxxxxxxxx/ >> >> Alan Maguire (3): >> tracing: support > 8 byte array filter predicates >> selftests/ftrace: add test coverage for filter predicates >> tracing: document > 8 byte numeric filtering support >> >> Documentation/trace/events.rst | 9 +++ >> kernel/trace/trace_events_filter.c | 55 +++++++++++++++- >> .../selftests/ftrace/test.d/event/filter.tc | 62 +++++++++++++++++++ >> 3 files changed, 125 insertions(+), 1 deletion(-) >> create mode 100644 tools/testing/selftests/ftrace/test.d/event/filter.tc >> >> -- >> 2.31.1 >> > >
