On Tue, Apr 24, 2018 at 11:59 AM, Joel Fernandes <joelaf@xxxxxxxxxx> wrote: [...] >>> > > By the way is there any limitation on using SRCU too early during >>> > > boot? I backported Mathieu's srcu tracepoint patches but the kernel >>> > > hangs pretty early in the boot. I register lockdep probes in >>> > > start_kernel. I am hoping that's not why. >>> > > >>> > > I could also have just screwed up the backporting... may be for my >>> > > testing, I will just replace the rcu API with the srcu instead of all >>> > > of Mathieu's new TRACE_EVENT macros for SRCU, since all I am trying to >>> > > do right now is measure the performance of my patches with SRCU. >>> > >>> > Gah, yes, there is an entry on my capacious todo list on making SRCU >>> > grace periods work during early boot and mid-boot. Let me see what >>> > I can do... >>> >>> OK, just need to verify that you are OK with call_srcu()'s callbacks >>> not being invoked until sometime during core_initcall() time. (If you >>> really do need them to be invoked before that, in theory it is possible, >>> but in practice it is weird, even for RCU.) >> >> Oh, and that early at boot, you will need to use DEFINE_SRCU() or >> DEFINE_STATIC_SRCU() rather than dynamic allocation and initialization. >> >> Thanx, Paul >> > > Oh ok. > > About call_rcu, calling it later may be an issue since we register the > probes in start_kernel, for the first probe call_rcu will be sched, Sorry, I need to start proof reading my emails. s/sched/skipped/ thanks, - Joel -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
