> I suspect that what you are trying to achieve is validation that > calls to functions that require to be within a RCU read-side critical > section such as cds_lfht_lookup are indeed invoked from within a > critical section.
Yes exactly, but not only for read sections. It could also be to validate that rcu_barrier isnt called within a callback function or that rcu_quiescent_state isnt called when thread is offline > We've added a "rcu_read_ongoing()" API for that purpose to liburcu > RCU flavors, but AFAIK it's not used for any kind of validation > within cds_lfht. This could indeed become a feature request that > would apply to all liburcu data structure APIs. I can't find any documentation on rcu_read_ongoing. Btw the documentation for urcu in general is scattered all around the repo it seems. It should have been all at one place imo. Should I make a feature request for it? I don't know how stuff works inside this repo though. man. 1. sep. 2025 kl. 17:09 skrev Mathieu Desnoyers < mathieu.desnoy...@efficios.com>: > On 2025-08-31 16:48, Thobias Knudsen wrote: > > BTW i've made a macro library which overrides the > > urcu and lfht functions. It checks that you call the functions in the > > correct order. This has been really useful for debugging and I think it > > would be useful to have it integrated into urcu to make the it more user > > friendly. you could have it integrated with the macro DEBUG_RCU or make > > a new one, maybe DEBUG_FUNCTION_CALL_ORDER. The only thing it doesn't > > catch is if you continue to use data from cds_lfht_lookup() after > > rcu_read_unlock() > > I suspect that what you are trying to achieve is validation that > calls to functions that require to be within a RCU read-side critical > section such as cds_lfht_lookup are indeed invoked from within a > critical section. > > We've added a "rcu_read_ongoing()" API for that purpose to liburcu > RCU flavors, but AFAIK it's not used for any kind of validation > within cds_lfht. This could indeed become a feature request that > would apply to all liburcu data structure APIs. > > Thanks, > > Mathieu > > > > > søn. 31. aug. 2025 kl. 22:42 skrev Thobias Knudsen <thob...@gmail.com > > <mailto:thob...@gmail.com>>: > > > > First question: why isn't Userspace RCU more popular? > > Second question: Why isn't it possible to create issues in the urcu > > repo? Im asking for a feature here: > > Is it possible to make a function which checks if there are more > > callbacks queued by call_rcu? I need that because there are some > > callbacks which call call_rcu, and then calling rcu_barrier once > > isn't enough and I therefore need a way to check if there are still > > callbacks to wait on before terminating the program. No worries if > > this is too much to ask for or if it isn't possible. This > > functionality is only needed in termination because otherwise > > isn't needed to call rcu_barrier multiple times (at least so far) > > > > Best regards > > Thobias > > > > > > > -- > Mathieu Desnoyers > EfficiOS Inc. > https://www.efficios.com >
