| ▲ | adrian_b an hour ago | |
Not true. If a writer writes continuously the shared data, it is impossible for the other thread to make the copy that must be edited. If the copy succeeds, then you are right that an updated version could be substituted to the original using an atomic operation on pointers. But there is no way to guarantee that the first copy succeeds. Of course, in practice RCU is used very frequently, because all the other threads are well behaved and access the shared data for a minimum time, so the copy will succeed in most cases. But absolute guarantees are impossible inside an algorithm expressible in an abstract programming language. Only using functions of the operating system to detect and stop a misbehaving thread can solve all cases. | ||
| ▲ | danbruc an hour ago | parent [-] | |
About what scenario are you actually talking? Are all threads using the read() and write() functions of the shared data structure? In that case it is absolutely possible for readers and writers to make progress even if a rogue writer is calling write() in a tight loop. Or are you talking about a scenario where a rogue writer essentially randomly modifies the shared data structure instead of using the designated write() function? Well, in that case all bets are obviously off. | ||