* Ingo Molnar <[EMAIL PROTECTED]> wrote: > there's one detail on PREEMPT_RT though (which i think you noticed too). > > Priority inheritance handling can be done in a pretty straightforward > way as long as no true read-side nesting is allowed for rwsems and > rwlocks - i.e. there's only one owner of a lock at a time. So > PREEMPT_RT restricts rwsem and rwlock concurrency: readers are > writers, with the only exception that they are allowed to 'self-nest'. > [...]
this does not affect read-side RCU, because read-side RCU can never block a higher-prio thread. (as long as callback processing is pushed into a separate kernel thread.) so RCU will be pretty much the only mechanism (besides lock-free code) that allows reader concurrency on PREEMPT_RT. Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/