On 2/2/21 5:04 PM, Pavel Begunkov wrote: > On 02/02/2021 19:52, Hao Xu wrote: >> This might happen if we do epoll_wait on a uring fd while reading/writing >> the former epoll fd in a sqe in the former uring instance. >> So let's don't flush cqring overflow list when we fail to get the uring >> lock. This leads to less accuracy, but is still ok. > > if (io_cqring_events(ctx) || test_bit(0, &ctx->cq_check_overflow)) > mask |= EPOLLIN | EPOLLRDNORM; > > Instead of flushing. It'd make sense if we define poll as "there might > be something, go do your peek/wait with overflow checks". Jens, is that > documented anywhere? Nope - I actually think that the approach chosen here is pretty good, it'll force the app to actually check and hence do what it needs to do. -- Jens Axboe
