On Wed, Sep 3, 2014 at 4:49 PM, Mark Johnston <[email protected]> wrote: > On Wed, Sep 03, 2014 at 02:09:48PM -0700, Shrikanth Kamath wrote: >> Thanks Mark/Andriy for helping with this query. I checked the define >> KDTRACE_HOOKS define that is set. Rather I tried this, I defined a >> fake provider just to check if that prompts sdt_kld_load to create the >> SDT probes from my kernel module. >> >> + SDT_PROVIDER_DEFINE(fake); >> And it does help load the SDT probes I created, even though I am not >> using the fake provider I defined. I feel that sdt_kld_load is flawed >> when it is looking for sdt_providers_set in the module. It expects at >> least a provider define and cannot use one of the defined ones in >> kernel by just declaring it. >> >> if (linker_file_lookup_set(lf, "sdt_providers_set", &begin, >> &end, NULL)) >> return; > > You're completely right; this issue was fixed in > http://svnweb.freebsd.org/base?view=revision&revision=267706 > >> >> I intended to use DTRACE_PROBE() instead of the conventional >> SDT_PROBE_DEFINE/SDT_PROBE usage because I wanted to create probes >> which have probe names based on __LINE__ macro...disclaimer...this was >> just for experiment sakes... >> >> E.g >> func_foo() >> { >> .... >> if () >> return EINVAL; >> ... >> if () >> return EINVAL; >> ... >> if () >> return EINVAL; >> } >> >> which I replaced with >> func_foo() >> { >> ... >> if () >> RETSDT(func_foo, EINVAL); >> ... >> if () >> RETSDT(func_foo, EINVAL); >> ... >> if () >> RETSDT(func_foo, EINVAL); >> } >> where RETSDT macro and other macros are defined as >> >> #define PROBENAME1(func, __LINE__) func ## __LINE__ >> #define PROBENAME(func, line) PROBENAME1(func, line) >> >> #define RETSDT(func, error_code) \ >> do { \ >> DTRACE_PROBE(PROBENAME(func, __LINE__));\ >> return (error_code); \ >> } while (0) >> >> With the fake provider I defined I get to see and execute my SDT probes >> % dtrace -l | grep func_foo >> 56455 sdt netstack func_foo1592 >> >> Here netstack is my module, and I have a probe name based on __LINE__ >> which is 1592. > > Why not just use a single probe and make the line number and function > name arguments to the probe? That is, write something like > > #define RETSDT(error_code) do { \ > DTRACE_PROBE2(error__return, __func__, __LINE__) > return (error_code); > } while (0) > Mark, for some reason using a single probe does not seem to fire the probe.
-- Shrikanth R K _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-dtrace To unsubscribe, send any mail to "[email protected]"
