On Mon, 17 Apr 2023 23:31:01 +0200 Lorenzo Bianconi wrote: > > If it's that then I'm with Eric. There are many ways to keep the pages > > in use, no point working around one of them and not the rest :( > > I was not clear here, my fault. What I mean is I can see the returned > pages counter increasing from time to time, but during most of tests, > even after 2h the tcp traffic has stopped, page_pool_release_retry() > still complains not all the pages are returned to the pool and so the > pool has not been deallocated yet. > The chunk of code in my first email is just to demonstrate the issue > and I am completely fine to get a better solution :) Your problem is perhaps made worse by threaded NAPI, you have defer-free skbs sprayed across all cores and no NAPI there to flush them :( > I guess we just need a way to free the pool in a reasonable amount > of time. Agree? Whether we need to guarantee the release is the real question. Maybe it's more of a false-positive warning. Flushing the defer list is probably fine as a hack, but it's not a full fix as Eric explained. False positive can still happen. I'm ambivalent. My only real request wold be to make the flushing a helper in net/core/dev.c rather than open coded in page_pool.c. Somewhat related - Eric, do we need to handle defer_list in dev_cpu_dead()?
