No, it forces I/O attempting processes to write out the dirty pages during their time slot, as I understand it.

So during the milliseconds-to-seconds that there's too many dirty pages, the CPU ignores I/O requests and instead spends those time slots writing out the dirty pages. If the gap between dirty_ratio and dirty_background_ratio is somewhat small, and the gap between flushes is reasonably small, it shouldn't cause too many issues on a human-perceptibility level.

I am not that knowledgeable on kernel parameters on the VM system though, so feel free to correct me, anyone who knows better.